Nano-10 User's Manual
Nano-10
Ladder+BASIC
Super PLC
USER’S
Revision 4.1
MANUAL
USER MANUAL
Copyright Notice and Disclaimer
All rights reserved. With the exception of legitimate TRi PLC users, who
may print or make copies of this manual for reference purposes, no parts
of this manual may be reproduced in any form without the express written
permission of TRi.
Triangle Research International, Inc. (TRi) makes no representations or
warranties with respect to the contents hereof. In addition, information
contained herein is subject to change without notice. Every precaution has
been taken in the preparation of this manual. Nevertheless, TRi assumes
no responsibility for errors or omissions or any damages resulting from the
use of the information contained in this publication.
MS-DOS and Windows are trademarks of Microsoft Inc.
MODBUS is a trademark of Mobdus.org
All other trademarks belong to their respective owners.
Revision Sheet
Release No.
Rev. 1
Date
4/13/2010
Rev. 2
Rev. 3
Rev. 4
Rev. 4.1
Rev. 5
6/22/2010
11/10/2010
6/22/2012
7/19/2012
5/01/2013
Revision Description
Added description of RC Servo Control in Chapter 11. Corrected wrong
or inconsistent numbering of figures.
Corrected header error on Chapter 16.
Change all <REMOTE> tag to <REMOTEFS>.
Added Chapter 18 and 19. Reformatted headers and footers.
Revised digital output driver specs
Revised Chapter 2 layout. Modified Section 1.7 and Chapter 17
Page i
USER MANUAL
Conditions of Sale and Product Warranty
Triangle Research International Inc. (TRi) and the Buyer agree to the following
terms and conditions of Sale and Purchase:
1.
The Nano-10 Programmable Controllers are guaranteed against defects in
materials or workmanship for a period of one year from the date of registered
purchase. Any unit that is found to be defective will, at the discretion of TRi,
be repaired or replaced.
2.
TRi will not be responsible for the repair or replacement of any unit damaged
by user modification, negligence, abuse, improper installation, or
mishandling.
3.
TRi is not responsible to the Buyer for any loss or claim of special or
consequential damages arising from the use of the product. The product
must NOT be used in applications where failure of the product could lead to
physical harm or loss of human life. Buyer is responsible to conduct their own
tests to meet the safety regulation of their respective industry.
4.
Products distributed, but not manufactured by TRi, carry the full original
manufacturers warranty. Such products include, but are not limited to: power
supplies, sensors, I/O modules.
5.
TRi reserves the right to alter any feature or specification at any time.
Notes to Buyer: If you disagree with any of the above terms or conditions you
should promptly return the unit to the manufacturer or distributor within 30 days
from date of purchase for a full refund.
Page ii
USER MANUAL
TABLE OF CONTENTS
Page #
1 INSTALLATION GUIDE FOR NANO-10 PLC
1.1 1-1 Overview .................................................................................................................................. 1-1 1.2 Physical Mounting & Wiring ..................................................................................................1-2 1.2.1 Digital Inputs, Analog Input and RS485 Communication Ports ...........................................1-2 1.2.2 Power Supply and Digital Output Ports................................................................................1-3 1.3 Power Supply .......................................................................................................................... 1-3 1.4 Digital Input Circuits............................................................................................................... 1-4 1.5 Digital Output Circuits............................................................................................................ 1-5 1.5.1 Electrical Specifications:....................................................................................................... 1-5 1.5.2 Digital Output Wiring Diagram..............................................................................................1-6 1.5.3 Inductive Load ...................................................................................................................... 1-6 1.6 Program and Data Memory....................................................................................................1-7 1.6.1 Program Memory.................................................................................................................. 1-7 1.6.2 Non-Volatile Data Storage....................................................................................................1-8 1.6.3 RAM Data Memory.............................................................................................................1-10 1.7 Jumpers J1 & J4 ...................................................................................................................1-10 1.7.1 Usefulness of Jumper J4....................................................................................................1-10 1.8 Real Time Clock ....................................................................................................................1-12 1.9 CPU Status Indicators ..........................................................................................................1-12 2 ETHERNET PORT
2-1 2.1 Configuring The Ethernet Port ..............................................................................................2-1 2.1.1 IP Address ............................................................................................................................ 2-3 2.1.2 GateWay IP Addr ................................................................................................................. 2-3 2.1.3 SMTP Server IP Address .....................................................................................................2-3 2.1.4 DNS Server IP Address........................................................................................................2-4 2.1.5 No. of Connections (FServer/ Modbus TCP) .......................................................................2-5 2.1.6 FServer Port No. .................................................................................................................. 2-5 2.1.7 Modbus/TCP Secondary Port No.........................................................................................2-5 2.1.8 LAN Speed ........................................................................................................................... 2-6 2.1.9 Node Name .......................................................................................................................... 2-6 2.1.10 Username and Password (FServer only).........................................................................2-6 2.1.11 Use Username/Password (Yes/No)?...............................................................................2-6 2.1.12 Access Level .................................................................................................................... 2-6 2.1.13 Advanced Configuration...................................................................................................2-6 2.1.14 Standalone Version of Ethernet Configuration Software .................................................2-6 2.2 Connecting Ethernet to the PLC ...........................................................................................2-8 2.2.1 Connecting the PLC to a Local Area Network .....................................................................2-8 2.2.2 Setting up Ethernet Communication Directly Between a PC and an FMD PLC ................2-10 2.3 On-line Monitoring/Programming via FServer...................................................................2-16 2.4 Using Fserver “Network Services” Commands .............................................................2-17 2.4.1 Get Our Local IP Address ..................................................................................................2-18 2.4.2 DNS command: Resolving Domain Name into IP Address ...............................................2-18 Page iii
USER MANUAL
2.4.3 2.4.4 2.4.5 2.4.6 Send Email .........................................................................................................................2-19 Open Connection to Remote FServer or TLServer to Use NETCMD$..............................2-20 Remote File Services .........................................................................................................2-21 Other Network Services Tags ............................................................................................2-21 2.5 MODBUS/TCP Server and Client Connection....................................................................2-22 2.5.1 Connecting To The PLC’s MODBUS/TCP Server .............................................................2-22 2.5.1.1 Bit Address Mapping .................................................................................................2-22 2.5.1.2 Word Address Mapping .............................................................................................2-24 2.5.2 MODBUS/TCP Access Security.........................................................................................2-24 2.5.3 Making A Modbus/TCP Client Connection to Other Modbus/TCP Server.........................2-25 2.6 Getting data from Internet: Connecting to The Internet Time Server .............................2-27 2.7 Web Service: Accessing PLC's data from MS Excel ........................................................2-28 2.8 Accessing The PLC from Internet.......................................................................................2-30 2.8.1 Small Local Area Network Using Consumer Grade Network Router ................................2-30 2.8.2 Large Corporate Local Area Network ................................................................................2-31 2.9 Setting up Ethernet Communication Directly Between a PC and Nano-10 PLCError! Bookmark not defined.
2.10 Installing a Web Page or Web Applet into the Nano-10 PLC using FileZilla ..................2-32 2.10.1 Installing the FileZilla program .......................................................................................2-32 2.10.2 Configuring FileZilla to Communicate with the Nano-10 ...............................................2-32 2.10.3 Transferring and Retrieving Files from the Nano-10 Web Server .................................2-34 2.10.4 Download the Web Page Files ......................................................................................2-35 2.10.5 Troubleshooting FileZilla File Transfer Problems ..........................................................2-35 2.11 Accessing and Customizing the HTML Web Interface for Control and Monitoring ...... 2-38 2.11.1 Accessing the HTML Files from a Standard Browser....................................................2-38 2.11.2 Control and Monitoring Components in the Default HTML Files ...................................2-39 2.11.3 Customizing the HTML Files..........................................................................................2-40 2.11.4 Level 2 User Modifications.............................................................................................2-44 3 DIGITAL I/O AND INTERNAL RELAYS PROGRAMMING
3.1 3-1 Introduction............................................................................................................................. 3-1 3.2 Programming DIO with Ladder Logic...................................................................................3-1 3.2.1 For Physical I/O .................................................................................................................... 3-1 3.2.2 For Internal Relays (Non-Latching) ......................................................................................3-1 3.2.3 For Internal Relays (Latching)..............................................................................................3-1 3.2.4 Programming Examples: ......................................................................................................3-2 3.2.4.1 Example 1 – Editing Label Names ..............................................................................3-2 3.2.4.2 Example 2 – Creating a Simple Ladder Logic Circuit..................................................3-2 3.2.4.3 Example 3 – Creating a Latching Relay Circuit...........................................................3-2 3.3 Programming DIO in a Custom Function .............................................................................3-3 3.3.1 Editing Label Names: ...........................................................................................................3-3 3.3.2 Controlling I/O from Custom Functions: ...............................................................................3-3 3.3.3 Example 1 – Turn on/off an Output ......................................................................................3-4 3.3.4 Example 2 – Toggle an Output ............................................................................................3-5 3.3.5 Example 3 – Test the Status of an Output ...........................................................................3-5 4 TIMERS, COUNTERS AND SEQUENCERS
4-1 4.1 Introduction............................................................................................................................. 4-1 4.1.1 Timer Coils ........................................................................................................................... 4-1 4.1.2 Counter Coils........................................................................................................................ 4-1 4.1.3 Sequencers .......................................................................................................................... 4-1 Page iv
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4.2 Programming timers and counters on Ladder Logic..........................................................4-2 4.2.1 For Timers ............................................................................................................................ 4-2 4.2.2 For Counters ........................................................................................................................ 4-2 4.2.3 Example 1 – Creating a Simple Timer Circuit in Ladder Logic ............................................ 4-2 4.2.4 Example 2 – Creating a Simple Counter Circuit in Ladder Logic......................................... 4-3 4.3 Programming timers and counters in Custom Function....................................................4-4 4.3.1 Programming Timers and Counters Present Values ...........................................................4-4 4.3.2 Accessing Inputs, Outputs, Relays, Timers and Counters Contacts ................................... 4-4 4.3.3 Changing The Timer and Counter Set Values in a Custom Function..................................4-4 4.3.4 Volatility of Nano-10 Timer & Counter Set Values ...............................................................4-4 4.3.5 Controlling a Timer or Counter in a Custom Function..........................................................4-5 4.4 Programming Sequencers on Ladder Logic........................................................................4-5 4.4.1 Introduction........................................................................................................................... 4-5 4.4.2 Advance Sequencer - [AVseq] .............................................................................................4-6 4.4.3 Resetting Sequencer - [RSseq]............................................................................................4-6 4.4.4 Setting Sequencer to Step N - [StepN] ................................................................................4-6 4.4.5 Reversing a Sequencer........................................................................................................4-7 4.4.6 Program Example................................................................................................................. 4-7 4.5 5 Programming Sequencers in Custom Function..................................................................4-7 ANALOG INPUTS
5.1 5-1 Analog Power Supply............................................................................................................. 5-1 5.2 Analog Inputs.......................................................................................................................... 5-1 5.2.1 Interfacing to two-wire 4-20mA sensors...............................................................................5-2 5.2.2 Using Potentiometer to Set Parameters...............................................................................5-3 5.2.3 Reading Analog Input Data ..................................................................................................5-3 5.2.4 Moving Average ................................................................................................................... 5-4 5.2.5 Scaling of Analog Data.........................................................................................................5-4 5.3 Temperature Measurement Using Analog Inputs ...............................................................5-5 5.3.1 Thermistor Temperature Sensors ........................................................................................5-5 5.3.2 Using LM34 Semiconductor Sensor.....................................................................................5-6 5.3.3 Using Thermocouple ............................................................................................................5-7 5.3.4 Using PT100 Temperature Sensor ......................................................................................5-7 5.4 Calibration of ADC & Moving Average Definition ...............................................................5-7 5.4.1 ADC Calib............................................................................................................................. 5-8 5.4.2 ADC Zero Offset................................................................................................................... 5-9 5.4.3 A/D Moving Avg.................................................................................................................... 5-9 6 SPECIAL DIGITAL I/OS
6-1 7 HIGH SPEED COUNTERS
7-1 7.1 Introduction............................................................................................................................. 7-1 7.2 Enhanced Quadrature Decoding...........................................................................................7-2 7.3 Configuring HSC as x1, x2 or x4 Counters ..........................................................................7-2 7.4 Interfacing to 5V type Quadrature Encoder .........................................................................7-3 1.1.1.1 Nano-10 PLC .................................................................................................................. 1 8 FREQUENCY / SPEED MEASUREMENT
8.1 8-1 Programming of PM Input......................................................................................................8-1 Page v
USER MANUAL
8.2 Applications ............................................................................................................................ 8-2 8.2.1 Measuring RPM Of A Motor .................................................................................................8-2 8.2.2 Measuring Transducer with VCO Outputs ...........................................................................8-2 8.2.3 Measuring Transducer with PWM Outputs ..........................................................................8-2 8.3 9 Frequency Measurement on High Speed Counter Inputs ..................................................8-3 INTERRUPTS
9-1 9.1 Input Interrupts ....................................................................................................................... 9-1 9.2 Periodic Timer Interrupt
9.3 Power Failure Interrupt (PFI) .................................................................................................9-3 10 (PTI) .............................................................................................9-2 STEPPER MOTOR CONTROL
10.1 10-1 Technical Specifications: ....................................................................................................10-1 10.2 Nano-10 As Stepper Motor Controller ................................................................................10-1 10.2.1 Interfacing to 5V Stepper Motor Driver Inputs ...............................................................10-2 10.3 Programming Stepper Control Channel.............................................................................10-3 10.3.1 Introduction ....................................................................................................................10-3 10.3.2 Setting the Acceleration Properties ...............................................................................10-3 10.3.3 Using the STEPMOVE Command .................................................................................10-4 10.3.4 Using the STEPMOVEABS Command..........................................................................10-4 Example: .....................................................................................................................................10-5 10.3.5 Demo Program for Stepper Motor Control.....................................................................10-5 11 PULSE WIDTH MODULATED OUTPUTS
11-1 11.1 Introduction...........................................................................................................................11-1 11.2 Nano-10 PLC PWM Outputs.................................................................................................11-1 11.3 Increasing Output Drive Current
(Opto-Isolated) ...........................................................11-2 11.4 Position Control Of RC Servo Motor ..................................................................................11-3 11.4.1 Using Nano-10 PWM Output To Control RC Servo (Non-Isolated)...............................11-4 11.4.2 Using Nano-10 PWM Output To Control RC Servo (Opto-Isolated) .............................11-5 11.4.3 RC Servo Positioning Resolution...................................................................................11-5 12 REAL TIME CLOCK
12-1 12.1 Introduction...........................................................................................................................12-1 12.2 TBASIC variables Used for Real Time Clock .....................................................................12-1 12.3 RTC Error Status On Ladder Logic.....................................................................................12-1 12.4 Setting the RTC Using TRiLOGI Software..........................................................................12-2 12.5 Setting the RTC from Internet Time Server........................................................................12-3 12.6 Setting up an Alarm Event in TBASIC ................................................................................12-3 12.7 Retrieving RTC Clock values using STATUS (18) .............................................................12-3 12.8 RTC Calibration (For FRAMRTC only) ................................................................................12-4 12.9 Control of RTC Hardware.....................................................................................................12-5 12.10 Troubleshooting the FRAMRTC......................................................................................12-5 Page vi
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13 LCD DISPLAY PROGRAMMING
13-1 13.1 SETLCD Command...............................................................................................................13-1 13.2 Special Commands For LCD Display .................................................................................13-1 13.3 Displaying Numeric Variable With Multiple Digits ............................................................13-2 13.4 Displaying Decimal Point.....................................................................................................13-3 14 14.1 SERIAL COMMUNICATIONS
14-1 Introduction:..........................................................................................................................14-1 14.2 COMM1: Two-wire RS485 Port .........................................................................................14-1 14.2.1 PROGRAMMING AND MONITORING..........................................................................14-1 14.2.2 Accessing 3rd Party RS485-based Devices ...................................................................14-2 14.2.3 Interfacing Other Devices to Modbus/TCP Host or to the Internet ................................14-2 14.2.4 Distributed Control .........................................................................................................14-2 14.3 Changing Baud Rate and Communication Formats: Use of the SETBAUD Statement 14-2 14.4 Support of Multiple Communication Protocols.................................................................14-4 14.5 Accessing the COMM Port from within TBASIC ...............................................................14-5 14.6 Using The PLC As a Modbus / Omron Slave
– SCADA, HMI Applications.............14-7 14.6.1 MODBUS ASCII Protocol Support .................................................................................14-7 14.6.1.1 BIT ADDRESS MAPPING FROM A MODICON / MODBUS DEVICE ......................14-9 14.6.1.2 WORD ADDRESS MAPPING .................................................................................14-10 14.6.2 MODBUS RTU Protocol Support.................................................................................14-10 14.6.3 OMRON Host Link Command Support .....................................................................14-11 14.6.4 Application Example: Interfacing to SCADA Software.................................................14-11 14.7 Using The PLC As a Modbus Master – Getting Data From Power or Flow Meters .......14-13 14.7.1 Nano-10 PLC As MODBUS RTU Master ..................................................................14-13 15 HOST LINK PROTOCOL INTRODUCTION
15-1 15.1 Multiple Communication Protocols ....................................................................................15-1 15.2 Native Mode Communication Protocols.............................................................................15-1 15.3 Point-To-Point Communication Format .............................................................................15-1 15.3.1 Command/Response Frame Format (Point to Point) ....................................................15-2 15.3.2 Error Response Format .................................................................................................15-2 15.4 MULTI-POINT COMMUNICATION SYSTEM ........................................................................15-3 15.4.1 Command/Response Frame Format (Multi-point) .........................................................15-3 15.4.2 Calculation of FCS .........................................................................................................15-4 15.4.3 Communication Procedure ............................................................................................15-4 15.4.4 Framing Errors ...............................................................................................................15-5 15.4.5 Command Errors............................................................................................................15-5 15.4.6 SHOULD YOU USE POINT-TO-POINT OR MULTI-POINT PROTOCOL? ..................15-5 15.5 RS485 Primer ........................................................................................................................15-6 15.5.1 RS485 Network Interface Hardware ..............................................................................15-6 15.5.2 Protection of RS485 Interface........................................................................................15-6 15.5.3 Single Master RS485 Networking Fundamentals..........................................................15-7 15.5.4 Multi-Master (Peer-to-Peer) RS485 Networking Fundamentals....................................15-8 15.5.4.1 Multiple Access with Collision Detection ...................................................................15-8 15.5.4.2 Token Awarding Scheme ..........................................................................................15-9 15.5.4.3 Rotating Master Signal ..............................................................................................15-9 Page vii
USER MANUAL
15.5.5 16 TROUBLE-SHOOTING AN RS485 NETWORK............................................................15-9 HOST LINK PROTOCOL FORMAT
16-1 16.1 Device ID Read......................................................................................................................16-1 16.2 Device ID Write......................................................................................................................16-1 16.3 Read Digital Input Channels................................................................................................16-1 16.3.1 Definition of Input Channels...........................................................................................16-2 16.4 Read Digital Output Channels.............................................................................................16-2 16.5 Read Internal Relay Channels .............................................................................................16-3 16.5.1 Definition of Internal Relay Channel Numbers ..............................................................16-3 16.6 Read Timer Contacts............................................................................................................16-4 16.6.1 Definition of Timer-Contact Channel Numbers..............................................................16-4 16.7 Read Counter Contacts........................................................................................................16-4 16.7.1 Definition of Counter-Contact Channel Numbers: .........................................................16-4 16.8 Read Timer Present Value (P.V.) .........................................................................................16-5 16.9 Read Timer Set Value (S.V.).................................................................................................16-5 16.10 Read Counter Present Value (P.V.).................................................................................16-5 16.11 Read Counter Set Value (S.V.) ........................................................................................16-6 16.12 Read Variable - Integers (A to Z).....................................................................................16-6 16.13 Read Variable - Strings (A$ to Z$) ..................................................................................16-6 16.14 Read Variable - Data Memory (DM[1] to DM[4000]).......................................................16-7 16.15 Read Variable - System Variables ..................................................................................16-7 16.16 Read Variable - High Speed Counter HSCPV[ ].............................................................16-8 16.17 Write Inputs.......................................................................................................................16-8 16.18 Write Outputs....................................................................................................................16-9 16.19 Write Relays ......................................................................................................................16-9 16.20 Write Timer-contacts........................................................................................................16-9 16.21 Write Counter-contacts ...................................................................................................16-9 16.22 Write Timer Present Value (P.V.) ..................................................................................16-10 16.23 Write Timer Set Value (S.V.) ..........................................................................................16-10 16.24 Write Counter Present Value (P.V.) ..............................................................................16-10 16.25 Write Counter Set Value (S.V.) ......................................................................................16-11 16.26 Write Variable - Integers (A to Z) ..................................................................................16-11 16.27 Write Variable - Strings (A$ to Z$) ................................................................................16-11 16.28 Write Variable - Data Memory (DM[1] to DM[4000]) ....................................................16-12 16.29 Write Variable - System Variables ................................................................................16-12 16.30 Write Variable - High Speed Counter HSCPV[ ] ..........................................................16-13 16.31 Halting the PLC...............................................................................................................16-13 16.32 Resume PLC Operation .................................................................................................16-13 Page viii
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16.33 Read Analog Input..........................................................................................................16-13 16.34 Read EEPROM Integer Data ..........................................................................................16-14 16.35 Read EEPROM String Data
16.36 Write Analog Output ......................................................................................................16-15 16.37 Write EEPROM Integer Data ..........................................................................................16-15 16.38 WRITE EEPROM String Data .........................................................................................16-16 16.39 Force Set/Clear Single I/O Bit........................................................................................16-16 (r47 Firmware Only).........................................................16-14 16.40 Using OMRON Host Link Commands ..........................................................................16-17 16.40.1 Read IR Registers........................................................................................................16-17 16.40.2 WRITE IR Registers.....................................................................................................16-18 16.40.3 Read Data Memory DM[1] to DM[4000] ......................................................................16-18 16.40.4 WRITE Data Memory DM[1] to DM[4000] ...................................................................16-19 16.41 Testing of Host Link Commands ..................................................................................16-20 16.42 Visual Basic Sample Program.......................................................................................16-21 16.43 Inter-PLC Networking Using NETCMD$ Command ....................................................16-21 16.44 Inter PLC Networking Using MODBUS Protocols.......................................................16-21 17 I2C COMMUNICATION
17-1 17.1 The I2C-FRTC Module ..........................................................................................................17-1 17.1.1 Installing the I2C-FRTC Module ....................................................................................17-1 17.1.2 I2C-FRTC Hardware Overview......................................................................................17-2 17.1.3 I2C-FRTC Availability.....................................................................................................17-2 17.2 New
17.2.1 17.2.2 17.2.3 17.2.4 17.2.5 17.2.6 17.2.7 18 TBASIC Commands: I2C_READ, I2C_WRITE and I2C_STOP..................................17-2 I2C_WRITE ....................................................................................................................17-3 I2C_READ......................................................................................................................17-4 I2C_STOP......................................................................................................................17-6 Random Write To M24M01 EEPROM ...........................................................................17-6 Page Write To M24M01 EEPROM ................................................................................17-6 Random Read From M24M01 EEPROM.......................................................................17-7 Sequential Read From M24M01 EEPROM ...................................................................17-8 EXTENDED FILE SYSTEM
18-2 18.1 Introduction...........................................................................................................................18-2 18.2 File Structure and File Naming of The Extended File System .........................................18-3 18.3 Transferring Files To The PLC’s Web Server ....................................................................18-4 18.4 Accessing The Extended Data Files Using TBASIC .........................................................18-4 18.4.1 Open A File For Writing New Data ................................................................................18-4 18.5 Open A File For Appending Data To The End Of The File................................................18-5 18.5.1 Delete A File...................................................................................................................18-5 18.5.2 Open A File For Reading ...............................................................................................18-5 18.6 Setting Up The FileZilla FTP Server....................................................................................18-7 18.6.1 Download and Setup FTP Server ..................................................................................18-7 18.6.2 Testing Connection To The FTP Server Using Telnet...................................................18-9 18.7 Uploading File From PLC to FileZilla FTP Server Directory...........................................18-12 18.7.1 Overview of The FTP Protocol.....................................................................................18-12 Page ix
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18.7.2 18.7.3 18.8 19 PLC FTP Upload Procedure ........................................................................................18-12 Monitoring The FTP Upload Progress .........................................................................18-13 Setting Up A FTP Server Behind a Windows Firewall. ...................................................18-14 USING PLC AS A MODBUS/TCP GATEWAY
19-1 19.1 Introduction...........................................................................................................................19-1 19.2 Application Ideas for Modbus/TCP Gateway .....................................................................19-1 19.3 Configuring The PLC As Modbus/TCP Gateway...............................................................19-1 19.4 Fine-Tuning The Modbus/TCP Gateway Function ............................................................19-2 19.5 Modbus/TCP Gateway Sample Program ............................................................................19-3 Page x
Chapter 1
Chapter 1
Installation Guide
Installation Guide
for Nano-10 PLC
Chapter 1
Installation Guide
1 INSTALLATION GUIDE FOR NANO-10 PLC
Power1 Power2
(AC/DC) (AC/DC)
Output LED
Indicators (Red)
LOAD
+ -
LOAD
+
LOAD
24V DC
Power Supply
+
for PLC
LOAD
-
NANO-10
24V 0V
OUT1 OUT2
OUT3
By TRi
OUT4
RELAY 1
RELAY 2
Reserved
NANO-10
Ethernet (RJ45)
Modbus/TCP
Remote programming
Email, peer-to-peer etc.
Super PLC
00-1F-2E-00-10-10
PAUSE
-RS485+ IN1
Input LED
Indicators (Green) Two-Wire
RS485 Port
IN2 IN3 IN4
AN1 AN2 +5V
J3
J4
4 Digital Inputs 2 Analog +5V Analog
(24V, NPN) Inputs (0-5V) Reference
Figure 1.1
1.1 Overview
The new TRi’s Nano-10 is quite possibly the world’s most powerful Nano-class PLC! Although measuring
only 2.75” x 3.25” and spots just 10 digital+analog I/Os, it comes with a built-in Ethernet port that can be
connected directly to a network router, switch, or hub for access to the LAN or to the Internet. The
Ethernet port supports the FServer (for remote programming or monitoring) and a Modbus/TCP server
(for access by third party devices) with up to 6 simultaneous connections. The user can also easily
program the Nano-10 to connect to another PLC (peer-to-peer networking) or to Modbus/TCP slave
devices via the Internet. It can email real time data to any email address(es), or connect to the Internet
Time Server to get the most accurate real time information.
The Ethernet port also supports “Web Services”, allowing enterprise software, such as a database
program or MS Excel, to query for information from multiple PLCs instantaneously. This also means that
you can even create your own Ajax based web page to monitor/control your PLC using an internet
1-1
Chapter 1
Installation Guide
browser on a smart phone such as the Apple’s i-Phone or just about any PC/Mac browser! An example
template will be provided to demonstrate this ability and you can easily modify the template to create the
web page that is specific to your own application.
The Nano-10 PLC comprises 2 analog inputs (12-bit, 0-5VDC), 4 digital Inputs, and 4 digital outputs. 2 of
the digital outputs (1 and 2) can each sink up to 4A peak and 2A continuous, 24VDC current from the
load and can be used to output stepper motor pulse/direction signals, or used as Pulse-Width Modulated
(PWM) output driver. The other 2 digital outputs each comprises a pair of voltage-free contacts, allowing
switching of two isolated loads of up to 5A current per channel (24VDC/AC or 120VAC).
In addition, all 4 of the digital inputs can be used for decoding and measuring pulses received from up to
2 digital encoders, allowing you to measure position and velocity of 2 moving objects in real time. All 4 of
the digital inputs can also be defined as interrupt inputs, allowing fast events to be handled in the shortest
possible time and to not be constrained by the program scan time.
The Nano-10 built-in RS485 port allows it to interface to many peripheral devices such as an LCD display
(e.g. MDS100-BW http://www.tri-plc.com/mds100bw.htm) or a serial touch panel (e.g. Maple System
HMI). The RS485 port is conversant in MODBUS protocol and can be used as a MODBUS master or
slave to construct a highly sophisticated control system. You can also use it to interface to bar-code
readers, serial printers, RFID readers, or use it for programming/monitoring via the TLServer software
(part of the i-TRiLOGI software suite).
The Nano-10’s RS485 port is also the only means to communicate with the Nano-10 CPU if your Ethernet
configuration settings are corrupted and it cannot be connected to your network router.
1.2 Physical Mounting & Wiring
The Nano-10 can be easily installed in many kinds of plastic or metal enclosures. You need to use 4 PCB
standoffs (or screws and nuts) to support the controller and fasten it to a console box.
The following subsections show some hardware details of the I/Os that are available on the Nano-10 PLC
model. Separate chapters in this manual will be devoted to discussing the programming methods for this
hardware.
1.2.1 Digital Inputs, Analog Input and RS485 Communication Ports
The two-wire RS485 port, 4 digital inputs and 2 analog inputs as well as a +5V analog reference voltage
are all available on a bank of screw terminal blocks along the lower edge of the PLC:
-RS485+ IN1
IN2 IN3 IN4
AN1 AN2 +5V
Two-Wire 4 Digital Inputs 2 Analog +5V Analog
RS485 Port (24V, NPN) Inputs (0-5V) Reference
Figure 1.2
1-2
Chapter 1
Installation Guide
Please refer to Section 1.4 regarding the specifications of the Digital Inputs. The specifications and
programming methods for the analog inputs are detailed in Chapter 5 of this manual. Chapter 14
describes the use of the RS485 serial communication port.
Note that the screw terminal block is actually detachable from its soldered pins to the PCB, which permits
easy replacement of the controller board when necessary, as shown below:
wire
Insulated crimp
ferrules
Tightening
screw
Figure 1.3 – Using Ferrules to connect to screw terminal block
Although wires may be connected directly to the screw terminal, insulated crimp ferrules should be used
to provide a good end termination to multi-stranded wires. Use of ferrules reduces the possibility of stray
wire strands short-circuiting adjacent terminals and their use is, therefore, highly recommended.
1.2.2 Power Supply and Digital Output Ports
The Nano-10 power supply and 4 digital outputs are available on the detachable screw terminal block
along the top edge of the Nano-10 PCB:
24V 0V
OUT1 OUT2
OUT3
OUT4
The following sections describe the specifications of the PLC power supply as well as digital I/Os.
1.3 Power Supply
The Nano-10 PLC requires a single regulated, 24V (+/- 5% ripple) DC power supply. The PLC typically
consumes less than 100mA and thus you may also use the same power supply to power the PLC and a
small output load, as long as the total load current is within the power supply maximum limit.
If the loads require higher current, then it is recommended that a separate power supply be used for the
output load. Note that if you choose to use two separate power supplies for non-isolated output (#1 and
#2), their 0V terminals should be tied together to provide a common ground reference for the two power
supplies.
The two power supplies are also recommended to be of the same output voltage. Otherwise, if the
voltage of the load power is lower than the voltage of the CPU power, the output LED will light up even
when the output driver is not energized. This is because the current could flow out of the PLC’s output
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into the (lower voltage) load power supply and therefore light up the LED. This can be very confusing to
users even though it should not damage the LED. Should this happen, you will need to add a series
diode to the output terminal to block the output LED currents from flowing through the load and back to
the load power.
Please use only an industrial grade linear or switching regulated power supply from established
manufacturers. Using a poorly made switching power supply can give rise to a lot of problems if the noisy
high frequency switching signals are not filtered properly.
Note: If your application demands very stable analog I/Os you should choose a linear power supply
instead of a switching power source for the CPU.
Always place the power supply as close to the PLC as possible and use a separate pair of wires to
connect the power to the PLC. Keep the power supply wires as short as possible and avoid running them
along side high current cables in the same cable conduit. The Nano-10 PLC will enter a shut down
procedure when the power supply voltage dips below approximately 16V. It is a good idea to connect a
470μF to 1000μF, 50V electrolytic capacitor near the power supply connector to suppress any
undesirable voltage glitches from conducting into the PLC. If other high current devices, such as a
frequency inverter, were to affect the operation of the PLC, you should then also connect a diode before
the capacitor to prevent reverse current which might flow back to the power supply, as shown in the
following diagram:
1N4007
+24V DC
Power
Supply
470uF 50V
+24V
Surge suppressor
(Recommended)
0V
Figure 1.4
If the AC main is affected by nearby machines drawing large amounts of current (such as large threephase motors), you should use a surge-suppressor to prevent any unwanted noise voltage from being
coupled into the Nano-10 power supply. The required current rating for the power supply depends mainly
on the total output current, taking into consideration the peak current demand and the duty cycle of the
operation.
1.4 Digital Input Circuits
All 4 digital inputs are NPN type (with green colored LED indicators), meaning that to turn ON an input,
you should connect it to the low-voltage rail (0V terminal) of the power supply as shown in the following
diagram. The input numbers are marked on the PCB alongside the side of the screw terminal block.
All digital inputs are directly programmable in Ladder Logic, as well as in TBASIC custom functions.
Some programming examples are detailed in “Chapter 3 –Digital I/Os and Internal Relays”
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+24V
NANO-10
NANO-10
Limit Switch
(Normally Open)
NPN sensor
Signal
Input
Input
0V
0V
Input = logic '1' when object is sensed
Input = logic '1' when Limit Switch is closed
Input Voltage for Logic 0:
Open Circuit or +10V to +24VDC
Input Voltage for Logic 1:
0V to +2.5V DC
Figure 1.5 –Interfacing to Limit Switch and NPN Sensor
1.5 Digital Output Circuits
1.5.1
Electrical Specifications:
Output Driver type
Maximum Breakdown Voltage
Maximum Output Current:
Output #1 & 2
NPN Darlington
Transistors
55V
Output #3 & 4
Voltage-free Contacts
(Isolated pair per output)
1000V RMS (1 min)
4A
5A @24V/120VAC
2A @ 250VAC
Continuous Output Current
2A
5A @24V/120VAC
2A @ 250VAC
Output Voltage when OFF
Resistor pulled up to
24V power rail
None
Output Voltage when ON:
0.2V @2A
0V @2A
Yes
(Intrinsic Zener @55V)
None
Inductive Back EMF Bypass
All outputs have red colored LED indicators. The Nano-10 PLC employs “sinking” (NPN) type power
MOSFET on its two solid state output #1 and #2 that turn ON by sinking current from the load to the 0V
terminal.
Note:
Output #1 and #2 can also be configured as
1) PWM outputs to drive heating elements or proportional valves using the SETPWM command –
please see Chapter 11 for more information.
2) Stepper Motor Controller: to send pulse and direction signals to an external stepper motor
driver in order to control motion of a stepper motor. See Chapter 10 for more details.
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1.5.2 Digital Output Wiring Diagram
24V DC
Power Supply
for PLC
LOAD
+
+ -
OUT1
OUT2
-
+
+24V
0V
LOAD
Power1
OUT4
LOAD
(AC/DC)
Power2
OUT4
LOAD
(AC/DC)
Figure 1.6 – Nano-10 Output Interfacing to Load
All digital outputs are directly programmable in Ladder Logic as well as in TBASIC custom functions.
Some programming examples are detailed in “Chapter 3 –Digital I/Os and Internal Relays”. Note that it
is possible to wire the four outputs to become a H-bridge (relay outputs #3 and #4 as high side switch and
MOSFET output #1 and #2 as low side switch), which can drive a DC motor in both forward and reverse
directions. You can even use the PWM outputs to control the speed of the motor and therefore make it
possible to use the Nano-10 as an internet-accessible, bi-directional motor speed controller!
1.5.3 Inductive Load
+24V
Inductive bypass
diode (DC only)
PLC NPN
Digital Output
Diode's reverse
break down voltage
should be at least
2 x load voltage
Figure 1.7
When switching inductive loads such as a solenoid or a motor, always ensure that a bypass diode is
connected to absorb inductive kicks, which will occur whenever the output driver is turned OFF. Although
Output #1 and #2 already incorporate intrinsic Zener bypass diodes to protect the driver, it only activates
when the inductive kick voltage rises above the maximum breakdown voltage (about 55VDC). This could
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result in a large dose of noise being introduced into the system and may have undesirable effects. For
DC we recommend using a fast recovery diode such as UF4001 to UF4007 connected as shown in the
above diagram to absorb the inductive noise.
For AC loads (output #3 & #4) you’ll need to select a suitable Metal Oxide Varistor (MOVs) to protect the
relay contacts, as shown below:
~
AC
Power
(b)
Metal Oxide
Varistor (MOV)
NANO-10
Relay Output
1.6 Program and Data Memory
Default Configuration
Program Memory
Non-Volatile Data Storage
Integers (16-bit)
Strings (40 chars max)
RAM Data Memory
DM
A to Z (32-bit)
A$ to Z$ (70 chars string)
EMINT[], EMLINT[], EMEVENT[]
8000 words*
With FRAM-RTC
Add On
16000 words
1024 words
51
11000 words
549
1000 words (volatile)
Yes (volatile)
Yes (volatile)
Yes (volatile)
4000 (non-volatile)
Yes (J1:non-volatile)
Yes (J1:non-volatile)
Yes (volatile)
* Each word is 16-bit (two bytes)
1.6.1 Program Memory
Standard Nano-10 PLC can store up to 8000 (16-bit) words of program memory stored in the CPU Flash
memory area. This can be expanded to 16,000 words with the addition of an optional FRAM-RTC
module.
Each ladder logic element (contacts or coils) takes up 1 word of memory. A TBASIC statement or function
takes up half a word to four or five words, depending on the number of parameters the statement or
function has.
The program memory can be erased and reprogrammed more than one hundred thousand times, which
is a limit that you are unlikely to ever reach. However, unlike on the T100M+ PLCs, the program memory
of the Nano-10 is not stored in an easily removable IC, so it is not possible to upgrade your customer’s
PLC program by swapping out a single IC (such as the M2017P or M2018P on a T100M+ PLC).
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1.6.2 Non-Volatile Data Storage
Users of the M-Series PLCs (T100MD+ and T100MX+ PLCs) may be familiar with the PLCs’ EEPROM
memory as well as some of its limitations. Standard Nano-10 PLC does not have any built-in EEPROM
on board. An optional FRAMRTC module can be added to the Nano-10 to provide up to 11K words of
non-volatile, high-speed ferromagnetic memory that behave just like EEPROM to the PLC.
However, if you have only limited use of the EEPROM memory say to store some non-volatile parameters
once in a while, and you do not wish to incur the expense of buying the FRAMRTC module, then you will
be glad to learn that the Nano-10 CPU cleverly uses its static RAM to shadow a flash memory area in the
CPU to provide up to 1024 words of “pseudo EEPROM”, that allows user to read and write to/from these
memory using the standard TBASIC SAVE_EEP, LOAD_EEP , SAVE_EEP$, LOAD_EEP$ commands.
The pseudo EEPROM data are normally stored in static RAM memory. This implies you can read/write to
the pseudo EEPROM at full speed with no limitation to the read/write life of the pseudo EEPROM area
since these are actually just RAM memory. However, since data stored in RAM are volatile, they need to
be saved into the non-volatile flash memory before power down. Nano-10 allows you to do so easily
using a single SETSYSTEM command, as follow:
SETSYSTEM 252, 0
Upon execution of the above command, the Nano-10 CPU will erase a special flash memory area used to
backup the pseudo EEPROM and it will then copy the entire pseudo EEPROM memory data to the flash
memory. However, the CPU will perform the backup only if there are any changes made to the pseudo
EEPROM area. This is to prevent unnecessary erase/write of the flash memory.
It is the responsibility of the programmer to determine when and how often to run the abovementioned
SETSYSTEM command before power to the Nano-10 is removed in order not to lose data. The reason
why the programmer should not backup the pseudo EEPROM space to the flash memory every time a
data has changed is because (a) The backup process can take tens of millisecond to complete. (b) the
backup involves erasing the flash sector and burning the new data into the flash sector, and the flash
memory does have a write cycle life of only about 100,000 cycles which should not be exceeded.
Note: The CPU will also automatically backup the pseudo EEPROM memory to the flash memory
whenever the PLC executes a software reset or reboot, or if the PLC is reset or rebooted via the serial or
Ethernet communication.
Upon power up, the CPU automatically loads the data from the flash memory into all the pseudo
EEPROM memory and therefore this memory can be used just like the standard EEPROM data memory
in the M-series and the F-series PLCs.
Important: If the PLC program runs any of the following commands: SETIPADDR, SETTIMERSV,
SETCTRSV, the command should also be followed by the SETSYSTEM 252, 0 command (or a RESET
command) at least once before the power to the PLC is turned off to ensure that the new parameters are
written to the flash memory (separate memory location from the data memory mentioned above). In the
case of SETIPADDR command, the new IP address only take effect after a REBOOT or power on reset.
Automatic Backup Using Power Failure Interrupt
On a Nano-10 PLC, an onboard power failure detection circuit detects a power failure when the power
supply voltage drops below approximately 16V, and you can setup the PLC to execute a user’s defined
power failure interrupt custom function. It is therefore tempting (and indeed possible) to include the
SETSYSTEM 252,0 function inside the power failure interrupt custom function to automatically backup
the pseudo EEPROM data during power failure. This is actually possible provided you are using a good
power supply that provides a gradual decay of supply voltage during power down.
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This is because the process of backing up the shadow RAM to the flash memory as well as executing
other user’s power failure interrupt service routine would require an execution time of at least tens of
milliseconds. It is therefore very important for the power supply voltage to the PLC to gradually decrease
to zero over several hundred milliseconds during power down. I.e. a nice power down voltage gradient is
required. This ensures that the CPU has sufficient time before it loses its operating voltage required for it
to properly backup the pseudo EEPROM data to the flash memory.
If you simply cut off the DC voltage to the PLC (e.g. by disconnecting the power supply terminal to the
PLC abruptly), then what could happen is that the PLC may only have time to erase the flash memory
sector for backing up the pseudo EEPROM, but does not have enough time to backup the pseudo
EEPROM data to the flash memory. The result could be loss of all the EEPROM data when the power is
returned to the PLC. (You will know that the backup area of the EEPROM has been erased but not rewritten if all the EEPROM data reads only –1 upon power up).
The additional diode and 470uF (or larger) capacitor connected to the PLC’s power supply input screw
terminal as shown in Figure 1.4 (also shown below) would also help to obtain a good voltage decay
gradient during power down, and is therefore highly recommended if you need to execute any power
failure interrupt service routines.
1N4007
+24V DC
Power
Supply
470uF 50V
+24V
Surge suppressor
(Recommended)
0V
To ensure that the power supply provides a slow voltage gradient during power down, the power switch
must be connected to the AC side of the power supply instead of to the DC side of the power supply. All
industrial DC power supplies usually have large filtering capacitors at the DC output, which means that
the power supply to the load would normally decrease slowly when power supply to the AC side has been
cut.
Note: if the user intends to execute the SAVE_EEP or SAVE_EEP$ commands during power failure,
then these commands must be executed BEFORE executing the SETSYSTEM 252, 0 command so that
they can be backed up to the flash memory.
FRAMRTC Based Non Volatile Memory
The optional FRAMRTC module provides a large array of state-of-the-art Ferromagnetic RAM (FRAM)
memory to the Nano-10 PLC, and these FRAM memories will be used as primary storage for the user’s
EEPROM data. With FRAMRTC the PLC would have a total of 11,000 words of all FRAM-based
EEPROM memory. These 11000 words of EEPROM data can also be used to store up to 549 strings of
40 characters per string.
Since these FRAM are truly non-volatile and they do not have to be backed up to any flash memory, the
data are therefore not easily corrupted by any unplanned power disruptions.
Also these FRAM memories allow an unlimited number of read and write cycles at full speed and they are
thus much better than the traditional “EEPROM” memory on the M-series PLC. However, for legacy
reasons we are still calling them EEPROM memory since they are to be accessed using the TBASIC’s
SAVE_EEP, LOAD_EEP, SAVE_EEP$ and LOAD_EEP$ commands.
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1.6.3 RAM Data Memory
All the TBASIC variables used in the Nano-10 PLC: A to Z, DM[1] to DM[1000] and string A$ to Z$,
EMINT[1] to EMINT[16] and EMLINT[1] to EMLINT[16] are normally stored in the CPU RAM area and
therefore they fall into the category of “volatile data memory” - meaning when you turn off power to the
PLC the memory content will be lost and they will be reset to zero when the PLC is powered up again.
Hence, you should use the SAVE_EEP command to save any data that must be preserved after the PLC
is powered down.
Also note that in a standard Nano-10 PLC, only the first 1000 DM memory locations are available. This
means that your program would not be able to access any DM beyond DM[1] to DM[1000]. Reading
from DM[1001]-DM[4000] will always return 0 and writing to these address will be ignored.
With FRAM-RTC
With addition of the FRAM-RTC module, the amount of DM memory is increased to 4000 words, making
it the same as those on standard T100M+ or F-series PLCs.
Also, since some FRAM memory area is reserved to store these variables, it is possible to make
variables A to Z, A$ to Z$ and DM[1] to DM[4000] non-volatile by shorting Jump J1 on the Nano-10 circuit
board (see Section 1.7). This provides for additional non-volatile data storage to applications that need
them.
1.7 Jumpers J1 & J4
Two jumpers, J1 and J4, are provided on the Nano-10 PLC in place of the DIP switches #1 & #4 that you
may already be familiar with on the M and F-series PLCs. The two jumpers have the following functions
when they are closed (i.e a jumper block is placed over the two pins to short them together):
Jumper
J1
OPEN
All RAM data memory
are volatile
CLOSE
If FRAM-RTC is installed, then A to Z, A$ to Z$ and DM[1]
to DM[4000] are non-volatile.
J4
Normal Run mode
Suspends execution of the ladder logic program. But host
communication remains active.
1.7.1 Usefulness of Jumper J4
We have taken every effort to ensure that the host communication is always available even when the
user-program ends up in a dead-loop. This allows the user to re-transfer a new program to the PLC and
overwrite the bad program. However, you may still encounter a situation whereby after transferring a new
program to the PLC, you keep encountering communication errors and you are unable to erase the bad
program. This is especially common if you have been experimenting with the communication
commands such as SETBAUD, SETPROTOCOL, PRINT or OUTCOMM. These commands may modify the
communication baud rate, format, or protocol or set the PLC to send data out of a COMM port that
conflict with i-TRiLOGI. In such cases, you can short the jumper J4 and perform a power-on reset for the
PLC. The PLC will not execute the bad program that causes communication problems and you can then
transfer a new program into the PLC to clear up the problem.
Note that when the PLC has been power-reset with Jumper J4 closed, the COMM1 (RS485) serial port
will boot up with default baud rate and communication format of 38,400, 8,n,1. (This differs from the
T100M+ PLC.)
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1.8 Real Time Clock
The Nano-10 PLC has a built-in Real-Time clock (RTC) that keeps track of the time and date and can be
used to trigger time-based events readily. However, on the standard Nano-10 there is no batterybackup of the RTC. This means that when the Nano-10 is powered up the real time clock is set to the
factory default date of 2000/1/1 and time at 0:00:00.
On the other hand, if you have connected the Nano-10 PLC to the LAN, you can program the PLC to
automatically access a time server on the Internet or on the local LAN upon power up. This means that
the PLC is able to synchronize its time accurately to that of the atomic clock source that the Internet Time
Server’s are often based on. This technique is described in Section 2.5
FRAM-RTC
As its name implies, the FRAM-RTC module adds a lithium battery-backed Real-Time Clock module to
the Nano-10 PLC. The Nano-10 CPU automatically detects the presence of the FRAM-RTC module and
will set its built-in RTC using the battery-backed RTC data in the FRAM-RTC module. The FRAM-RTC
therefore is useful to applications that are not connected to the LAN or the Internet (to set the RTC) but
requires non-volatile RTC to control time-based events.
When the FRAMRTC is present, the Nano-10 PLC also tries to take advantage of the FRAMRTC’s more
accurate real-time clock by updating its internal RTC every hour when the seconds and minutes both
become zero. This can be optionally disabled by using the SETSYSTEM command described in Chapter
12.
1.9 CPU Status Indicators
There is a single red LED indicator on Nano-10 board marked “PAUSE”. This indicator will light up for
about 0.5 seconds during power-on. Thereafter it should go off. The PAUSE indicator will be turned ON if
one of the following has occurred:
1.
2.
3.
4.
5.
The PLC’s program is corrupted.
A PAUSE statement has been executed
The user halts the PLC by pressing the <P> key during On-Line Monitoring.
Jumper J4 is turned ON, which halts the program.
A run-time error has occurred.
If this light is ON, please connect the host computer running i-TRiLOGI to the PLC and run the “On-Line
Monitoring” program. You will be informed of the reason that caused the PAUSE condition. Except for
condition (1) and (4), you can release the PLC from the PAUSE state by clicking on the “Pause” button or
by pressing the <P> key during “On-Line Monitoring”. If the PLC’s program is corrupted, then you must
re-transfer your program to the PLC.
If a run-time error has occurred the PLC will halt at the CusFn where the error took place. If the
programmer now executes the “On-Line Monitoring” command in I-TRiLOGI, the cause of the run-time
error and the CusFn where the error occurred will be reported on TRiLOGI screen. Although the Nano-10
PLC does not have built-in LCD port, you will still be able to view the virtual LCD display on the Online
Monitoring/View Variable screen that displays the cause of the runtime error and the function where it
occurred.
The TBASIC simulator captures many possible run-time errors including out-of-range values, but in the
Nano-10, only a few most important run-time errors are reported. The remaining errors are ignored. The
following are the few run-time errors that will be reported in the Nano-10 PLC:
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2.
3.
4.
5.
Installation Guide
Divide By Zero
FOR-NEXT loop with STEP = 0!
Call Stack Overflow! Circular CALL suspected!
Illegal Opcode - Please inform manufacturer!
System Variable Index out-of-range: This is normally caused by using an unavailable subscript.
E.g. DM[0], INPUT[-1], DM[5000], etc. Check the subscript value, especially if it contains a
variable (e.g. DM[X], if X=0 this will lead to a runtime error).
All run-time errors should be identified and corrected before you proceed any further.
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Chapter 2
Ethernet Port
Ethernet Port
Chapter 2
Ethernet Port
2 ETHERNET PORT
Incredibly, every Nano-10 PLC has a single, built-in 10/100
Base-T Ethernet port that does everything that its bigger
brother, the F-series PLCs are designed to do.
You can easily connect the Nano-10 PLC to your network
router, switch, or hub using the straight CAT-5 cable. When a
connection is made, the yellow “Connection LED” on the RJ45
connector will light up, indicating that the PLC has been
connected to the network router.
Figure 2.1.1
Once connected to the network, the i-TRiLOGI programming software works instantaneously with the
PLC, allowing remote programming and process monitoring over the LAN or the Internet. In addition, the
Ethernet facility at this port can host web pages and Java applets so that users of the equipment can
control/monitor their equipment using their web browser from anywhere.
Before connecting the PLC’s Ethernet port, you should configure it using the configuration tool that is now
built into the 6.3x or higher version of the i-TRiLOGI programming software. Previously, a standalone
Ethernet Configuration program was required to setup the basic and advanced Ethernet, ADC, and RTC
(Real Time Clock) options. This standalone version is still available and more information on this
program, including where to download it, is available at the end of section 2.1 (2.14 Standalone Version
of Ethernet Configuration Software). Now these settings can be configured directly from the TRiLOGI
programming software, as described next.
2.1 Configuring The Ethernet Port
This tool, which is located in the "Controller" Menu of TRiLOGI, allows you to configure the Ethernet Port
and ADC/RTC calibration settings on a TRi's PLC with built-in Ethernet port, such as the Nano-10 and Fseries PLCs. When the “Ethernet & ADC Calibration” is selected from the “Controller” menu, you will see
the following screen:
The configuration program communicates with the
PLC the same way as i-TRiLOGI, which is either
through the TLServer software + serial port, or
directly through the Ethernet Fserver port.
If your i-TRiLOGI is not yet connected to the
TLServer software or directly to the PLC’s built-in FServer, then you will be prompted to login to the
PLC’s server.
(See the i-TRiLOGI Programmers
Manual for more information on this)
Reference
Figure 2.1.2
2-1
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Ethernet Port
Notes to New Users
If this is the first time that you are configuring the PLC’s Ethernet port, and if your PC is not on the
same default subnet of 192.168.1.xxx as the Nano-10, then you may not be able to communicate with
the Nano-10 Ethernet port using its default IP address of 192.168.1.5:9080. In that case you can only
communicate with the Nano-10 PLC through a serial port connection, until you have changed the
PLC’s IP address to match that of your network’s address.
However, In order to communicate with the Nano-10 PLC via serial port connection, you will need to
run the TLServer software on your PC. TLServer acts as a serial-to-Ethernet gateway such that the
commands it receives from I-TRiLOGI software via TCP/IP are conveyed to the PLC via the PC’s
serial port, and vice versa
Since the Nano-10 PLC only has 1 RS485 serial port, this will require that the PC running TLServer to
have an RS485 interface. However, most new PCs today no longer have any built-in serial port.
Thus, the easiest way to install an RS485 interface on the PC is to purchase a USB to RS485
converter (e.g. http://www.tri-plc.com/U-485.htm). Since the USB toRS485 converter is powered by
USB port, you can simply plug the converter into the PC’s USB port and connect two wires to the
Nano-10’s RS485 port and immediately communicate with the PLC via serial communication.
Before you make any changes to the PLC's Ethernet configuration parameters, it is a good idea to
retrieve the current settings. You can do this by clicking on the “Retrieve Parameters from PLC” button
and answer "Yes" when prompted.
After you have retrieved the existing parameters from the PLC, you will see that various fields in the
configuration software screen are filled up. The following sections describe the significance of each field.
Important:
If you make changes to any of these fields, you must select the “Reboot PLC After Save”
checkbox before clicking the “Save Parameters to PLC button” so that the new parameters
will be saved to the flash memory of the PLC and the new parameter can take effect
immediately.
Note that the Nano-10 PLC has two built-in “Server” programs that listen on a few different ports on the
PLC for incoming TCP/IP request packets:
1) The FServer supports the TRi proprietary programs such as the i-TRiLOGI software and TRiExcelLink program. By default the FServer listens on the default port 9080.
2) A MODBUS/TCP server that listens on port #502 and supports the industry standard
MODBUS/TCP protocols.
Note:
•
These two servers share the same Ethernet port and therefore the same IP address and gateway
addresses described in the following sections.
•
Nano-10 PLCs host both the FServer and the Modbus/TCP servers, each providing multiple
simultaneous connections to external clients. This means that it is possible to connect multiple
TRiLOGI, ExcelLink and Modbus/TCP clients to the PLC, all at the same time! Section 2.1.5
shows you how you can change the maximum number of connections for each server.
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Ethernet Port
2.1.1 IP Address
One of the most important Ethernet parameters that you must define here is the “IP Address” field. By
default, every Nano-10 PLC is shipped with the static IP address: “192.168.1.5”. You will need to assign
the PLC’s with an IP address that is unique on your network and yet is accessible from your PC. If you
are on a company network, then you must consult your company’s system administrator to assign you a
useable IP address.
However, if your PC is connected to a small local area network, then most likely you will have a LAN IP
address of 192.168.XXX.YYY. For proper networking, you should set the PLC’s IP address to
“192.168.XXX.ZZZ”. i.e. The first three numbers should match each other. The fourth number (ZZZ)
should be an IP address that is not used by any other devices on your network.
Note that majority of small LANs are built using a network router that assigns dynamic IP addresses
(called DHCP server) to the PC. You should enter the administrator page of the router and define the
range of DHCP for use by the PCs and then you may assign the PLC with any IP address that is outside
of the DHCP range. E.g. If you define the DHCP address range to be 192.168.1.100 to 192.168.1.150,
then you may assign the PLC with any IP address between 192.168.1.2 to 192.168.99 (Usually the router
itself would have the IP address 192.168.1.1 so that address is not available) and also between
192.168.151 to 192.168.1.254 (again making sure that 192.168.1.254 is not already used by your router).
2.1.2 GateWay IP Addr
The Gateway IP address lets the Nano-10 PLC communicate with other LAN segments or connect to the
Internet. The gateway address is usually the local IP address of the router where the PLC is connected.
For small local networks with no plan for connection to the Internet, the Gateway IP Address is not
needed and can be set to 0.0.0.0. But if you plan to use the FServer’s email capability then you must fill in
the correct Gateway IP Address. Ask your system administrator if you have any question about this.
2.1.3 SMTP Server IP Address
The SMTP (Simple Mail Transport Protocol) Server field lets you define the IP address of the email server
that the PLC can use to send out emails from user’s program (please see section 2.4.2 for more details
on how to program the PLC to send emails). This is the same SMTP server that your normal email client
software such as Thunderbird or MS Outlook uses to send out email. You can ask your Internet Service
Provider (ISP) for the IP address of their SMTP server. The ISP usually provides the SMTP server in
domain name form (such as “mail.sbcglobal.net”), but you should also be able to request the numerical IP
address of the SMTP server from the ISP.
For Windows XP or Vista users, you can resolve the IP address as follows: First, launch the “Command
Prompt” window. Then enter the command nslookup <smtpserver name>” to get the IP address. An
example is shown below where the IP address of mail.sbcglobal.net is resolved to the IP address:
“207.115.36.120”:
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Figure 2.1.3
Windows users may also search the Internet for a free “host.exe” tool that lets you resolve the IP address
from a given domain name (one host.exe tool that we found to work was downloaded from
http://pigtail.net/LRP/dig/). For example, executing the command line: “host mail.sbcglobal.net” will
resolve its IP address. (Of course you can only use this smtp server provided your ISP is SBC, almost no
SMTP server will relay emails from a client that is not its one of its own subscribers).
If you do not plan to use the FServer to send out emails yet, then you can leave the default SMTP Server
IP Address = 0.0.0.0. You can change the settings anytime later when you need it.
2.1.4 DNS Server IP Address
DNS (Domain Name Server) allows the FServer to contact a remote server by means of domain name
instead of IP Address. The DNS takes in the given domain name (such as yahoo.com) and returns the IP
address of the target server. You will need to fill in the DNS IP Address if you intend to ask the Fserver to
resolve a domain name into an IP address, or you intend to contact a client directly by using domain
name instead of using IP Address.
Note: Only Nano-10 PLC with firmware version r72 and above supports the use of domain
name when contacting a remote server.
The DNS server IP address could be the same as the Gateway IP Addr described in section 2.1.3. But it
will be more efficient to define the actual DNS server IP address that your ISP provides. You can usually
obtain the DNS server IP address by going to the Administrator page of your router and pull up
information on the WAN. E.g. The DNS server address you can see from the following screen is
64.59.144.92.
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Figure 2.1.4
2.1.5 No. of Connections (FServer/ Modbus TCP)
The Nano-10 CPU assigns sufficient memory to support up to a maximum of 6 simultaneous TCP/IP
connections to the FServer and Modbus/TCP server. By default, each server is assigned a maximum of 3
connections each. However, to improve flexibility, you can re-assign the mix of maximum connections
between the two servers as long as the number of Modbus/TCP connections does not exceed 5 and the
number of FServer connections does not exceed 4. This means that you can define 1 to 4 FServer
connections and 2 to 5 Modbus/TCP connections. When you change the number in one box the other
box will change automatically so that the total number of possible connections remains at 6.
2.1.6 FServer Port No.
The Port number is a 16-bit integer (range 0 to 65535) that needs to be specified on top of the IP address
when accessing the FServer from across the network. The default value is 9080, which is the same
default value used by the TLServer and TRiLOGI client software. Please see the TRiLOGI programmer’s
manual for an explanation of the use of the port number. One reason why you may want to change the
port number is to use the “port forwarding” capability of an NAT router so that different Nano-10 or Fseries PLCs may be accessible from the Internet using the same public IP address of the router but with
different port numbers.
2.1.7 Modbus/TCP Secondary Port No.
According to MODBUS.ORG specifications, all Modbus/TCP servers must listen on port #502. However,
Modbus.org also permits the device to be assigned a different secondary port number. As such, the
Modbus/TCP server will always listen on port #502 for all of its connections by default. Should you
choose to define a secondary port number, then the Modbus/TCP server will only listen on port 502 on
one connection while the additional connections (1 to a maximum of 4) would be listening on the
secondary port.
You may specify any port number between 1024 and 65535 (except for the port number already used by
the FServer) to be the secondary port number. Please see the TRiLOGI programmer’s manual for an
explanation of the use of the port number. One reason why you may want to change the port number is
to use the “port forwarding” capability of an NAT router so that different Nano-10 or F-series PLCs may
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be accessible from the Internet using the same public IP address of the router but with different port
numbers.
2.1.8 LAN Speed
You can set the LAN speed of the Nano-10 PLC to be either 10 Mbps or 100 Mbps (default) per second
using this menu option. Most modern Ethernet switch or router will automatically connect to the PLC
using its default LAN speed and there is usually no need for user to configure this option except in very
special application where the devices are connected via a 10Mbps Ethernet “hub”, which demands all
connected device to be set to the same 10Mbps LAN speed.
2.1.9 Node Name
You can assign up to 16 ASCII characters (any character) in naming a PLC. The node name is currently
not used by the network router so it is merely a convenient name for user to identify a PLC.
2.1.10 Username and Password (FServer only).
You can use the username and password feature to prevent unauthorized access to the FServer. It
adopts the same proprietary encryption scheme used in the TLServer and TRiLOGI software to encrypt
the password transmission. However, unlike the TLServer software that allows you to define unlimited
number of usernames and passwords, the FServer only permits a single username and password and
this is limited to a length of 16 characters each.
2.1.11 Use Username/Password (Yes/No)?
In applications where there is no danger of unauthorized access to the PLC via FServer, you can elect
not to use the username/password. With the “No” option selected, the TRiLOGI client or Java Applet can
log-in to the FServer using whatever username and password since FServer will bypass the username
and password authentication and allow the client to log in.
2.1.12 Access Level
You can define the access level that the TRiLOGI client is permitted to operate on the PLC. Three access
levels are currently defined: 1 for Programmer, 2 for User and 3 for Guest. Choose “1-Programmer” if you
wish to be able to program the PLC. Please see the i-TRiLOGI Programmer’s Reference manual for the
definition of the access levels.
2.1.13 Advanced Configuration
The Advanced Configuration button lets you configure other more advanced (beyond the basic Ethernet
configuration), but less often used features of the PLC. This includes definition of the “Trusted IP”
addresses (see Section 2.4.2) as well as calibrations of the PLCs Analog I/Os and RTC (see Section 5.4).
2.1.14 Standalone Version of Ethernet Configuration Software
The standalone version of the Ethernet Configuration software, which was previously the only option for
configuring the Ethernet port and advanced settings on the F-series PLCs, can also be used to configure
the Nano-10 PLC’s Ethernet port. You can download the software from our website at the following URL:
http://www.tri-plc.com/download/FserverConfig/index.htm
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Please download and run the “SetupFPLCConfig.exe” file from the above URL to install the “F-series
Ethernet Configuration Utility” program.
After you have installed the configuration program, please click on the Windows “Start” button and open
the “F-series PLC Configuration” group and select the “Ethernet Configuration Utility” program. The
following screen should appear:
This configuration program can only communicate
with the PLC via its serial port (RS485 in the case
of Nano-10). If you PC already has an RS232 port
(or USB-RS232 adapter), you can purchase an
Auto485 adapter to obtain the required RS485
interface. Otherwise, it may be more convenient to
purchase
a
USB-to-RS485
adapter
(e.g
http://www.tri-plc.com/U-485.htm ) for the program
to work with the Nano-10 PLC.
First, click on the “Serial Setup” button and set the
PC’s COM port to the same settings as the PLC’s
RS485 port. (default settings are 38,400bps, 8
data bit, 1 stop bit and no parity). It is important
that you select a valid COM port on the PC,
otherwise the program will report an error when it
fails to open the COM port. The selected COM port
number is shown in a small text box below the
“Serial Setup” button so that you can see the
currently selected COM port readily.
Figure 2.1.5
Next, click on the “Retrieve Parameters from F-PLC” so that you can capture a copy of the current
configuration stored in the Nano-10 PLC. You can then selectively modify the parameters of interest.
The main difference between this standalone version of the F-series Ethernet Configuration software and
the built-in version on i-TRiLOGI 6.3x is that the stand-alone version can only communicate directly with
the PLC via the serial port, and it does not require the i-TRiLOGI or TLServer software. The built-in
version in i-TRiLOGI, on the other hand, can communicate with the PLC through either locally via the
serial port or remotely via the Ethernet connection.
The standalone version can be useful for OEMs who want to provide their customers a way to configure
the Ethernet settings, and/or calibrate the ADC, and RTC settings but don’t want to provide access to the
programming software. However, the OEMs must remember that their customers’ PC would require the
RS485 interface converter to use this standalone software with the Nano-10 PLC.
Important:
If you make changes to any of these fields, you must select the “Reboot PLC After Save”
checkbox before clicking the “Save Parameters to PLC button” so that the new parameters
will be saved to the flash memory of the PLC and the new parameter can take effect
immediately.
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2.2 Connecting Ethernet to the PLC
Introduction
All FMD PLCs can connect to the PC running TRiLOGI many ways as follows:
a) Wired connection to a router that the PC is also connected to (PC connection can be wired or
wireless).
b) Direct connection to the PCs wired Ethernet port via crossover cable
c) Wireless connection to a wireless router if the PLC is connected to a wireless bridge (adapter)
Only the first two options, which are most common, will be described here.
2.2.1 Connecting the PLC to a Local Area Network
In a typical local area network (LAN) there would be one router (wired or both wired and wireless) that the
network devices connect to, one modem that provides Internet to the router, and the devices connected
to the router (such as the PLC and PC).
Before You Begin
The first thing you need to do is configure the network settings in the PLC to match those of the LAN.
This is typically done as follows:
1) Find out what your routers gateway address is (typically 192.168.1.1 or 192.168.0.1) and what
static IP addresses are free to use with your PLC.
NOTE: if the routers gateway address is “192.168.1.1”, the default PLC IP address (192.168.1.5)
will most likely work unless it is already used by another device on the same network. If it is free
to use, the next two steps can be skipped as the PLC will already be able to connect to the LAN.
2) Connect to the PLCs serial port from the PC with TRiLOGI and TLServer.
3) Edit the PLC network settings using the Ethernet & ADC Configuration tool from the “Controller”
menu in TRiLOGI. Only the IP address is necessary to configure for basic connection to the LAN.
Please refer to the Quick Connection guide in appendix 1 of the i-TRiLOGI Programmers Reference
Manual. to connect the PLC to your PC via serial port.
Please refer to section 2.1 of this manual for more detailed information on network configuration.
Network Wiring
You will likely already have a network available that consists of an Internet modem that provides Internet
to a wired or wireless router, which has at least one PC connected to it.
In this case, all that needs to be done is connect the PLC to the router with standard Ethernet cable. The
final network configuration will likely resemble the below simple network diagram.
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If you are on a corporate network, then you will need to consult the IT administrator to get the PLC
connected to the network.
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2.2.2 Setting up Ethernet Communication Directly Between a PC and an FMD
PLC
It is possible for your PC to communicate directly with an NANO-10 PLC through the Ethernet port. This
means that you can have a peer-to-peer connection between the NANO-10 PLC and your PC without an
Internet connection or any additional network equipment. The PC being used would need a spare
Ethernet port in order to do this.
What You Will Need
1. A PC with a spare Ethernet port (RJ45 connection)
2. An Ethernet cable**
3. A NANO-10 PLC
**There are two types of Ethernet cables: A standard straight through cable, which is used in most
situations, and a crossover cable, which is required when there is no auto-switching hardware in either of
the two Ethernet ports (PC and PLC). The NANO-10 PLC does NOT have auto-switching capabilities so it
will depend on the PCs Ethernet port whether or not a crossover cable is required. If you are not sure if
your PC’s Ethernet port is able to perform auto-switching (most modern PC has auto-switching built-in),
then it is best to use a crossover cable. A crossover Ethernet cable will work in both situations, but a
straight through Ethernet cable will only work if one or both of the Ethernet ports can perform autoswitching.
How to Set Up Your PC
Before you can communicate with the PLC, you will need to configure the Ethernet port on your PC to
match the settings that you configured in the PLC (default IP is 192.168.1.5). For more information on
configuring the PLC Ethernet settings, see section 2.1 Configuring The Ethernet Port. Once you have
configured your PLC’s Ethernet settings (If you decided to change the default IP), you will need to set
your PCs Ethernet port to have a static IP address that is on the same subnet as the IP address that is
set for your PLC. How you do this is a bit different depending on your operating system, so the following
sections will show step-by-step instructions for configuring your PCs Ethernet settings on Windows XP,
Windows 7, and Windows 8.
Windows XP Ethernet Configuration
1. Open Network Connections. The first thing you will need to do is open the Network Connections
window from the “Start” menu by selecting “Show all connections” from the “Connect To” menu, as
shown here:
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Figure 2.8.1
2. Local Area Network Properties. Next the Network Connections window should open, which will
display all of your network connections.
Now you can either right click on the
Local Area Connection and select
“Properties” or highlight it and click on
“Change settings of this connection”
from the Network Tasks sidebar, as
shown above. When you do this, the
following window will open.
Figure 2.8.2
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3. Edit TCP/IP Properties
Now you want to highlight the Internet Protocol
(TCP/IP) item and click on Properties. This will
open up a new window that allows you to change
the network settings for the Ethernet port that you
selected. The Ethernet hardware you are
configuring is shown under “Connect using:” in
the current window.
Figure 2.8.3
4. Configure IP Address and Gateway
By default your Ethernet settings will be
configured to be obtained automatically (in this
case only the IP settings are set to be obtained
automatically). This setting will not work since
the NANO-10 PLC does not have the ability to
assign IP address to the PC’s Ethernet port. So
you need to manually set the IP address and
the Subnet mask. The IP address should be on
the same subnet as the IP address you have
set for your PLC. For example, if your PLCs IP
address is set to the default address of
“192.168.1.5”, then you should set your PCs IP
address to be:
192.168.1.xxx
The xxx can be any number between 1 and
255, except for 5 (your PC can’t have same IP
address as your PLC)
Figure 2.8.4
The Subnet mask should be set to
“255.255.255.0” no matter what and the other
settings should be left blank because you won’t
be connecting this Ethernet port to the Internet.
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5. Sample Configuration
Here is an example of a configuration that will work
if your PLC has an IP address of 192.168.1.xxx,
where xxx is anything from 1-255 except 2.
Once you have set the IP address and Subnet
mask, you can click on OK and then click on OK
again to close the “Local Area Connection
Properties” window shown in Figure 2.8.5
Figure 2.8.5
Now your Ethernet port has been configured and you can try to connect to your PLC from TRiLOGI using
your PLCs IP address and port number.
Note:
1. Connecting the PC’s Ethernet port directly to the PLC only establishes a private network
connection between the two devices. That is to say, the PLC connected this way is ONLY
accessible to this PC. Even if the PC is connected to a LAN (e.g. via Wi-Fi connection), the PLC
connected to this PC via direct Ethernet connection will not be accessible by any other devices
on the same LAN. and the PLC will not be able to open network connection to any other devices
beyond the PC that it is connect to this way.
2. Sometimes the PC that is connected directly to the PLC via Direct Ethernet Connection may
lose its Internet connection via Wi-Fi. This is because the O/S thinks that the direct Ethernet
connection to the PLC is a real network connection and attempt to route TCP/IP packets through
it. That will result in a connection failure. If this occurs and you need to access the Internet, then
please temporarily remove the Ethernet cable from the PLC and the PC should then be able to
access the Internet again.
Windows 7 Ethernet Configuration
1. Open the Network Window. The first thing you will need to do is open the Network window from the
“Start” menu by selecting “Network", as shown here:
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2. Open Network and Sharing Center: In the Network window, click on the Network and Sharing
Center option on the top pane as in the below picture.
3. Manage Network Connections: In the Network and Sharing Center window, click on the Manage
network connections option under the tasks pane on the left side of the window as in the below
picture.
4. Follow steps 2-5 in the Windows XP Ethernet Configuration section above to complete the setup, as it
is the same process.
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Windows 8 Ethernet Configuration
1. Open the Network Window. The first thing you will need to do is open the Control Panel from the
“Start” menu by right-clicking in the bottom left corner of the screen where the Start Menu is accessed
(below left screenshot):
2. Open View Network Status and Tasks Window. Next you need to click on the "View network
status and tasks" link under the "Network and Internet" category (above-right screenshot), which will
bring up the "Network and Sharing Center" window (below screenshot).
3. Click on the "Change Adapter Settings" Link. This will bring up the "Network Connections"
window where you can configure the necessary network settings for the local adapter.
Follow steps 2-5 in the Windows XP Ethernet Configuration section above to complete the setup, as it is
the same process.
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2.3 On-line Monitoring/Programming via FServer
If you have used the i-TRiLOGI software to connect to TLServer or the X-Server previously, the
procedure is identical. To test i-TRiLOGI communication with the Nano-10 PLC, click on “Controller ->
On-Line Monitoring”, or simply press <CTRL-M> keys.
Figure 2.2.1
When the “Login To TLServer” screen pops up, enter the “IP address : port”, the username and the
password that you have defined for the FServer earlier using the configuration tool, and click on the
“Detect ID” button to detect the PLC’s ID. If i-TRiLOGI is able to connect to the Nano-10 PLC via the
Ethernet network, then the PLC’s ID will appear in the ID box. When you click the “OK” button, the on-line
monitoring screen should appear and you should see the “Activity LEDs” on the RJ45 connector blinking
away. You have now successfully connected to the FServer and you can run all the commands under
the “Controller” menu, including transferring your new program to the PLC or setting the PLC’s Real Time
Clock, etc. For more details on using these commands, please refer to i-TRiLOGI Programmer’s
Reference.
Likewise, to transfer your new program to the PLC, you can click on the “Controller” menu and select
“Program Transfer to PLC” or press the <Ctrl-T> keys. If i-TRiLOGI is already connected to the FServer,
the program transfer will begin immediately after you’ve confirmed your action. Otherwise the same
“Login to TLServer” screen, as shown on Figure 2.2.1, will appear for you to complete the login
sequence.
Note:
1) Unlike the TLServer software that runs on the PC, which allows unlimited connection time, the
FServer on the Nano-10 PLC will disconnect the client if there is no activity for more than 10
minutes. The older version of the i-TRiLOGI program may not detect that the connection has
been closed and it may instead think that the PLC is not present. When this happens you should
click on “Controller” menu and select “Disconnect” to properly shut down the connection that has
already been reset by the PLC.
2) If you are unable to connect to the PLC, then check that both the PLC and the PC running your iTRiLOGI software are connected to the same local area network (LAN) and are on the same
subnet. Generally for a subnet mask of 255.255.255.0, if the PC’s IP address is 192.168.1.xxx
then the PLC should have an IP address of 192.168.1.yyy and it will not work if the PLC has IP
address such as 192.168.0.yyy or 192.168.2.yyy, since this means that the two devices are on
different subnets. Likewise, if your PC’s IP address is “192.168.0.xxx”, then please change your
PLC’s IP address to “192.168.0.yyy”. Also ensure that the PLC’s IP address is not already
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assigned to another device on the same network, otherwise a conflict would occur and
communication is not possible.
2.4 Using Fserver
“Network Services” Commands
The F-Server firmware in the Nano-10 PLC implements a list of “Network Services” commands similar to
what you may have read in the User’s Manual of the X-Server (“NS commands) and TLServer (“Files
and Email Services”).
These “Network Services” or NS in short, can be used to instruct the Nano-10 PLC’s operating system to
perform a number of network related client connection via the Ethernet port. These commands allow the
PLC to connect remotely to another PLC in another building or another part of the world via the Internet!
This allows peer-to-peer networking, or so-called “M2M” (machine to machine communication) to take
place between the PLCs.
Notes:
1. In the case of the X-Server and TLServer, the PLC typically communicates with these
external hardware or software servers via its COMM1 serial port, and thus TBASIC
statements and functions such as PRINT #1, INPUT$(1) and NETCMD$(1) are used since
the NS commands are sent through the serial port #1.
2. Since the Ethernet is already built-in on the Nano-10 PLCs, you do not need to send NS
commands via any of its serial port (this also means that no serial port is sacrificed in order
to have access to Ethernet communication). However, to help users of the XServer and
TLServer migrate easily to the Nano-10 PLC Ethernet port, we implement the NS
commands using similar command format as that on the XServer and TLServer. But
instead of sending the commands through COMM1, you will interact with the O/S through
COMM port #4.
d
Of course, since the Nano-10 PLC doesn’t have 4 serial ports, COMM port #4 is therefore
only a “virtual comm. port” and its creation is merely to simplify implementation of the NS
commands.
3. The “TestEthernet.pc6” (download from: http://www.tri-plc.com/trilogi/Nano10Samples.zip)
includes all examples of how to use the NS commands via virtual comm. port #4, which
serves as a good starting point for you to learn these simple but yet powerful methods for
making a client connection over the LAN or the Internet.
4. The PLC reserves only a single client socket to implement the Network Services. If you use
any of the NS commands listed below, please ensure that the command is completed (so
that the client socket can be closed) before issuing a different NS command.
All NS commands begin with a string enclosed within the angle bracket called a “tag”, e.g. “<EMAIL>”,
“<CONNECT>”. Most NS commands end with a closing tag “</>” except the “<REMOTEFS>” tag, which
ends with a “</REMOTEFS>” closing tag. Depending on the command type, the Nano-10 CPU may
return one or more response strings via virtual comm. port #4, from which the PLC can read to determine
if the NS command has been executed properly.
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The PLC can operate the Ethernet port by means of TBASIC INPUT$ and PRINT # commands operating
on COMM 4. It uses the PRINT #4 command to send out NS commands and the INPUT$(4) command to
receive response data via the Ethernet port.
Notes:
1. UNLIKE the case of T100MD PLC + XServer, the CPU does not route communication data
that the FServer (or Modbus/TCP server) is exchanging with external clients to the virtual
comm port #4. This means that there would not be interference to the NS command/response
being sent and received by the PLC program via virtual comm. port #4. As such, there is no
need to implement the “arbitration” method mentioned in the XServer User’s Manual for this
PLC.
2. Only PRINT #4 and INPUT$(4) are implemented on virtual COMM port #4. Nano-10 PLC
DOES NOT support the INCOMM (4) and OUTCOMM 4 commands. However, you may send
any non -zero ASCII data using the PRINT #4 command.
The following subsections describe the various Network Service commands available to the Nano-10
PLC.
2.4.1 Get Our Local IP Address
Format:
<IP>
Response:
xxx.xxx.xxx.xxx:nnnn (IP address:port
of FServer)
Example:
PRINT #4
“<IP>”
SETLCD 1,1,”Our IP=”+INPUT$(4)
Note:
This IP address is returned instantly, so there is no need to wait for INPUT$(4).
There is also no need for the closing tag </>
2.4.2 DNS command: Resolving Domain Name into IP Address
In order to use this command successfully, you must first correctly define the DNS Server IP
address mentioned in Section 2.1.4.
Format:
<DNS [domain name]>
Response:
xxx.xxx.xxx.xxx
IP address string returned by DNS server
ERR:07-DNS Unresolved
Either DNS server not properly defined or the
domain name does not exist.
Response:
xxx.xxx.xxx.xxx (IP address string returned by domain name server)
STATUS(3):
This function returns 1 on success and 0 on failure.
Example:
PRINT #4 “<DNS tri-plc.com>“
FOR I = 1 to 10000
A$ = INPUT$(4)
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IF LEN(A$) <> 0
SETLCD 1,1,” IP=”+A$
RETURN
ENDIF
NEXT
Notes:
a) There is no need for the closing tag </> to end this command.
b) If your DNS server has been correctly defined, the above program should return the IP
address as a string such as “130.94.216.144”. You can then use this IP address string in all
the other NS commands to be described in the following sub-sections.
c) The DNS server may take some time to resolve the domain name. If it is unable to resolve
the domain name then it will return an error string, so your program should test to see if it
receives the ERR07 error message to determine whether the returned string is useable.
d) Although it is possible to embed the domain name directly in the NS command in place of
IP address, it is usually much more efficient to use the IP address directly if it is known in
advance. This is because the DNS server may take some time to resolve the domain name
into IP address each time it is called, and there is a possibility that the domain name server
may be overloaded or down momentarily when it is needed, and hence complicating the
attempt for the PLC to connect to a remote server. Therefore we recommend that you use
the <DNS domain > tag to resolve the domain name into IP address first and then use the
resulting IP address for all Network Services commands via the Internet.
2.4.3 Send Email
Format:
<EMAIL [recipient email address]>
SENDER: [sender email address]
SUBJECT: [whatever text string]
[body of the email line 1]
[body of the email line 2]
…..
</>
Response:
STATUS(3):
<OK>
Email successfully sent
ERR:04-Not Connected
Failed to connect to SMTP server (Section 2.1.3)
ERR:06-Email Failure
Failed to complete email transmission.
This function returns 1 on success and 0 on failure. Note that this function only
returns the email status after the closing tag </> has been sent. If the function is
polled before the last closing tag is sent, the status is indeterminate.
Description: You can use this command to send out an email for you at any time. The
FServer uses the SMTP server and Gateway IP addresses defined by the Nano10 (See Section 2.1) to perform this task. If it encounters any errors, it will send
back an error string, which begins with the “ERR:” followed by the reason for the
error. Although the sender’s email address does not have to be a valid email
address, it is good to at least use a valid domain name as the sender address.
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Otherwise the SMTP server may refuse to send the email because it may
deduce that an email with an invalid domain name is likely to be a Spam mail.
Example:
Please refer to the fnEmail function in the “TestEthernet.PC6” file.
2.4.4 Open Connection to Remote FServer or TLServer to Use NETCMD$
Format:
<CONNECT [IP address:port of TLServer or XServer]>
[username string]
[password string]
Response:
<CONNECTED>
Successfully connected to remote
TLServer or XServer at the IP address.
FServer,
ERR:05-Prev Conn.ON
Another NS command has been executed and left
the client socket opened but did not execute the
PRINT #4 “</>” to close the client socket.
ERR:04-Not Connected
Failed to connect to remote Fserver or TLServer.
STATUS(3):
This TBASIC function returns 1 if the connection is active and returns 0 if the
connection has ended. You can test the connection status to determine if the
connection is still alive.
Description:
This service allows your PLC to log in to another Nano-10, an F-Series PLC or
a T100MD+ PLC connected via TLServer or XServer through the Internet.
You execute this command by first sending the string “<CONNECT
xxx.xxx.xxx.xxx:9080>” using the PRINT #4 command, where xxx.xxx.xxx.xxx
is the IP address of the remote FServer or TLServer, followed by sending the
username and password needed to log in to the remote server. Each line
should be terminated with a CR (carriage return) character. (The PRINT #4
command automatically appends the CR character).
Once a connection with the remote server is established, the CPU will return
the response string <CONNECTED> to the user program, which can read it
using the INPUT$(4) function. The STATUS(3) function can also be used to
test if the connection is successful and alive. When the program gets the
confirmation of connection, it can then use the TBASIC “NETCMD$(4, x$)”
command to read or write data to the remote PLCs as if the remote PLC is
locally connected to COMM4 port of this PLC, as shown in the following
example:
A$ = NETCMD$(4, “@01RI00”)
Multiple NETCMD$ commands can be executed as long as the connection is
alive. You can test the connection status by checking the result of the
STATUS(3) function.
Once all the command exchanges have been completed, you should send a
</> tag to close the client connection to the remote server so that other NS
commands can be executed in other parts of the program.
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Example:
Ethernet Port
Please refer to the “fnConnect” and “fnNetCmd” custom functions in the demo
program: “TestEthernet.PC6”.
2.4.5 Remote File Services
Format:
<REMOTEFS [IP Address of remote TLServer 2.1 & above]>
[File Service tag for TLServer]
…..
</REMOTEFS>
Response:
The response strings sent by the remote TLServer in response to the [File
Service tag] sent by this PLC. Or,
ERR:04-Not Connected
Failed to connect to remote TLServer.
Example:
Please refer to the “fnRFS1” and “fnRFS2” custom functions in the demo
program: “TestEthernet.PC6”.
Description:
This commands allows the Nano-10 PLC to connect to a remote
TLServer to perform any of the “Files & Email Services” that a TLServer normally
provides to PLCs that are connected to it. This includes creating text files on a
remote PC running the TLServer software and writing or appending data to it
anytime. This makes it very convenient for the PLC to collect large amounts of
data and save them to the easily accessible, virtually limitless hard disk storage
space that is available in today’s PCs.
For detailed descriptions of the available [File Service Tags] please refer to TRiLOGI
programmer’s reference manual under the chapter “File & Email Services”.
All TLServer’s “File & Email Services” tags, such as <Email>, <WRITE>,<APPEND>, <READ>
and <READ RTC> are available to the Nano-10 PLCs through the use of the <REMOTEFS>
tag. You simply have to wrap the abovementioned command tags between the <REMOTEFS
IPAddr:port> and </REMOTEFS> tag, where “IPAddr:port” is the IP address and listening port
of the remote TLServer. E.g. through the <READ RTC[]> tag, the PLC can synchronize its
Real Time clock with a remote TLServer. (As you will later see, this feature is probably not
very useful for the Nano-10 PLC anymore since Nano-10 has the ability to connect to the NIST
Time Server to update its real time clock to Atomic clock accurately!)
Note: Only TLServer version 2.1 or above can handle the <REMOTEFS> command tag sent
by the Nano-10 or F-series PLC.
2.4.6 Other Network Services Tags
We will describe two more Network Services commands:
<MBTCPCONNECT> in separate sections later in this manual.
<TCPCONNECT>
and
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2.5 MODBUS/TCP Server and Client Connection
The Nano-10 PLC supports both the FServer and the industry standard MODBUS/TCP server
simultaneously. This means that all Nano-10 PLCs are ready to interface directly with many third party
industrial control devices that support the MODBUS/TCP protocol. These include the SCADA software,
HMI hardware, OPC Server, HVAC controllers and many other industrial control devices.
In addition, the Nano-10 PLC can be used both as a MODBUS/TCP SERVER as well as a
MODBUS/TCP CLIENT simultaneously. This means that the Nano-10 PLC can readily read data from
any device that has a MODBUS/TCP server, such as: flow meters, AC/DC drives, HVAC elements,
RTUs, network sensors etc. It is also possible to perform peer-to-peer networking with other
MODBUS/TCP controllers (e.g. another Nano-10 or F-Series PLC) over a LAN or over the Internet!
2.5.1 Connecting To The PLC’s MODBUS/TCP Server
By default, the Nano-10 CPU supports up to 3 simultaneous MODBUS/TCP connections. You can
change the number of simultaneous MODBUS/TCP connections from 2 to 5 using the “Ethernet Basic
Configuration Tool” program as described in Section 2.1.
The PLC will listen on the default, well-known MODBUS/TCP port #502 for one or all of the connections.
However, it is also possible to define a secondary port number using the Nano-10 Ethernet Configuration
program as described in Section 2.1.7 (Note that if you define a secondary port number, then only one of
the MODBUS/TCP connection will listen on port #502 and the remaining connections will only be listening
on the secondary port number.)
If you have a MODBUS/TCP client program (e.g. you can download a trial version of “Modbus Poll” from
http://www.modbustools.com for testing), you simply specify the Nano-10 IP address and connect to it.
Once connected, you will then be able to read from or write to most of the Nano-10 PLC’s internal data
from the MODBUS/TCP client. The PLC’s I/O and internal variables are mapped to the MODBUS device
space according to Table 2.1.
2.5.1.1
Bit Address Mapping
All the Nano-10 PLC I/O bits are mapped identically to both the MODBUS “0x” and 1x space. The bit
register offset is shown in the last column of Table 2.1. Although MODBUS names the “0x” address
space as “Coil” (which means output bits) and the “1x” address space as “Input Status” (which means
input bits only), the Nano-10 PLC treats both spaces the same. Some MODBUS drivers only allow a
“read” from 0x space and a “write” to 1x space but you still use the same offset shown on Table 2.1.
Example:
1. To map an element to the PLC Input 4, you select the MODBUS register address 0-0004. You
can also map the element to the PLC’s output #2. In that case, you should map it to MODBUS
register address 0-0258.
2. To map an HMI toggle switch symbol to the PLCs input #4, if you are restricted to select only
MODBUS 1x address space, then you will have to map the switch to 1-0004, and, likewise, you
can map the switch to output #2 using the MOBDUS address 1-0258. However, if the driver
allows the switch to be mapped to the 0x space then you can use MODBUS register space 10258 and 0-0258 for the output #2 mapping with identical result.
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Table 2.1 Memory Mapping of Nano-10 CPU Internal Data to MODBUS Register
NANO I/O #
Input
Output
Timer
Counter
Relay
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
n
1 to 16
17 to 32
33 to 48
49 to 64
n
1 to 16
17 to 32
33 to 48
49 to 64
MODBUS Word Addr.
Mapping
MODBUS Bit
Addr. Mapping
40049.1 to 40049.16
40050.1 to 40050.16
40051.1 to 40051.16
40052.1 to 40052.16
n
1 to16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
256 + n
257 to 272
273 to 288
289 to 304
305 to 320
321 to 336
337 to 352
512+n
513 to 528
529 to 544
545 to 560
561 to 576
768 + n
769 to 784
785 to 800
801 to 816
817 to 832
n
1 to 16
17 to 32
33 to 48
49 to 64
40065.1 to 40065.16
40066.1 to 40066.16
40067.1 to 40067.16
40068.1 to 40068.16
1024 + n
1025 to 1040
1041 to 1056
1057 to 1072
1073 to 1088
65 to 80
81 to 96
97 to 112
113 to 128
129 to 144
145 to 160
161 to 176
177 to 192
40069.1 to 40069.16
40070.1 to 40070.16
40071.1 to 40071.16
40072.1 to 40072.16
40073.1 to 40073.16
40074.1 to 40074.16
40075.1 to 40075.16
40076.1 to 40076.16
1089 to 1104
1105 to 1120
1121 to 1136
1137 to 1152
1153 to 1168
1169 to 1184
1185 to 1200
1201 to 1216
193 to 208
209 to 224
..
497 to 512
40077.1 to 40077.16
40078.1 to 40078.16
..
40097.1 to 40097.16
1217 to 1232
1233 to 1248
..
1521 to 1536
40001.1 to 40001.16
40002.1 to 40002.16
40003.1 to 40003.16
40004.1 to 40004.16
40005.1 to 40005.16
40006.1 to 40006.16
40017.1 to 40017.16
40018.1 to 40018.16
40019.1 to 40019.16
40020.1 to 40020.16
40021.1 to 40021.16
40022.1 to 40022.16
40033.1 to 40033.16
40034.1 to 40034.16
40035.1 to 40035.16
40036.1 to 40036.16
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2.5.1.2
Nano-10 PLC’s
Timer
Present Values
Variables
1 to 64
MODBUS
40129 to 40192
Counter
Present Values
1 to 64
40257 to 40320
Clock
TIME[1]
TIME[2]
TIME[3]
40513
40514
40515
Date
DATE[1]
DATE[2]
DATE[3]
DATE[4]
40517
40518
40519
40520
Data Memory
DM[1]
DM[2]
….
DM[4000]
41001
41002
….
45000
Ethernet Port
Word Address Mapping
As shown in Table 2.1, to access the PLC’s DM[1], you use MODBUS address space 4-1001 and so on.
To access the Real Time Clock Hour data (TIME[1]), use 4-0513. The I/O channels can also be read or
written as 16-bit words by using the addresses from 4-0001 to 4-0320.
Some MODBUS drivers (such as National Instruments “Lookout” software) even allow you to manipulate
individual bits within a 16-bit word. So it is also possible to map individual I/O bits to the “4x” address
space. E.g. Input bit #1 can be mapped to 4-0001.1 and output bit #2 is mapped to 4-0257.2, etc. This is
how it is shown in Table 2.1. However, if you do not need to manipulate the individual bit, then you simply
use the address 4-0001 to access the system variable INPUT[1] and address 4-0257 to access the
system variable OUTPUT[1]. Note that INPUT[1] and OUTPUT[1] are TBASIC system variables and they
each contain 16 bits that reflect the on/off status of the actual physical input and output bits #1 to #16.
2.5.2 MODBUS/TCP Access Security
If a Nano-10 PLC is to be accessible only on the local area network, then the direct connections offered
by MODBUS/TCP provide simplicity without time-consuming login sequences. However, if the
MODBUS/TCP port is to be exposed to the public Internet, then you ought to consider the security issues
associated with MODBUS/TCP connections.
Since a MODBUS/TCP connection does not require a username/password login sequence (unlike the
FServer login), the only way to protect against unauthorized access is through the “Trusted IP” addresses
defined using the Ethernet Configuration software.
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You can use either the Ethernet Configuration Tool mentioned in Section 2.1, or the standalone F-series
Ethernet Configuration program mentioned in Section 2.1.14 to define a list of “Trusted IP” addresses.
Please click on the “Advanced” button on the “Basic Configuration screen” (as shown in Figure 2.4.1) and
you should see the following Advanced Configuration screen.
The first thing you should do is to click on
the “Retrieve Parameters from PLC” so
that you can capture a copy of the current
configuration in the PLC and you can then
modify selectively.
You can define a list of up to 6 “Trusted
IP” addresses in this panel. To enable the
Modbus/TCP Trusted IP, click on the
“Yes” button next to the “Modbus/TCP
Use Trusted IP”.
Note: The FServer can also be enabled to
only allow connections from devices that
match one of the “Trusted IP” defined in
this panel. This is on top of the
username/password login sequence that
can be enabled/disabled from the Basic
Configuration screen. In other words, you
can choose either security method to
access the FServer or implement both
security methods at the same time.
Figure 2.4.1
After you have defined the list of trusted
IP addresses and checked the “Use
Trusted IP” radio button, click on the
“Save Parameters to PLC” to save your
data to the PLC’s non-volatile memory.
When “MODBUS/TCP Use Trusted IP” is enabled, it means that only TCP/IP packets that come from a
client whose IP address matches one of the “Trusted IP” would be allowed connection to the
MODBUS/TCP server.
2.5.3 Making A Modbus/TCP Client Connection to Other Modbus/TCP Server
By using the “Network Services” commands described in Section 2.4, it is unbelievably easy for the
Nano-10 PLC to be used as a MODBUS/TCP client to access any industrial control or HVAC device and
sensors that support a MODBUS/TCP server. Best of all, you can do it without learning any specifics of
TCP/IP programming!
To open a client socket and connect to a Modbus/TCP Server that is listening on port 502 (default
Modbus/TCP port), you only need to send the command tags <MBTCPCONNECT xxx.xxx.xxx.xxx:502>
to the CPU via virtual COMM port #4. E.g.
PRINT #4 "<MBTCPCONNECT 192.168.1.105:502>"
If connection is successful, the system will return the string “<CONNECTED>” on virtual comm. port #4,
which you can check with the INPUT$(4) command.
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Once the connection is successfully established, you can begin to use the built-in TBASIC commands:
READMODBUS, WRITEMODBUS, READMB2 and WRITEMB2 operating on virtual comm. port #4 to
send MODBUS commands and receive processed dresponses from a remote MODBUS/TCP Server!!
This greatly simplifies your programming task, since it is very similar to communicating with a Modbus
RTU slave that is connected to the serial port #1, 2, or 3. Although in this case, the Modbus/TCP device
could be located in the other hemisphere and connected via the Internet!
The full syntax for the <MBTCPCONNECT> tag is described below:
Format:
<MBTCPCONNECT
[IP address:502] of another Modbus/TCP Server>
Response:
<CONNECTED>
Successfully connected to the
server of the specified IP address.
Modbus/TCP
ERR:05-Prev Conn.ON
Another NS command has been executed and left
the client socket opened but did not execute the
PRINT #4 “</>” to close the client socket.
ERR:04-Not Connected
Failed to connect to the targeted Modbus/TCP
Server
STATUS(3):
This TBASIC function returns 1 if the Modbus/TCP connection is live and
returns 0 if the connection has ended. You can test the connection status to
determine if the connection is still alive.
Description:
This service allows your PLC to log in to any device that supports a
Modbus/TCP server and is connected to the same LAN or to the Internet. Of
course, you may also use it to connect to another Nano-10 or F-Series PLC on
the Internet since every these PLCs all have MODBUS/TCP server too.
Once the connection with the Modbus/TCP server is established, the CPU will
return the response string <CONNECTED> to the users program, which can
read it using the INPUT$(4) function. The STATUS(3) function can also be
used to determine if the connection is successful and alive.
When the program gets the confirmed connection, it can then use any one of
the four TBASIC commands: READMODBUS, WRITEMODBUS, READMB2,
WRITEMB2 to read or write data to the remote devices via the virtual comm.
port #4, as if a Modbus slave device has been locally connected to a COMM4
port of this PLC. (You do not need to distinguish between Modbus ASCII and
RTU in this case, simply use comm. port #4 in your all your commands).
Multiple Modbus master commands can be sent as long as the connection is
live. You can test the connection status by checking the result of the
STATUS(3) function at any time.
Once all the command exchanges have been completed, you should send a
</> tag to close the client connection to the remote server so that other NS
commands can be executed in other parts of the program.
Example:
Please refer to the “fnMBTCP”, “fnRdMBTCP” and “fnWrtMBTCP” custom
functions in the demo program: “TestEthernet.PC6”.
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2.6 Getting data from Internet: Connecting to The Internet Time
Server
The Nano-10 PLC features a special NS command tag <TCPCONNECT xxx.xxx.xxx.xxx: portno> that
allows you to connect to any server to download data. However, since the PLC does not have a lot of
memory for storing incoming text data, it is not suitable for downloading information from a commercial
website that sends many kilobytes of data in a single download. It can however, be very useful to connect
to some servers that send small amounts of information. For example, there are many Internet Time
Servers on the Internet that allow users to synchronize their computer clocks via the Internet. The service
responds to time requests from any Internet client in several formats, including the DAYTIME, TIME, and
NTP protocols. The simplest are those that send responses in ASCII data and you can extract the date
and time information from the response ASCII string once you know the format.
You can search on the Internet for a suitable timeserver and use the TELNET program on your PC to
access them to examine their display format. Most timeservers listen either on port 13 or port 123 so you
need to specify the port number together with their IP address when sending the <TCPCONNECT>
command.
Format:
<TCPCONNECT
[IP address:portno] of time server>
Response:
- none
-
Successfully connected to the
server of the specified IP address.
Modbus/TCP
ERR:05-Prev Conn.ON
Another NS command has been executed and left
the client socket opened but did not execute the
PRINT #4 “</>” to close the client socket.
ERR:04-Not Connected
Failed to connect to the targeted server.
STATUS(3):
This TBASIC function returns 1 if connected, or 0 if connection fails..
Description:
Once a connection is made, you can then interact with the remote server using
the PRINT #4 and INPUT$(4) command. You use the INPUT$(4) command to
read CR-terminated text strings sent by the server. You can also send data to
the remote server using the PRINT #4 command.
Example:
Please refer to the “fnTCPconn1” custom function in the demo program:
“TestEthernet.PC6” to see an example of how the PLC can connect to an NIST
timer server and use the returned data to update the PLC’s real-time clock.
A better, standalone program “TimeServer.PC6” can also be found in the
Nano10Samples.zip folder. This program not only updates the time but also
updates the calendar and computes the time zone and adjust for daylight
saving time automatically.
Note: Some NIST time servers have strict policy against abuse so you should
avoid sending repeated request within a short period of time, otherwise further
connections may be denied once you are considered to have violated their
connection policy.
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2.7 Web Service: Accessing PLC's data from MS Excel
The FServer provides an extremely useful feature called “Web Service”. You can actually use your web
browser to access the Nano-10 PLC internal data by specifying the following URL:
<IP Address: portno of FServer>/HOSTLINK/<Point-to-point hostlink command without “*”>
E.g.
Please enter the following URL into your web browser URL address space:
192.168.1.5:9080/HOSTLINK/IR
You will see the following data appear on your browser screen:
IR01
“IR” is one of the many “host link commands” that allows a host computer to read or write to the PLC’s
internal data space using ASCII strings. This particular command “IR” is for reading the PLC’s ID and in
this case the PLC returns “01” by default. For more details on the list of host link commands, please refer
to Chapter 15 of this manual.
Normally the host link commands are sent to the PLC via the serial port (as per all other PLC models
produced by TRi). The FServer, however, permits these host link commands to be sent using the HTTP
protocol, which enables the Nano-10 and F-series PLC to be easily accessible by enterprise software
using what is known as “Web Query” methods. The enterprise software only needs to know the format of
the host link command required to read the target data and then they can use their web query capability
to query the PLC and extract the required data from the response string.
One example, which you can try immediately, is to use the Microsoft Excel 2000 (or later version)
spreadsheet program. First, open a blank spreadsheet, then click on the “Data” menu and select “Get
External Data” -> New Web Query, as shown below:
Figure 2.6.1
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Next, please enter the text as shown in the following diagram and then click OK. This will command the
Excel spreadsheet to send the web query string “RI00” to the Nano-10 PLC that is connected to the
network with IP address = 192.168.1.5 and port 9080. The query string “RI00” is for reading the status of
8-bit input channel #0 (which covers the logic states of input bit 1 to 8).
If the FServer is accessible by the PC from the network router, it will send the response data, which will
be displayed on the selected spreadsheet cell where the New Web Query was defined earlier.
The response data shown on the cell could be RI00. The response data includes the command header
“RI” as defined in the HostLink Command protocol described in Chapter 15. The data 00 indicates that
none of the inputs 1 to 4 are currently turned ON.
Figure 2.6.2
To see how the response data changes in response to the actual PLC’s input, please turn on some of
PLC’s digital inputs 1 to 8, then right-click on the cell where the web query was defined and select te
“Refresh Data” command. You should see a new “RIXX” string appear at the selected cell where “XX” is
the hexadecimal representation of the 8 input bits 1-8. E.g. if only inputs 2 and 8 are turned ON, then
the binary pattern is 1000 0010 which in hexadecimal form is 82 and the response string would therefore
be “RI82”. You can then write an excel formula to extract the data “82” and use it for your other
computation purpose. By using a different Host Link command, the Excel spreadsheet can read and
write to the PLC’s internal data very easily.
Notes:
1.
If you have enabled “Use Username/Password” for the FServer, you will be prompted by your Excel
program to enter the Username and password before you can receive the response data.
2.
We have provided a more complete Excel spreadsheet example “ExcelQuery.xls” which can be
http://www.tri-plc.com/appnotes/F-series/ExcelQuery.xls The macro in this file
downloaded from:
converts the RIXX data it receives into ON/OFF indicators on the Excel Spreadsheet cells. Note that
this spreadsheet file uses the “HEX2DEC” function that is not normally available when you first install
the Excel program. But you can add it in by installing the “Analysis Toolpak”. Please search your
Excel Help file for the specific method of adding in this toolpak as it may change from one version of
Excel to another. On Excel 2000, you can click on the “Tools->Add Ins”, check the “Analysis
Tookpak” check box and then click OK. MS Excel will automatically install the toolpak for you.
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2.8 Accessing The PLC from Internet
2.8.1 Small Local Area Network Using Consumer Grade Network Router
When you connect an Nano-10 PLC to your home Ethernet router, the PLC would have joined a “private”
local area network (LAN). It is accessible, through its private static IP address, by other devices on the
same LAN as long as each device is on the same “subnet” (See section 2.1 for an explanation of subnet
settings). The PLC is also able to access the Internet through the router because the router would
translate a private TCP/IP packet sent from the PLC into a public TCP/IP packet out of the Internet and if
there is any return data from the Internet meant for the PLC, the router would know that and automatically
routes the return packet back to the PLC. The router performs what is known as “Network Address
Translation (NAT)” and such routers are called NAT routers.
However, the same FServer and Modbus/TCP servers on the PLC are typically inaccessible from the
public Internet. This is because the router has a built-in firewall that does not permit external TCP/IP
packets from the public Internet to reach the devices on the private LAN. In other words, the NAT router
allows the PLC outgoing access to the Internet but by default does not allow incoming access.
Most small NAT routers for home use such as those produced by Linksys, Netgear, D-Link or Belkin do
allow you to configure the router to “open” and “forward” a specific port number to a specific device on the
private network. For example, if your PLC static IP address is 192.168.1.5 and you wish to open its
FServer port (9080) but not its Modbus/TCP port (502) to the public internet, you would configure your
router such that it will forward the incoming TCP/IP packet destined for port number 9080 to the device at
IP address 192.168.1.5. Once you have done that, you will then be able to access the FServer from the
Internet using the router’s public IP address (this is typically assigned by the Internet Service Provider)
and the port number 9080. However, the Modbus/TCP port is not accessible from the Internet since this
port number is not opened and not mapped by the router.
You should read your router’s User’s Manual to find out how to configure the router to perform the “port
forwarding” described above since each router model has a different user interface. For example, on the
D-Link DI-624 router you configure the router by clicking on the “Advanced” tab and selecting “Virtual
Server” from the router configuration page, as shown below:
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On the Linksys WRT54G router, you would configure it from the “Applications & Gaming” menu under the
“Port Range Forward” tab, as shown below:
2.8.2 Large Corporate Local Area Network
In the case of a medium to large corporate LAN, whether incoming and outgoing TCP/IP packets are
allowed to go through the corporate firewall is entirely decided by the System Administrator according to
the company’s security policy. Most corporate LANs will not allow incoming packets from reaching an
internal server until the System Administrator has given the permission to do so. Some company’s
network may not even allow devices such as the PLC to open a connection to the Internet to access
external data. If your application requires the PLC to access the Internet or to be accessible from the
Internet, then you would need to consult your system administrator on the required procedure.
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2.9 Installing a Web Page or Web Applet into the Nano-10 PLC using
FileZilla
With the Nano-10 PLC it is possible to transfer a custom web page to the Nano-10’s built-in web server
using the Filezilla FTP transfer program, which is available for free download at the following link:
http://filezilla-project.org
The Nano-10 PLC comes prepackaged with two ready-to-use web pages installed in its web server.
These web pages run on HTML and JavaScript code so they are accessible from standard browsers
such as Internet Explorer, Firefox, and Safari. However, the HTML files are designed to be easily
modified by anyone, even if you don’t have any programming experience. The purpose is to be able to
easily customize the web page layout for your specific application without having to worry about the
control and monitoring portion, which is already programmed. More information can be found on this in
section (2.10 Accessing and Customizing the HTML Web Interface for Control and Monitoring). The
purpose of this section is to learn how to install the Filezilla FTP transfer program and how to use it to
transfer the required files.
2.9.1 Installing the FileZilla program
Once you have gone to the web page from the above link, you will need to select the client version to
download. Then you need to select the software version for your computers platform, typically the
Windows version, and download it to your computer. This is the installation setup file, which you will need
to execute after it has downloaded. Please perform a default installation by following the installation
steps.
2.9.2 Configuring FileZilla to Communicate with the Nano-10
After installing the FileZilla client, please open it from the start menu or desktop icon and then go to the
“File” menu and select “Site Manager”. The following menu will then pop up:
Under the default “General” tab, you will
need to enter the Host IP address and
configure the “Logontype”.
The Host should be the IP address of the
Nano-10 PLC (default IP is shown in the
example). The Port can be left blank and
the Servertype can be left as the default
as shown.
The Logontype should be set to Normal
and the User and Password should be set
to the same as for the login to the Nano10 Server in the Ethernet port.
Nothing else needs to be configured in
this area. Next go to the “Transfer
settings” tab.
Figure 2.9.1
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Under the “Transfer settings” tab you
need to set the Transfer mode to
“Active” and check the box to Limit
number of simultaneous connections.
The maximum number of connections
should be 1.
This is everything that needs to be
configured, so you can now click on
connect.
Figure 2.9.2
If FileZilla has made a
successful connection, the
status
should
be:
“Connected”, and “Directory
listing successful”.
Also, you should be able to
see all three of the preloaded
files in the remote site
directory, which is the bottom
right window shown here.
The three files are “0.HTM”,
“2.HTM” and “N.JS”.
Figure 2.9.3
If you are not able to connect to the Nano-10 server or if you can’t get a successful directory listing, then
you should first double check the settings you have configured for FileZilla compared to the settings
configured in the Nano-10 server. The next thing to check is your Windows firewall. You can disable the
firewall temporarily to check if it is affecting your FileZilla connection, but it is not recommended to leave
your firewall disabled. If you have confirmed that disabling the firewall allows you to successfully connect
to the Nano-10 server and view the directory listing, then you can add FileZilla to the firewall exception list
so that you can leave your firewall enabled.
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To add FileZilla to the Windows firewall exception list, you will need to open the Windows firewall from
your network settings configuration area. Then you will need to click on “Change settings”, which will
open up a new window. You will need to go to the “Exceptions” tab in the new window and look for
FileZilla in the list of programs. If you see FileZilla in the list, then you will need to check the box beside it
to add it to the exception list. Otherwise, you will need to manually add it to the list by clicking “Add
program” and searching for FileZilla in its installation directory. Here is a picture of the Windows Firewall
status window and the Change settings window with the Exceptions tab:
Figure 2.9.4
2.9.3 Transferring and Retrieving Files from the Nano-10 Web Server
Now that you have a connection to the PLC’s web server and can view the directory listing, you should be
able to see the three preloaded files: “0.HTM”, “2.HTM”, and “N.JS”.
Downloading Files
The first thing to do is download the preloaded files from the Nano-10 server and store them somewhere
on your computer. To do this you will need to open up the folder on your computer that you want to store
the files in. Then you can drag the files from the Nano-10 web server via FileZilla into your destination
folder. It is best to make a copy of these files as a backup on your computer so that you have the original
copies available in case you need them.
Now you can make any necessary changes to the 0.HTM file and/or 2.HTM file (this is explained further
in section 2.10), but the N.JS file shouldn’t be changed unless you are very experienced with JavaScript.
File Names
Note that the filenames are important and the N.JS file should not be renamed or it will not work. The
0.HTM file and 2.HTM can be renamed (outside of the PLC’s Web Server) with or without the “.HTM”
extension, but there are limitations. There is a very simple, pre-configured file system in the Nano-10 web
server that is implemented as follows:
•
•
Files can have the name “0” through “9” (one digit) or “A” through “M” (one character)
Files can have any extension (“.HTM” is used for the pre-loaded files), but only a few MIME
types are respected. These include HTM, JPG, GIF, CSS, JS, BIN, TXT, JAR. From firmware
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•
•
•
Ethernet Port
version r77 onwards the following MIME type are also supported: ZIP, XLS. Any unsupported
extension will be converted to “???”.
There is 2Kb of reserved space for each File “0” through “9” and “A” through “T”
If the HTML file is more than 2kb, then more than one file space will be used.
If a file takes up multiple 2kb locations and another file is added within one of the used locations,
the larger file will be corrupted and no longer accessible.
For Example, the file “0.HTM” is about 3.5kb so it takes up two 2kb locations (“0” and “1”), which is why
the second preloaded file is “2.HTM”. If you attempted to add a file named “1.HTM”, it would corrupt
“0.HTM” but “1.HTM” would work.
Uploading Files
When you are ready to transfer your modified .HTM file, you just need to drag it from the folder it is saved
to on your computer into the bottom right window of FileZilla where the current files are shown. If you
didn’t change the filename, you can tell the new file to overwrite the old file. Otherwise, you will need to
manually delete the old file “0.HTM” or “2.HTM” from the Nano-10 web server in FileZilla by right clicking
on it and selecting Delete.
2.9.4 Download the Web Page Files
If you have modified the original “0.htm” and “2.htm” or “N.JS” files that were preloaded in the Nano-10
server and need to retrieve the original files, it is possible to download them from the following web page:
http://www.tri-plc.com/nano/updates/nanoHMI.zip
Note that the “N.JS” file within the above zip file is password protected, so you will need the password
to open it. This information is stored at the beginning of the N.JS file, which can be opened with any
standard text editor such as Notepad. If you have lost this file, then you will need to email support
(support@tri-plc.com) with proof of purchase of the Nano-10 PLC and the password will be provided.
2.9.5 Troubleshooting FileZilla File Transfer Problems
1) FileZilla appears to have connected to the PLC’s FTP server, but it cannot list the directory or
transfer any file to the PLC.
The reason almost always have something to do with the PC’s software firewall. You need to
configure the Windows Firewall (and any software anti-virus firewall on your PC) to allow incoming
connections to the FileZilla program. You can try to disable the firewall temporarily to test the
connection and if does work, you can then be sure that it is the firewall configuration issue that need
to be resolved.
The following paragraphs explain how the firewall can affect the FTP communications for those who
are interested:
The File Transfer Protocol is unique in that it requires two socket connections between two devices
that are communicating via FTP. When FileZilla is connected to the PLC’s FTP server on port 21, it
establishes a “command” channel and it is thru this command channel that FTP commands are being
sent.
However, once the command channel is established (FileZilla is “connected” to the FTP Server), a
second socket connection (known as the “data channel”) needs to be made between FileZilla and the
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PLC. All data, such as the directory information and content of any files to be transferred between
FileZilla and the PLC will need to go through the data channel. They are two possible ways of
establishing this data channel, one is called the “Active Transfer” and the other is known as “Passive
Transfer”.
FileZilla is able to operate in either transfer mode, but the PLC FTP Server can only operate in
“Active Transfer” mode. “Active Transfer” mode requires that the client (FileZilla) provides a listening
socket for the server (PLC) and the server (PLC) will then try to connect to this socket to establish the
data connection. So if the FileZilla program sits behind the software firewall and no exception has
been configured, then the PLC FTP Server will not be able to make a connection to the FileZilla data
socket because it is blocked by the firewall and the connection will therefore fail. This explains why
FileZilla seemingly able to connect to the PLC but yet is unable to send any data or list the directory –
because there is no data channel connection for it to do so.
However, sometimes the problem could persist after disabling all firewalls and in that case the only
option is to revert to an older version of FileZilla, and then transfer the files by doing a right-click
download or right-click upload (if drag and drop doesn't work). You can do this as follows :
a. Download the FileZilla client version 3.1.5.1 from http://www.oldapps.com/filezilla.php
b. Remove the current version and then install version 3.1.5.1
c.
Connect to the PLC
d. There should be two directories (same as always) : local site (your PC) and remote site
(Nano-10). You should see your files in the Nano-10 directory.
e. Open the folder in the local site that you would like to save the Nano-10 files to.
f.
Right click on a file in the Nano-10 directory such as 0.HTM and select download. You
should see the file in the folder on your local site.
g. To move files from the PC to the Nano-10, open the folder in the local site where the file
is located and right click it to select upload. You should see it in the Nano-10 or you will
be asked to overwrite it if the same file name is there already.
2) FileZilla Can Connect The First Time But Could Not Re-connect After Time-Out
FileZilla is normally setup to time out after 1 minutes of no activity. However, Since the PLC’s FTP
server can only handle a single FTP connection at a time, it is good to avoid letting FileZilla time out
due to no activity. This is because when FileZilla times out it cutoff the connection to the PLC. But if
for whatever reason the PLC were to miss the disconnection information it will be left in a "half-open"
state and will not be able to accept a new connection. When this happens and if you try to reconnect
to the PLC again after the connection has been dropped by FileZilla, you will most likely be unable to
connect to the PLC again until after the PLC time out its FTP connection due to no activity. The only
quick fix is to power-on reset the PLC so that it starts up fresh and can accept new connection again.
You can set the FileZilla timeout settings to a larger number (e.g. 300 seconds) using the FileZilla’s
“Edit->Settings” menu item so that it will not time-out automatically too quickly. You should always
select "disconnect" after a file transfer to properly close the connection and then the PLC will be
properly disconnected and is ready to accept new connection.
3) Problem Using FileZilla To Transfer Files to Multiple PLCs Configured To The Same Default IP
Address Even Though Only One PLC Is Connected To The Router At A Time.
When you connect FileZilla to a PLC with a particular IP address (e.g. 192.168.1.5) for the first time,
Windows will memorize the MAC-ID address of that PLC and associate it with this IP address in its
“ARP cache” (ARP = Address Resolution Protocol). So when you power off one PLC and immediately
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plug another PLC with the same IP address to the network, then Windows will pass to FileZilla the
MACID of the PREVIOUS PLC instead of the new PLC using data in its ARP cache memory. When
FileZilla tries to connect to the right IP address but a wrong MACID, it of course would not be able to
connect properly.
In such a scenario, you must clear the Windows ARP cache first using a command prompt as follow:
The “arp –d” command tells windows to delete its ARP cache data. So when you use FileZilla to
connect to a new PLC Windows will do the necessary to properly connect to the new PLC that has a
different MACID from the previous PLC.
Note that the same issue applies to using I-TRiLOGI to transfer program to multiple PLCs that are
all set to the same default IP address, even though only one PLC will be connected to the network at
a time. You will need to clear the ARP cache after every transfer to avoid problem. Or else you have
to wait for windows to expire its ARP cache data before connecting the next PLC.
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2.10 Accessing and Customizing the HTML Web Interface for Control
and Monitoring
In the previous section (2.9 Installing a Web Page or Web Applet into the Nano-10 PLC using FileZilla)
you were shown how to transfer html files to the Nano-10 web server. These files can be accessed from
any standard web browser that supports AJAX technology (Internet Explorer, Firefox, Safari) locally as
long as your Nano-10 is connected to the LAN (local area network) or from anywhere in the world as long
as your Nano-10 is connected to the Internet. Even the iPhone and other smartphones that support AJAX
can be used to access these web pages, which means your application can be controlled and monitored
from anywhere while on the go.
The Nano-10 PLC comes prepackaged with two ready-to-use web pages installed in its web server and a
JavaScript file that interfaces to the PLC. These web pages run on HTML and JavaScript code, which is
why they are only accessible from standard browsers that support AJAX technology. However, the HTML
files are designed to be easily modified by anyone, even if you don’t have any programming experience.
The purpose is to be able to easily customize the web page layout for your specific application by defining
some label names and a background image without having to worry about the programming required to
interface to the PLC, which is already taken care of.
As mentioned in the previous section, the two html files that come with the Nano-10 are “0.HTM” and
“2.HTM” and the JavaScript file is “N.JS”. The N.JS file should generally be left alone unless you are very
experienced with JavaScript and would like to expand on the interface between the Nano-10 PLC and the
html files. Note that we do not support customizing the “N.JS” file if you choose to do so.
2.10.1 Accessing the HTML Files from a Standard Browser
In order to access the web pages stored in the Nano-10 web server, you need to open your web browser
and enter the IP address and port number of the Nano-10 server in the address bar. You also need to
append the filename of the web page to the end of the address. All this should be done in the following
format :
IP:Port/Filename
For example, if the IP address of the Nano-10 is 192.168.1.5 and the port number is 9080 (these are the
default values), then you should enter the following in the address bar in order to access the “2.HTM” file :
http://192.168.1.5:9080/2.HTM
If you want to access the “0.HTM”, then you can change the filename in the address or you can remove
the filename so that only the IP:Port are in the address bar. This will work only for the “0.HTM” file
because it is loaded by default when no other filenames are specified. If you have removed “0.HTM” from
the Nano-10 server, then you will always have to specify the filename of the web page you want to
access.
This is what the default web pages will look like when they are loaded into your browser:
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0.HTM
Ethernet Port
2.HTM
Figure 2.10.1
Figure 2.10.2
2.10.2 Control and Monitoring Components in the Default HTML Files
The 0.HTM and 2.HTM files both include the same components but they are arranged and configured
differently with a different background image set. Both files have the following components available:
•
•
•
•
•
Background Image, which can be defined in the HTML file
LCD Display, which will display whatever the PLC program is displaying on an LCD screen
8 internal relay bits as buttons with configurable label names
4 Data Memory variables (DM[1]-DM[4]) with configurable label names
Continuous Update checkbox with cycle count and refresh button
Background Image:
In the 0.HTM file, the background image is set to the blue border picture and all the other components are
positioned inside the blue border. The background image should be a JPEG file loaded from any
weserver. The 0.HTM and 2.HTM background images are loaded from the TRI-PLC server.
LCD Display:
Figure 2.10.3
The LCD display is positioned at the top of the image in 0.HTM and it is displaying a world clock, which is
controlled by the “i-Relay.PC6” PLC program. The display in the HTML files is showing the 4-line by 20character virtual LCD display controlled by the Nano-10 program using the SETLCD command. This
means you can configure your PLC program to display up to four lines and up to 20 characters on each
line.
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Internal Relay Bits:
Figure 2.10.4
The 4 “Output” buttons and 4 “Input” buttons shown on 0.HTM are all mapped to internal relay bits #129
to #134 in the Nano-10 PLC. Even though the buttons are labeled as “Input” and “Output”, they are not
actually connected directly to any physical I/O so it is up to the PLC program to map the internal relay bits
to the physical I/O in the PLC program. The “i-Relay.PC6” program maps these relay bits to the physical
inputs and outputs of the PLC. However, the relay bits don’t have to just interact with physical I/O, they
can control anything in the PLC program such as custom functions, timers, counters, etc.
Note: The Nano-10 PLC is preloaded with the “i-Relay.PC6” program. A copy of the program may be
download it from: http://www.tri-plc.com/nano/i-Relay.zip.
Data Memory:
Figure 2.10.5
There are four data memory locations that can both display the values set by the PLC program and
accept new values to be stored in the PLC DM[] locations. The first four DM[] locations are used, which
are DM[1], DM[2], DM[3], and DM[4]. These are also the label names set in the 0.HTM file, but they could
be set to anything such as what is shown in the 2.HTM file.
2.10.3 Customizing the HTML Files
Now that you know about the components included in the HTML files, you can try to customize the HTML
files to fit your application or just for fun. In order to customize the HTML files, you will need to open them
with a text editor such as Notepad. The file 0.HTM will be used as the example in this section, but 2.HTM
may be referred to occasionally as well. These files typically open with your default web browser so you
will need to right click on 0.HTM, select “Open With”, and then choose Notepad.exe or your preferred text
editor. Once you have opened 0.HTM in your text editor, you will need to scroll down to the area in the file
where it says: “* Level 1 User Modifications Begins here”. You should then see the following in your text
editor:
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Setting the Background Image
The first line of code you can edit is:
bgimagesrc="http://tri-plc.com/nano/hmipics/panelblue1.jpg"
This is how you set the background image for your web page. All you need to do is replace URL of the
JPEG file (http://tri-plc.com/nano/hmipics/panelblue1.jpg) with the URL of your own
background graphics file hosted on any web server.
Changing Label Names
The names of the eight Internal Relay Bit buttons and the four Data Memory labels can be changed to
anything or even left blank. All you need to do is replace the words in the single quotes with anything from
the following lines of code.
Internal Relay Bit buttons:
Ioname = ['Output1','Output2','Output3','Output4','Input1',
'Input2','Input3','Input4']
Data Memory labels:
DMlabel =['DM[1]','DM[2]','DM[3]','DM[4]']
Relocating Display Data, Buttons, and Labels
It is possible to change the default locations of the interactive objects, which are the Data Memory labels
and fields, the Internal Relay Bit buttons, and the LCD Display. All of these things have x,y coordinates
that are defined in the level 1 user modification area. The coordinates are relative to the top left of the
browser window, which would be 0,0. These coordinates can be easily modified, but in order to find the
right values for your desired location you will need to do some trial and error with different numbers.
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Relocating the LCD Display:
Note that the LCD Display content is not configured in the HTML files because it is displaying what is set
in the PLC program. The display is grouped as a single unit so it is not possible to define separate
locations for each display line (remember it is a 4-line by 20-character display emulation). This is the code
to change the coordinates for the starting location of the LCD screen:
LCDXY = [22,52]
// starting [x,y] location of LCD panel
All you need to do is change the numbers in the square brackets. The x location is 22 by default and the y
location is 52 by default, both relative to the top left corner of the browser display area.
Relocating the Internal Relay Bit Buttons:
Each of the eight buttons (4 input buttons and 4 output buttons) can be moved individually by editing the
following code:
IOLocX = [24,120,24,120,24,120,24,120]
IOLocY = [142,142,164,164,267,267,290,290]
The values in the square brackets for “IOLocX” are the x coordinates and the values in the square
brackets for “IOLocY” are the y coordinates for each button. The button for Output1 is the first value and
the next value is for Output2, etc.
Relocating the Data Memory Labels and Fields:
The labels and fields are grouped together for each of the four data memory locations used, so each label
and field group will move as one item. Here is the code to change the coordinates for the starting location
of the data memory items:
DMLocX = [24,24,24,24]
DMLocY = [185,205,225,245]
The values in the square brackets for “DMLocX” are the x coordinates for each data memory item. The
label and field for DM[1] is the first value and the next value is for DM[2], etc. Note that the default x
coordinates are all the same so they are in line vertically, but they each have different y coordinates.
The values in the square brackets for “DMLocY” are the y coordinates for each data memory item. The
label and field for DM[1] is the first value and the next value is for DM[2], etc.
Changing the Size of Display Data, Labels, and Buttons
It is possible to change the default size of the interactive objects, which are the Data Memory labels and
fields, the Internal Relay Bit buttons, and the LCD Display. Only the values need to be edited in the
corresponding lines of code in the HTML file, just like how the x,y coordinates can be edited. Again, some
trial and error will be required to find the desired size.
Resizing the LCD Display:
LCDSIZE=[185,21]
// [width, height] of each line of LCD
The specified size is reflected equally in all four of the display lines so each line cannot have a different
size.
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Resizing the Internal Relay Bit Buttons:
IOwidth = 80
// Fixed width for I/O button. Set to 0 for Auto width.
IOheight= 0
// Use Auto height.
If you set the IOwidth or IOheight to 0 then the program will adjust the I/O button size based on the width
of height of the entire label name. But if you specify a fixed value (such as 80 as shown above), then the
specified size is reflected equally in all eight of the buttons so each one cannot have a different size.
Resizing the Data Memory Labels and Fields:
DMWidth = 175
DMHeight = 20
The specified size is reflected equally in all four of the label and field items so each item cannot have a
different size.
Changing the Color of Display Data, Labels, and Buttons
It is possible to change the default color of the interactive objects, which are the Data Memory labels and
fields, the Internal Relay Bit buttons, and the LCD Display. Each of these objects has different
configurable color properties, which will be explained further.
Color can be set one of two ways:
1. Using the specific name in single quotes. Eg. ‘Yellow’
2. Using a unique code called an RGB value that equates to a color (also in single quotes). Eg.
‘#FFFF00’ for the color Yellow
Here is a link to a website that converts colors to color codes:
http://jdstiles.com/colorchart.html
Changing the LCD Display Color:
The LCD display has a background color and a text color, which can be individually configured as per the
following code.
LCDbgColor = '#ffffAA' // LCD background color in RGB value.
// Can also be set as "white" for white background
LCDTextColor = 'black' // LCD text color
Changing the Internal Relay Bit Buttons Color:
The eight Input and Output buttons have two background color settings (one for an ON status and one for
an OFF status) and a text color setting that can each be configured.
Text Color:
IOnameColor = 'black'
Background Color:
ONcolor= 'yellow' // 'yellow' can also be written in RGB value as '#ffff00'
OFFcolor='grey'
// 'grey' can also be written in RGB value as '#7f7f7f'
The “ONcolor” value is the color that a relay bit button will turn when it has been activated. The
“OFFcolor” value is the color that a relay bit button will turn when it is deactivated.
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Changing the Data Memory Labels and Fields Color:
Only the background color for the Data Memory labels can be changed in the user level 1 user
modification area, but not the Data Memory field (where the actual data is shown) background color or
the Data Memory label/field text color.
Data Memory Label Background Color:
DMlabelBgColor = '#efffff'
The Data Memory label text color is defined by <style>body{} at the top of the 0.HTM file. The Data
Memory field text and background colors can be changed in the level 2 user modification area.
2.10.4 Level 2 User Modifications
The level 1 user modification area allowed you to quickly and easily customize the layout of the
interactive objects as well as their main color, size, and name properties. However, the level 2 user
modification area allows you to go further and customize some style details, such as: font, text size, more
colors, and other layout/style properties. We recommend that only expert HTML programmers make any
changes to this area, but even users with basic HTML knowledge should be able to make some changes
by trial and error. However, we do not provide support for making changes to this area and we advise that
back-up copies are kept in case you find that the web page is not working and you may need to refer to
the original copy.
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I/O and Internal Relays Programming
Digital I/O and Internal Relays
Programming
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3 DIGITAL I/O AND INTERNAL RELAYS PROGRAMMING
3.1 Introduction
Although the Nano-10 PLC has only 4 physical Digital Inputs and 4 Digital Outputs, all additional input
and output bits that are supported by the i-TRiLOGI software are still available to the Nano-10 PLCs as
internal inputs and output bits. Nano-10 also supports all 512 internal relays available in both ladder logic
and BASIC.
3.2 Programming DIO with Ladder Logic
The physical I/O and internal relays can be programmed in ladder logic in a few simple steps.
3.2.1 For Physical I/O
1. Create or Edit the label names
2. Place the input contact(s) into the ladder logic circuit
3. Place the output coil at the end of the ladder logic circuit
3.2.2 For Internal Relays (Non-Latching)
1. Create or Edit the label names
2. Place the relay contact(s) into the ladder logic circuit
3. Place the relay coil at the end of the ladder logic circuit
3.2.3 For Internal Relays (Latching)
1.
2.
3.
4.
Create or Edit the label names
Place the activating input/relay contact into the ladder logic circuit
Place the latching relay in parallel with the activating contact
Place the relay coil at the end of the ladder logic circuit
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3.2.4 Programming Examples:
3.2.4.1
Example 1 – Editing Label Names
The Digital I/O can be named by selecting “I/O Table” from the “Edit” menu
and choosing the particular digital I/O that you want to name. In Figure 3.1,
physical input #1 is being named “Input1”.
Figure 3.1: I/O Table
3.2.4.2 Example 2 – Creating a Simple Ladder Logic Circuit
You can place components in the circuit by clicking in the green area to the right of the red arrow, as
shown in Figure 3.2 below. This will bring up the component tool bar in the gray area above the green
circuit area.
Figure 3.2: Creating Ladder Circuit
Once the component toolbar is shown, you can place your input/relay contact by selecting the #1
and then selecting the digital input from the I/O Table. The contact
component from the toolbar
will then be automatically placed in the ladder logic circuit. The same can be done for the output coil by
and then selecting an output that has been entered
selecting the #7 component from the toolbar
into the I/O Table. After selecting one input and one output, the ladder logic circuit should like something
like Figure 3.3, below:
Figure 3.3: Completed Ladder Circuit
3.2.4.3 Example 3 – Creating a Latching Relay Circuit
The first part of the circuit follows the same procedure as the previous example, except that the #7 coil
should be a Relay coil. So it should look similar to the circuit in Figure 3.3. The next part requires a
parallel contact to be added to the Input1 contact. This is done by selecting the Input1 contact (or
whichever contact was used) and then adding the #3 contact
, as shown in Figure 3.4 below.
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I/O and Internal Relays Programming
Figure 3.4: Completed Latching Circuit
3.3 Programming DIO in a Custom Function
In order to program digital I/O or anything in a custom function, a custom function must be created in the
I/O Table and added in a ladder logic circuit. Custom functions act the same way as coils in ladder logic,
in that that they need a contact to activate them. Once they are activated, the code inside them will
execute.
To create a custom function circuit, follow these 3 steps:
1. Edit the name of the custom function in the I/O Table
2. Place the activating contact in the ladder logic circuit
3. Place the custom function at the end of the circuit
3.3.1 Editing Label Names:
This is the same as for the digital I/O, except that the I/O table window needs to be scrolled to the custom
function area for editing custom function names.
Placing the custom function in the circuit is done the same way as other ladder logic contacts and coils,
by selecting the
and then choosing the Differential custom function {dCusF} from the pop-up
. The circuit should look something like below:
window
Figure 3.5: Circuit with custom function {dCusF}
3.3.2 Controlling I/O from Custom Functions:
An empty custom function looks like this:
3-3
Chapter 3
I/O and Internal Relays Programming
TBASIC code is entered into the custom function, which allows the possibility of total control of all of the
PLCs functions and hardware.
There are 7 TBASIC functions available to control all of the digital I/O, which are:
1.
2.
3.
4.
5.
6.
7.
SETIO labelname
CLRIO labelname
TOGGLEIO labelname
TESTIO (labelname)
SETBIT v,n
CLRBIT v, n
TESTBIT (v, n)
Each function has its own advantage depending on what needs to be done to a digital I/O. Each of these
functions is explained in the programmer’s reference manual, which should be referred to for further
information. Here are some examples of how to control digital I/O using these functions.
3.3.3 Example 1 – Turn on/off an Output
This can be done using both the SETBIT v,n / CLRBIT v,n command and the SETIO labelname / CLRIO
labelname command.
1.
Using SETBIT v,n / CLRBIT v,n
SETBIT OUTPUT[1], 0
CLRBIT OUTPUT[1], 7
2.
‘This will turn on the first output using the output[] register
‘This will turn off the 8th output using the output[] register
Using SETIO labelname / CLRIO labelname
SETIO out1
CLRIO out5
‘This will turn on the output out1
‘This will turn off the output out5
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Chapter 3
I/O and Internal Relays Programming
In this case, out1 and out5 would need to be entered in the I/O Table as an output. Otherwise, there will
be a compilation error.
3.3.4 Example 2 – Toggle an Output
TOGGLEIO light
‘This will change the output, light, from off to on or on to off
The output, light, would need to be entered into the I/O Table as an output as well and could represent
any desired output.
3.3.5 Example 3 – Test the Status of an Output
This can be done using both the TESTBIT (v, n) and TESTIO (labelname) command.
Using TESTBIT (v, n)
X = TESTBIT (INPUT[2], 1)
‘status of input #10 (on = 1, off = 0) is stored in variable X
Using TESTIO (labelname)
X = TESIO (button) ‘status of input button (defined in the I/O table) is stored in variable X
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Chapter 4
Chapter 4
Timers, Counters & Sequencers
Timers, Counters & Sequencers
Chapter 4
Timers, Counters & Sequencers
4 TIMERS, COUNTERS AND SEQUENCERS
4.1 Introduction
The Nano-10 PLC supports 64 timers with 0.1s or 0.01s time base, and 64 counters with range of 0 to
9999. You can define timer #1 to #n to become high speed timers (with 0.01s time base) by executing
the “HSTIMER n“ command (i.e. High Speed Timer always start from timer #1 up to timer #n).
4.1.1 Timer Coils
A timer is a special kind of relay that, when its coil is energized, must wait for a fixed length of time before
closing its contact. The waiting time is dependent on the "Set Value" (SV) of the timer. Once the delay
time is up, the timer's N.O. contacts will be closed for as long as its coil remains energized. When the coil
is de-energized (i.e. turned OFF), all the timer's N.O. contacts will be opened immediately. However, if
the coil is de-energized before the delay time is up, the timer will be reset and its contact will never be
closed. When the last aborted timer is re-energized, the delay timing will restart and use the SV of the
timer rather than continue from the last aborted timing operation.
4.1.2 Counter Coils
A counter is also a special kind of relay that has a programmable Set Value (SV). When a counter coil is
energized for the first time after a reset, it will load the value of SV-1 into its count register. From there on,
every time the counter coil is energized from OFF to ON, the counter decrements its count register value
by 1. Note that the coil must go through an OFF to ON cycle in order to decrement the counter. If the coil
remains energized all the time, the counter will not decrement. Hence, a counter is suitable for counting
the number of cycles an operation has gone through. When the count register hits zero, all of the
counter's N.O. contacts will be turned ON. These counter contacts will remain ON regardless of whether
the counter's coil is energized or not. To turn OFF these contacts, you have to reset the counter using a
special counter reset function [RSctr].
4.1.3 Sequencers
A sequencer is a highly convenient feature for programming machines or processes that operate in fixed
sequences. These machines operate in a fixed, clearly distinguishable step-by-step order, starting from
an initial step, progressing to the final step, and then restarting from the initial step again. At any moment,
there must be a "step counter" to keep track of the current step number. Every step of the sequence must
be accessible and can be used to trigger some action, such as turning on a motor or solenoid valve, etc.
As an example, a simple Pick-and-Place machine that can pick up a component from point 'A' to point 'B'
may operate as follow:
Step #
0
1
2
3
4
5
6
7
8
Action
Wait for "Start" signal
Forward arm at point A
Close gripper
Retract arm at point A
Move arm to point B
Forward arm at point B
Open gripper
Retract arm at point B
Move arm to point A
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Timers, Counters & Sequencers
4.2 Programming timers and counters on Ladder Logic
The timers and counters can be programmed in ladder logic in a few simple steps.
4.2.1 For Timers
1.
2.
3.
4.
Create/Edit the label names
Place the input contact(s) into the ladder logic circuit
Place the timer coil at the end of the ladder logic circuit
Place the timer contact in one or more ladder logic circuits
4.2.2 For Counters
1.
2.
3.
4.
Create/Edit the label names
Place the input contact(s) into the ladder logic circuit
Place the counter coil at the end of the ladder logic circuit
Place the counter contact in one or more ladder logic circuits (optional)
4.2.3 Example 1 – Creating a Simple Timer Circuit in Ladder Logic
You can place components in the circuit by clicking in the green area to the right of the red arrow, as
shown in Figure 4.1 below. This will bring up the component tool bar in the gray area above the green
circuit area.
Figure 4.1: Creating Timer Circuit
Once the component toolbar is shown, you can place your activating contact by selecting the #1
and then selecting the activating contact from the I/O Table. The
component from the toolbar
contact will then be automatically placed in the ladder logic circuit. The same can be done for the timer
and then selecting a timer that has been
coil by selecting the #7 component from the toolbar
entered into the I/O Table. Then a timer contact needs to be added as an input to a ladder logic circuit.
This contact will activate once the timer counts down. This could be used to turn on an output a certain
amount of time after the timer coil is activated. Placing a timer contact in a circuit is the same as placing
any contact in a ladder circuit, except that the corresponding timer should be selected from the “Timers”
section of the I/O table.
After creating a ladder circuit that contains one input and one timer output and another ladder circuit that
contains one timer contact and one output, the ladder logic circuit should like something like Figure 4.2,
below:
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Chapter 4
Timers, Counters & Sequencers
Figure 4.2: Completed Timer Circuit
4.2.4 Example 2 – Creating a Simple Counter Circuit in Ladder Logic
You can place components in the circuit by clicking in the green area to the right of the red arrow, as
shown in Figure 4.3 below. This will bring up the component tool bar in the gray area above the green
circuit area.
Figure 4.3: Creating Ladder Circuit
Once the component toolbar is shown, you can place your activating contact by selecting the #1
and then selecting the activating input from the I/O Table. The
component from the toolbar
contact will then be automatically placed in the ladder logic circuit. The same can be done for the counter
and then selecting a counter that has been
coil by selecting the #7 component from the toolbar
entered into the I/O Table. Then a counter contact needs to be added as an input to a ladder logic circuit.
This contact will activate once the counter counts down. This could be used to turn on an output after a
certain count is reached. Placing a counter contact in a circuit is the same as placing any contact in a
ladder circuit, except that the corresponding counter should be selected from the “Counters” section of
the I/O table.
After creating a ladder circuit that contains one input and one counter output and another ladder circuit
that contains one counter contact and one output, the ladder logic circuit should like something like Figure
4.4, below:
Figure 4.4: Completed Counter Circuit
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Chapter 4
Timers, Counters & Sequencers
4.3 Programming timers and counters in Custom Function
4.3.1 Programming Timers and Counters Present Values
The present values (PV) of the 64 timers and 64 counters in the PLC can be accessed directly as system
variables:
timerPV[1] to timerPV[64], for timers' present value
ctrPV[1] to ctrPV[64], for counters' present value
4.3.2 Accessing Inputs, Outputs, Relays, Timers and Counters Contacts
The bit addressable I/Os elements are organized into 16-bit integer variables TIMERBIT[n] and
CTRBIT[n] so that they may be easily accessed from within a CusFn. These I/Os are arranged as shown
in the following diagram:
4.3.3 Changing The Timer and Counter Set Values in a Custom Function
You can use the SetTimerSV and SetCtrSV functions to change the Set Value (SV) for a timer and
counter respectively. An example of this is shown below:
SetTimerSV 1,500
SetCtrSV 10,1000
‘Define Timer #1 to have a Set Value of 500
‘Define Counter #10 to have a Set Value of 1000
4.3.4 Volatility of Nano-10 Timer & Counter Set Values
It is important to know that, regardless of whether an FRAMRTC is installed, all the Set Values (SV) of
timers and counters in Nano-10 PLC are stored at special pseudo EEPROM areas reserved for storing
configuration data. We have described in detail how the pseudo EEPROM are implemented in the Nano10 PLC (see section 1.6.2). Although this pseudo EEPROM area for storing configuration data is
separate from the user-EEPROM area that you access with the SAVE_EEP and LOAD_EEP commands,
the underlying mechanism works the same way.
That is to say, if your TBASIC program changes the SVs using the SetTimerSV and SetCtrSV command,
the new SVs are only temporarily stored in the PLC RAM area until they are backup to the flash memory.
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Chapter 4
Timers, Counters & Sequencers
As described in section 1.6.2, the backup process only occurs when the PLC is reset, rebooted or when
the SETSYSTEM 252, 0 command has been executed. Therefore, if you want the new SVs to be
permanently stored in the PLC you will have to either run the SETSYSTEM 252, 0 command once, or
perform a software reset to backup these new data to the flash memory so that the changes can become
permanent.
4.3.5 Controlling a Timer or Counter in a Custom Function
You can activate a timer or a counter directly from within a custom function simply by assigning their
present value counter to a desired value.
E.g. To start a 50 seconds timer:
TIMERPV[2] = 500
‘ Timer #2 will time out 50.0 seconds later.
E.g. To decrement a counter or a sequencer:
CTRPV[10] = CTRPV[10] - 1 ‘ Counter #10 is decremented by 1.
4.4 Programming Sequencers on Ladder Logic
4.4.1 Introduction
TRiLOGI Version 6.xx supports eight sequencers of 32 steps each. Each sequencer uses one of the first
eight counters (Counter #1 to Counter #8) as its step counter. Any one or all of the first eight counters can
be used as sequencers "Seq1" to "Seq8".
To use a sequencer, first define the sequencer name in the Counter table by pressing the <F2> key and
scroll to the Counter Table. Any counter to be used by the sequencer can only assume label names
"Seq1" to "Seq8" corresponding to the counter numbers. For e.g. if Sequencer #5 is to be used, Counter
#5 must be defined as "Seq5". Next, enter the last step number for the program sequence in the "Value"
column of the table.
A circuit that uses the special function "Advance Sequencer" [AVSeq] will need to be constructed. The
first time the execution condition for the [AVseq] function goes from OFF to ON, the designated
sequencer will go from inactive to step 1. Subsequent changes of the sequencer's execution condition
from OFF to ON will advance (increment) the sequencer by one step. This operation is actually identical
to the [UPCtr] instruction.
The upper limit of the step counter is determined by the "Set Value" (SV) defined in the Counter table.
When the SV is reached, the next advancement of sequencer will cause it to overflow to step 0. At this
time, the sequencer's contact will turn ON until the next increment of the sequencer. This contact can be
used to indicate that a program has completed one cycle and is ready for a new cycle.
Accessing individual steps of the sequencer is extremely simple when programming with TRiLOGI.
Simply create a "contact" (NC or NO) in ladder edit mode. When the I/O window pops up for you to pick a
label, scroll to the "Special Bits" table as follow:
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Chapter 4
Timers, Counters & Sequencers
The "Special Bits" table is located after the "Counters" table and before the "Inputs" table. Click on the
"SeqN:x" item to insert a sequencer bit. You will be prompted to select a sequencer from a pop-up menu.
Choose the desired sequencer (1 to 8) and another dialog box will open up for you to enter the specific
step number for this sequencer.
Each step of the sequencer can be programmed as a contact on the ladder diagram as "SeqN:X" where
N = Sequencers # 1 to 8 and X = Steps # 0 - 31.
e.g.
Seq2:4 = Step #4 of Sequencer 2.
Seq5:25 = Step #25 of Sequencer 5.
Although a sequencer may go beyond Step 31, if you define a larger SV for it, only the first 32 steps can
be used as contacts to the ladder logic. Hence it is necessary to limit the maximum step number to not
more than 31.
Quite a few of the ladder logic special functions are related to the use of the sequencer. These are
described below:
4.4.2 Advance Sequencer - [AVseq]
Increment the sequencer's step counter by one until it overflows. This function is identical to (and hence
interchangeable with) the [UpCtr] function.
4.4.3 Resetting Sequencer - [RSseq]
The sequencer can also be reset to become inactive by the [RSseq] function at any time. Note that a
sequencer that is inactive is not the same as sequencer at Step 0, as the former does not activate the
SeqN:0 contact. To set the sequencer to step 0, use the [StepN] function described next.
4.4.4 Setting Sequencer to Step N - [StepN]
In certain applications it may be more convenient to be able to set the sequencer to a known step
asynchronously. This function will set the selected sequencer to step #N, regardless of its current step
number or logic state. The ability to jump steps is a very powerful feature of the sequencers.
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Timers, Counters & Sequencers
4.4.5 Reversing a Sequencer
Although not available as a unique special function, a sequencer may be stepped backward (by
decrementing its step-counter) using the [DNctr] command on the counter that has been defined as a
sequencer. This is useful for creating a reversible sequencer or for replacing a reversible "drum"
controller.
4.4.6 Program Example
Assume that we wish to create a running light pattern which turns on the LED of Outputs 1 to 4 one at a
time every second in the following order: LED1, LED2, LED3, LED4, LED4, LED3, LED2, LED1, all LED
OFF and then restart the cycle again. This can be easily accomplished with the program shown in Figure
4.5.
The 1.0s clock pulse bit will advance (increment) Sequencer #2 by one step every second. Sequencer 2
should be defined with Set Value = 8. Each step of the sequencer is used as a normally open contact to
turn on the desired LED for the step. A "Stop" input resets the sequencer asynchronously. When the
sequencer counts to eight, it will become Step 0. Since none of the LEDs are turned ON by Step 0, all
LEDs will be OFF.
Figure 4.5
4.5 Programming Sequencers in Custom Function
You can change the current step of Sequencer easily from within a Custom Function by changing the
present value of their equivalent counter. E.g. Sequencer #3 is the same as Counter #3, thus if you wish
to assign Sequencer #3 to Step 10, you can achieve it as follows:
CTRPV[3] = 10
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Chapter 5
Chapter 5
Analog Inputs
Analog Inputs
Chapter 5
Analog Inputs
5 ANALOG INPUTS
5.1 Analog Power Supply
The analog power of the PLC is derived from the same 24VDC power supply as the CPU. It will generate
a 5V regulated DC voltage source that will be used internally as voltage reference and is available
externally for use by other analog input devices. The reference voltage output is available on the analog
I/O connector terminal block, and may be used as the source voltage for connecting to potentiometers. Its
current is limited to 30mA. Thus if you need more current for your analog device, you will need to supply
your own +5V DC source.
5.2 Analog Inputs
Each Nano-10 has two channels of built-in 0-5V, 12-bit Analog inputs. The terminal block location for
these analog inputs is described in Section 1.2.1.
Electrical Characteristics
No. of A/D channel
Resolution
Input Impedance
Ch #1 to 2
Moving Average
Conversion Time
2
12-bit
20.00K Ohms
1 to 9 points (user definable)
< 4 μs per channel.
ADC(n) value
4095
4094
4093
3
2
1
0
0
Input Voltage
5.00
Figure 5.1 Transfer Function for 12-bit ADC.
The DC input impedance of Analog inputs #1 to 2 are all 20.00K ohms (0.1%). This is not a problem
when connected to a 0-5V low impedance analog source.
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Analog Inputs
However, if you need to connect to 0-10V inputs or a 4-20mA analog source to either channel, you have
to take into consideration the low A/D input impedance in your design. The following figures show how to
connect 4-20mA current source signals and 0-10V signals to the A/D inputs #1 to 2.
:
A/D #1 - #2
0-20mA or
4-20mA
Current loop
A/D #1 - #2
V1 : 0-10V
V2 :0-5V
R1=20.0KΩ 0.1%
250Ω 1%
0.0 - 5.0V or
1.0 - 5.0V
Internal
20.00K
Internal
20.00K
3.16Ω 1%
Analog
0V
Analog
0V
Converting 20mA current-loop to 0-5V
Converting 0-10V signal to 0-5V
Figure 5.1
You can see that interfacing to a 0-10V analog signal is extremely simple since all you need is to add a
20.0K ohm series resistor and it will be divided into 0-5V when it enters the AD #1 or #2
However, to convert a 0-20mA or 4-20mA current source into 0-5V or 1-5V voltage signal, you should use
a 253.16 ohm resistor which, when paralleled with the 20K ohm of internal impedance, will yield a 250.0
ohm total resistance. You can obtain 253.16 ohm by combining a 250 ohm and a 3.16 ohm metal-film
resistor.
5.2.1 Interfacing to two-wire 4-20mA sensors
Many 4-20mA analog sensors only have two wire connections and are designed to be powered by the 420mA output current that flows through it. These types of sensors can be interfaced easily to the 0-5V
analog inputs of the PLC as shown in the following diagram:
5-2
Chapter 5
Analog Inputs
PLC’s V+
V+
24V
P.S. for PLC
And Sensors
+
4-20mA
Sensor
ADC Input
253.16 Ω
0V
*
PLC’s 0V
Use a 250.0 + 3.16 ohm resistors in series to obtain 253.16 ohm.
Again due to the 20.00K ohm internal resistance on the PLC’s ADC inputs, you need to wire a 253.16
ohm resistor (formed by a 250 ohm and 3.16 ohm resistors in series) to the circuit in order to convert the
4-20mA signal to 1.00-5.00V analog voltage and can be read by the PLC using the ADC(n) statement,
which will return readings of between 819 and 4095.
5.2.2 Using Potentiometer to Set Parameters
A potentiometer can provide a very low cost means for users to input parameters to the PLC such as
temperature settings, timer or counter preset values, etc. The diagram above shows how easy it is to
implement such a device using the 5V reference output and an analog input. Very accurate parameters
can be set if an external LCD display (e.g. MDS100-BW) is used as visual feedback of the settings.
Alternatively, a paper scale can be printed to give approximate set value at various angles of the
potentiometer’s rotating arm.
A/D#1 to 8
10KΩ
Potentiometer
+5V
GND
Figure 5.2
5.2.3 Reading Analog Input Data
The 2 analog input signals are read by the TBASIC command ADC(1) to ADC(2). The ADC(n) function
will return a number between 0 and 4095 (12-bit resolution), which corresponds to the measured voltage
at any of the analog inputs n. The resolution of a 12-bit ADC is 1/4096, this means that for the 0-5V ADC
range, the resolution is 5/4096V = 1.22mV.
That means that if you apply a 2.500V to the PLC’s analog input #3, ADC(3) should return a value of
2.500/5.000 x 4096 = 2048.
Note that the CPU only accesses the analog input #n when the TBASIC function ADC(n) is called. Hence,
in order to monitor the analog input, you have to execute the ADC function periodically. The frequency
that the ADC function is called is known as the “sampling rate” and it depends on how fast the analog
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Analog Inputs
data changes. If the analog data changes slowly (such as room temperature) then there may be no need
to sample the analog at high frequency.
A very simple example of sampling the analog input #1 to #2 every second and converting the data into
voltage readings of 0 to 5000 (which represents 0 to 5.000V) is shown as follow:
Figure 5.3
You can examine the readings of DM[11] to DM[12] from the “Online Monitoring - View Variables-DM[n]”
screen. These readings represent the voltages measured at the analog input pins. You can also read the
raw ADC readings (which will change in the range between 0 to 4095) from the “View Variables - integer”
screen.
5.2.4 Moving Average
The Nano-10 PLC offers a built-in “Moving Average” computation routine for each ADC channel. When
moving average is enabled the PLC firmware would store the past analog readings for each channel in its
own historical memory array, and each new instantaneous reading would overwrite the oldest reading.
When you run the ADC(n) function, the PLC firmware would return the average of these past readings
instead of the instantaneous new reading.
You can define a moving average of 1 to 9 points using the procedure described in Section 5.4.3
Defining a larger moving average can better help to even out fluctuations in ADC readings that can be
caused by interference from digital noise. However, the larger the moving average, the slower the ADC(n)
function can detect a sudden change in the amplitude of the analog signal due to the averaging effect.
For a system that needs to quickly detect a signal change, consider using either a smaller number of
moving average points or call the ADC(n) function more frequently so that a sudden change can be
detected earlier.
5.2.5 Scaling of Analog Data
The 12-bit analog inputs on the Nano-10 PLC returns data in the range of 0 to 4095, which corresponds
to the full range of the voltage input presented at the analog pin. However, very often a user needs a
formula to translate this numeric data into units meaningful to the process (e.g. degree C or F, psi
etc). To do so, you need to know at least two reference points of how the native unit maps to the PLC's
ADC reading.
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Chapter 5
Reference Point
x1
x2
Analog Inputs
ADC Reading
a1
a2
Hence, for any reading A = ADC(1), the corresponding X is derived from:
X - x1
⎯⎯⎯⎯⎯
x2 - x1
=
A - a1
⎯⎯⎯⎯
a2 - a1
==> X = (x2 - x1)*(A - a1)/(a2 - a2) + x1
Note that since x1, x2, a1, and a2 are all constants the actual formula is much simpler then it appears
above.
E.g. Temperature measurement
ADC(n)
Temp
200
30o
3000
100o
So for any ADC readings A, the temperature is:
X = 70*(A - 200)/2800 + 30
Note: To get better resolution , you can represent 30 degree as 300 and 100 degree as 1000 so if X =
123 it means 12.3 degree.
5.3 Temperature Measurement Using Analog Inputs
5.3.1 Thermistor Temperature Sensors
A thermistor is a kind of resistor whose resistance decreases when its surrounding temperature
increases. It is a very low cost and stable device that can be used to measure a wide range of ambient
temperature from freezers to hot water boilers, which are commonly used in HVAC applications.
In order to convert the resistance changes into voltage readings to be read by the PLC’s analog input,
you can use it to form an arm of a voltage divider circuit which would present a variable voltage to the
analog input when the temperature changes. A type of thermistor that measures 10.0K ohm at 25 degree
C (simply called 10K thermistor) is especially suitable for use with the Nano-10 PLC because you can
simply connect the 10K thermistor directly to the analog input due to its internal impedance of 20.00K
ohm (0.1% accuracy).
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Analog Inputs
A/D #1 - #2
+5V
10K Thermistor
Internal
20.00K
Analog
0V
Figure 5.6: Connecting 10K Thermistor to NANO-10 ADC# 1-2
Note that since the thermistor resistance value vs. temperature change is a non-linear function, you
cannot simply use a formula to calculate the temperature from the voltage value. For better accuracy you
need to use a look up table plus a linear interpolation technique to determine the temperature based on
the ADC readings. The look up table and interpolation method can be implemented using TBASIC quite
easily. For your convenience, we have provided a sample TBASIC program that you can download from
the following URL:
http://www.tri-plc.com/appnotes/Nano10/ThermistorSensor.zip
This example uses the R-T (Resistance-Temperature) graph of the Precon Type III thermistor to
implement the temperature look up. We have provided an Excel file that computes the ADC reading vs
ambient temperature for this thermistor type. The TBASIC program uses these ADC readings to
determine the temperature.
The sample program is structured such that the lookup table values are stored in DM area and you can
readily adapt it to other types of thermistors with a different R-T graph. The program only implements
lookup for a temperature range of –10oF to 110oF, but you can also easily change the temperature range
of interest.
5.3.2 Using LM34 Semiconductor Sensor
Figure 5.4
The LM34 is a wonderful, low cost semiconductor temperature sensor with a range of –50 oF to 300 oF. It
is extremely easy to use for measuring temperature above 0 oF. You simply connect one pin to the
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Analog Inputs
positive voltage (+5 to +30V) and the other pin to 0V, and the signal pin will output a voltage that is
directly proportional to the ambient temperature in oF. The output voltage is 10mV per degree F.
So at room temperature of 72 degrees F, the device will output a voltage of 72 x 0.01 = 0.72V. If you
connect this to the PLC’s analog input, you can obtain the temperature in degree F or degree C using the
formula:
OR
F = ADC(1)*500/4096
C = (F – 32)*5/9
‘ in degree F
‘ in degree C
Although another part number LM35 can output temperature in 10mV per degree C, the output falls into
even lower ADC range for ambient temperature measurement since the same 72 degree F is only 22
degree C, which means LM35 only outputs 22 x 0.01 = 0.22V. Hence for better accuracy and resolution
we recommend using LM34 instead of LM35 and if need be then convert it to degree C using TBASIC.
o
Another advantage for using LM34 instead of LM35 is that you can measure down to 0 F (-17 degree C)
without using a negative voltage source as shown in the circuit on the right in Figure 5.5.
5.3.3 Using Thermocouple
Thermocouples are very rugged devices that are widely used in the industry because of their stability,
accuracy, and wide functional temperature range. They are commonly used in measuring temperature in
ovens that may go up to several hundred degrees C.
However, thermocouple output signals are in the range of tens of microvolts to mille-volts, which is too
small to be measured by the Nano-10’s analog input directly. You will need a “signal conditioner” that can
amplify the thermocouple output to 0-5V, which can then be connected to the PLC’s analog input.
5.3.4 Using PT100 Temperature Sensor
PT100 is a positive temperature coefficient thermistor that is made from platinum. It has the advantage of
being very stable and highly accurate. It is usually connected to a signal conditioner in a balanced bridge
configuration and the signal conditioner will convert temperature changes to 0-5V output for the PLC.
5.4
Calibration of ADC & Moving Average Definition
The ADC on the Nano-10 are factory-calibrated such that a voltage of 2.500V should return a value of
2048 when read by the ADC(n) function. However, if there is a need to re-calibrate the ADC you can
follow the procedure outlined below.
To perform calibration of an ADC channel, you need to supply a precise DC voltage to the ADC channel,
and then check the analog readings obtained via the ADC(n) function and compare it to the expected
value. If there is an error, you can apply a correction factor to it.
To perform the ADC calibration, you would need to use the “Ethernet Configuration Tool” mentioned in
Chapter 2.1. Click on the “Advanced” button on the Basic Configuration screen and open the “Advanced
Configuration” screen. The bottom half of the screen contains ADC and DAC calibration constants that
you can enter and transfer to the PLC, as shown below:
5-7
Chapter 5
Analog Inputs
Figure 5.6
5.4.1 ADC Calib.
These fields are used to apply a multiplication factor to the value returned by ADC function. The
multiplication factor = (1+ x/10000).
Example 1:
If you apply 2.500V to ADC #1, you would expect the value returned by ADC(1) to be
2048. But the actual average reading centers around 2060.
Proportional Error = 2060/2048 = 1.005859
Multiplication factor required to correct this error = 1/1.005859 = 0.9942 = (1 – 58/10000)
=> x = -58
You should therefore enter a value of 58 into the “ADC Calib” field for Ch #1 and save it to the PLC.
After the PLC has rebooted, the CPU would apply the multiplication factor of 0.9942 to the readings it
received, which would correct the reading to: 2060 x 0.9942 = 2048.
Example 2:
If you apply 4.000V to ADC #2, you would expect the ADC(2) function to return a value of
4.000/5.000 x 4096 = 3277. However, your program returned a value of 3230 from ADC(2).
Proportional Error = (3230)/3277 = 0.985658
Multiplication factor required to correct this error = 1/0.985658 = 1.0146 = (1+ 146/10000)
=> x = +146
To compensate for this error, enter a value of 146 in the “ADC Calib.” for Ch 2 and save it
to the PLC.
After the PLC has rebooted, the CPU would apply the multiplication factor of 1.0146 to the readings it
received, which would correct the reading to: 3230 x 1.0146 = 3277.
Notes:
1) We have created an MS-Excel spreadsheet file “AnalogCalibration.xls” to facilitate the
computations of the correction factor, X, used in the ADC and DAC Calibration of F-series PLC.
The same file can also be used to compute the calibration factor for the Nano-10. This file can be
downloaded from the following web page:
http://www.tri-plc.com/appnotes/F-series/AnalogCalibration.xls
5-8
Chapter 5
Analog Inputs
2) Changes to the ADC calibration data only take effect after the PLC has been cold-booted. You
can either power cycle the PLC or simply check the “Reboot PLC After Save” checkbox and the
PLC will re-boot after you have transferred the parameters to it.
5.4.2 ADC Zero Offset
ADC(n) value
4095
4094
4093
3
Zero
Offset
2
1
0
0
Input Voltage
5.00
Figure 5.7
The zero offset error can be corrected by entering a value into the “ADC Zero Offset” field. Any number
between –100 and 100 can be entered here. The ADC(n) function would add the zero-offset value that
you entered here to the measured value and return the total sum to the calling routine.
5.4.3 A/D Moving Avg
This field lets you define the number of points of moving average that the Nano-10 CPU firmware uses to
compute the value returned by the ADC(n) function (Please see explanation of moving average in Section
5.2.5).
A larger number of moving Average points has the positive effect of filtering out large noise spikes seen
at the analog input, but the disadvantage is that the PLC would be slower in noticing a sudden step
change at the analog input. If you specify a moving average of 1 point, that means no moving average will
be used and the ADC(n) function will return the most recently sampled data at the analog input #n.
5-9
Chapter 6
Chapter 6
Special Digital I/Os
Special Digital I/Os
Chapter 6
Special Digital I/Os
6 SPECIAL DIGITAL I/OS
All of the 4 digital inputs of the Nano-10 PLC can be configured as “special inputs” such as High Speed
Counters, Interrupts and Pulse Measurement. 2 of the 4 digital outputs can also be configured as PWM,
or stepper motor controller pulse-outputs. If these are not used as special I/Os, then they can be used as
ordinary ON/OFF type I/O in the ladder diagram. The High Speed Counters and Pulse measurement
inputs share physical inputs, but they can be used simultaneously as HSC and PMON (unlike M-Series).
Note that if any other two special functions share the same I/O then only one of them can be active at any
one time. The location of these special I/Os are tabulated as follows:
Special Inputs
Input #
1
2
3
4
High Speed Counter
Ch #1: Phase A
Ch #1: Phase B
Ch #2: Phase A
Ch #2: Phase B
Interrupt
Ch #1
Ch #2
Ch #3
Ch #4
Pulse Measurement
Ch #1
Ch #2
Ch #3
Ch #4
Note: While inputs 1-4 can be used simultaneously as High Speed Counters and Pulse Measurement
pins, any pins defined as interrupts can only be interrupts.
Special Outputs
Output #
1
2
3
4
Stepper Pulse/Dir outputs
Ch #1 Direction
Ch #1 Pulse
-
PWM output
Ch #1
Ch #2
-
These special I/Os therefore share the same electrical specifications as the ON/OFF type I/Os, which
have already been described in the Chapter 1 - Installation Guide. We will describe each of these special
I/Os in greater details in the following chapters.
6-1
Chapter 7
Chapter 7
High Speed Counters
High Speed Counters
Chapter 7
High Speed Counters
7 HIGH SPEED COUNTERS
Technical Specifications:
No. of Channels
Maximum acceptable pulse rate
Quadrature signal decoding
Relevant TBASIC Commands
2
10KHz per channel
Automatic
HSCDEF, HSCOFF, HSCPV[ ]
7.1 Introduction
Digital inputs #1 + 2, #3 + 4, form two channels of high speed counter inputs which can interface directly
to a rotary encoder that produces “quadrature” outputs. A quadrature encoder produces two pulse trains
at a 90o phase shift from each other as follows:
Direction of Rotation
90
o
Phase A
Phase B
90
o
Direction of Rotation
Figure 7.1
When the encoder shaft rotates in one direction, phase A leads phase B by 90 degrees. When the shaft
rotates in the opposite direction, phase B will lead phase A by 90 degrees. The quadrature signals
therefore provide an indication of the direction of rotation.
The F-Series PLC handles the quadrature signals as follows: if the pulse train arriving at input #1 leads
the pulse train at input #2, the High Speed Counter (HSC) #1 increments on every pulse. If the pulse train
arriving at input #1 lags the pulse trains at input #2, then the HSC #1 decrements. Note that if input #2 is
OFF, then pulse trains arriving at input #1 are considered to lead the input #2 and HSC #1 will be
incremented. Likewise if input #1 is OFF, then pulse trains arriving at input #2 will decrement HSC #1.
Inputs #3 and #4 form the inputs for High Speed Counter channel #2,
as HSC#1 described above.
which operates in the same way
The fact that the Nano-10 PLC automatically takes care of the direction of rotation of the quadrature
encoder greatly simplifies the programmer’s task of handling high-speed encoder feedback. The
HSCDEF statement can be used to define a CusFn to be executed when the HSC reaches a certain predefined value. Within this CusFn you can define the actions to be taken and define the next CusFn to be
executed when the HSC reaches another value. Please note that the HSDDEF statement will also
activate the Pulse Measurement hardware as described in the Pulse Measurement section.
A programming example of the HSC can be found in your iTRiLOGI program folder:
C:\TRiLOGI\TL6\usr\samples\HighSpeedCtr.PC6
7-1
Chapter 7
High Speed Counters
7.2 Enhanced Quadrature Decoding
The default method in which the PLC handles quadrature signals as described above is somewhat
simplistic. It does not take into consideration the “jiggling” effect that occurs when the encoder is
positioned at the transition edge of a phase. Mechanical vibration could cause multiple counts if the rotor
shaft “jiggles” at the transition edge of the phase, resulting in multiple triggering of the counter. This
simplistic implementation, however, does have the advantage that the HSC can also be used for singlephase high-speed counting.
For the Nano-10 PLC, an enhanced quadrature decoding routine is provided which will lock out multiple
counting by examining the co-relationship between the two phases. You can configure the Nano-10 PLC
to use the enhanced quadrature counting by using the SETSYSTEM command, as follows:
SETSYTEM 4, n
The value of n at bit 0, 1, and 2 respectively defines if the HSC channel 1, 2, and 3 is to run in “Simple”
(when the bit is 0) or “Enhanced” (when the bit is 1) mode. As such:
N (bit 1,0)
0 (00)
1 (01)
2 (10)
3 (11)
HSC #2
Simple
Simple
Enhanced
Enhanced
HSC #1
Simple
Enhanced
Simple
Enhanced
7.3 Configuring HSC as x1, x2 or x4 Counters
By default the HSC in Nano-10 only increment or decrement the counter by 1 for each full cycle of pulses.
However, since there are two pulse trains and therefore a full cycle produces 4 rising and falling edges in
total. It is possible to configure the HSC to either count by 1 for every two transition edges (x2) or to count
every transition edge (x4).
A new, special SETSYSTEM 24,N command can be used to configure the 2 channels of HSCs on the
Nano-10 PLC so that they can become simple, x1, x2 or x4 quadrature high speed counters. This new
command (not available to T100M+ PLCs) overwrites the settings performed by SETSYSTEM 4, xx
mentioned in Section 7.2 and is the new, preferred method for configuring the HSC channel.
N
E.g.
is defined as a two-byte integer:
Upper byte : channel number (&H01 or &H02)
Lower byte : &H00 =simple; &H01=x1; &H02=x2;
To define HSC #1 as x2 HSC, N =
To define HSC #2 as x4 HSC, N =
&H03= x4
&H0102
&H0203
An example program: “HSC-x4.PC6” that uses this command is included in the “Nano10Samples.zip” file
that you can download from: http://www.tri-plc.com/trilogi/Nano10Samples.zip.
7-2
Chapter 7
High Speed Counters
7.4 Interfacing to 5V type Quadrature Encoder
If you have a choice, you should select an encoder that can produce 12V or 24V output pulses so that
they can drive the inputs #1,2,3,4 directly. If you have a 5V type of encoder only, then you need to add a
transistor driver to interface to the PLC’s inputs. The simplest way is to use an IC driver ULN2003
connected as shown in Figure 7.2.
+5V
ULN2003A
5V Phase A
1
16
5V Phase B
2
15
Input #3
Input #4
T100MD1616+
1.1.1.1 Nano-10
PLC
Encoder
8
GND
PLC’s 0V terminal
0V
Figure 7.2
Interfacing 5V type Rotary Encoder
7-3
Chapter 8
Chapter 8
Frequency / Speed Measurement
Frequency / Speed Measurement
Chapter 8
Frequency / Speed Measurement
8 FREQUENCY / SPEED MEASUREMENT
The Nano-10 PLC provides a very straightforward means to measure the pulse width (of the ON cycle),
the frequency, or the period of a rectangular-wave pulse-train arriving at its Pulse Measurement (PM)
inputs #1,2,3,4. (Which are mapped to digital inputs #1 to #4 – see Chapter 6).
8.1 Programming of PM Input
1) To use the PM input to measure pulse width or frequency, execute the PMON statement ONCE
to configure the relevant input to become a pulse measurement input. You usually put the PMON
statement in the init custom function and execute it with a “1st.Scan” pulse.
2) Thereafter the pulse width (in μs) or the pulse frequency (in Hz) can be easily obtained from the
PULSEWIDTH(n) or PULSEFREQUENCY(n) functions. You can also obtain the pulse period
(inverse of frequency) using the PULSEPERIOD function.
E.g.
A = PULSEWIDTH(1)
B = PULSEPERIOD(1)
C = PULSEFREQUNCY(1)
3) All PM inputs by default return the measured pulse width and pulse period in unit of microsecond.
However, for those who desire better resolution, you can define PM #1 to #4 to return the
measured pulse width and pulse period in 0.1 microsecond resolution by executing the following
command once only during initialization:
SETSYSTEM 20, 1
Once the above statement is executed, if PUSLEWIDTH(1) - PULSEWIDTH(4)
value 1234 it means the measured pulse width is 123.4 μs.
returns the
A sample program can also be found on your i-TRiLOGI installation folder at:
C:\TRiLOGI\TL6\usr\samples\PulseMeasurement.PC6
8-1
Chapter 8
Frequency / Speed Measurement
8.2 Applications
+24V
NPN type
Optical
Sensor
Input #3
Nano-10 PLC
T100MD
PLC
Motor
0V
Figure 8.1
Setting Up a
Simple Tachometer or Encoder
8.2.1 Measuring RPM Of A Motor
One useful application of the PM capability is to measure the speed of rotation (RPM) of a motor. A
simple optical sensor, coupled with a rotating disk with slots fitted to the shaft of a motor (See Figure
8.1) can be fabricated economically. When the motor turns, the sensor will generate a series of pulses.
The frequency of this pulse train directly measures the rotational speed of the motor (RPM = Frequency x
60) and can be used to provide precise speed control.
Note that the above setup can also double as a low cost position-feedback encoder when used with the
high speed counter, since the number of pulses counted can be used to determine the displacement.
With the Nano-10 PLC, the pulses can be both counted and measured simultaneously on the same
input.
8.2.2 Measuring Transducer with VCO Outputs
Some transducers incorporate a Voltage-Controlled-Oscillator (VCO) type of output that represents the
measured quantities in terms of varying frequency of the output waveform. Such transducers may be
used conveniently by the Nano-10 PLCs using the pulse measurement capability. However, the
frequency of such signals should be below the maximum input pulse rate.
8.2.3 Measuring Transducer with PWM Outputs
Some transducers may output the readings of their measurands (the quantity that is being measured) in
the form of “pulse-width modulated” outputs. This means that the transducer would send rectangular
pulses with varying duty cycles that are proportional to the measured quantities. You can then easily use
the PULSEWIDTH and PULSEPERIOD functions to compute the duty cycle of the incoming PWM pulses
and readily convert it to the actual units of the measurands. The Nano-10 PLC should be able to measure
with reasonable accuracy the pulse width of incoming pulses not exceeding 10KHz.
8-2
Chapter 8
Frequency / Speed Measurement
8.3 Frequency Measurement on High Speed Counter Inputs
For applications that require frequency measurement and pulse counting of the same signal, you only
need to feed the pulse input into any pair of the inputs #1 & 2, or inputs #3 & 4, or inputs #5 & 6 and
define it as a High Speed Counter (see Chapter 7). This is because an input pin that has been defined as
an HSC will automatically be enabled for pulse measurement.
In other words, if you need to use the HSC and the Pulse Measurement on the same channel, then you
don’t execute both the HSCDEF and PMON, you only need to execute the HSCDEF. The HSCDEF
function will automatically start the Pulse Measurement hardware so it is not necessary to use the PMON
statement. If you use only the PMON statement, it would not enable the HSC function. However, if you
execute the HSCDEF statement and followed by the PMON statement, the HSC will be disabled, even
though it was previously enabled.
8-3
Chapter 9
Chapter 9
Interrupts
Interrupts
Chapter 9
Interrupts
9 INTERRUPTS
9.1 Input Interrupts
During normal PLC ladder program execution, the CPU scans the entire ladder program starting from the
first element, progressively solving the logic equation at each circuit until it reaches the last element.
After which it will update the physical Inputs and Outputs (I/O) at the end of the scan. Hence, the location
of a logic element within the ladder diagram is important because of this sequential nature of the program
execution.
When scanning the ladder program, the CPU uses some internal memory variables to represent the logic
states of the inputs obtained during the last I/O refresh cycle. Likewise, any changes to the logic state of
the outputs are temporarily stored in the output memory variable (not the actual output pin) and will only
be updated to the physical output during the next I/O refresh.
You can see that the CPU will only notice any change to the input logic state when it has completed the
current scan and starts to refresh its input variables. The input logic state must also persist for at least
one scan time to be recognized by the CPU. In some situations this may not be desirable because any
response to the event will take at least one scan time or more.
An interrupt input, on the other hand, may occur randomly and the CPU will have to suspend whatever it
is doing as soon as it can and start “servicing” the interrupt. Hence, the CPU responds much faster to an
interrupt input. In addition, interrupts are “edge-triggered”, meaning that the interrupt condition occurs
when the input either changes from ON to OFF or from OFF to ON. Consequently, the input logic state
need not persist for longer than the logic scan time for it to be recognized by the CPU.
Any one or all of the Nano-10’s digital inputs #1 to #4 can be defined as interrupt inputs using the
INTRDEF statement. The Interrupt inputs may also be defined as either rising-edge triggered (input goes
from OFF to ON) or falling-edge triggered (input goes from ON to OFF), or both using the following
statement:
INTRDEF ch, fn_num, edge
parameters:
ch
= channel number
fn_num = Custom Function # to execute when interrupt edge occurred.
This is the Interrupt Service Routine (ISR)
edge
= +1 :rising edge-triggered,
-1 :falling edge-triggered
0 : both rising and falling edge-triggered.
When the defined edges occur, the defined CusFn will be immediately executed irrespective of the
current state of execution of the ladder program.
9-1
Chapter 9
Interrupts
A simple interrupt test function is as follow:
Variable A will be incremented on every rising edge
sensed on Input #9 (not available on Nano but
available on F-series PLCs).
Note:
1) Since inputs 1 to 4 can also be used as other special inputs such as High Speed Counter
(HSC) inputs and/or Pulse Measurement (PM) as described in Chapter 6, 7 and 8, if these
inputs are defined as interrupts using the INTRDEF statement, then they will lose their other
special function. i.e., they can only be defined either as a HSC/PM or as an interrupt input and
not both.
2) When the digital inputs are used as interrupt inputs, the PLC operating system does not
perform software filtering on these inputs. That means these interrupt inputs are extremely
sensitive and will trigger the interrupt service routine even with the shortest input pulse.
While the high sensitivity could be useful for some applications that need to capture events
that produce very short, sharp pulses, it could be problematic for other applications that need
to filter out such narrow pulses since they can trigger the interrupt inputs multiple times. You
can add in some hardware filtering by connecting a small, 100pF (or large capacitor) across
the interrupt input and the power supply ground (0V).
9.2 Periodic Timer Interrupt
(PTI)
The Periodic Timer Interrupt (PTI - not available on T100M+ PLC) lets you define a custom function that
will be executed by the CPU precisely every x number of milliseconds (ms). The syntax for setting up a
PTI is as follow:
INTRDEF 18, cfnum, x
cfnum
x
E.g.
-
‘ Interrupt 18 is reserved for PTI
custom function number to execute when PTI event takes place.
The period in number of milliseconds between two PTI events.
INTRDEF 18, 101, 15
‘ call function #101 every 15 ms.
The Periodic Timer Interrupt runs independently of the ladder logic and its execution is therefore not
affected by the total PLC program scan time.
9-2
Chapter 9
Interrupts
When the PTI timer times up, the CPU will suspend the execution of the ladder logic or a (non-interrupt)
TBASIC function and immediately calls up the custom function defined by the INTRDEF 18 statement.
However, if the CPU is currently executing a user-interrupt service routine (e.g. an input interrupt or HSC
interrupt), then the CPU will have to complete the current interrupt service routine before it will run the PTI
interrupt function.
Notes:
1) Limit the use of PTI only for critical code that requires precise timing between two events.
Program bugs that occur due to problems in the PTI interrupt routine may be quite hard to debug.
2) For normal periodic routines, such as checking for temperature or checking serial port for
incoming bar code data every few seconds, it is better to use the system clock pulses e.g.
“Clk:1.0s” to trigger a {dCusF}.
3) Always try to keep your interrupt service routine short and simple and ensure that it will not end
up in an endless loop. The TBASIC custom function execution time should be much shorter than
the period of the PTI events. Otherwise, you may find that the CPU will be spending most of its
time servicing the PTI interrupt routine, leaving very little time for scanning the ladder program,
and that will have an adverse impact on the CPU performance.
9.3 Power Failure Interrupt (PFI)
The Nano-10 CPU has a built-in power failure sensing circuit that will call a custom function when it
detects an impending power failure. This allows you to perform such critical function such as
saving critical data to the PLC’s non-volatile memory (see Section 1.6.2) just before power failure.
The syntax for the PFI is as follow:
INTRDEF 17, cfnum, 1
cfnum
E.g.
-
‘ Interrupt 17 is reserved for PFI
custom function number to execute when PTI event takes place.
INTRDEF 17, 256, 1
‘ call function #256 when power failure occur.
9-3
Chapter 10
Chapter 10
Stepper Motor Control
Stepper Motor Control
Chapter 10
Stepper Motor Control
10 STEPPER MOTOR CONTROL
10.1 Technical Specifications:
No. of Channels (control signal)
Max. Pulse Rate (pps)
Continuous Current per phase
Driver Breakdown Voltage
Velocity Profile
(Defined by STEPSPEED)
Maximum number of steps
TBASIC commands
1
10000
2A @24V DC
+55V
Trapezoidal
-accelerate from 1/8 max pps to max pps.
-decelerate from max pps to 1/8 max pps)
2 ~ 231 (= 2.1 x 109)
STEPSPEED, STEPMOVEABS, STEPCOUNTABS( ),
STEPMOVE, STEPSTOP, STEPCOUNT( )
It is essential to understand the difference between a stepper motor “Controller” and a stepper motor
“Driver”. A stepper motor “Driver” comprises the power electronics circuitry that provides the voltage,
current, and phase rotation to the stepper motor coils. A stepper motor controller, on the other hand, only
supply the direction and output a number of pulses to an external stepper motor driver to actually drive
the stepper motor.
Since the Nano-10 PLC only has two high speed digital outputs, the PLC is only capable of acting as
stepper motor controller to supply the direction and pulse control signals to an external stepper motor
driver.
10.2 Nano-10 As Stepper Motor Controller
When configured as a Stepper-Motor Controller, the PLC would generate the required number of "pulses"
and sets the direction signal according to the defined acceleration and maximum pulsing rate specified by
"STEPSPEED" and “STEPMOVE” commands. The "pulse" and “direction” outputs are not meant to be
connected directly to the stepper motor. Instead, you will need a stepper motor "driver", which you can
buy from the motor vendor. Depending on the power output, the number of phases of the stepper motor,
and whether you need micro-stepping, the driver can vary in size and cost. Most stepper motor drivers
have opto-isolated inputs which accept a direction signal and stepping-pulse signal from the "Stepper
Motor Controller". In this case the F-Series PLC is the "Stepper Motor Controller" which will supply the
required pulse and direction-select signals to the driver.
Note that the digital output #1 automatically becomes the direction-select signals for the Stepper
controller channels #1 and digital output #2 automatically becomes the pulse signal output when the
stepper controller is being used. The direction pin is turned ON when the motor moves in the negative
direction and turned OFF when the stepper motor moves in the positive direction. The STEPMOVEABS
command makes it extremely simple to position the motor at an absolute location, while the STEPMOVE
command lets you implement incremental moves in either direction for each channel.
10-1
Chapter 10
Stepper Motor Control
10.2.1 Interfacing to 5V Stepper Motor Driver Inputs
Some stepper motor drivers accept only 5V signals from the stepper motor controller. In such a case, you
need to determine whether the driver’s inputs are opto-isolated. If they are, then you can simply connect
a 2.2K current limiting resistor in series with the path from the PLC’s output to the driver’s inputs, as
shown in Figure 10.1.
Stepper Motor Driver
Direction Select Input
Nano-10 PLC
24V DC
Power
for PLC
S
R
2
OUTPUTS
0V
If
R
1
+V
Stepping Pulse Input
3
Calculation :
IF = 10mA
4
If
R = (V - 5)/0.01
e.g. for V=24V,
R = (24-5)/0.01 =1.9K
GND
Select R=2K2
Rating = 19 2/2200
= 0.16W
Use 0.5W resistor.
+24V
PLC’s Power Supply
GND
Figure 10.1
However, if the stepper motor driver input is only 5V CMOS level and non opto-isolated, then you need to
convert the 24V NPN PLC outputs to 5V. This can be achieved using a low cost transistor such as a
2N4403. A better way is to use an opto-isolator with a logic level output, as shown in Figure 10.2. This
provides a galvanic isolation between the PLC and the stepper motor driver.
+5V 0V (Stepper’s supply)
+V
24V DC
Power Supply 0V
for PLC
Logic output
Optoisolator
H11L2
or H11L3
(Quality Technology)
1
OUTPUTS
1
2
2
2K2 resistor
(2.2K)
6
5
4
To 5V CMOS
stepper driver input
(5mA max)
GND
Figure 10.2
Conversion of Nano-10 outputs to 5V logic level
10-2
Chapter 10
10.3
Stepper Motor Control
Programming Stepper Control Channel
10.3.1 Introduction
The PLC’s stepper motor controller channel #1 is controlled by the PLC program using the “STEPMOVE”
and “STEPMOVEABS” commands. These commands have the same parameters as they did when they
were used on M-Series PLCs. For example,
STEPMOVE ch, count, r
STEPMOVEABS ch, position, r
The ch parameter is the channel. This is how the PLC knows which stepper motor channel to turn on.
Now this parameter is also used to set the stepper motor channel to controller mode, full-step driver
mode, or half-step driver mode.
To set the stepper motor channel to controller mode, the ch parameter should be a “1”.
The same format should be used for STEPMOVEABS, except that the count parameter is changed to the
position parameter (more details provided in the Programmers Reference manual and also in the
program examples section of this chapter).
10.3.2 Setting the Acceleration Properties
Before the stepper motor channel can be used to control a stepper motor driver, the STEPSPEED
command must be executed first in order to define the acceleration settings. Once this command has
been executed, the acceleration settings will not change until another STEPSPEED command is
executed with different settings or if the PLC is powered down. If the PLC is powered down, the
STEPSPEED command will need to be executed again before the stepper motor channels can be used.
However, if a software reset executed (from online monitoring or within the program), the STEPSPEED
command does not need to be re-executed.
STEPSPEED ch, pps, acc
The ch parameter should be a 1. Speed, pps, is based on the no. of pulses per second (pps) output by
the pulse generator. The pps parameter should be set to a value between 1 and 10000 (max rated pps for
the Nano-10 PLC). The acceleration, acc, determines the total number of steps taken to reach full speed
from a standstill and the number of steps from full speed to a complete stop. The stepper motor controller
calculates and performs the speed trajectory according to these parameters when the STEPMOVE or
STEPMOVEABS commands are executed.
To set stepper motor channel #1 to a speed of 100 pps in 50 steps, the command would be as follows:
STEPSPEED 1, 100, 50
This would be equivalent to an acceleration of 100 pulses/s2, which can be calculated using the following
expression:
A = V2/2S = 1002/2*50 = 100pps2
10-3
Chapter 10
10.3.3
Stepper Motor Control
Using the STEPMOVE Command
Once the STEPSPEED command is executed, the STEPMOVE command can be used to move the
stepper motor forwards or backwards.
STEPMOVE ch, count, r
The ch parameter specifies which stepper motor channel is being used and should be ‘1’ on Nano-10
PLC.
The count parameter specifies how many pulses the motor will move. If the motor were in half-step driver
mode, then count would be in half steps.
The r parameter specifies which internal relay will be activated once the motor has moved count number
of steps. This relay would be cleared when the STEPMOVE command is executed in case it was already
activated.
Example 1:
Moving Forwards
STEPMOVE 1, 500, 101 ‘ channel 1 would send 500 pulses
‘ to a driver and then turn on relay 101
Example 2: Moving Backwards
STEPMOVE 1, -500, 101 ‘ channel 1 would send 500 pulses
‘ to a driver and then turn on relay 101
10.3.4
Using the STEPMOVEABS Command
This command allows you to move the stepper motor # ch to an absolute position indicated by the
position parameter. At the end of the move the relay # r will be turned ON. Position can be between -231
to +231 (i.e. about ± 2 x 109). The absolute position is calculated with respect to the last move from the
"HOME" position. (The HOME position is set when the STEPHOME command is executed). The speed
and acceleration profile are determined by the STEPSPEED command as in the original command set.
This command automatically computes the number of pulses and the direction required to move the
stepper motor to the new position with respect to the current location. The current location can be
determined at any time by the STEPCOUNTABS() function.
Once the STEPMOVEABS command is executed, re-execution of this command or the STEPMOVE
command will have no effect until the entire motion is completed or aborted by the STEPSTOP command.
The STEPMOVEABS command is also used to specify whether the PLC is a motor controller, a full-step
motor driver, or a half-step motor driver.
STEPMOVEABS ch, position, r
The ch parameter would specify which stepper motor channel is being used and should be a “1” on Nano10.
The position parameter specifies how many pulses the motor will move relative to its home position.
10-4
Chapter 10
Stepper Motor Control
The r parameter specifies which internal relay will be activated once the motor has moved to its new
position. This relay would be cleared when the STEPMOVEABS command is executed in case it was
already activated.
Example:
STEPMOVEABS 1,500,101
‘ Stepper #1 to move fwd 500 steps
‘ from home and turn on relay 101
10.3.5
Demo Program for Stepper Motor Control
A demo program for programming the Stepper Motor Controller and Driver:
“StepperMotor.PC6”
can be found in the Nano10Samples.zip file which can be downloaded from:
http://www.tri-plc.com/trilogi/Nano10Samples.zip
10-5
Chapter 11
Chapter 11
Pulse Width Modulated Outputs
Pulse Width Modulated Outputs
Chapter 11
11
Pulse Width Modulated Outputs
PULSE WIDTH MODULATED OUTPUTS
11.1 Introduction
Pulse-Width Modulation (PWM) is a highly efficient and convenient way of controlling output voltage to
devices with large time constants, such as controlling the speed of a DC motor, the power to a heating
element, or the position of a proportional valve.
The PWM works by first turning on the output to full voltage for a short while and then shutting it off for
another short while and then turning it on again, and so on, in consistent and accurate time intervals. This
can be illustrated with the following diagram:
Load
Voltage
a
b
Average
voltage =
V Full
a
a+b
x V Full
Figure 11.1
The average voltage seen by the load is determined by the “duty cycle” of the PWM waveform. The duty
cycle is defined as follow:
a
Duty Cycle =
a+b
x 100%
Period = (a + b)
Frequency = 1/period Hz
Average voltage = % duty cycle multiplied by the full load voltage VFull. Since the voltage applied to the
load is either “Fully ON” or “Fully OFF”, it is highly efficient because the switching transistors are working
in their saturated and cut-off region and dissipate very little power when it is fully turned ON.
11.2 Nano-10 PLC PWM Outputs
Technical Specifications:
No. of Channels
Duty Cycle range
Worst case resolution
Available Frequencies (Hz)
% Frequency Errors
Relevant TBASIC commands
:
4
0.00 to 100.00
0.1%
50Hz to 50 KHz,
< + 0.01% @ 100Hz
< + 0.5% @ 10KHz
< + 2% @ 50KHz
SETPWM
11-1
Chapter 11
Pulse Width Modulated Outputs
Unlike in the T100M+ PLCs, which only support 8 fixed frequencies settings, the PWM channels in the
Nano-10 PLC can generate pulses with frequency ranging from 50Hz all the way to 50KHz. At the lower
frequency range, the output frequency can be extremely accurate (less than 0.01% error). Even at 10KHz
the output frequency error is less than 0.5%. This makes it possible to use the PWM channels to
generate square wave pulses of a certain frequency.
Usually it is better to select as high a frequency as possible because the resulting effect is smoother for
higher frequencies. However, some systems may not respond properly if the PWM frequency is too high,
in such cases a lower frequency should be selected.
The TBASIC SETPWM statement controls the frequency and duty-cycle settings of the PWM channel. The
Nano-10 PLC features two channels of PWM on its digital outputs #1 and #2(PWM channel #1 and #2).
Since both PWM outputs are high voltage, high current outputs (24V, 4A peak, 2A continuous) they can
be used to directly control the speed of a small DC motor. They can also directly drive proportional
(variable position) valves whose opening is dependent on the applied voltage. Note: When using the
PWM output to drive a motor or solenoid valve, please take note of the need to add a bypass diode to
absorb the inductive kick that will occur when the output current to the load is turned OFF, as mentioned
in Chapter 1.5.3.
11.3 Increasing Output Drive Current
(Opto-Isolated)
The advantage of using the PWM is that you can easily amplify the drive current to a larger load such as
a larger permanent magnet DC motor by using a power transistor or power MOSFET to boost the current
switching capability. If the load is of a different voltage and the load current is high, you should use an
opto-isolator to isolate the PLC from the load, as in Figure 11.2
Flyback Diode
24V DC
Power
For PLC
+V
0V
OUTPUTS
-
220K
1
1
Bridge
Rectifier
4N35
Optoisolator
M
+
6
~
5
2
4
2 (PWM2)
AC
D
G
R1
3
2K2
4
R2
S
GND
Voltage divider to obtain approx.
10V DC at gate G. For DC48V
load, choose R1 = 3.9K, R2=1K
Figure 11.2
N-channel Power MOSFET
e.g. IRF530 can sink 12A DC
at up to DC100V max.
PWM Speed Control of a large DC Motor.
Note:
1. The opto-isolator must be able to operate at a frequency matching that of the PWM frequency,
otherwise the resulting output waveform will be distorted and effective speed control cannot be
attained.
11-2
Chapter 11
Pulse Width Modulated Outputs
2. The simple PWM speed control scheme described above is the open-loop type and does not regulate
the speed with respect to changing load torque. Closed-loop speed control is attainable if a
tachometer (either digital or analog) is used which feeds back to the CPU the actual speed. Based on
the error between the set point speed and the actual speed, the software can then adjust the PWM
duty cycle accordingly to offset speed variation caused by the varying load torque. A PID function
may also be invoked to provide sophisticated PID type of speed control.
3. The Nano-10 PWM can be used to control the speed of small motors only (up to the maximum
current limit that the PLCs output can safely drive). For larger motors, industrial-grade variable-speed
drives should be used instead.
11.4 Position Control Of RC Servo Motor
RC Servo is a class of DC servo motor commonly used in remote control (hence the term RC) for
positioning a device at a desired location. It is often termed “proportional control” because the position
where the motor will turn to is directly proportional to the pulse width of the control signal. When chosen
appropriately, RC Servo can provide an extremely inexpensive and versatile solution for positioning a
device. For example, for controling the percentage opening of a HVAC damper, or to rotate the angle of
window blinds or to position a solar panel to track the sun light. There are many sizes of RC Servo
available in the market, from those that weigh just a few grams to those for controlling an industrial scale
unmanned vehicle (e.g. UAV or unmanned submarine). A small, self-contained RC servo typically cost
less than $20 retail price and is incredibly easy to control using the Nano-10.
1ms
1.5ms
2.0ms
Figure 11.3
RC Servo and Control Signal
RC Servo typically only have 3 wires: Power “ + ” (typically 4.8 to 6V),
“–“
and a “Control” input.
To position the RC Servo to a position within its range of travel (Some are 0 to 90 degree and there are
those that can go from 0 to 180 degree), you send a positive pulse with pulse width between 1.00 ms to
2.00 ms to the “Control” input once every 20ms. The servo will position the actuator to one end when it
receives a pulse of 1.00ms and the other end when it receive a pulse of 2.00ms. If you send it a pulse of
1.50ms it will position the actuator to the center.
In PWM term, 1.00ms pulse width every 20ms means a duty cycle of 1.00/20.00 = 5.00%. 2.00ms pulse
width every 20ms means a duty cycle of 2.00/20.00 = 10.00% duty cycle. So to control the position of the
actuator one only needs to send it a positive PWM signal with frequency = 1/0.02 = 50Hz and duty cycle
between 5% and 10%.
The gear and servo feedback mechanism within the RC Servo produces a huge amount of torque relative
to its weight for positioning the actuator to the position determined by the pulse width at the “control”
input. Yet once it is in the correct position the servo draws only minimum current required to maintain its
11-3
Chapter 11
Pulse Width Modulated Outputs
position. Hence being a closed-loop controller an RC Servo is actually a much more efficient and effective
positional control device (for a limited range) than a stepper motor which relies on a constant current in its
winding to provide the “holding torque” for positioning. The open loop nature of stepper motor means that
it does not know if the device is actually being knocked out of its desired location whereas in the Servo
any deviation from its desired location is instantly being corrected by the servo mechanism.
11.4.1 Using Nano-10 PWM Output To Control RC Servo (Non-Isolated)
As you probably have realized by now that you can use a single PWM output to very easily position the
RC Servo to whatever position within its range of travel.
However, since the Nano-10 power supply is 24V (vs 4.8 to 6V on the typical RC Servo) and the PWM
output is NPN (current sink) type, the signal to the servo is actually inverted if you connect the PLC’s
output to the Servo’s “control” input directly.
+V
24V DC
Power
For PLC
0V
+6V
+
4.8V to 6V
DCPower
For Servo
0V
OUTPUTS
1
1N4001
1K
RC
Servo
Control
2 (PWM2)
3
4
-
0V
Figure 11.4
Non-isolated Interace to RC Servo
As shown in the above figure, we use a 1K ohm resistor to pull up the “Control” input to the RC Servo’s
power supply so that when the PLC’s output is OFF, the Control input is +6V and when the PLC output is
ON, the “Control” input is pulled to low.
The 1N4001 diode is to prevent the 24V weak pullup signal at the PLC output from entering the servo’s
“Control” input. As such, when the PLC output is ON, the “Control” input is pulled down to about 1 diode
drop (about 0.7V).
In other words, the RC Servo connected above are controlled by the PLC’s PWM output but the duty
cycle is inverted. I.e. To send a 5% positive PWM control pulse to the Servo, you can run the following
statement:
SETPWM 2, 9500, 50
‘ Set PWM 2 output to 95% duty cycle at 50 Hz
Likewise, to send a 10% positive PWM control pulse to the Servo, you will need to run the following
statement:
SETPWM 2, 9000, 50
‘ Set PWM 2 output to 90% duty cycle at 50 Hz
11-4
Chapter 11
Pulse Width Modulated Outputs
11.4.2 Using Nano-10 PWM Output To Control RC Servo (Opto-Isolated)
You can also use the PLC’s PWM output to drive an optocoupler (such as 4N35) and the output from the
optocoupler is use to provide control pulse to the RC Servo, as shown in Figure 11.5
4N35
Optoisolator
+V
0V
24V DC
Power
For PLC
OUTPUTS
1
1
5
2
4
2 (PWM2)
+6V
2K2
0V
+
1K
RC
Servo
Control
3
4
4.8V to 6V
DCPower
For Servo
-
GND
Figure 11.5
Opto-Isolated Interace to RC Servo
In the opto-isolated interface shown above, the power supply to the PLC and that to the RC Servo are
completely isolated (no common ground required). Also since the interface inverts the output signal from
the PLC, no software inversion is necessary. i.e When the PLC NPN output is OFF, the “control” input to
the RC Servo will be OFF, and when the PLC NPN output is ON, the “control” input to the RC Servo =
+6V.
Hence, to send a 5% positive PWM control pulse to the Servo, you can run the following statement:
SETPWM 2, 500, 50
‘ Set PWM 2 output to 5% duty cycle at 50 Hz
Likewise, to send a 10% positive PWM control pulse to the Servo, you can run the following statement:
SETPWM 2, 1000, 50
‘ Set PWM 2 output to 10% duty cycle at 50 Hz
Of course you can replace the duty cycle with a value (e.g. DM[1]) and run statement such as:
SETPWM 2, DM[1], 50
‘ Set PWM 2 output to DM[1]/100% duty cycle at 50 Hz
11.4.3 RC Servo Positioning Resolution
Since the resolution on the Nano-10 PLC’s PWM output is precise to 0.01% at 50Hz, this means that you
can get a maximum of 500 discrete positions within the travel range of the RC Servo. This should be
sufficiently accurate for many applications such as HVAC damper control or control of proportional
valves. The actual positioning accuracy and precision, however, will depend on the quality of the RC
Servo.
11-5
Chapter 12
Chapter 12
Real Time Clock
Real Time Clock
Chapter 12
Real Time Clock
12 REAL TIME CLOCK
12.1 Introduction
A Real Time Clock (RTC) is a device that keeps accurate date and time information down to the second.
The Nano-10 has a built-in Real Time Clock that provides calendar and time data for year, month, date,
day of week, hour, minute and second, but it is not battery-backed. You can however easily add an
optional battery-backed FRAMRTC module and the Nano-10 will sense it automatically and use it upon
installation.
NOTE:
If the RTC battery is not installed or the battery is removed for more than 15 seconds from the
FRAMRTC, then the PLC will lose its real time clock data when it is powered up even with the FRAMRTC
installed. When this happens the RTC.Err bit in the ladder logic special bit will be ON so that user
program can use it to alert the operator. The PLC can also use the RTC.Err bit to trigger an automatic
RTC update from an Internet Time Server or from a TLServer that it connects to.
12.2 TBASIC variables Used for Real Time Clock
Date
Time
YEAR
DATE[1]
HOUR
TIME[1]
MONTH
DATE[2]
MINUTES
TIME[2]
DAY
DATE[3]
SECOND
TIME[3]
Day of Week
DATE[4]
There are 7 registers available in TBASIC that are used to access and configure the date and time.
These registers, which are shown above, can be read from and written to just like any other integer
variable. The data for these registers are in integer format.
DATE[1] : may contain four digits (e.g. 1998, 2003 etc).
DATE[4] : 1 for Monday, 2 for Tuesday, .... 7 for Sunday.
12.3 RTC Error Status On Ladder Logic
There is a special bit available in TRiLOGI that allows you to notify the PLC program if the RTC Error
event occurs and the RTC Error status light is turned on. The RTC Error event occurs if the RTC is
corrupted or damaged (see section 12.8 for more detail) or if the battery is not installed. The special bit is
called RTC.Err and can be obtained from the “Special Bits” I/O Table. The RTC.Err contact can be used
to activate an alarm of some kind. The following ladder logic circuit is an example of this using the
RTC.Err bit as an input that controls an output called RTC_Alarm:
12-1
Chapter 12
Real Time Clock
In the circuit above, RTC.Err is a special bit that cannot be renamed in your program. The output
RTC_Alarm is a user-defined output that could be named to anything. If the RTC Error event occurs for
any reason, the RTC.Err bit would activate the RTC_Alarm output.
12.4 Setting the RTC Using TRiLOGI Software
The RTC date and time can be easily set within TRiLOGI by selecting “Set PLC’s Real Time Clock” from
the “Controller” menu. A window will pop up with default values entered as shown below in Figure 12.1.
All of these values can be edited and then written to the PLC by clicking on “Set PLC’s Clock”
Figure 12.1: Set Real Time ClockSetting the RTC Using TBASIC
The PLCs RTC can be set from TBASIC using the DATE[] and TIME[] registers shown in section 12.2.
Figure 12.2: Set Date & Time in TBASIC, shown below, is an example of a custom function where the
date is set to October 1st 2008, the day of the week is Wednesday, and the time is 14:30:01 (2:30:01 pm).
Figure 12.2: Set Date & Time in TBASIC
12-2
Chapter 12
Real Time Clock
12.5 Setting the RTC from Internet Time Server
Please refer to Section 2.5 for more detailed information on how your PLC may be able to automatically
set its own real time clock using the time server data available on the Internet. A sample program is also
included in that section.
12.6 Setting up an Alarm Event in TBASIC
Since, to the TBASIC program, the RTC data are simply integer arrays DATE[1] to DATE[4] and TIME[1]
to TIME[3], they are fully accessible at any time by your PLC program. Therefore, if you want your
program to execute a certain routine on a specific date and or/time, you would need to periodically check
these variables against the desired settings and activate the action when the RTC variable(s) reach the
set value.
Example:
Set up a 1 minute clock pulse to monitor the RTC as follows:
Figure 12.3: Using Real Time Clock Example
12.7 Retrieving RTC Clock values using STATUS (18)
For Nano-10 PLC with firmware version r72 and above, you can read the hour, minute and second of the
Nano-10 RTC in a single STATUS(18) function. The RTC hours, minutes and second values are returned
as a single integer in the following format: hhmmss.
This could be faster and more convenient to use than to perform 3 comparison statements using TIME[1],
TIME[2] and TIME[3]. However, please note that this function is not available on the M-series PLC or Fseries PLC with older firmware version and it is currently not supported by the i-TRiLOGI version 6.30
simulator. You will need to transfer your program to the PLC in order to test it.
12-3
Chapter 12
Real Time Clock
Example
Time
0:0:0
0:1:5
10:5:3
23:59:59
STATUS(18)
0
105
100503
235959
You can therefore easily test the value of the RTC using a single command:
E.g.
IF STATUS(18) >= 100000
SETIO Pump
ENDIF
‘ After 10 am in the morning
12.8 RTC Calibration (For FRAMRTC only)
The RTC calibration routine is only applicable to the FRAMRTC module installed on a Nano-10 PLC. The
FRAMRTC uses a battery-back real time clock that derived its clock from a 32.768KHz crystal, which
should provide reasonably good accuracy for normal use. However, if you like the FRAMRTC to be of
greater accuracy, you can calibrate it using the “Advanced Configuration” page of the “Ethernet
Configuration Tool” in the PLC configuration routine mentioned in Chapter 2. The data field to be used
is the “RTC Calib” textbox as shown below:
In the above field you will need to enter the number of seconds that you want the PLC to add or subtract
over a period of 72 hours. Therefore, first you must check the PLC’s RTC reading against a super
accurate clock source (e.g. a clock that regularly updates itself with atomic clock data in the airwaves)
and find out how many seconds the clock would have gained or lost over 72 hours.
For example, if the RTC is too slow and it loses 5 seconds over 72 hours, you would want the RTC to add
5 seconds over 72 hours and you therefore should enter the value of +5 in the “RTC Calib + “ field. If the
RTC is too fast and gains 8 seconds over the 72 hours, then you should enter a value of “-8” in this field
to compensate for the inaccuracy.
Note that the RTC does not compensate for temperature variation. Hence, its accuracy is temperaturedependent. If you require the PLC’s RTC to be very accurate you should keep the PLC under a
constant operating temperature.
If your Nano-10 is connected to a LAN, then you also have the option of having the RTC periodically set
itself using the very accurate RTC data that can be obtained from a time-server on the Internet (See
Section 2.5).
12-4
Chapter 12
Real Time Clock
12.9 Control of RTC Hardware
On Nano-10 PLC with r72 and above firmware, you can use the following command to control the RTC
hardware:
SETSYSTEM 253,n
n
=
0
1
2
3
‘ Stop built-in RTC
‘ Run built-in RTC
‘ Disable auto RTC update from FRAMRTC
‘ Enable auto RTC update from FRAMRTC
An example program “RTCcontrol.PC6” is included in the “Nano10Samples.zip” file that you can
download from: http://www.tri-plc.com/trilogi/Nano10Samples.zip
12.10 Troubleshooting the FRAMRTC
If the RTC.Err bit is ON (indicating a bad RTC) and the battery is properly installed on the FRAMRTC,
then the RTC component on the FRAMRTC could be corrupted or damaged. This could happen if there
was any damage to the components on the board, such as I/O drivers, communications drivers, or any of
the IC’s or PCB circuitry. Also, if a voltage spike came into the PLC through its I/O, power supply, or
communications ports, that could cause some corruption even if there was no component damage.
If the RTC is only corrupted, then you should only have to set the RTC to resolve the problem. This can
be done most easily by using the TRiLOGI method of setting the RTC that was described in section 12.4.
After setting the RTC, the PLC should be powered off and then powered on again. The RTC.Err bit
should be off at this point, but if it isn’t, then there is a possibility of damage to the PLC. At this point you
should contact Triangle Research tech support or if you have purchased the unit from a local distributor,
then you should contact the distributor for assistance.
12-5
Chapter 13
Chapter 13
LCD Display Programming
LCD Display Programming
Chapter 13
LCD Display Programming
13 LCD DISPLAY PROGRAMMING
Although the Nano-10 PLC lacks a connector for connecting to a physical LCD display, it does support
the SETLCD command available to all the M-series and F-series PLC. The content of the non-existent
LCD display however can still be displayed as a “Virtual LCD” screen using the I-TRiLOGI On-line
monitoring function. Thus the SETLCD command can still be an effective debugging tool for the PLC to
display internal or computed data.
The LCD content is also accessible from a web browser using the appropriate web services commands.
Hence it can still be extremely useful for a Nano-10 to use the SETLCD command to manipulate its
virtual LCD display, and the content is visible on the user configurable control web page (described in
Section 2.10 for controlling the Nano-10 PLC using a web browser. The virtual LCD would then
become a real display on the web browser.
If you require a physical LCD display to be used with the Nano-10 PLC, then there are many options,
One of which is to purchase an RS485 based MDS100-BW that is produced by TRi. However, it is
important to note that what we describe in this chapter is not applicable to MDS100-BW. MDS100-BW
is a peripheral device and it is controlled by a set of communication protocol described in the MDS100BW installation guide.
13.1 SETLCD Command
The SETLCD y, x, string TBASIC command allows you to easily display any string of up to 20
characters on the yth line starting from the xth column. E.g., to display the message “Super Nano-10”
on the 3rd line starting from the 5th character position from the left end of the screen, you use the
command:
SETLCD 3, 5, “Super Nano-10”
Normally, y = 1,2,3, 4; x = 1, 2, …. 20. Integers must be converted to strings using the STR$() or
HEX$() function before they can be displayed using SETLCD. You can use the concatenation operator
“+” to combine a few components together in the command. E.g.
SETLCD 1,1,“Rm Temp = ”+ STR$(ADC(1)/100,3)+CHR$(223)+”C”
The function STR$(ADC(1)/100,3) reads the content of ADC channel #1, divides it by 100 and converts
the result into a 3-digit string. The CHR$(223) appends a special character which corresponds to the ‘ o ‘
symbol. E.g. if ADC(1) returns the value 1234, the final string being displayed will be :
Rm Temp = 012 oC.
13.2 Special Commands For LCD Display
If you use the SETLCD command with line #0, then the strings will be treated as special “instructions” to
be sent to the LCD module to program it for various modes of operation. This includes: blinking cursor,
underline cursor or no cursor, as well as display shift mode. You have to refer to the LCD manufacturer’s
data sheet for the detailed commands. Some of the most useful commands are listed below:
13-1
Chapter 13
Action
1. Clear screen
2. No cursor
3. Underline Cursor
4. Blinking Cursor
5.
Underline +
Cursor
LCD Display Programming
Command
SETLCD 0,1, CHR$(1)
SETLCD 0,1, CHR$(12)
SETLCD 0,1, CHR$(14)
SETLCD 0,1, CHR$(13)
Blinking SETLCD 0,1, CHR$(15)
13.3 Displaying Numeric Variable With Multiple Digits
The “SETLCD y, x, string” command only overwrites the exact number of characters in the string
parameter to the LCD display, and thereafter the cursor is placed back to the location specified by the x
and y parameters. Thus if there exists some old characters right after the last character it can cause
confusion, especially if you are displaying a number. E.g. If you first display the following string at row 1
and column 1:
Pressure = 12345
And if you subsequently display the string “Pressure = 983” at the same location without first clearing the
line, then you will see the following string being displayed:
Pressure = 98345
What happens is that the string “Pressure = 983” is correctly displayed but the two old characters “45”
left over from previous display would appear to be part of the new data. This can cause confusion.
There are several ways you can eliminate such a display problem:
1) Clear the line first before overwriting with a new string. You can create a custom function just to clear
a particular line. E.g. if you pass the parameter DM[100] to the custom function and inside the custom
function you do the following:
SETLCD DM[100],1, “
”
Hence calling this custom function with DM[100] = 1,2,3, or 4 would clear the corresponding line.
2) A “ quick and lazy” way to do it is to add a few more characters to the back of the string to be
displayed which will wipe out old characters that could be present adjacent to the new string.
E.g.
SETLCD 1,1, “Money = $”+ STR$(D) + “
”
3) If there is data to the right of the currently displayed string that you cannot overwrite with spaces, then
you can restrict the number of digits that a numeric variable may be converted to using the two
parameters from the STR$ or HEX$ command.
E.g SETLCD 1,1, “Temp = ”+ STR$(T,4)
The STR$(T,4) function will always return 4 digits of the data stored in T. If T is less than 4 digits,
then one or more preceding “0”’s will be added. E.g. if T = 12 then this function will return the string
“0012. Note that for negative numbers the negative sign is counted as part of the digit count so you
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Chapter 13
LCD Display Programming
need to provide enough spaces to take care of the sign if you need to handle both positive and
negative numbers.
13.4 Displaying Decimal Point
Although the Nano-10 PLC does not handle floating-point computation, it is still possible to perform
computations involving fractions by using “fixed point” notation. E.g. If each unit represents 0.01, then the
number 1234 represents the value 12.34.
It is quite simple to display a number on the LCD display with a decimal point as follows: You first divide
the numeric variable by 100 to obtain the integer component (i.e. the portion to the left of the decimal
point) and use the MODULUS operator to obtain the decimal component (i.e. the portion to the right of
the decimal point) of the number. So to display a number contained in X with two decimal places, do the
following:
E.g.
SETLCD 1,1, “Data=“+STR$(X/100)+”.”+ STR$(X MOD 100)
Hence, if the number X = 12345,
display the string “Data=123.45”.
then (X/100 = 123)
and (X MOD 100 = 45) and the above would
13-3
Chapter 14
Chapter 14
Serial Communications
Serial Communications
Chapter 14
Serial Communications
14 SERIAL COMMUNICATIONS
14.1 Introduction:
There is only a single, RS485 serial port on the Nano-10 PLC. This serial port supports full Modbus
ASCII/RTU and Host Link Protocol drivers and it can also be programmed to accept or send ASCII or
binary data using the TBASIC built-in commands such as INPUT$(n), INCOMM(n), PRINT #n,
OUTCOMM n, d.
This serial port is designated as COMM1 to the TBASIC and it is a two-wire RS485 port that allows
multiple PLCs to be connected to a single host computer or a master PLC for networking or to implement
a distributed control system.
14.2 COMM1:
Two-wire RS485 Port
This half-duplex RS485 ports is meant for serial bus type networking or for connecting to optional
peripherals such as a serial LCD message-display unit (e.g. MDS100-BW), external analog modules (e.g.
I-7018), touch panel HMI, or it can be used for inter-communication between PLCs.
Up to 255 RS232/RS485 peripheral devices may be linked together in an RS485 network on this port.
The RS485 port signal is carried on a 2-way screw terminal connector (please refer to Chapter 1Installation Guide). For successful communication using the RS485 port, you need to correctly connect
the ‘+’ and ‘-’ terminals to the RS485 equipment using a twisted pair cable. If you are using the PC as the
network host, you will need an USB-to-RS485 converter such as the U-485 converter.
The following describes some possible uses of the RS485 ports.
14.2.1 PROGRAMMING AND MONITORING
The Nano-10 PLC can be programmed via its RS485 port on a one-to-one or multi-drop manner. If your
PC already has an RS232 port or your already own a USB-to-RS232 converter, then you can convert the
RS232 port into RS485 port using the Auto485 adapter in order to communicate with the PLC.
If your PC only has USB ports, then the easiest way is to purchase a USB-to-RS485 adapter (U-485),
which is port-powered so you only need to connect two wires from the U-485 to the PLC’s RS485 port to
establish communication.
Programming via COMM1 is particularly useful if the Nano-10 PLC is not yet connected to the LAN, and if
your PC does not have a spare Ethernet port for direct connection (see Section 2.8) that can be used for
programming. Another reason for programming via RS485 is if your Ethernet port default IP address is
not compatible with the subnet of your network. You will then need to connect i-TRiLOGI to the PLC via
RS485 port in order to change the IP address.
14-1
Chapter 14
Serial Communications
14.2.2 Accessing 3rd Party RS485-based Devices
There are more and more industrial devices such as electric power meters, analog I/O modules (e.g. the
I-70xx modules by ICPDAS), variable frequency drives, servo controller, etc that allows data
communication via their RS485 port. The Nano-10 PLC can readily use its RS485 port to communicate
with these devices. The PLC has many built-in commands for reading/writing to the serial port, including
built-in commands for communicating with devices that deploy the MODBUS ASCII or RTU protocols.
14.2.3 Interfacing Other Devices to Modbus/TCP Host or to the Internet
Since the Nano-10 PLC supports serial MODBUS protocols, it can operate as a master PLC and serve as
a gateway to interface non MODBUS-enabled PLCs (such as the H-series and E10+ PLCs, or the I-7000
analog modules) to third party SCADA software or MMI hardware that speaks MODBUS. The Nano-10
PLC also makes it easy for these devices to be controlled or monitored over the Internet. The master
Nano-10 will use its RS485 port to pull data from these devices into its data-memory. The data memory in
the Nano-10 is in turn accessible by a SCADA program using the Modbus/TCP protocol. Through the
Nano-10 PLC, these other connected devices thus become accessible from the Internet.
14.2.4 Distributed Control
Another important use of the RS485 port will be to connect a Nano-10 PLC to other Nano-10, F-Series,
M-series, H-series or E10+ PLCs. One of these PLCs will act as the master and all other PLCs will act as
slaves. Each PLC must be given a unique ID. The master will send commands to all the slaves using
the “NETCMD” or READMODBUS, WRITEMODBUS, READMB2, WRITEMB2 statements and coordinate
information flow between the PLCs. In this way, a big system can be built by employing multiple units of
Nano, F, M, E or H-series PLCs connected in a network. This results in more elegant implementation of
complex control systems and simplifies maintenance jobs.
14.3 Changing Baud Rate and Communication Formats: Use of the
SETBAUD Statement
The Nano-10 PLC’s COMM port is highly configurable. It can be set to a wide range of baud rates. You
can also program it to communicate in either 7 or 8 data bits, 1 or 2 stop bits, odd, even or no parity. The
baud rate and communication formats of the serial port are set by the following command:
SETBAUD
ch, baud_no
ch represents the COMM port number (1 only). The baud_no parameter takes a value from 0 - 255
(&H0 to &HFF), which allows for additional configuration of the communication format. The upper 4 bits of
baud_no specify the communication format (number of data bits, number of stop bits, and parity) and
the lower 4 bits represent the baud rate. Hence the baud_no for 8 data bit, 1 stop bit, and no parity is the
same as the old models, providing compatibility across the PLC families.
Once the new baud rate has been set, it will not be changed until execution of another SETBAUD
statement. The baud rate is not affected by a software RESET but the settings will be lost when the
power is turned OFF. The available baud rates and their corresponding baud rate numbers for COMM1,
2, and 3 are shown below:
Format
baud_no
Format
baud_no
14-2
8, 1, n
8, 1, e
8, 1, o
7, 1, n
7, 1, e
7, 1, o
0000 xxxx
0100 xxxx
0110 xxxx
1000 xxxx
1100 xxxx
1110 xxxx
Where xxxx represents the baud rate of the comm port, as follow:
0000
0001
0010
0011
xxxx
2400
2400
4800
9600
Baud Rate
xxxx
Baud Rate
1000
100K
1001
115.2K
1010
230.4K
1011
110
Chapter 14
Serial Communications
8, 2, n
8, 2, e
8, 2, o
7, 2, n
7, 2, e
7, 2, o
0001 xxxx
0101 xxxx
0111 xxxx
1001 xxxx
1101 xxxx
1111 xxxx
0100
19200
1100
150
0101
31250
0110
38400
0111
57600
1101
300
1110
600
1111
1200
A table of all the available baud rates and COMM formats is shown in the following page. The
communication format written as “7,2,e”, which means 7 data bits, 2 stop bits and even parity. Likewise,
“8,1,n” means 8 data bits, 1 stop bit and no parity. You can use the table to select the baud number for a
certain baud rate and COMM format. COMM1 can work at high baud rate of up to 230.4 K bps.
Baud No Table (All numbers in Hexadecimal: &H00 to &HFF)
Format
Baud
8,1,n 8,1,e 8,1,o
110
0B
4B
6B
150
0C
4C
6C
300
0D
4D
6D
600
0E
4E
6E
1200
0F
4F
6F
2400
01
41
61
4800
02
42
62
9600
03
43
63
19200
04
44
64
31250
05
45
65
38400
06
46
66
57600
07
47
67
100K
08
48
68
115K2
09
49
69
230K4
0A
4A
6A
E.g. To set the baud rate of COMM1
statement: SETBAUD 1, &HC4
7,1,n 7,1,e 7,1,o
8B
CB
EB
8C
CC
EC
8D
CD
ED
8E
CE
EE
8F
CF
EF
81
C1
E1
82
C2
E2
83
C3
E3
84
C4
E4
85
C5
E5
86
C6
E6
87
C7
E7
88
C8
E8
89
C9
E9
8A
CA
EA
to 19200, 7 data bit,
8,2,n
1B
1C
1D
1E
1F
11
12
13
14
15
16
17
18
19
1A
1 stop
8,2,e 8,2,o
5B
7B
5C
7C
5D
7D
5E
7E
5F
7F
51
71
52
72
53
73
54
74
55
75
56
76
57
77
58
78
59
79
5A
7A
bit and even
7,2,n
9B
9C
9D
9E
9F
91
92
93
94
95
96
97
98
99
9A
parity,
7,2,e 7,2,o
DB
FB
DC
FC
DD
FD
DE
FE
DF
FF
D1
F1
D2
F2
D3
F3
D4
F4
D5
F5
D6
F6
D7
F7
D8
F8
D9
F9
DA
FA
execute the
Important:. Please note that if you change the baud rate or communication format of the COMM port to
something that is different from that set in the TLServer, then both the TLServer and TRiLOGI will no
longer be able to communicate with the PLC via this COMM port. You will have to either configure the
TLServer’s serial port setting using its “Serial Communication Setup” routine to match the PLC, or you
can cycle the power to the PLC to reset the COMM port to the default format (38,400, 8,n,1).
If you had used “1st.Scan” contact to activate the SETBAUD command than you will need to cycle the
power to the PLC with Jumper J4 shorted to halt the execution of the SETBAUD command. When the
PLC is reset this way, its COMM1 will power up at the default format of 38,400, 8,n,1 only so you will
need to configure TLServer’s serial port to 38,400bps to communicate with it.
14-3
Chapter 14
Serial Communications
14.4 Support of Multiple Communication Protocols
The Nano-10 PLC is a real communication wizard! It has been designed to understand and speak many
different types of serial communication protocols, some of which are extremely widely used de facto
industry standards, as follows:
a) NATIVE HOST LINK COMMAND
b) MODBUS ASCII
(Trademark of Modbus.org)
c) MODBUS RTU*
(Trademark of Modbus.org)
d) OMRON C20H protocols. (Trademark of Omron Corp of Japan)
The command and response formats of the “NATIVE” protocols are described in detail in Chapter 15 and
16. The other protocols and their address mapping to the Nano-10 PLC are described in Section 14.7.
Each COMM port can communicate using the same or different protocols, independent of the other. The
most wonderful feature of Nano-10 PLCs is that the support of all the above-mentioned protocols can be
fully automatic and totally transparent to the users. There is no DIPswitch to set and no special
configuration software to run to configure the port for a specific communication protocol. The following
describes how the automatic protocol recognition scheme works:
1. When the PLC is powered ON, the COMM1 port is set to the “AUTO” mode, which means that
they are open-minded and listen to all serial data coming through the COMM ports. The CPU
tries to determine if the serial data conforms to a certain protocol and if so, the COMM mode is
determined automatically.
2. Once the protocol is recognized, the CPU sets that COMM port to a specific COMM mode, which
enables it to process and respond only to commands that conform to that protocol. Error
detection data such as the “FCS”, “LRC” or CRC are computed accordingly which method is used
to verify the integrity of the received commands. If errors are detected in the command, the CPU
responds in accordance with the action specified in the respective protocols.
3. When the COMM port enters a specific COMM mode, it will regard commands of other protocol
as errors and will not accept them. Hence, for example, if COMM #1 has received a valid
MODBUS RTU command (which puts it in an “RTU” mode), it will no longer respond to
TRiLOGI’s attempts to communicate with it using the “NATIVE” mode. You will receive a
communication error if you try to use TRiLOGI to access a PLC COMM port that has just been
communicating in other protocol modes.
4. To improve the flexibility of switching from one COMM mode to another, The Nano-10
incorporates a COMM mode self-reset timer such that a specific COMM mode will time out
automatically and enters into “AUTO” mode after 10 seconds if no more commands are received
from that COMM port. When a user wants to switch from one COMM mode to another, he/she
often will be changing the serial connector from one device to another. During this time there is
no data received by the COMM port, which presents an opportunity for it to reset its COMM
mode. However, the surest way to reset the specific COMM mode is to cycle the power to the
PLC so that its COMM port will be reset to “AUTO” mode and ready to communicate with any
supported protocols.
5. If you wish to use the COMM port for serial data input only, you can use the SETPROTOCOL
command to set the COMM port to NO PROTOCOL. This can prevent the PLC from erroneously
treating some serial data as the header of an incoming communication protocol and respond to it
automatically.
The SETPROTOCOL command can also be used to set the PLC to a specific protocol. This may be
desirable if the COMM port has a specific role and you do not want it to enter other modes by mistake.
14-4
Chapter 14
Serial Communications
Please refer to the TBASIC Programmer’s Reference manual for a detailed description of the
SETPROTOCOL command.
Note: If you fix a COMM port to a non-native, non-auto mode, TRiLOGI will not be able to communicate
with the PLC anymore. You may have to power-cycle the PLC to reset the COMM mode. If you
use the “1st.Scan” contact to activate the SETPROTOCOL command, then you will need to cycle
the power to the PLC with Jumper J4 shorted to halt the execution of the SETPROTOCOL
command. (Also remember that when the PLC is reset this way, its COMM1 will power up at
default format of 38,400, 8,n,1 only so you will need to configure TLServer’s serial port to
38,400bps to communicate with it.)
14.5 Accessing the COMM Port from within TBASIC
Besides responding automatically to specific communication protocols described in section 14.5, the
COMM #1 is fully accessible by the user program using the TBASIC commands: INPUT$, INCOMM,
PRINT # and OUTCOMM. It is necessary to understand how these commands interact with the
operating system, as follow:
When a COMM port receives serial data, the operating system of the Nano-10 automatically stores them
into a 256 bytes circular buffer so that user programs can retrieve them later. The serial data are buffered
even if they are incoming commands of one of the supported protocols described in section 14.5. In
addition, processing of a recognized protocol command does not remove the characters from the serial
buffer queue so these data are still visible to the user’s program.
As long as the user-program retrieves the data before the 256-byte buffer is filled up, no data will be lost.
If more than 256 bytes have been stored, the buffer wraps around and the oldest data is overwritten first
and so on. The following describes how INCOMM and INPUT$, PRINT # and OUTCOMM functions
interact with the serial buffer:
a) INCOMM (n)
Every execution of the INCOMM(n) function removes one character from the circular buffer. When no
more data is available in the buffer this function returns a -1. The data removed by INCOMM will no
longer be available for the INPUT$(1) command.
b) INPUT$(n)
When the INPUT$(1) function is executed, the CPU checks the COMM1 buffer to see if there is a
byte with the value 13 (the ASCII CR character) which acts as a terminator for the string. If a string is
present, all the characters that make up the string will be removed from the COMM1 buffer. If a
completed string is not present, then the COMM1 buffer will not be affected, and INPUT$(1) returns
an empty string. This ensures that before a complete string is received, the serial characters will not
be lost because of the unsuccessful execution of the INPUT$(1) function.
c) INPUT$(n) in Blocking Mode
INPUT$(n) is designed to be non-blocking and to return immediately – i.e. either it returns a complete
string or it returns an empty string. This means that INPUT$(n) will not suspend the CPU and wait for
a valid string from the COMM port. However, in real world communication very often you will need
to send a command to a device and it takes a while for the device to be able to send back a response
string.
14-5
Chapter 14
Serial Communications
The most efficient way of handling such serial communication exchange with other devices is to send
a command string using the PRINT #n and then start a timer and let the PLC program continue to
scan the ladder program. When timer times out, the timer contact is used to activate a custom
function and use INPUT$(n) to read the return message from the device. This is most efficient use of
the CPU time since the program will not have to waste time to wait for response string from the
device and that’s the reason for INPUT$(n) to default to non-blocking mode.
Another way to deal with this is to use the NETCMD$ function (terminated with “~”). NETCMD$
sends a command string and will return immediately when it receives a response string or if more
than 0.15s has passed. If the device is slow to response the CPU basically sits in a loop to wait for
the response for up to a maximum of 0.15s. NETCMD$ function also re-tries the communication
several times if it does not receive a response in the first try.
A third way of handling serial exchange with other devices is to use the INPUT$(n) command in
blocking mode. Starting from CPU firmware r72 and above, if you run the command
SETSYSTEM 19,
t
This will configure the INPUT$(n) command to block the CPU for up to maximum of (t x 10)
rd
milliseconds to wait for a valid string from 3 party device. Although this command also wastes
CPU cycles to wait for a response and hence it is not as efficient compared to using the timeractivated method mentioned above, it nonetheless is very simple to implement and can be used for
non time-critical applications.
You only need to execute SETSYSTEM 19, t once and INPUT$(n) will block for the same t x 10
millisecond every time it is executed until SETSYSTEM 19,t is run again. To return the INPUT$(n) to
non-blocking mode, run SETSYSTEM 19, 0.
d) PRINT #n
The PRINT statement transfers its entire argument to a 256 byte serial-out buffer, which is separate
from the serial-in buffer. The PRINT statement, therefore, does not affect the content of the serial
buffer for incoming characters. The operating system handles the actual transfer of each byte of data
out of the serial-out buffer in a timely manner.
Note that the PLC automatically enables the RS485 transmit driver when it sends serial characters
out of its RS485 port. When the stop bit of the last character in the serial-out buffer has been sent
out, the operating system immediately disables the RS485 driver and enables the receiver. This
greatly eases the use of the RS485 port since there is no need for a user to bother with the oftencritical timing of controlling the RS485 driver/receiver direction.
d) OUTCOMM
This command sends only a single byte out of the serial COMM port without going through the serial
out buffer. It enables the RS485 transmitter before sending the character and disables it immediately
after the last stop bit has been sent out.
14-6
Chapter 14
14.6
Serial Communications
Using The PLC As a Modbus / Omron Slave
– SCADA, HMI Applications
The Nano-10 PLC supports a subset of the OMRON™ C20H and MODBUS™ (Both ASCII and RTU
modes are supported) compatible communication protocols so that it can be easily linked to third-party
control software/hardware products such as SCADA software, LCD touch panels etc. The PLC
automatically recognizes the type of command format and will generate a proper response. These are
accomplished without any user intervention and without any need to configure the PLC at all!
Both MODBUS and Omron protocols use the same device ID address (00 to FF) as used by the native
“Hostlink Command” protocol described in Chapter 15. Since the addresses of I/O and internal
variables in the Nano-10 PLC are organized very differently from the OMRON or Modicon PLCs, we need
to map these addresses to the corresponding memory areas in the Modbus address space so that they
can be easily accessed by their corresponding protocols.
All I/Os, timers, counters, internal relays and data memory DM[1] to DM[4000] are mapped to the Modbus
Holding Registers space. The Inputs, Outputs, Relays, Timers and Counters bits are mapped to the
MODBUS Bit address space as shown in Table 14.1. Note that input and output bits are always
mapped according to Table 14.1 whether it is MODBUS function 01, 02 or 05.
However, 32 bit variables and string variables are not mapped since they are fundamentally quite
different in their implementation among different PLCs. Internal variables that are not mapped can be
still be accessed by copying the contents of these variables to unused data memory DM[n] (this can be
easily accomplished within a CusFn) so that they can be accessed by these third party protocols.
14.6.1 MODBUS ASCII Protocol Support
The Nano-10 PLC supports MODBUS ASCII protocols with the following command and response format:
START
:
Address
2 chars
Function
2 chars
Data
# chars
LRC Check
2 chars
CRLF
2 chars
The following Function Codes are supported:
01/02
03/04
05
06
16
Read I/O bit (Use Bit Address Mapping in Table 14.1)
Read I/O Word registers
Force I/O Bit (Use Bit Address Mapping in Table 14.1).
Preset Single Word Register
Preset Multiple Word Registers
The exact command/response format of the MODBUS protocol can be found at http://www.modbus.org.
However, if your only purpose is to interface the PLC to other MODBUS hosts such as an LCD touch
panel or SCADA software then there is no need to know the underlying protocol command format. All you
need to know is which PLC’s system Variable is mapped to which MODBUS register, as shown in Table
14.1.
14-7
Chapter 14
Table 14.1:
PLC I/O #
Input
Output
Timer
Counter
Relay
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
N
1 to 16
17 to 32
33 to 48
49 to 64
n
1 to 16
17 to 32
33 to 48
49 to 64
Memory Mapping of
OMRON
Serial Communications
to other PLCs
MODBUS Word Addr.
mapping
MODBUS Bit Addr.
Mapping
IR00.0 to IR00.15
IR01.0 to IR01.15
IR02.0 to IR02.15
IR03.0 to IR03.15
IR04.0 to IR04.15
IR05.0 to IR05.15
40001.1 to 40001.16
40002.1 to 40002.16
40003.1 to 40003.16
40004.1 to 40004.16
40005.1 to 40005.16
40006.1 to 40006.16
IR16.0 to IR16.15
IR17.0 to IR17.15
IR18.0 to IR18.15
IR19.0 to IR19.15
IR20.0 to IR20.15
IR21.0 to IR21.15
40017.1 to 40017.16
40018.1 to 40018.16
40019.1 to 40019.16
40020.1 to 40020.16
40021.1 to 40021.16
40022.1 to 40022.16
IR32.0
IR33.0
IR34.0
IR35.0
to
to
to
to
IR32.15
IR33.15
IR34.15
IR35.15
40033.1 to 40033.16
40034.1 to 40034.16
40035.1 to 40035.16
40036.1 to 40036.16
IR48.0
IR49.0
IR50.0
IR51.0
to
to
to
to
IR48.15
IR49.15
IR50.15
IR51.15
40049.1 to 40049.16
40050.1 to 40050.16
40051.1 to 40051.16
40052.1 to 40052.16
n
1 to16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
256 + n
257 to 272
273 to 288
289 to 304
305 to 320
321 to 336
337 to 352
512+n
513 to 528
529 to 544
545 to 560
561 to 576
768 + n
769 to 784
785 to 800
801 to 816
817 to 832
n
1 to 16
17 to 32
33 to 48
49 to 64
IR64.0
IR65.0
IR66.0
IR67.0
to
to
to
to
IR64.15
IR65.15
IR66.15
IR67.15
40065.1 to 40065.16
40066.1 to 40066.16
40067.1 to 40067.16
40068.1 to 40068.16
1024 + n
1025 to 1040
1041 to 1056
1057 to 1072
1073 to 1088
65 to 80
81 to 96
97 to 112
113 to 128
IR68.0
IR69.0
IR70.0
IR71.0
to
to
to
to
IR68.15
IR69.15
IR70.15
IR71.15
40069.1 to 40069.16
40070.1 to 40070.16
40071.1 to 40071.16
40072.1 to 40072.16
1089 to 1104
1105 to 1120
1121 to 1136
1137 to 1152
129 to 144
145 to 160
161 to 176
177 to 192
IR72.0
IR73.0
IR74.0
IR75.0
to
to
to
to
IR72.15
IR73.15
IR74.15
IR75.15
40073.1 to 40073.16
40074.1 to 40074.16
40075.1 to 40075.16
40076.1 to 40076.16
1153 to 1168
1169 to 1184
1185 to 1200
1201 to 1216
193 to 208
IR76.0 to IR76.15
40077.1 to 40077.16
209 to 224
IR77.0 to IR77.15
40078.1 to 40078.16
..
..
..
497 to 512
IR96.0 to IR96.15
40097.1 to 40097.16
*
MODBUS is a registered trademark of Groupe Schneider.
OMRON is a registered trademark of OMRON Corporation.
1217 to 1232
1233 to 1248
..
1521 to 1536
14-8
Chapter 14
Timer
Present Values
PLC Variables
1 to 64
Serial Communications
IR128
OMRON
to IR191
MODBUS
40129 to 40192
to
40257 to 40320
Counter
Present Values
1 to 64
IR256
Clock
TIME[1]
TIME[2]
TIME[3]
IR512
IR513
IR514
40513
40514
40515
Date
DATE[1]
DATE[2]
DATE[3]
DATE[4]
IR516
IR517
IR518
IR519
40517
40518
40519
40520
Variables A to Z
(32-bit)
A
B
….
Z
IR714 & IR715
IR715 & IR716
..
IR764 & 765
4-0715 & 4-0716
4-0717 & 4-0718
DM[1]
DM[2]
….
DM[4000]
DM[1]
DM[2]
….
DM[4000]
41001
41002
….
45000
(Firmware >= r79)
Data Memory
IR319
4-0763 & 4-0764
14.6.1.1 BIT ADDRESS MAPPING FROM A MODICON / MODBUS DEVICE
The bit register offset is shown in the last column of Table 14.1. Note that this is the Modicon addressing
style, which uses 1-based addressing. When the Modicon variation of the Modbus protocol is used to
access the Nano-10 (from software or a master device), the above bit addressing should be used.
When the standard Modbus protocol is used, 0-based addressing is required. This means that the
addresses should be one less than indicated in the last column of Table 14.1. Meaning you would use
address 0 to access input #1 on the Nano-10 instead of address 1.
All the Nano-10 I/O bits are mapped identically to both the MODBUS “0x” and 1x space. Although
MODBUS names the 0x address space as “Coil (which means output bits) and the “1x” address space as
“Input Status” (which means input bits only), the Nano-10 PLCs treat both spaces the same. Some
MODBUS drivers only allow you to “read” from 0x space and “write” to 1x space but you still use the
same offset shown on Table 14.1.
Example 1 – Modicon Variation:
To map a lamp symbol to PLC Input 4, you select the MODBUS register address 0-0004. You can also
map a lamp symbol to the PLC’s output #2. In that case, you should map it to MODBUS register address
0-0258.
To map a toggle switch symbol to the PLC input #4, if you are restricted to select only MODBUS 1x
address space, then you will have to map the switch to 1-0004, and likewise you can map the switch to
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Chapter 14
Serial Communications
output #2 using MOBDUS address 1-0258. But if the driver allows the switch to be mapped to 0x space,
then you can use MODBUS register space 0-0004 and 0-0258 for the mapping, with identical results.
Example 2 – Standard Modbus Variation:
To map a lamp symbol to PLC Input 4, you select the MODBUS register address 0-0003. You can also
map a lamp symbol to the PLC’s output #2. In that case, you should map it to MODBUS register address
0-0257.
To map a toggle switch symbol to the PLC input #4, if you are restricted to select only MODBUS 1x
address space, then you will have to map the switch to 1-0003, and likewise you can map the switch to
output #2 using MOBDUS address 1-0257. But if the driver allows the switch to be mapped to 0x space,
then you can use MODBUS register space 0-0003 and 0-0257 for the mapping, with identical results.
14.6.1.2 WORD ADDRESS MAPPING
As shown in Table 14.1, to access DM[1] from the PLC, you use MODBUS address space 4-1001 and so
on. To access the Real Time Clock Hour data (TIME[1]), use 4-0513. The I/O channels can also be read
or written as 16-bit words by using the addresses from 4-0001 to 4-0320.
Some MODBUS drivers (such as National Instruments “Lookout” software) even allow you to manipulate
individual bit within a 16-bit word. So it is also possible to map individual I/O bits to the “4x” address
space. E.g. Input bit #1 can be mapped to 4-0001.1 and output bit #2 is mapped to 4-0257.2, etc. This is
how it is shown in Table 14.1. However, if you do not need to manipulate the individual bit then you
simply use the address 4-0001 to access the system variable INPUT[1] and address 4-0257 to access
the system variable OUTPUT[1]. Note that INPUT[1] and OUTPUT[1] are TBASIC system variables and
they each contain 16 bits that reflect the on/off status of the actual physical or internal input and output
bits #1 to #16.
14.6.2 MODBUS RTU Protocol Support
The Nano-10 PLC also supports the MODBUS RTU protocol. The difference between the ASCII and RTU
protocols is that the latter transmits binary data directly instead of converting one byte of binary data into
two ASCII characters. A message frame is determined by the silent interval of 3.5 character times
between characters received at the COMM port. Other than that, the function codes and memory
mappings are identical to the MODBUS ASCII protocol. Table 14.1 therefore applies to the MODBUS
RTU protocol as well.
MOBBUS RTU has the following command and response format:
Start
Silence of 3.5
char times
Address
1 byte
Function
1 byte
Data
# byte
CRC 16
2 bytes
END
Silence of 3.5
char times
The following Function Codes are supported:
01/02
03/04
05
06
16
Read I/O bit (Use Bit Address Mapping in Table 14.1)
Read I/O Word registers
Force I/O Bit (Use Bit Address Mapping in Table 14.1).
Preset Single Word Register
Preset Multiple Word Registers
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Chapter 14
14.6.3 OMRON Host Link Command
Command Type
a)
b)
c)
d)
e)
TEST
STATUS READ
ERROR Read
IR Area READ
HR, AR, LR Area
& TC Status READ
f) DM AREA READ
g) PV READ
h) Status Write
l) IR Area WRITE
j) HR, AR, LR Area
& TC Status WRITE
k) DM Area WRITE
l) FORCED SET
m) Registered I/O Read
for Channel or Bit
Serial Communications
Support
Header
Level of Support
TS
MS
MF
RR
RH
Full support
Full support
Dummy (always good)
Full support (0000 to 1000)
Dummy (always returns “0000”)
RD
RC
SC
WR
WH, WJ,
WL, WG
WD
KSCIO
KRCIO
QQMR/
QQIR
Full support
Dummy (always returns “0000”)
Dummy (always OK)
Full Support
Dummy (always OK)
Full Support (from DM0001-DM4000)
Full Support for IR Area only
Dummy for other areas.
Full Support for IR and DM only
Dummy for other areas (always 0000)
Some OMRON host link commands are described in Section 16.40. For other commands please refer to
the Omron C20H/C40H PLC Operation manual published by OMRON Corporation. If your purpose is only
to use the PLC’s OMRON mode with SCADA or HMI, then there is no need to learn the actual
command/response format.
14.6.4 Application Example: Interfacing to SCADA Software
SCADA software or MMI systems (also known as LCD Touch Panels) normally use an object-oriented
programming method. Graphical objects such as switches indicator lights or meters, etc., are picked from
the library and then assigned to a certain I/O or internal data address of the PLC. When designing a
SCADA system, first you need to define the PLC type. You can choose the MODBUS ASCII, MODBUS
RTU or OMRON C20H. Once a graphical object has been created, you will need to edit its connection
and at this point you will be presented with a selection table that corresponds to the memory map of that
PLC type.
Example 1: To connect an indicator lamp to Input #9 of the PLC.
You will need to program the switch to connect to IR00.8 for the OMRON protocol. However, If you have
defined the PLC as MODBUS type, then this indicator lamp should be connected to bit address 1-0265.
In either case there is no need to learn about the actual command format of the protocol itself, as the
SCADA software will automatically generate the required commands to access the input address that has
been chosen for the object.
Example 2: To display readings from ADC #2 as a bar graph on SCADA.
Since the data from ADC #2 is not directly mapped to MODBUS or OMRON in Table 14.1, you need to
add a statement in the custom function that reads ADC #2 and copies it into a data memory, e.g.,
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Chapter 14
Serial Communications
DM[100] = ADC(2)
Now you can program the bar graph on the SCADA screen to be connected to DM[100] if you use the
OMRON protocol. For the MODBUS protocol, the object should be connected to the address: 4-1100
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Chapter 14
14.7
Serial Communications
Using The PLC As a Modbus Master
– Getting Data From Power or Flow Meters
The Nano-10 PLC support for the MODBUS protocol goes beyond being a MODBUS slave only. You can
use the TBASIC READMOBUS and WRITEMODBUS commands, as well as READMB2 and WRITEMB2
to send out MODBUS ASCII or RTU commands to access any other Nano-10, F-series or T100M+ series
PLC or any third party MODBUS slave devices. The READMODBUS or READMB2 commands use
MODBUS Function 03 (this can be changed to function 04 using SETSYSTEM 6,4 command) to read
from the slave, and WRITEMODBUS or WRITEMB2 use MODBUS Function 16 to write to the slave.
Note that when using the READMODBUS or WRITEMODBUS commands, the 40001 address stated in
Table 14.1 should be interpreted as address 0000, and 40002 as address 0001, and 41001 as address
1000, etc. This is in accordance with the specifications stated in MODBUS protocol. MODICON defined
zero offset addresses for the MODBUS protocol, yet in their holding register definition these are
supposed to start from address 40001 - hence the unusual correspondence. But to maintain compatibility
with the MODBUS specifications, we have to adhere to their definitions.
14.7.1 Nano-10
PLC As MODBUS RTU Master
The Nano-10 PLC can also act as a MODBUS RTU master! The same READMODBUS and
WRITEMOBUS commands can be used to send and receive MODBUS RTU commands. What you need
to do is add 10 (decimal) to the COMM port number to signal to the processor that you wish to use
MODBUS RTU instead of MODBUS ASCII to talk to the slaves.
In other words, you should specify port #11 to use RTU commands on COMM1.
E.g. the statement DM[10] = READMODBUS (11, 8, 16)
will access, via COMM1, the slave with ID = 08 and read the content of register #16. This register
corresponds to MODICON address 40017 and is the OUTPUT[1] of the slave PLC.
The ability to speak MODBUS RTU greatly extends the type of peripherals that can be used with a Nano10 PLC. You can now make use of many off-the-shelf, third party RTU devices to extend the PLC
capability.
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Chapter 15
Chapter 15
Host Link Communication Protocol
Host Link Communication Protocol
Chapter 15
Host Link Communication Protocol
15 HOST LINK PROTOCOL INTRODUCTION
While a Nano-10 PLC is running, it may receive ASCII string commands that read or write to its inputs,
outputs, relays, timers, counters, and all the internal variables from a host computer or another Nano-10,
F-Series or T100M+ PLC. These ASCII commands are known as the "Host-link commands" and are to be
serially transmitted (via RS485 port) to and from the controller. The default serial port settings of the
Nano-10 PLC for host-link communication are: 38400 baud, 8 data bit, 1 stop bit, no parity. The baud rate
and the communication format may be changed using the “SetBAUD” TBASIC command described in the
i-TRiLOGI Programmer’s Reference.
Nano-10 PLC supports the full set of Host Link command protocol found on F-series and M-series PLCs.
Hence if you are already familiar with the F or M-series host link protocol the command formats are
identical.
15.1 Multiple Communication Protocols
The Nano-10 PLC, just like the F-series and T100M+ PLCs, supports many different communication
protocols to allow maximum application flexibility. In addition to its own native set of communication
protocols, the Nano-10 PLC also understands and speaks the following protocols:
a) *MODBUS™ ASCII mode compatible communication protocol.
b) *MODBUS™ RTU mode compatible communication protocol.
c) *OMRON™ Host Link Commands for the C20H PLC family.
*Note:
all trademarks belong to their respective owners.
The native host link command protocol will be described in detail in this and the next chapter. The
MODBUS and OMRON compatible protocols have already been discussed in Section 14.7.
15.2 Native Mode Communication Protocols
When the Nano-10 receives a native host-link command via COMM1, it will automatically send a
response string corresponding to the command. This operation is totally transparent to the user and does
not need to be handled by the user’s program.
All Nano-10 PLCs support both the point-to-point (one-to-one) and multi-point (one-to-many)
communication protocols. Each protocol has a different command structure as described below.
15.3 Point-To-Point Communication Format
In a point-to-point communication system, the host computer's RS485 serial port is connected to the
PLC’s COMM1. At any one time, only one controller may be connected to the host computer. The hostlink commands do not need to specify any controller ID code and are therefore of a simpler format, as
shown below:
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Chapter 15
Host Link Communication Protocol
15.3.1 Command/Response Frame Format (Point to Point)
x
x
....
Header
....
Data
....
*
Terminator
Each command frame starts with a two-byte ASCII character header, followed by a number of ASCII data
and ends with a terminator which is comprised of a '*' character and a carriage return (ASCII value =
1310). The header denotes the purpose of the command. For example, RI for Read Input, WO for Write
Output, etc. The data is usually the hexadecimal representation of numeric data. Each byte of binary data
is represented by two ASCII characters (00 to FF).
To begin a communication session, the host computer must first send one byte of ASCII character: Ctrl-E
(=05Hex) via its serial port to the controller. This informs the controller that the host computer wishes to
send a (point-to-point) host-link command to it. Thereafter, the host computer must wait to receive an
echo of the Ctrl-E character from the controller. Reception of the echoed Ctrl-E character indicates that
the controller is ready to respond to the command from the host computer. At this moment, the host
computer must immediately send the command frame to the controller and then wait to receive the
response frame from the controller. The entire communication session is depicted in Figure 15.1.
After the controller has received the command, it will send a response frame back to the host computer
and this completes the communication session. If the controller accepts the command, the response
frame will start with the same header as the command, followed by the information that has been
requested by the command and the terminator.
As you can probably see, proper handshaking using the Ctrl-E character between the host and the PLC is
important to communicate successfully using the Point-to-point protocol.
Although the “Multi-point” format discussed in the next section seems more complex, the communication
exchange using multi-point protocol is actually simpler than point-to-point since it involves only a single
exchange of command/response string. We therefore recommend using the multi-point format if you are
writing your own communication program.
Note: TBASIC has a built-in command “NETCMD$” that lets a Nano-10 PLC access another slave PLC
using the multipoint Host-link protocol format very easily.
If an unknown command is received or if the command is illegal (such as access to an unavailable output
or relay channel), the following error response will be received:
15.3.2 Error Response Format
E
R
*
The host computer program should always check the returned response for possibilities of errors in the
command and take necessary actions.
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Host Link Communication Protocol
The F-Series PLC
Host Computer
Send Ctrl -E
(05H) and wait
for echo
Ready to process
command: return
Ctrl-E (05H)
Send Command
string to controller
Wait for response
Execute command.
Return Response
string to host
Accept Response
Check for errors
Figure 15.1
15.4 MULTI-POINT COMMUNICATION SYSTEM
In this system, one host computer may be connected to either a single PLC (via RS485) or multiple PLCs
on an RS485 network.
15.4.1 Command/Response Frame Format (Multi-point)
@
n
n
Device ID
x
x
Header
.... .... ....
Data
x
x
FCS
*
Terminator
Each command frame starts with the character "@" and two-byte hexadecimal representation of the
controller's ID (00 to FF), and ends with a two-byte "Frame Check Sequence" (FCS) and the terminator.
FCS is provided for detecting communication errors in the serial bit-stream. If desired, the command
frame may omit calculating the FCS simply by putting the characters "00" in place of the FCS.
Note: we call “00” the “wildcard” FCS, which is available when the PLC is in “auto protocol” mode. This is
to facilitate easy testing of the multi-point protocol. However, the wildcard FCS can be disabled if the PLC
has executed the SETPROTOCOL n, 5 to put its COMM port n into pure native mode. In that case you will
have to supply the actual FCS to your command string.
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Host Link Communication Protocol
15.4.2 Calculation of FCS
The FCS is 8-bit data represented by two ASCII characters (00 to FF). It is a result of performing an
Exclusive OR on each character in the frame sequentially, starting from @ in the device number to the
last character in the data. An example is as follows :
@
0
4
R
Device ID
@
0
4
R
V
I
A
V
I
Header
A
4
Data
8
*
FCS
0100 0000
XOR
0011 0000
XOR
0011 0100
XOR
0101 0010
XOR
0101 0110
XOR
0100 1001
XOR
0100 0001
0100 1000
= 4816
Value 4816 is then converted to ASCII characters '4' (0011 0100) and '8' (0011 1000) and placed in the
FCS field.
FCS calculation program example
The following C function will compute and return the FCS for the "string" passed to it.
unsigned char compute_FCS(unsigned char *string){
unsigned char result;
result = *string++;
/*first byte of string*/
while (*string)
result ^= *string++; /* XOR operation */
return (result);
}
A Visual Basic routine for FCS computation is included in the source code of a sample communication
program you can download from:
http://www.tri-plc.com/applications/VBsample.htm#VB6sample
15.4.3 Communication Procedure
Unlike the point-to-point communication protocol, the host computer must NOT send the CTRL-E
character before sending the command frame. After the host computer has sent out the multi-point hostlink command frame, only the controller with the correct device ID will respond. Hence it is essential to
ensure that every controller on the RS485 network assumes a different ID (If a master PLC is used, then
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Host Link Communication Protocol
the master PLC should also have a different ID from all the slaves). Otherwise, contention may occur
(i.e., two controllers simultaneously sending data on the receiver bus, resulting in garbage data being
received by the host). On the other hand, if none of the controller IDs match that specified in the
command frame, then the host computer will receive no response at all.
The PLC automatically recognizes the type of command protocols (point-to-point or multi-point) sent by
the host computer and it will respond accordingly. If a multi-point command is accepted by the controller,
the response frame will start with a character '@', followed by its device ID and the same header as the
command. This will be followed by the data requested by the command, a response frame FCS and the
terminator.
15.4.4 Framing Errors
When the controller receives a multi-point host-link command frame, it computes the FCS of the
command and compares it with the FCS field received in the command frame. If the two do not match,
then a "framing error" has occurred. The controller will send the following Framing Error Response to the
host:
Framing Error Response Frame (Multi-point only)
@
x
x
Device ID
F
E
Header
x
x
FCS
*
Terminator
15.4.5 Command Errors
If an unknown command is received or if the command is illegal (such as an attempt to access an
unavailable channel), the following error response will be received:
Error Response Format
@
x
x
Device ID
E
R
Header
x
FCS
x
*
Terminator
The host computer program should always check the returned response for possibilities of errors in the
command and take necessary action.
15.4.6 SHOULD YOU USE POINT-TO-POINT OR MULTI-POINT PROTOCOL?
Although at first the point-to-point protocol appears simpler in format (having no ID and no FCS
computation), the communication procedure is actually more complex since it involves the need to
synchronize the two communicating devices by exchanging the Control-E character. The lack of error
checking also makes the protocol less reliable especially in noisy environment.
In fact, the TLServer software will only accept multi-point communication protocol from the client software
with the exception of the “IR*” command, which is needed to obtain the ID of a PLC with unknown ID.
Hence, if you were to write your own communication program to talk to the PLCs, we would strongly
recommend using only the multi-point protocol exclusively due to its simplicity and built-in error checking
capability.
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Chapter 15
15.5
Host Link Communication Protocol
RS485 Primer
15.5.1 RS485 Network Interface Hardware
The built-in RS-485 interface allows the Nano-10 PLC to be networked together using very low cost
twisted-pair cables. Since the Nano-10 PLCs are fitted with a 1/8-power RS485 driver such as the
75HVD3082, up to 256 devices can be connected together. The twisted-pair cable goes from node to
node in a daisy chain fashion and should be terminated by a 120-ohm resistor as shown below.
+5V
Twisted -pair RS485 network cable
RS485
+
_
Host Computer with
RS-485 or
Nano-10 PLC
+
_
+
F-series
RS485
_
T100MD+
RS485
Terminating
resistor
+
_ 120Ω
560
+
560
_
0V
T28H-Relay
RS485
Figure 15.2
Note that the two wires are not interchangeable so they must be wired the same way to each controller.
The maximum wire length should not be more than 1200 meters (4000 feet). RS-485 uses balanced or
differential drivers and receivers, which means that the logic state of the transmitted signal depends on
the differential voltage between the two wires and not on the voltage with respect to a common ground.
As there will be times when no transmitters are active (which leaves the wires in "floating" state), it is
good practice to ensure that the RS-485 receivers will indicate to the CPUs that there is no data to
receive. In order to do this, we should hold the twisted pair in the logic '1' state by applying a differential
bias to the lines using a pair of 560Ω to 1KΩ biasing resistors connected to a +9V (at least +5V) and 0V
supply as shown in Figure 15.2. Otherwise, random noise on the pair could be falsely interpreted as data.
The two biasing resistors are necessary to ensure robust data communication in actual applications.
Some RS485 converters may already have biasing built-in so the biasing resistors may not be needed.
However, if the master is an F-series, M-series or Nano PLC then you should use the biasing resistor to
fix the logic states to a known state. Although in a lab environment the PLCs may be able to
communicate without the biasing resistors, their use is strongly recommended for industrial applications.
15.5.2 Protection of RS485 Interface
The simple, direct multi-drop wiring shown in Figure 15.2 will work well if all the networked PLCs are in
close proximity and they all share a common power supply. They will even work for long distance as long
as there are no wiring errors. However, in an industrial environment, the PLCs are most likely far apart
and may each have their own power supply. Since processes are often modified regularly, should
somebody on one occasion by mistake short one of the PLC’s RS485 to high voltage, all the PLCs
connected to the same RS485 wiring will be fried simultaneously. This can result in very costly down time
for the whole process because all of the PLCs connected to the network will need to be repaired.
Hence, for networking over long distances and involving more than a few PLCs, it is important to either
strengthen or protect the RS485 interface, as described below:
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Host Link Communication Protocol
1. You can replace the standard RS485 driver (75HVD3082) on the PLC with a fault-tolerant RS485
driver IC; part number LT1785AIN8. This 8 pin IC is made by Linear Technology and can
withstand wrong voltages of up to +60V! The LT1785AIN8 is a 1/4 power RS485 driver, which
means up to 128 PLCs can be connected together.
Unfortunately this IC is much more expensive than 75HVD3082 and hence it is not provided as
standard component on the PLC. You can purchase the IC from any major electronic catalog
company such as www.digikey.com.
2. When using non fault-tolerant RS485 drivers such as SN75176 or SN75HVD3082, we strongly
recommend the following protection circuit to be added between every PLC’s RS485 and the
twisted pair multi-drop network cable:
RS485 Network
+
10 Ω 1/2 W 0.1A Fuses
RS485
24V
9V 1W
Zener
Power
0V
Ground the
Shield
Figure 15.3
Note:
As can be seen from the circuit, the two 9V Zener diodes clamp the signal voltage on the PLC’s RS485
interface to between +9V and - 0.7V. If the high voltage persists, the 0.1A fuse will blow, effectively
disconnecting the PLC from the offending voltage on the network.
Even if you choose to replace the RS485 driver by an LT1785AIN8 IC instead of using the zener/fuse pair
wiring, you should still use shielded twisted pair cables as the multi-drop network “backbone” and connect
the shield to the 0V (DC ground) power terminal of every PLC. The grounded shield then provides a
common ground reference for all the different PLCs’ power supplies. Even though the RS485 network
may still work without a common ground reference because the signal wire pair will somehow “pull” all the
RS485 devices to some reference point. Failure to provide a common ground is a potential source of
serious trouble as signal wires with a floating ground easily induce large voltage differences between
nodes when subjected to electromagnetic interference. Hence, for reliable operation it is important to
provide the common ground. A grounded shield also has the additional advantage of shielding the
electrical signals from EMI.
15.5.3 Single Master RS485 Networking Fundamentals
RS485 is a half-duplex network, i.e., the same two wires are used for both transmission of the command
and reception of the response. Of course, at any one time, only one transmitter may be active. The Nano10 PLC implements a master/slave network protocol. The network requires a master controller, which is
typically a PC equipped with an RS485 interface. In the case of a PC, you can purchase an RS-485
adapter or an RS232C-to-RS485 converter and connect it to the RS232C serial port. Any F-series, Mseries, or even the Nano-10 PLC can be programmed to act as the master, it can communicate with other
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Host Link Communication Protocol
PLCs by executing the “NETCMD$” function or the “READMODBUS” or the “WRITEMODBUS”
commands (the latter two are for communicating using MODBUS protocols only and are covered in
Section 14.8).
Only the master can issue commands to the slave PLCs. To transmit a command, the master controller
must first enable its RS-485 transmitter and then send a multi-point command to the network of
controllers. After the last stop bit has been sent, the master controller must relinquish the RS485 bus by
disabling its RS485 transmitter and enabling its receiver. At this point the master will wait for a response
from the slave controller that is being addressed. Since the command contains the ID of the target
controller, only the controller with the correct ID would respond to the command by sending back a
response string. For the network to function properly, it is obvious that no two nodes can have the same
ID. You can use the “Setup Serial Port” command in TLServer to set the ID for each PLC on the node.
You can also use the "IW” Host Link command to set the device ID. Also, all nodes must be configured to
the same baud rate and communication format.
Care should be taken to ensure that the power supplies for all the controllers are properly isolated from
the main so that no large ground potential differences exist between any controllers on the network.
15.5.4 Multi-Master (Peer-to-Peer) RS485 Networking Fundamentals
The built-in Ethernet port of Nano-10 PLC inherently supports multi-master, peer-to-peer network
connection without any arbitration. Therefore if there is a need to perform peer-to-peer networking, it will
be much easier to do it via the Ethernet port. However, if the Nano-10 is not connected to LAN or a low
cost local networking solution via RS485 is desired, then the following discussion will be relevant.
Since any F, M or Nano PLC is capable of sending out network commands, the obvious question is
whether multiple masters are allowed on the RS485 network? It is possible to have multiple masters on a
single RS485 network provided the issues of collision and arbitration are taken care of. There are several
means to achieve these objectives.
15.5.4.1 Multiple Access with Collision Detection
There is nothing to stop any PLC from sending out host-link commands to other PLCs. However, if more
than one PLC simultaneously enables their transmitters and send out host-link commands, then the
signals will conflict and the messages will be garbled up. If the network traffic is low, then the solution
may be a matter of having the master check for the correct response after sending out a command string.
If there is error in the response string, the master should back off the network for a short while (use
different timing for different PLCs) and then re-send the command until a correct response string is
obtained.
Fortunately, the “NETCMD$” function of these PLCs always checks the integrity of the response string for
correct FCS (Frame Check Sequence) characters before returning the string (Please refer to the
Programmer’s Reference for detail description of the NETCMD$( ) function).
However, the program must still check the following items in the response string to verify that the string
returned from NETCMD$( ) function indeed comes from the PLC that it had talked to and not from
another PLC (which tries to send a command to someone else):
i)
ii)
iii)
The ID is correct
The header is identical to the command string
The length of response string is correct.
Pros and Cons: This method does not incur any hardware cost, but it requires careful programming and
strict checking of the response string and hence requires more effort to program. It is also the least
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Host Link Communication Protocol
desirable if the network traffic is moderately high as many collisions will occur and there is danger of
some undetected error being allowed to pass through.
15.5.4.2 Token Awarding Scheme
A “token” is a software means of telling a PLC that it has been given the right to temporarily act as the
master. A Nano-10 PLC or a host PC can serve as the token master. An internal relay bit or a variable of
the PLC can be defined as the token. The token master will begin by giving the token (i.e., by setting the
token relay bit to ‘1’ or the token variable to some fixed value) to the first PLC on the list. The PLC that
has the token can then send host-link commands to other PLCs. When it has finished the job it can then
send a command to the token master to relinquish its token. If it is based on a fixed timing scheme the
master can assume that the PLC will complete its job after a fixed time (say 0.1 seconds) and turn off its
corresponding token relay bit.
The token master then passes the token to the next PLC on the list and so on until the last PLC has
relinquished its token, and the token is passed back to the first PLC on the list again. This way at any one
time there will only be one active network master (the one with the token) and hence there is no danger of
conflicting signals or garbled messages to handle.
Pros and Cons: This method also does not incur any hardware cost, but it requires the programmer to
draw up a plan on what internal relay or variable to use as the token and how the PLC can relinquish its
token to the token master. (It could be by fixed timing or by returning a message to relinquish the token) It
is a challenging job for programmers unfamiliar with networking schemes, but with some experimentation
it can be achieved readily.
15.5.4.3 Rotating Master Signal
In this scheme we make use of the digital inputs of the PLC to grant the PLC the right to act as the
network master. Lets call this input the “Be the Master” input. We can use a low cost H-series PLC
running a sequencer to activate the “Be the Master” input line of each PLC one at a time. Each PLC is
given a fixed amount of time to be the master (e.g. 0.1s each). Only when the “Be the Master” input is
ON can the new master PLC start sending out host-link commands to other PLCs. So at any one time
there will only be one master on the network and no conflict will occur as a result.
Pros and Cons: This method is the easiest to program since there is no need to handle the token with the
token master or perform extensive error check on the response string. However, this method uses one
input of each PLC and as many outputs on the master-signal generator PLC as there are PLC masters. It
also requires wiring the PLCs to the master-signal generator PLC.
15.5.5 TROUBLE-SHOOTING AN RS485 NETWORK
1)
Single faulty device
If a single device on the RS485 network becomes inaccessible, problems can be isolated to this particular
device. Check for loose or broken wiring or wrong DIP switch settings. Also double check the device ID
using the host-link command "IR*" sent via the RS232C port of the PLC. If all attempts fail, either
replace the entire PLC or the 75HVD3082 chip that handles the RS485 interfacing and try again.
2) Multiple faulty devices
If all the PLCs are inaccessible by the host computer, it may possibly be due to a faulty RS232C-toRS485 converter at the host computer. If this is the case, disconnect the RS485 converter from the
network and check it using a single PLC. Replace the converter if it is confirmed to be faulty. Next check
the wire from the converter to the beginning of the network. A broken wire here can lead to the failure of
the entire network.
15-9
Chapter 15
Host Link Communication Protocol
Since an RS485 network links many PLCs together electrically and in a daisy chain fashion, problems
occurring along the RS485 network sometimes affect the operation of the entire network. For example, a
broken wire at the terminal of one node may mean that all the PLCs connected after this node become
inaccessible by the master. If the RS485 interface of one of the PLCs has short-circuited because of
component failure, then the entire network goes down with it too. This is because no other node is able to
assert proper signals on the two wires that are also common to the shorted device.
Hence, when trouble-shooting a faulty RS485 network, it may be necessary to isolate all the PLCs from
the network. Thereafter, reconnect one PLC at a time to the network, starting from the node nearest to
the host computer. Use the TRiLOGI program to check communication with each PLC until the faulty unit
has been identified.
15-10
Chapter 16
Chapter 16
Host Link Command/Response Format
Host Link Protocol Format
Chapter 16
Host Link Command/Response Format
16 HOST LINK PROTOCOL FORMAT
This chapter describes the detailed formats of the command and response frames for Nano-10 PLC host
link commands. Only the formats for the point-to-point communication protocol are presented, but all
these commands are available to the multi-point protocol as well.
To use a command for multi-point system, simply add the device ID (@nn) before the command header
and the FCS at the end of the data (See Chapter 3 for detailed descriptions of multi-point communication
command format).
16.1
Device ID Read
Command Format
I
R
*
Response Format
I
R
161
160
*
Device ID (00 to FF)
The device ID is to be used for the multi-point communication protocol so that the host computer can
selectively communicate with any controller connected to a common RS485 bus (see Chapter 3 for
details). The ID has no effect for point-to-point communication. The device ID is stored in the PLC's nonvolatile memory and, therefore, will remain with the controller until it is next changed.
16.2
Device ID Write
Command Format
I
W
161
160
*
New Device ID (00 to FF)
Response Format
I
W
*
E.g. To set the PLC’s ID to 0A, send command string “IW0A*” to PLC.
16.3
Read Digital Input Channels
Command Format
R
I
n
n
*
8-bit Channel # (Hex)
16-1
Chapter 16
Host Link Command/Response Format
Response Format
R
I
161
8-bit
160
*
Data (Hex)
16.3.1 Definition of Input Channels
The following table shows the input numbers as defined in TRiLOGI's Input entry table corresponding to
the input channel number.
Bit7
CH00:
CH01:
CH02:
CH03:
CH04:
CH05:
CH06:
CH07:
CH08:
CH09:
CH0A16:
CH0B16:
CH0C16:
….
CH1E16:
CH1F16:
Input/Output Numbers
Bit0
8
16
24
32
40
48
56
64
72
80
88
96
104
7
15
23
31
39
57
55
63
71
79
87
95
103
6
14
22
30
38
56
54
62
70
78
86
94
102
5
13
21
29
37
45
53
61
69
77
85
93
101
4
12
20
28
36
44
52
60
68
76
84
92
100
3
11
19
27
35
43
51
59
67
75
83
91
99
2
10
18
26
34
42
50
58
66
74
82
90
98
1
9
17
25
33
41
49
57
65
73
81
89
97
..
..
..
..
..
..
..
..
248
256
247
255
246
254
245
253
244
252
243
251
242
250
241
249
The 8-bit inputs of each channel are represented by a two byte ASCII text expression of its hexadecimal
value. For example: if inputs 1 to 3 are logic '0's, inputs 4 to 10 are logic '1's and all other inputs are
logic '0's, then if you send command “RI00*”, you will get the response “RIF8*” (F816 =1111 10002).
16.4
Read Digital Output Channels
Command Format
R
O
n
n
*
8-bit Channel # (Hex)
Response Format
R
O
161
160
*
8-bit data (Hex)
16-2
Chapter 16
Host Link Command/Response Format
Please refer to the Input/Output vs Channel Number table described in the section “16.3. Read Digital
Input Channels” for details.
16.5
Read Internal Relay Channels
Command Format
R
R
n
n
*
8-bit Channel # (Hex)
Response Format
R
161
R
8-bit
160
*
data (Hex)
16.5.1 Definition of Internal Relay Channel Numbers
Nano-10 supports 512 internal relays, the channel definition of the first 256 internal relays is the same as
the inputs and the outputs. The remaining relays and their assigned channels are shown in the following
table:
bit7
CH2016:
CH2116:
CH2216:
CH2316:
CH2416:
CH2516:
CH2616:
CH2716:
CH2816:
CH2916:
CH2A16:
CH2B16:
..
CH3A16:
CH3D16:
CH3E16:
CH3F16:
264
272
280
288
296
304
312
320
328
336
344
352
..
488
496
504
512
Relay numbers
263
271
279
287
295
303
311
319
327
335
343
351
..
487
495
503
511
262
270
278
286
294
302
310
318
326
334
342
350
..
486
494
502
510
261
269
277
285
293
301
309
317
325
333
341
349
..
485
493
501
509
260
268
276
284
292
300
308
316
324
332
340
348
..
484
492
500
508
bit0
259
267
275
283
291
299
307
315
323
331
339
347
..
483
491
499
507
258
266
274
282
290
298
306
314
322
330
338
346
..
482
490
498
506
257
265
273
281
289
297
305
313
321
329
337
345
..
481
489
497
505
16-3
Chapter 16
Host Link Command/Response Format
16.6 Read Timer Contacts
Command Format
R
T
n
n
*
8-bit Channel # (Hex)
Response Format
R
161
T
160
*
8-bit data in Hex
16.6.1
Definition of Timer-Contact Channel Numbers
A timer contact is a single bit of memory and 8 timer contacts are grouped into one 8-bit channel similar
to that of the inputs, outputs etc.
The following table shows the timer numbers defined in TRiLOGI's Timer entry table and their
corresponding channel numbers.
bit7
CH0:
CH1:
CH2:
CH3:
CH4:
CH5:
CH6:
CH7:
16.7
Timer Contact numbers
8
16
24
32
40
48
56
64
7
15
23
31
39
57
55
63
6
14
22
30
38
56
54
62
5
13
21
29
37
45
53
61
4
12
20
28
36
44
52
60
bit0
3
11
19
27
35
43
51
59
2
10
18
26
34
42
50
58
1
9
17
25
33
41
49
57
Read Counter Contacts
Command Format
R
C
n
n
*
8-bit channel # (Hex)
Response Format
R
C
161
160
*
8-bit data in Hex
16.7.1 Definition of Counter-Contact Channel Numbers:
The 64 counter contacts are assigned channel #’s in exactly the same way as the 64 timers. Please refer
to the last section: “16.6. Read Timer Contacts” for details.
16-4
Chapter 16
Host Link Command/Response Format
16.8 Read Timer Present Value (P.V.)
Command Format
R
M
n
nn:
*
n
Timer1=00,
..... Timer16=0F.... Timer64=3F
Response Format
R
M
103
102
101
100
*
Timer present value in Decimal
The present value (PV) of the specified timer is returned in decimal form as four byte ASCII text
characters from 0000 to 9999.
16.9 Read Timer Set Value (S.V.)
Command Format
R
m
n
nn:
*
n
Timer1=00,
..... Timer16=0F.... Timer64=3F
Response Format
R
m
103
102
101
100
*
Timer Set Value in Decimal
The Set Value (S.V.) of the specified timer is returned in decimal form as four byte ASCII text characters
from 0000 to 9999. Note that this command header contains small letter “m” instead of “M” in the “RM”
command.
16.10 Read Counter Present Value (P.V.)
Command Format
R
U
n
nn:
*
n
Counter1=00,
..... Counter16=0F.... Counter64=3F
Response Format
R
U
103
102
101
100
*
Counter present value in Decimal
The Present Value of the specified counter is returned in decimal form as four byte ASCII text characters
from 0000 to 9999.
16-5
Chapter 16
Host Link Command/Response Format
16.11 Read Counter Set Value (S.V.)
Command Format
R
u
n
nn:
*
n
Counter1=00,
..... Counter16=0F.... Counter64=3F
Response Format
R
u
103
102
101
100
*
Counter Set Value in Decimal
The Set Value of the specified counter is returned in decimal form as four byte ASCII text characters from
0000 to 9999. Note that this header contains small letter “u” instead of “U” in the “RU” command.
16.12 Read Variable - Integers (A to Z)
Command Format
R
V
I
alphabet
*
A,B.C....Z
Response Format
R
V
167
I
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
E.g. To read the value of the variable “K”, send host-link command “RVIK*”. If variable K contains
the value 12345610 (=1E24016), the PLC will send the response string as “RVI0001E240*”.
16.13 Read Variable - Strings (A$ to Z$)
Command Format
R
V
$
*
alphabet
A,B.C....Z
Response Format
R
V
$
a
a
a
...
...
a
a
a
*
ASCII characters of the string (variable length)
E.g.
To read the value of the string variable “M$”, send host-link command “RV$M*”. If variable
M$ contains the string “Hello World”, the PLC will send the response string as “RV$Hello
World*”.
16-6
Chapter 16
Host Link Command/Response Format
16.14 Read Variable - Data Memory (DM[1] to DM[4000])
Command Format
R
V
D
163
162
161
160
*
0001 to 0FA0 (400010)
Response Format
R
V
D
163
162
161
160
*
4 Hexadecimal Digit for 16-bit integer
E.g. To read the value of DM[3600], send host-link command “RVD0E10*”. If variable DM[3600]
contains the value 1234510 (=303916), PLC will send the response string as “RVD3039*”.
16.15 Read Variable - System Variables
This command allows you to read all the Nano-10 PLC’s 16-bit system variables such as the inputs[ ],
outputs[ ], relays[ ], counters[ ], timers[ ], timers’ P.V., counters’ P.V., CLK[ ] and DATE[ ]. Although inputs,
outputs etc. are also accessible via the “RI”, “RO”, “RR”... commands, the RVS command can access
them as 16-bit words instead of as 8-bit bytes in those commands. For the 32-bit system variable
HSCPV[ ], use the “RVH” command described in the next section to access it. It may be more
conventional for some SCADA software driver to use a single header command “RVS” to access all the
I/O, varying only the “type” number to access different I/O types.
The RVS command also can be used to access the internal variables used to store ADC, DAC and PWM
values obtained during the latest execution of the ADC(), setDAC or setPWM statement. These are
however not system variables in the TBASIC sense. E.g. it is illegal to use ADC[2] to access the ADC
channel #2 in TBASIC (you have to use the ADC(2) function instead). An 8-bit hexadecimal number is
used to denote the “type” of system variable, as shown in the following table:
System
Variable
input[ ]
output[ ]
relay[ ]
timer[ ]
ctr[ ]
timerPV[ ]
ctrPV[ ]
type
01
02
03
04
05
06
07
System
type
Variable
clk[ ]
08
date[ ]
09
0A
ADC*
0B
DAC*
0C
PWM*
0D
*Not a system variable in
TBASIC, but readable.
16-7
Chapter 16
Host Link Command/Response Format
Command Format
R
V
S
n
161
n
type
160
*
Index
type
(01 to 0D) - denotes the type of system variable to access,
index (01 to 1F) - index into the array, starting from 01.
Response Format
R
V
163
S
162
161
160
*
4 Hexadecimal Digit for 16-bit integer
Example: To read the value of DATE[2] (which represents the month of the RTC), send command
“RVS0902*” and if the PLC responds with “RVS0005”, it means the month is May.
16.16 Read Variable - High Speed Counter HSCPV[ ]
Command Format
R
V
H
n
*
Channel: 1 or 2
Response Format
R
V
167
H
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
E.g.
To read the value of HSCPV[2], send hostlink command “RVH2*”. If variable HSCPV[2]
contains the value 12345610 (=1E24016), the PLC will send the response string as
“RVH0001E240*”.
16.17 Write Inputs
Command Format
W
I
n
n
Channel #
(00 to 0F)
161
160
*
Data
Response Format
W
I
*
16-8
Chapter 16
Host Link Command/Response Format
16.18 Write Outputs
Command Format
W
O
n
n
161
Channel #
(00 to 0F)
160
*
160
*
160
*
160
*
Data
Response Format
W
O
*
16.19 Write Relays
Command Format
W
R
n
n
161
Channel #
Response Format
W
R
Data
*
16.20 Write Timer-contacts
Command Format
W
T
n
n
161
Channel #
(00 to 07)
Data
Response Format
W
T
*
16.21 Write Counter-contacts
Command Format
W
C
n
n
Channel #
(00 to 07)
161
Data
16-9
Chapter 16
Host Link Command/Response Format
Response Format
W
C
*
16.22 Write Timer Present Value (P.V.)
Command Format
W
M
n
n
103
102
101
100
*
Timer1=00,
New timer PV
........
Timer64=3F (Hex)
Response Format
W
*
M
Please note that the timer number starts from 00, which represent timer #1, then 01 represents timer #2.
and so on.
16.23 Write Timer Set Value (S.V.)
Command Format
W
m
n
103
n
102
101
100
*
Timer1=00,
New timer SV
....
Timer64=3F (Hex)
Response Format
W
Note:
*
m
the 2nd character is a lower case “m” instead of the upper case “M” of “WM” command.
16.24 Write Counter Present Value (P.V.)
Command Format
W
U
n
n
103
102
101
100
*
Counter1=00,
New PV
....
Counter64=3F (Hex)
16-10
Chapter 16
Host Link Command/Response Format
Response Format
W
*
U
16.25 Write Counter Set Value (S.V.)
Command Format
W
u
n
103
n
102
101
100
*
Counter1=00,
New Counter SV
....
Counter64=3F (Hex)
Response Format
W
*
u
Note: the 2nd character is a lower case “u” instead of the upper case “U” of the “WU” command.
16.26 Write Variable - Integers (A to Z)
Command Format
W
V
167
alphabet
I
A,B.C....Z
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
Response Format
W
E.g.
V
*
I
To assign variable
“WVIK00000DD5*”.
“K”
to
number
5678910(=0DD516),
send
hostlink
command
16.27 Write Variable - Strings (A$ to Z$)
Command Format
W
V
$
alphabet
a
a
...
...
a
a
*
A,B.C....Z ASCII characters of the
string (variable length)
Response Format
W
V
$
*
16-11
Chapter 16
Host Link Command/Response Format
E.g. To assign the string “ Super PLC” to the string variable P$, send hostlink command “WV$P
Super PLC*”.
16.28 Write Variable - Data Memory (DM[1] to DM[4000])
Command Format
W
V
D
163
162
161
160
163
16-bit Index to array
0001 to 0FA0 (400010)
162
161
160
*
16-bit Integer Data
Response Format
W
E.g.
V
D
*
To write the value 123410 (=4D216)to DM[1000], send hostlink command “WVD03E804D2*”.
(100010 = 3E816)
16.29 Write Variable - System Variables
System
Variable
input[ ]
output[ ]
relay[ ]
timer[ ]
ctr[ ]
timerPV[ ]
ctrPV[ ]
type
System
type
Variable
clk[ ]
08
date[ ]
09
0A
ADC*
0B
DAC*
0C
PWM*
0D
*Not a system variable in TBASIC
01
02
03
04
05
06
07
Command Format
W
V
S
n
n
type
161
160
Index
163
162
161
160
*
16-bit Integer Data
type
(01 to 0D) - denotes the type of system variable to access,
index (01 to 1F)
- index into the array, starting from 01.
Response Format
W
E.g.
V
S
*
To set clk[1] (which represents the hour of the RTC) to 14, send the command
“WVS0801000E*” to the PLC.
16-12
Chapter 16
Host Link Command/Response Format
16.30 Write Variable - High Speed Counter HSCPV[ ]
Command Format
W
V
H
n
167
1 or 2
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
Response Format
W
E.g.
V
H
*
To clear the value of HSCPV[2],
send hostlink command “WVH200000000*”.
16.31 Halting the PLC
Command Format
C
2
*
Response Format
C
2
*
When the PLC receives this command, it temporarily halts the execution of the PLC's ladder program
after the current scan. However, the PLC continues to scan the I/Os and processes host link commands
sent to it and will report the current I/O data and internal variables to the host computer.
16.32 Resume PLC Operation
Command Format
C
1
*
Response Format
C
1
*
When the PLC receives this command, it will resume execution of the ladder program if it had been
halted previously by the "C2" command. Otherwise, this command has no effect.
16.33 Read Analog Input
This command forces the PLC to refresh the value of its ADC data at the analog channel before returning
its value in the response string (i.e. no need for the PLC to execute ADC(n) function to refresh the analog
input)
16-13
Chapter 16
Host Link Command/Response Format
Command Format
R
A
n
n
c
Starting Analog
Channel # (01-08h)
*
c
Channel count
(01 to 08h)
Response Format
R
163
A
162
161
160
162
…
Starting channel
16-bit Data (Hex)
…
161
160
*
Ending channel
16-bit Data (Hex)
E.g. To read 4 channels of Analog inputs starting from Ch #2, Send
string will contain 4 sets of data for channel 2, 3, 4 and 5.
“RA0204*”. The response
16.34 Read EEPROM Integer Data
Command Format
R
X
n
I
n
n
n
c
EEPROM starting
Address (Hex)
*
c
Word Count
(01 to 20h)
Response Format
R
X
163
I
162
161
160
162
…
1st EEPROM Integer
16-bit Data (Hex)
…
161
160
*
Last EEPROM
16-bit Data (Hex)
Maximum allowable word count per command is 32 (01 to 20 Hex). If “count” is > 32, only the first 32
words will be returned.
E.g. To read the 10 words of EEPROM data starting from address 100, send host-link command
“RXI00640A*”. The response string will contain 10 sets of 16-bit data (4 ASCII hex digit per
set).
16.35 Read EEPROM String Data
(r47 Firmware Only)
Command Format
R
X
$
n
n
n
n
*
EEPROM String starting
Address (Hex)
16-14
Chapter 16
Host Link Command/Response Format
Response Format
R
X
$
a
a
a
...
...
a
a
*
a
E.g. To read the string data stored at EEPROM address 10, send host-link command
“RX$000A*”. The response string will contain string data stored in the EEPROM (maximum
40 characters).
16.36 Write Analog Output
Upon receiving this command, the PLC updates the value of its DAC data at the analog output channel
(i.e. no need for PLC to execute SETDAC to update the analog output).
Command Format
W
A
n
n
c
Starting Analog
channel # (01-02h)
163
c
channel
count
(Hex)
162
161
160
…
DAC output data
of 1st channel
161
160
*
DAC output data
for subsequent ch
Response Format
W
A
c
*
c
channel count (Hex)
16.37 Write EEPROM Integer Data
Command Format
W
X
n
I
n
n
n
c
Starting EEPROM
Address (0001-xxxx)
163
162
161
160
c
count
(01-10h)
…
161
163
162
161
160
…
Hex data for starting
EEPROM address
160
*
data for subsequent
EEPROM addresses
Response Format
W
X
I
*
Maximum allowable word count per command is 16
(01 to 10 Hex).
16-15
Chapter 16
Host Link Command/Response Format
16.38 WRITE EEPROM String Data
Command Format
W
X
$
n
n
n
n
a
a
EEPROM String
Address (Hex)
...
...
a
*
ASCII characters
(max. 40 characters)
Response Format
W
E.g.
X
*
$
To write the string data “Hello TRi” at EEPROM String address 12, send host-link
command “RX$000CHello TRi*”.
16.39 Force Set/Clear Single I/O Bit
This new “Wbnnnnxx” command allows you to change a single I/O bit on the PLC. You can force set or
clear any single input, output, relay, timer or counter bit. This has an advantage over other write
commands such as WI, WO, etc that affects the entire group of 8 or 16-bits organized into “channels”.
Command Format
W
b
n
n
n
I/O Bit address
(Hex)
n
x
x
*
00 – Clear I/O bit (OFF)
FF – SET I/O bit (ON)
Response Format
W
E.g.
b
*
I/O Type
Bit address nnnn (Hex)
Input #1 to #256
0000 to 00FF
Output #1 to #256
0100 to 01FF
Timer #1 to #256
0200 to 02FF
Counter #1 to #256
0300 to 03FF
Relay #1 to #256
0400 to 04FF
Relay #257 to #512
0500 to 05FF
To force output 1 to ON, send “Wb0100FF*”. To turn it OFF, send “Wb010000*”
16-16
Chapter 16
Host Link Command/Response Format
16.40 Using OMRON Host Link Commands
Since the PLCs also support OMRON C20H Host Link commands, which are very similar in construct to
our multi-point command/response format, you can also make use of OMRON commands to supplement
the native host link commands.
We will only discuss four of the OMRON host link commands “RR”, “WR”, “RD” and “WD” in this section
because these commands can be used by users to read/write to multiple I/O registers and data memory
in a single command (Note: maximum length of command string should be <=80 characters).
Note: Since the Nano-10 native protocol command set typically only supports read/write of single
variables and data memory, if you want to read/write multiple memory locations in a single command, you
can make use of these OMRON host link commands.
16.40.1 Read IR Registers
This command refers to Table 14.1 in Chapter 14 to map the PLC’s I/Os to OMRON IR register space
from IR0 to IR519
Command Format
@
d
d
R
Device ID
R
n
Header
f
n
n
n
c
c
IR count
IR Address (Dec)
f
c
c
(Hex)
*
FCS
Response Format
@
d
d
Device ID
163
R
R
Header
162
s
s
163
162
160
Last data
160
…
…
1st Data (Hex)
Status
00 – OK
15 - Bad
161
161
f
f
*
FCS
E.g. To read Timer PV #1 to #7 using this command, send:
“@01RR012800074D*”
The PLC will send return a response “@01RR00xxxxyyyyzzzz….*”
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Chapter 16
Host Link Command/Response Format
16.40.2 WRITE IR Registers
This command refers to Table 14.1 in Chapter 14 to map the PLC’s I/Os to OMRON IR register space
from IR000 to IR519
Command Format
@
d
d
W
R
n
Device ID
n
n
163
n
Header
162
161
160
IR Start Addr(Dec)
….
1st
data
163
162
161
160
f
Last data
*
f
FCS
Response Format
@
d
d
W
Device ID
R
s
s
f
Header
f
*
Status
FCS
00 – OK
E.g. To Write to CtrPV #1 to #2 using this command, send:
“@01WR0256xxxxyyyyff*”
where xxxx and yyyy are the hex values
to be written to CtrPV 1 & 2.
16.40.3 Read Data Memory DM[1] to DM[4000]
Command Format
@
d
d
R
Device ID
D
n
Header
f
f
n
n
n
c
c
DM Address (Dec)
c
DM count
c
(Hex)
*
FCS
Response Format
@
d
d
Device ID
163
R
D
Header
162
s
s
163
Last data
160
161
160
…
…
1st Data (Hex)
Status
00 – OK
161
162
f
f
*
FCS
16-18
Chapter 16
Host Link Command/Response Format
E.g. To read DM#112 to #130 (19 words), send:
“@01RD0112001357*”
The PLC will send return a response “@01RD00xxxxyyyyzzzz…*”
16.40.4 WRITE Data Memory DM[1] to DM[4000]
Command Format
@
d
d
Device ID
163
W
D
n
Header
162
n
n
163
n
162
160
Last data
f
160
….
1st data
DM Start Addr(Dec)
161
161
*
f
FCS
Response Format
@
d
d
Device ID
W
D
s
s
Header
f
f
*
Status
FCS
00 – OK
E.g. To Write to DM#1200 to #1201 using this command, send:
“@01WD1200xxxxyyyyff*”
where xxxx and yyyy are the values to be written to DM[1200] & DM[1201].
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Chapter 16
Host Link Command/Response Format
16.41 Testing of Host Link Commands
You can try out all the Host-Link commands using TLServer’s “Serial Communication Setup”. However,
TLServer is designed to accept only multi-point protocol commands except the “IR*” command (which is
necessary to obtain the device ID from the PLC). You, therefore, have to enter all your host link
commands in multi-point format.
Since the multi-point protocol requires an FCS (frame check sequence) character to be appended to the
end of the command string, you may be able to get around it by using the “wildcard” FCS “00” in place of
the actual FCS. E.g. To read input channel 02 from a PLC with ID = 01, you can enter the command
string as “@01RI0200*”.
For TLServer version 2.1 and above, there is an “FCS” button that lets you compute the actual FCS for
the string in the command string text field. You can then use the actual FCS with the command string to
completely test your command. E.g. If you type in the string “@01RI02” in the command string (but do not
press Enter) and then click on the “FCS” button, the FCS for this string will be computed and shown as
“FCS = 58”, as shown in the following figure:
You now can enter the complete command string as “@01RI0258*” and it will be accepted by TLServer.
(Note: If the PLC has executed a SETPROTOCOL n,5 to configure its serial port into pure native mode,
then wildcard FCS will not be accepted and you must use the actual FCS with your command. The FCS
button makes it much easier than computation by hand).
If you have changed some data using the write command, then activate On-Line Monitoring and examine
the changes made using the “View Variables” window.
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Chapter 16
Host Link Command/Response Format
16.42 Visual Basic Sample Program
To help users get started writing their own Visual Basic program to communicate with the PLC, we have
created a sample Visual Basic program with full source code listing. Please visit the following web page
to download the visual basic sample program.
http://www.tri-plc.com/applications/VBsample.htm
16.43 Inter-PLC Networking Using NETCMD$ Command
Nano-10 is able to send out host link commands to another Nano-10, FMD, F-series, M-series or even
the E10 PLCs using the built-in TBASIC function NETCMD$(). This function accepts host link
commands in multi-point format and automatically computes the Frame Check Sequence (FCS)
characters, appends them to the command string and sends out the whole command string together with
the terminators. The function then waits for a response string and checks the integrity of the received
response string for errors. This function returns a string only if a proper response string has been
received. Please refer to the TBASIC Reference for a detailed explanation of this command.
The NETCMD$() function therefore greatly simplifies the programming tasks for handling networking
between PLCs. The programmer only needs to construct the correct command string according to the
formats described in this chapter, pass the formatted string to the NETCMD$() function, and then check
for the response string. The Nano-10 PLC may use the NETCMD$ to map the I/O of another PLC into
its internal relays and use the other PLC as its remote I/O.
There are some programming examples in your “TRILOGI\TL6\usr\samples” folder that illustrate the
use of NETCMD$() to map I/Os of a slave PLC to the master. Please study the two examples:
“RemoteIO-Hseries.PC6” and “RemoteIO-Mseries.PC6” carefully to understand the mechanism of
mapping I/Os between the PLCs. The TRiLOGI program “REMOTE-Hseries.PC6” will work on the Hseries, M-series or F-series PLCs as slaves, whereas the program “REMOTE-Mseries.PC6” will only
work with another FMD, F-series, Nano-10 or M-series slaves. This is because the F-series and M-series
host link command set is a superset of the H-series host link command set, and this example uses the
more efficient M-series host link commands to read/write 16-bit data for networking between M-series
PLCs.
An application note and example programs demonstrating how to use our other PLC models as slave
remote I/O for the F- or M-series PLC can be found at the following web page:
http://www.tri-plc.com/appnotes/AppnoteMain.htm
16.44 Inter PLC Networking Using MODBUS Protocols
The PLCs may also pass data to each other using special MODBUS commands, which are even simpler
to use than NETCMD$ but are restricted to accessing variables that are mapped into MODBUS address
structure. Please refer to the Section 14.7 and 14.8 as well as the TBASIC Reference manual for details
on using the READMODUS, WRITEMODBUS, READMB2 and WRITEMB2 commands.
16-21
Chapter 17
Chapter 17
I2C Communication
I2C Communication
Chapter 17
I2C Communication
I2C COMMUNICATION
17
The Nano-10 PLC (with firmware r76 or later) supports the Inter-Integrated Circuit – IIC, also commonly
known by the acronym I2C or I2C bus. Please refer to the I2C specifications of your device for detailed
explanation of the I2C protocol.
Nano-10 only supports the I2C as a master and operates at 100KHz, which allows it to connect to many
off-the-shelve components such as GPS, accelerometers, thermometer, analog I/O chips, etc. The PLC
can connect to multiple I2C slaves in a multi-drop I2C bus, which greatly expands its capability. The builtin TBASIC commands also greatly simplify the I2C communication with the slave devices.
However, you can only use the I2C communication capability provided your Nano-10 meets all the
following conditions:
1) You have installed the I2C interface module (such as the I2C-FRTC supplied by TRi) on the
Nano-10.
2) You have upgraded your I-TRiLOGI software to version 6.40 or later.
3) The PLC firmware is >= r76,
Note: The I2C-FRTC is intended for advanced users only, so it may not be available for general online
sales in the shopping cart system. If you wish to obtain pricing or would like to place an order, please
contact sales directly via email (sales@tri-plc.com) or phone (877 874 7527) to inquire.
17.1
17.1.1
The I2C-FRTC Module
Installing the I2C-FRTC Module
CR1632 battery
Nylon
standoff
Female
2x5 socket
To install the I2C-FRTC module, first ensure that you have turned OFF power to the PLC.
The I2C-FRTC module has a row of 2x5 male header pins that is to be inserted into the single mating 2x5
female socket on the PLC. Please ensure that the pins are aligned correctly with the socket. There is a
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I2C Communication
single mounting hole on other end of the I2C-FRTC module, which provides support to the module via a
nylon standoff included in the I2C-FRTC package. You should also find a matching hole on the Nano-10
PLC which is aligned with the mounting hole on the I2C-FRTC module. The nylon standoff has two
supporting catches that will mate to the mounting holes on both the I2C-FRTC and the PLC and it
provides a fairly strong support to the I2C-FRTC module.
17.1.2
I2C-FRTC Hardware Overview
Device Logic Power
+2V to +15V
2x5 Male
Header Pins
Mounting hole
for Standoff
V+
SCL
SDA
GND
The I2C-FRTC modules adds the following hardware to the Nano-10:
a. I2C communication interface chip
b. 11K words of FRAM memory, Expand program memory to 16K words, DM[1001] to DM[4000]
and a Battery-backed Real Time Clock (RTC) *
c. 128K bytes of I2C EEPROM memory (M24M01) – Expandable to 256K bytes by soldering an
additional M24M01 chip next to it on the blank solder pad.
d. Additional Analog output channel #3 and #4 (0-5V only)
*
The FRAM memory and battery-backed RTC on the I2C-FRTC is identical to that found on the
FRAM-RTC module. I2C-FRTC = FRAM-RTC + additional I2C hardware.
The I2C interface chip allows the Nano-10 PLC to interface to external I2C devices that are of different
logic voltage level from the PLC. You must connect the positive logic voltage of the target device to the
“V+” terminal shown in the above diagram and 0V of the target device to the “GND” terminal. Then
connect the SCL and SDA signal between the I2C-FRTC module and target device and you are good to
go.
A 1 M bits I2C EEPROM chip (M24M01) is also included in the I2C-FRTC module. This allows you to use
the new I2C_READ and I2C_WRITE command (available only in I-TRiLOGI version 6.40 or later) to store
and retrieve up to 128K bytes of non-volatile EEPROM memory to store additional data. This will be
described in the next section.
17.1.3 I2C-FRTC Availability
The I2C-FRTC is intended for advanced users only, so it may not be available for general online sales in
the shopping cart system. If you wish to obtain pricing or would like to place an order, please contact
sales directly via email (sales@tri-plc.com) or phone (877 874 7527) to inquire.
17.2
New TBASIC Commands: I2C_READ, I2C_WRITE and I2C_STOP
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I2C Communication
These 3 new TBASIC commands are only available on i-TRiLOGI version 6.40 and above, and they are
only enabled on Nano-10 or FMD PLCs that are installed with I2C-FRTC. If you are still running the older
version of I-TRiLOGI, you can get a free update by clicking on the “Help” menu on your production
version of I-TRiLOGI software and follow the “Upgrade TRiLOGI” link to download the latest I-TRiLOGI
software in order to use these 3 newly added commands.
Both I2C_WRITE and I2C_READ commands use a range of data memory DM[ ] to transmit the data to
be written into the device or to be read from the device. The parameters comprise the I2C slave
address, the starting index of the DM[] memory location to use and the number of bytes to be
sent/received from the slave.
17.2.1
I2C_WRITE
An I2C_WRITE command begins with the master (PLC) sending the START bit, followed by a 7-bit slave
address, and then a “R/W” bit set to low, which indicates that it is a WRITE command. If the slave device
with the targeted slave address is present, it will send the ACK response to the master on the 9th clock
cycle. Otherwise the master sends a STOP bit and quits the I2C_WRITE function.
If the slave does send the ACK bit, the master will then send out a number of data bytes to be written to
the slave and the slave will respond with the ACK bit with the completion of each byte it received. After
the last data byte has been written to the slave, and if the master is not expecting to read any data from
the slave, the master must then immediately send the STOP bit by executing the I2C_STOP command
(to be described later) to indicate the End-of-Write to the slave.
The PLC program can determine if the I2C_WRITE is successful by checking with the STATUS(2)
command. The syntax of the I2C_WRITE command is as follow:
I2C_WRITE i2cslave, dmstart, count
Purpose
Examples
Comments
Special command to execute a I2C WRITE out of the PLC's I2C port (if so
equipped). The CPU will send a I2C START, followed by the slave address byte
(i2cslave) and count number of data bytes from the DM[dmstart] up to
DM[dmstart+count-1]
i2cslave - The 7-bit slave address that the CPU is writing to.
dmstart -
The starting index of the DM[ ] that contains the first data byte
count -
number of byte data to send (maximum is dependent on the slave).
DM[5]= 12: DM[6]= 34 : DM[7]= 56
I2C_WRITE &H60,5,3
I2C_STOP
Following the START bit, the CPU will write the 7-bit slave address &H60 (=110
0000 binary) and a R/W bit set to 0, followed by the byte data stored in DM[5],
DM[6] and DM[7].
The command automatically checks for ACK received from the slave device and the user
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Chapter 17
I2C Communication
program can check the status of this operation by testing the STATUS(2) function.
STATUS(2) returns a 1 if ACK is received , and 0 if no ACK is received after time out.
Note: This command does not automatically generate the I2C STOP bit, this is to allow the
CPU to perform a I2C_READ following a I2C_WRITE. I2C READ after WRITE is
commonly encountered in I2C protocol which requires using the I2C_WRITE to set the
internal pointer address in the slave device and then followed by the I2C_READ command.
Therefore, if your command involves only I2C_WRITE, you must end the WRITE command
by executing a I2C_STOP statement.
17.2.2
I2C_READ
An I2C_READ command begins with the master (PLC) sending the START bit, followed by a 7-bit slave
address, and then a “R/W” bit set to high, which indicates that it is a READ command. If the slave device
with the targeted slave address is present, it will send the ACK response to the master. Otherwise the
master sends a STOP bit and quit the I2C_WRITE function.
If the slave does send the ACK bit, the master will then toggle the SCL (clock) signal and the slave will
send the data byte one bit at a time in response to the SCL pulses. After an 8-bit byte has been received,
the master will automatically send the ACK bit to the slave and the slave will continue to send the next
byte sequentially out to the master.
After the last data byte has been read from the slave, the master will not send the ACK bit but will
automatically send the STOP bit to the slave. This indicates the End-of-Read to the slave and the
communication is complete.
I2C_READ i2cslave, dmstart, count
Purpose
Examples
Special command to execute a I2C_READ out of the PLC's I2C port (if so
equipped). The CPU will send a I2C START bit, followed by the slave address byte
(i2cslave) with "R/W" bit set to high, and then send out the number of clock pulses
required to read count number of data bytes from the the slave. The data bytes
received from the slave will be stored in the memory location DM[dmstart] to
DM[dmstart+count-1]. After receiving all the required data bytes the CPU
automatically send the I2C STOP bit to the slave to end the communication.
i2cslave -
The 7-bit slave address that the CPU is reading from.
dmstart -
The starting index of the DM[ ] that is to receive the first data
count -
number of byte data bytes to read from the slave.
I2C_READ &H0C,21,2
' read 2 bytes into DM[21] and DM[22]
17-4
Chapter 17
Comments
I2C Communication
After sending the START bit, the CPU will write the 7-bit slave address &H60 (=110
0000 binary) and a R/W bit set to 1, followed by 16 clock pulses to read 2 bytes
of data and store into DM[21] and DM[22], and then the CPU will generate the
STOP bit.
i.e. there is no need execute the I2C_STOP command after an I2C_READ
command.
17-5
Chapter 17
17.2.3
I2C Communication
I2C_STOP
This command has no parameter. It sends a STOP bit to the slave and complete the I2C_WRITE
command.
17.2.4
Random Write To M24M01 EEPROM
The first M24M01 EEPROM on the I2C-FRTC (U2) has two binary slave device addresses: 101 0000 b
(&H50) and 101 0001b (&H51). Device address &H50 is for accessing the first bank of 64K bytes of
EEPROM, and address &H51 is for accessing the second bank of 64K bytes of EEPROM.
There is also a blank solder pad on the bottom layer of the I2C-FRTC module, which allows you to solder
an additional M24M01 (U3) to the I2C-FRTC PCB. When assembled this second M24M01 chip will
assume the binary address of 101 0010b (&H52) and 101 0011b (&H53). Device address &H52 on U3
is for accessing the first bank of 64K bytes while device address &H53 is for accessing the second bank.
Please refer to the M24M01 EEPROM data sheet for the detailed description of the addressing scheme
for writing a byte of data to a random EEPROM address. The following picture depict the necessary
command:
Example. To write a byte of data XX to the EEPROM address 54321 (&HD431) in first 64K bank, you
need to do the following:
DM[11] = &HD4
DM[12] = &H31
DM[13] = xx
‘ your data byte
I2C_WRITE &H50, 11, 3
‘ write 3 bytes of data from DM[11] to DM[13]
I2C_STOP
‘ necessary to end the byte write.
The data XX will be written to the EEPROM address 54321
If you want to store the data to second bank of EEPROM address, then replace the I2C_WRITE line with:
I2C_WRITE &H51, 11, 3
17.2.5
Page Write To M24M01 EEPROM
As you can see, writing a single byte of data to a random location involves 4 bytes of data transfer, which
is not very efficient. Fortunately, the EEPROM allows you to write more than one byte to the EEPROM
and the EEPROM will write to the subsequent location sequentially. This is known as “Page Write” and
you can write up to 256 bytes in the same page. A page is defined as the memory location having the
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I2C Communication
same upper address byte (bit 8 to bit 15). E.g. Address &HA011 and &HA0FF are in the same page.
But address &HA0FF and &HA100 are NOT in the same page even though they are adjacent memory
location. So you have to keep the page boundary in mind when performing a page write.
The following picture depict the page write command:
Example. To write 4 byte of data XX to the EEPROM address 19876 to 19879 (&H4DA4) in first 64K
bank, you need to do the following:
DM[11]
DM[12]
DM[13]
DM[14]
DM[15]
DM[16]
= &H4D
= &HA4
= xx
= yy
= zz
= ww
‘
‘
‘
‘
your
your
your
your
data
data
data
data
byte
byte
byte
byte
1
2
3
4
I2C_WRITE &H50, 11, 6
‘ write 6 bytes of data from DM[11] to DM[16]
I2C_STOP
‘ necessary to end the write cycles.
The data contained in DM[13] to DM[16] will be written to the EEPROM address &H4DA4 to &H4DA7.
17.2.6
Random Read From M24M01 EEPROM
17-7
Chapter 17
I2C Communication
Reading data from a random EEPROM location is slightly more involved than writing. You need to first
use the I2C_WRITE command to set the memory pointer inside the M24M01 to point to the memory
address location, then immediately followed by I2C_READ command to read one or more data bytes
starting from the pointer address. After every byte is read the internal pointer will be incremented
automatically and point to the next address byte, this allows you to read a large number of data
sequentially from the EEPROM with minimum overhead. This can be very useful for “data dump” to the
TLServer to rapidly upload the collected data
Example. To Read 100 bytes from EEPROM address 12345 (&H3039) to 12444 in first 64K bank, you
need to do the following:
DM[11] = &H30
DM[12] = &H39
I2C_WRITE &H50, 11, 2 ‘ write 2 bytes of address in DM[11] to DM[12]
I2C_READ &H50,21,100
‘ read 100 bytes data into DM[21] to DM[120]
The returned data will be stored in the DM[21] to DM[120].
Note: There is no need to execute the I2C_STOP command after the I2C_READ since the I2C_READ
command automatically sends a STOP bit after the last byte is read.
17.2.7
Sequential Read From M24M01 EEPROM
Note that after a random read, the memory pointer inside the M24M01 will be pointed to the next address
following the very last read memory address. This means that you could repeatedly execute only the
I2C_READ command to read more data sequentially from the EEPROM memory.
Example:
DM[11] = &H30
DM[12] = &H39
I2C_WRITE &H50, 11, 2
‘ write 2 bytes of address in DM[11] to DM[12]
FOR I = 1 to 10
I2C_READ &H50,21,100 ‘ read 100 bytes data into DM[21] to DM[120]
CALL Datadump
‘ call some subroutine to upload data to server.
NEXT
In the above example, the I2C_READ command was executed 10 times, each time 100 data point is read
into DM[21] to DM[120] and the program then calls another custom function to dump these data points to
the server. The loop then continue for another 9 times, and hence altogether 1000 data points from
address 12345 to 13344 can be uploaded to the server in a simple FOR..NEXT loop.
17-8
Chapter 18
Chapter 18
Extended File System
Extended File System
Chapter 18
18
Extended File System
EXTENDED FILE SYSTEM
Before you begin, please download a sample I-TRiLOGI program that will be referred to throughout this
section from our website:
http://www.tri-plc.com/trilogi/ExtendedFileSystem.zip
18.1
Introduction
A Nano-10 or FMD PLC with r77 or later firmware may be used with a new module - FRAM-RTC-256,
which, besides adding 11K words of FRAM (see Section 1.7.2) and a battery-backed RTC module, also
adds 256K bytes of extended data file space to the PLC.
Note:
The I2C EEPROM memory on the I2C-FRTC module (default =128K bytes, user-expandable to
256K) described in Chapter 17 can also be used as extended data file in exactly the same way
as the FRAM-RTC-256. However, in the rest of this chapter we will only refer to the FRAM-RTC256.
Without the FRAM-RTC-256, the Nano-10 PLC only has 60K bytes of file memory to be used for storing
control web pages as described in Chapter 2.9 (Note the default file space on the Nano-10 PLC before
firmware r77 was 64K bytes, but it has been reduced to 60K to make space for the new r77 firmware).
FRAM-RTC-256 adds an additional 256K bytes of file space to the PLC. You can use the extended file
space for storing additional web pages. But more importantly, a PLC with a new r77 or later firmware can
open a local data file in this file space and write/append data to it. The PLC can therefore log a large
amount of data into one or more data files, which can be retrieved for analysis.
There are two ways to retrieve the stored data files from the PLC:
1. Download the file from the PLC’s built-in web server: The file created by the PLC can be
downloaded from the PLC’s built-in web server using any web browser. This allows the user to
access the data file at any time of the day.
2. Automatic FTP upload from the PLC to an external web-server: You can program the PLC to
make an FTP client connection to any web server on the local network or on the Internet/Cloud
and upload the data file it has created to the web-server using any filename.
Imagine what the Nano-10 or FMD PLC can do with this new uploading capability! The ability to log data
locally and automatically upload the data to a web server transforms the FMD PLC into a potent datalogger! The PLC can be programmed to capture daily, weekly or monthly data and then periodically
upload the data file to an Internet web server with a unique, time-stamped filename (E.g.
“temperaturelog2012-01-01.xls”). This allows the PLC to log data completely unattended.
The data uploaded by the PLC to the external web server can be viewed or downloaded into a PC using
any web browser, anywhere in the world. This allows you to carry out analysis of past logged data file for
performance or diagnostic analysis at any time without having to physically access the PLC to retrieve the
logged data.
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Extended File System
Advantage of Data Uploading
1. Although it is possible to directly access the PLC’s internal web server to download the data file it
has created, this require active action by the user and to ensure that the data are retrieved before
the file is full and has to be deleted by the PLC to create space to log new data.
2. By programming the PLC to upload the data periodically the PLC can delete the file after it has
successfully uploaded the data file to free up space to accept new data. In other words the PLC
will never run out of data space to log data since it can store the logged files on any server
including the Cloud!
3. To directly access the file stored on the PLC from outside of the LAN, you will need to setup the
router or firewall to “forward” the PLC’s server port (e.g. 9080) to the PLC. If you have multiple
PLCs logging data, then each PLC will need to have a different port number in order to properly
forward the port. This not only complicates the setup, but also is often frown upon by System
Administrator and may not even be permitted by the corporate network security policy.
4. The PLC is designed to upload data to any web server via FTP passive mode by providing the
login username and password. Using FTP passive mode allows the PLC to open a network
connection to an external web-server to upload a file and then close the connection immediately.
It does not require opening a port on your router firewall to permit external access to the PLC
from the Internet. Hence there is no complicated router setup involved as there is no port
forwarding required. It also eliminates the security risk from someone trying to take control of
the PLC from outside of your LAN and is generally much more acceptable to the System
Administrator.
5. If you have multiple PLCs in use, you can program each PLC to upload data to a different
directory or append a different file name prefix, or to different servers, and once programmed all
PLCs will happily log data unattended indefinitely!
18.2
File Structure and File Naming of The Extended File System
All of the information in chapters 2.9 and 2.10 of this manual regarding the built-in 60K bytes of web
server space will apply to the extended 256K bytes of data file storage on the FRAM-RTC-256, with
exception on the naming scheme which will be explained below:
1. All files in the Extended File space can only use the file name “Zxxx.yyy”.
2. The xxx part of the beginning of the filename is a 3 digit decimal number which can be any
number from 000 to 127.
3. The ‘yyy’ part of the file name is the “extension”, and only the following MIME extension are
accepted by the PLC:
HTM, JPG, GIF, CSS, JS, BIN, TXT, JAR, ZIP, XLS
Any other extension names will be replaced with “???”. The MIME extension are respected by the
web browser when you download a file from the built-in web server so you should always only
store files with one of the above extension.
4. The file space is divided into 128 “slots” with each “slot” occupying 2K bytes. The file “Z000.yyy”
occupies the first slot, “Z001.yyy” occupies the 2nd slot .., and the file “Z127.yyy” the last 2K slot.
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Extended File System
5. Any file may occupy more than 1 slot so you can specify “Z000.yyy” to occupy the entire 256K
bytes of the file space. Or you can configure “Z000.yyy” to occupy the first 5 slots (10K total) and
the next valid file should start from Z005.yyy which can occupy the next 10 slots (20K bytes total).
i.e. If you want to allocate 10K bytes of file space to file Z000.yyy you cannot not use name any
file Z001, Z002, Z003 and Z004, otherwise these file will corrupt the file space of Z000.yyy
6. This means that the programmer will have to design the file space carefully and determine how to
best use the file structure to provide the right balance between the number of data files and the
amount of data space allocated to each data file.
Note: The file name restriction only applies to files stored on the PLC’s internal file space. When you
use the FTP upload function described later, you can specify any destination filename as long as they
are acceptable to the external FTP server.
18.3
Transferring Files To The PLC’s Web Server
If you are only using the extended file space for the purpose of storing additional web pages on the builtin web server, then you can use the FTP client software such as FileZilla client to transfer the program to
the PLC. Section 2.9 of this Manual describes in details how to configure the FileZilla client to
communicate with the PLC.
Please take note that files that are name 0.yyy, 1.yyy……to T.yyy are only stored on the PLC’s on chip
flash memory. Only files that are named Z000.yyy, Z001.yyy….Z127.yyy are stored on the FRAM-RTC256 as explained in the last section.
18.4
Accessing The Extended Data Files Using TBASIC
A Nano-10 PLC with r77 firmware can access the extended data file space (i.e. only file names from
Z000.yyy to Z128.yyy) from within TBASIC. The PLC can open a new file for writing new data
(essentially deleting the old file content), or open an existing file and append data to the end of the file. It
can also open a file and read data from the file as ASCII strings. It can achieve this by using the PRINT
#8 and INPUT$(8) functions, which will be described in details in the following sections.
18.4.1
Open A File For Writing New Data
Syntax:
PRINT #8 “<WRITE
Zxxx.yyy>”
where “Zxxx.yyy” is the file name. If successfully executed, the “<WRITE>” command will open the file
and set the file pointer to the beginning of the file. Thereafter the PLC can start writing ASCII data to the
file using the PRINT #8 <string data> command. [Note: the PRINT #8 command automatically
appends a carriage return to the end of the string data unless the string data is terminated with a semicolon (‘;’) ].
When the PLC has completed writing data, it must close the file by executing the command:
“</>”.
E.g.
PRINT #8 “<WRITE Z005.TXT>”
PRINT #8 “The current Greenwich Mean Time is”
PRINT #8 STR$(TIME[1]);”:”;STR$(TIME[2]);”:”;”00”
PRINT #8 “</>”
PRINT #8
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The CPU should use the STATUS(2) command to check whether the <WRITE> has been successfully
executed before begin writing data to it. STATUS(2) command returns a 1 if “<WRITE>” operation is
successful and returns a ‘0’ if the operation failed. The following are some possible reasons that could
cause the “<WRITE>” command to fail:
1. A previously opened File was not closed. The CPU can only write to a single file at a time so any
opened file must be closed by the PRINT #8 “</>” command before another file can be opened
for writing.
2. The FRAM-RTC-256 is not installed. The PLC can only write data to the extended data file space
(i.e. file name Zxxx.yyy) which are only available if an FRAM-RTC-256 is installed.
18.5
Open A File For Appending Data To The End Of The File
Syntax:
PRINT #8 “<APPEND Zxxx.yyy>”
where “Zxxx.yyy” is the file name. If successfully executed, the “<APPEND>” command will open the file
and set the file pointer to the end of the file. Thereafter any string data following a PRINT #8 command
will be appended to the end of the file. When the PLC has completed appending data, it must close the
file by executing the command: PRINT #8 "</>".
As per the “<WRITE>” command, the CPU should also use the STATUS(2) command to check whether
the <APPEND> command has been successfully executed before begin writing data to it. Since the
same reasons that could cause a “<WRITE>” command to fail would also cause the “<APPEND>”
command to fail, please refer to the last section on a list of possible causes of failure.
Example
PRINT #8 "<APPEND Z"+STR$(F,3)+".txt>"
S = STATUS(2)
‘ Status(2) returns 1 if successful.
IF S <> 1 RETURN: ENDIF
FOR I = 1 to 100
PRINT #8 STR$(I,4)+":This is the Appended first line"
PRINT #8 STR$(I,4)+":This is the Appended second line"
SETLCD 1,1, "Append #"+STR$(I,4)
NEXT
PRINT #8 "</>"
‘ close the file
18.5.1 Delete A File
Syntax:
PRINT #8 “<DELETE Zxxx.yyy>”
where “Zxxx.yyy” is the file name of the file to be deleted. There is no need to close a deleted file.
18.5.2 Open A File For Reading
Syntax:
PRINT #8 “<READ Zxxx.yyy>”
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where “Zxxx.yyy” is the file name of the file to be opened for reading. If the file has been successfully
opened for reading after execution of the PRINT #8 “<READ>” command, the PLC can start to retrieve
ASCII data from the file line-by-line using the INPUT$(8) command. A line is either a string that is
terminated with a Carriage Return character (ASCII 13), or is a 70-character long string (which is the
maximum length of any string variables A$ to Z$) without carriage return. In either case the return string
does not contain the CR character itself.
The PLC can check if a file has been successfully opened for reading using the STATUS(2) function
AFTER executing the PRINT #8 “<READ>” command. STATUS(2) will only return a 1 if a file has been
successfully opened.
The PLC can determine if the End-of-File (EOF) has been reached using the STATUS(2) function after
every INPUT$(8) command has been executed. STATUS(2) returns a 255 if the EOF has been reached.
The PLC should then close the file by executing the PRINT #8 “</>” command.
A$ = "<READ Z"+STR$(F,3)+".txt>"
S = STATUS(2)
IF S <> 0
SETLCD 1,1, "Failed to Open File"
GOTO @100
ENDIF
C = 0
PRINT #8 A$
SETLCD 1,1, A$
WHILE 1
A$ = INPUT$(8)
S = STATUS(2)
IF S = 255 EXIT : ENDIF
' S = 255 means EOF
SETLCD 2,1,A$
DELAY 50
' So that reader can read from the screen.
C = C+1
ENDWHILE
SETLCD 1,1, "Read ” +STR$(C) + " lines "
@100
PRINT #8 "</>"
' close the opened file
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18.6
Extended File System
Setting Up The FileZilla FTP Server
One important capability of the Nano-10 PLC with r77 firmware is the ability to upload files created by the
PLC to an external server on a local area network or on the Internet via the FTP protocol. If you have
access to an FTP username and password on your company’s server (or if the SysAdmin is authorized to
set up an account for you) you can certainly use your own account for testing. If not, you can download
the free Filezilla FTP Server and set it up for testing. The “ExtendedFileSystem.PC6” has an FTP upload
demo and it was configured to work with a FileZilla FTP server.
Using Filezilla has the advantage that you can see the login sequence performed by the PLC when it
attempts to connect to the FTP Server so that it is easier to troubleshoot connection problem. (For
professional grade troubleshooting, one handy program to have is the “Wireshark” program which is a
TCP/IP packet sniffer that allows you to look at the actual TCP/IP packets sent between your PC and the
PLC). However, it is important to setup the Filezilla server program properly to minimize connection
trouble.
18.6.1
Download and Setup FTP Server
1. First download the FileZilla server installer from the following website:
http://filezilla-project.org/download.php?type=server
2. Run the “FileZilla Server Interface” program, which is meant for managing the FTP Server settings.
3. If the FileZilla Server is running on the same PC that you are running the FileZilla Server Interface
program then you can use the localhost IP address which is 127.0.0.1 – the Port can be anything
since this is a client port that the Interface program is using to interact with the FTP Server (don’t be
confused with the FTP Server listening port which is by default = 21).
4. If this is the first time you run the program after setting up Filezilla FTP Server there will be no
Administration password so you can leave it blank. Click OK to connect.
5. Click “Edit->Settings” and then “General Settings -> Welcome message” – leave only one line of
welcome message so that the PLC has less work to do. Then click OK to accept the change.
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6. Click “Edit –> Users” in order to setup a user name and password for your test. The
“ExtendedFileSystem.PC6” program uses a username = “PLC” and password = “1234” so for a
quick test you may like to setup the same username and password:
7. At the “General” page of the setup screen, click “Add” button at the “Users” pane to add a username
“PLC”. Since no group has been defined simply leave the default as “<none>” in the second text box
as shown in the following diagram.
8. Next click “Shared folders” page and you must setup a folder that is to be used to receive uploaded
file. Click “Add” at the “Directories” pane to add the folder. You can choose any folder on your PC to
be used for the FTP upload and you just have to remember the location so that you can look for the
uploaded file later in the test. However, make sure that you check all the check boxes for “Read”,
“Write”, “Append” etc as shown in the diagram.
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9. Click “OK” to complete the setup.
Extended File System
The FTP server should now be waiting for connection.
18.6.2 Testing Connection To The FTP Server Using Telnet
You can now test the FTP Server using the FileZilla client as mentioned in Chapter 2.9 of the PLC User’s
Manual.
But a better way to test is to use the “Telnet” program on your PC (if you are running Windows Vista or
Windows 7 you may need to enable the Telnet program since it is disabled by default – do a quick
Google search on how to enable the Telnet client software on your PC).
Also you may want to find out the IP address of your PC that is running the FileZilla Server. If you have
TLServer running on your PC your IP address is reported on the TLServer’s front panel. You can also get
the IP address from the Windows “Network Connection Status” as shown below. Our test PC has an IP
address = 192.168.1.168 which will be used in the following tests as well as used in the PLC program to
connect to the FTP Server.
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1. First open a command prompt window and then type “telnet 192.168.1.168 21” - this will
open a telnet connection to the FTP server on our test PC with IP address 192.168.1.168 and
listening at port 21. Please replace the IP address with the actual IP address of your PC. The
following screen shot captures the test sequence. Note that the same command/response
sequence with the server is also shown on the FileZilla Server Interface program front panel:
USER PLC
PASS 1234
2. Once you get the “230 Logged On” message you know that the FTP setup is done correctly. Note
that the welcome message from the FTP Server shows only one line “220 FileZilla Server
Version x.xx” which is what we have set it up to be. You can now disconnect from the FTP server
by typing “Quit” at the command prompt.
3. There is one more things you need to do before you proceed to test the FTP upload features of the
PLC to avoid connection problem – that is to temporarily TURN OFF the Windows Firewall and any
software firewall setup by anti-virus software during your test. You can always re-enable your
software firewall(s) after the test if you wish. PC operating system are designed to run client program
normally instead of acting as a server so Windows Firewall by default is to block all incoming
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Extended File System
connections to the FTP Server. Thus it can give you a lot of headache when you are trying to connect
to the FTP server operating behind the Windows Firewall.
Notes:
a) The main purpose of Windows Firewall is to protect your PC when you are connected to say
a public wi-fi network. But if your PC is connected to the Internet via a router at work or at
home, the router hardware itself would act as a firewall to isolate your PCs and a software
Firewall is actually redundant. (If a hacker tried to connect to a port using your public
Internet IP address what he reached would be the port on the router and he would not be
able to reach your PC unless you have specifically set up to forward all TCP/IP messages
sent to that port to a specific PC).
b)
If you really want to use the Filezilla FTP Server as a permanent server on a PC to receive
files, and still want to have the Windows Firewall enabled, you can refer to the last section in
this chapter which describes how to do it.
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18.7
Extended File System
Uploading File From PLC to FileZilla FTP Server Directory
18.7.1 Overview of The FTP Protocol
The FTP protocol requires two socket-connections between the devices performing the file transfer. One
connection is the “command” channel where FTP commands such as STOR or DELE and the responses
are sent as plain ASCII text strings between the FTP client and the FTP server. The second connection is
the “data” channel where only the file content or the file directory data are being transferred.
There are two transfer modes: “Active” mode and “Passive” mode. Active mode requires that the server
establish a data connection back to the client. Passive mode on the other hand, requires that the client
also be the one to establish the data connection. i.e. For passive mode, both the command and the data
connections are performed by the client (the PLC in this case).
The PLC has been designed to use only passive mode to transfer file to the FTP server. Passive mode is
preferred because that is the only way to transfer file if the FTP Server is located on the Internet. The
alternative active mode transfer requires the server to make a data connection back to the PLC that is
sitting behind a router firewall, and that can be problematic unless the router is specifically configured to
forward the data port to the PLC.
18.7.2 PLC FTP Upload Procedure
In order to upload file to the FTP Server, the PLC would use the PRINT #4 “<TCPConnect
xxx.xxx.xxx.xxx:21>” command tag to connect to the FTP server port 21 to establish the “command”
connection to the FTP Server. The PLC uses its PRINT #4 to send and INPUT$(4) to receive ASCII text
strings from the FTP server via the command channel. The PLC would then send the command “PASV” to
inform the FTP server that it wants to transfer a file in passive mode.
At this point you can use the PRINT #4 command to send any valid FTP command to the server, including
changing directory (CWD command – make sure the directory exist), deleting a file (DELE command –
beware of what you are deleting!) etc.
When the PLC is ready to start a file transfer to the FTP server, the server will in turn provide the PLC with
the port number that it has opened for the PLC to connect to establish a data connection. Upon receiving this
port number the PLC will make a second TCP connection to the given port and then the actual file transfer
will begin.
A new, network service command tag named “FTPUPLD” handles the negotiation between the FTP Server
and the PLC as well as handling of the data transfer from the PLC to the FTP server. The following is the
syntax:
PRINT #4 “<FTPUPLD Zxxx.yyy
Where:
[destination file name]>”
Zxxx.yyy is the file name of the extended file that the PLC has access to. The [destination file
name] can be any legal name acceptable to the server so you can attach a date or time stamp
to the file name for easy identifications.
When the above <FTPUPLD> command is run, the PLC will send the actual “STOR” command in the
background to the FTP server and then obtain the port number from the server and it will then make a data
connection to it, and file transfer can then begin.
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18.7.3
Extended File System
Monitoring The FTP Upload Progress
Once the file transfer begins the PLC firmware will handle the rest of the file transfer until either the file has
been completely transferred or the transfer is aborted due to a network or server trouble. You can monitor the
progress of the file transfer using either the STATUS(4) or STATUS(20) functions.
STATUS(4)=
0
1
2
3
:
:
:
:
FTP client was idle or last FTP failed
FTP data transfer just started
1st FTP segment transferred, now transferring the rest
FTP data transfer completed.
STATUS(20) > 0: Number of bytes uploaded to FTP Server. Transfer is in progress.
< 0:
Total number of bytes uploaded. Transfer completed.
For example, If 2,345 bytes has been uploaded to the server and the transfer has ended, STATUS(20) will
return the number = –2345.
Since file transfer can take substantial amount of time to complete, it is not wise to run a loop to wait for the
file transfer to complete since this will block the PLC from processing any other part of the program. The
demo “ExtendedFileSystem.PC6” shows you how to setup a monitoring function to periodically monitor the
progress of the file transfer and report the transfer status on the LCD display.
Please refer to the comments in the custom function “fnConnFTP” and “fnMonFTP” of the
“ExtendedFileSystem.PC6” program for more detailed descriptions of each command involved in the FTP file
transfer.
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18.8
Extended File System
Setting Up A FTP Server Behind a Windows Firewall.
Please refer to the following Microsoft document describing issues and solutions related to FTP server behind
the Windows Firewall.
http://technet.microsoft.com/en-us/library/dd421710(WS.10).aspx
Microsoft focuses mainly on the FTP server in their IIS server (for obvious reasons) instead of Filezilla. If you
are setting Filezilla as a permanent FTP server behind a software firewall you can try to make the following
configuration setup:
1) You must specifically setup a range of port number for Passive mode use. These are the port number that
Filezilla will assign to the PLC to make a data channel connection when it attempts to transfer a file using
passive mode. The following is an example where two port numbers are assigned so that two PLCs may
connect to the Filezilla simultaneously. You can add a larger port range if more PLCs may connect to the FTP
Server simultaneously.
Next, open up Windows Firewall and add to the Exception list the port 21 (command port) and ports 41000 to
41001 (or whatever range limit you have set to in the FileZilla Setup screen). This should allow the FTP
Server to receive connection from these ports that the PLC will be using to make the command and data
connections.
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Chapter 19
Chapter 19
Using PLC As a Modbus/TCP Gateway
PLC As A Modbus/TCP Gateway
Chapter 19
Using PLC As a Modbus/TCP Gateway
19 USING PLC AS A MODBUS/TCP GATEWAY
19.1 Introduction
A Nano-10, FMD or F-series PLC with r77 firmware or later can be configured to act as the
"MODBUS/TCP GATEWAY" for other Modbus serial devices while continue to function as a Super PLC!
A Modbus/TCP gateway essentially translates a Modbus/TCP command packet it receives from its
Ethernet port into a Modbus RTU serial command and sends it out of its serial port (RS232 or RS485). If
the Modbus RTU slave sends back a serial response, the gateway will in turn translate the RTU response
data back to Modbus/TCP response packet and return to the client via the Ethernet port.
As such the Modbus/TCP gateway enables any non-Ethernet equipped, both TRi or 3rd party serial
Modbus slave device to be directly accessible by a Modbus/TCP client via the Ethernet or the Internet. In
addition, the user PLC program does not need to handle the gateway function at all as the CPU performs
the translation functions automatically and transparently to the PLC’s program.
Best of all, while acting as a gateway, the Nano-10, FMD or F-series PLC program can simultaneously
act as a Modbus master PLC and read/write to any registers inside any of the attached Modbus RTU
slave! The CPU firmware automatically schedules the order of the command/response packets whether
it is originated from the client or from the PLC itself so that the Modbus/TCP command from the client will
be responded to in the correct order and in a timely manner.
19.2
Application Ideas for Modbus/TCP Gateway
The Modbus/TCP gateway function can be very useful for many large area control systems, such as a
building automation system. A master FMD or F-series PLC is linked to many Modbus RTU slave
controllers via RS485 bus distributed across an entire building. The master PLC can perform
sophisticated control functions since it has read/write access to ALL the Modbus RTU slaves it connects
to. At the same time, a Modbus TCP client software such as a Building Management System (BMS) can
access any registers in the master PLC or ANY of the slave Modbus RTU controller directly via the
master PLC acting as a gateway for the slave PLCs.
19.3
Configuring The PLC As Modbus/TCP Gateway
The command used to define a serial port to become Modbus/TCP Gateway serial port is as follow:
SETSYSTEM 12, n
Where n = 1, 2 or 3 for COMM1, COMM2 and COMM3 port.
This statement must be run once (could be during start up via 1st.Scan pulse) to configure the serial port
#n to be used to send out RTU commands and received RTU responses. If SETSYSTEM 12,n is not run
then the Modbus gateway function will be disabled.
Here is how it works: A Modbus/TCP client (such as a SCADA, HMI etc) would send a Modbus/TCP
request with a specific 8-bit Modbus slave ID to the gateway PLC. If the ID matches the native ID that is
assigned to the gateway PLC then the PLC will react normally by sending its own Modbus/TCP response
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Using PLC As a Modbus/TCP Gateway
packet back to the client. The PLC will not send any RTU command out of the gateway serial port. This
means that the client can access the master PLC’s own register as per normal.
However, if the client send a Modbus/TCP packet with a different ID from that of the gateway PLC’s ID,
then the gateway PLC will translate the command into a Modbus RTU command and send it out of the
gateway serial port #n defined by the “SETSYSTEM 12, n” statement. The PLC will also wait for a
response from the RTU slave via the gateway serial port, and if it does receive a response it will translate
it into Modbus/TCP response packet and return to the client.
Note:
1) If the Modbus/RTU slave being addressed does not respond to the RTU command, then the
gateway PLC will wait till time-out (default is about 150ms) and then resend the Modbus RTU
command and wait for a response again. By default the gateway PLC will repeat this procedure
twice and if it still doesn’t receive a response after repeated attempts, it will send back a
“TARGET DEVICE FAILED TO RESPOND” error packet back to the Modbus/TCP client. (i.e. It
will set the 7th bit of the function code to “1” and send back an exception code “0B” hex).
2) The CPU firmware is designed to handle only one Modbus gateway translation for each
Modbus/TCP connection per ladder logic scan. This is to ensure that the CPU is not completely
bogged down by its Modbus gateway job and will have time to run its own program. If the
Modbus/TCP clients attempt to overload the PLC with more requests than it can handle the PLC
will frequently return “SLAVE DEVICE BUSY” error response packets back to the client. (i.e. It will
set the 7th bit of the function code to “1” and send back an exception code “06”).
19.4
Fine-Tuning The Modbus/TCP Gateway Function
It is important to know that every time the PLC runs a Modbus/TCP to Modbus RTU translation its own
program scan time increases due to the need for the CPU to wait for a response from the slave Modbus
RTU devices. The delay becomes much more pronounced when a Modbus slave device fails to respond
(e.g. not online). The system designer must therefore take this into consideration when designing the
system:
1) The Modbus/TCP client should not overload the Modbus gateway with unnecessarily frequent
Modbus requests. Whenever the PLC report a “TARGET DEVICED FAILED TO RESPOND”
function the client program should back off for a while before re-trying communication with the
Modbus/RTU slaves again.
2) You can change the number of wait states
Modbus/RTU slave by running:
the gateway will wait for a response from the
SETSYSTEM 1, w
Where w = number of serial port wait states for each COMM port as follow:
Bit 7
Bit 6
Ethernet
Bit 5
Bit 4
COMM3
Bit 3
Bit 2
COMM2
Bit 1
Bit 0
COMM1
Thus each COMM port could be configured to wait from 0 to 3 wait states for a response. The
default settings for w = &H55 (or 01010101 binary) which means each COMM port as well as the
Ethernet port uses 1 wait state of about 150ms..
3) You can change the number of retries (default = 2) the gateway will attempt to get a response
from the Modbus RTU slave by running:
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Using PLC As a Modbus/TCP Gateway
SETSYSTEM 2, n
Where n = number of retries for each COMM port as follow:
Bit 7
Bit 6
Ethernet
Bit 5
Bit 4
COMM3
Bit 3
Bit 2
COMM2
Bit 1
Bit 0
COMM1
Thus each COMM port could be configured to re-attempt to send the command from 0 to 3 times
if it does not get a response from a Modbus RTU slave.
The default settings for n = &HAA (or 10101010 binary) which means each COMM port as well as
the Ethernet port will retry twice (making a total of 3 attempts). E.g. If you run SETSYSTEM 2, 0
the gateway will not resend the RTU command on any of its COMM port if does not receive a
response on the first attempt. This can help to reduce the CPU scan time if a Modbus RTC slave
does not respond.
4) We strongly recommend that the serial port #n that is to be used as a gateway serial port be
configured to be “No protocol” by running the SETPROTOCOL n, 10 statement once. This is to
ensure that the serial data returned from the RTU slaves will never be interpreted wrongly by the
master PLC as incoming commands, which could lead to errors. (The same advise applies to
PLC programs that use the serial port to run READMODBUS, WRITEMODBUS, READMB2
and WRITEMB2 commands).
19.5
Modbus/TCP Gateway Sample Program
Please download the following self-explanatory I-TRiLOGI sample program that demonstrates the new
Modbus/TCP Gateway capability via any of the selected COMM port:
http://www.tri-plc.com/trilogi/modbusgateway.zip
19-3
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