7, Using the 1769-SDN Scanner Module with MicroLogix Controllers. Allen-Bradley 1769-SDN
Allen-Bradley 1769-SDN is a DeviceNet Scanner Module that provides a gateway between CompactLogix controllers and DeviceNet devices. It allows you to connect up to 64 DeviceNet slave devices and communicate with them using the RSNetWorx for DeviceNet software. The 1769-SDN is ideal for applications where you need to control a large number of devices, such as in a manufacturing or automation setting.
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Chapter
7
Using the 1769-SDN Scanner Module with
MicroLogix Controllers
MicroLogix 1500
Controllers
This chapter contains an example where the 1769-SDN scanner module is used with a MicroLogix 1500 controller. The following table describes what this chapter contains and where to find specific information.
For information about
Configuring a Local DeviceNet Message
See page
The MicroLogix 1500 programmable controller has two different processors that are compatible with the 1769-SDN scanner module.
The 1764-LSP and 1764-LRP processors can use the scanner as a
DeviceNet master and own DeviceNet slave devices. This allows either processor to communicate with intelligent devices like drives, scales, starters and many others, or use DeviceNet to expand the processors I/O capabilities/capacity.
The 1764-LRP processor allows messaging functionality over
DeviceNet, so non-I/O data may be exchanged. Multiple 1769-SDN scanner modules may be used in a 1764-LRP system, however only the first two scanners can be used for messaging. This is discussed in
greater detail in Configuring a Local DeviceNet Message on page 7-11.
The amount of power that modules draw from the processor or expansion power supply, and the amount of data that the processor can support will determine how many can be used. To determine if an application can be supported, configuration tools are available from www.ab.com/micrologix. In addition to electrical limitations, data space limitations also exist. The maximum size of the input and output images for each module in the system is 250 input and 250 output words of data.
1
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7-2 Using the 1769-SDN Scanner Module with MicroLogix Controllers
RSLogix 500 I/O
Configuration
One of the advanced features of RSLogix 500 is the ability to have the programming software establish a communications connection with the controller and read which I/O modules are attached to the controller. This capability significantly reduces the effort involved in configuring a system.
This section will illustrate how to read which I/O modules are attached to the controller, and manually configure them. We will then configure the scanner. An example network is shown below:
DeviceNet Network
PC with RSNetWorx for DeviceNet software
MicroLogix 1500 Controller I/O
Bank with 1769-SDN Module
1770-KFD PC
Communication
Module
DANGER
Series 9000
Photoeye
RediSTATION
1305 Drive Connected via 1203-GU6
Enhanced DeviceNet Communications Module
DANGER
MicroLogix 1000 Controller
Connected via 1761-NET-DNI
MicroLogix 1200 Controller
Connected via 1761-NET-DNI
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Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-3
Starting the Project
1.
Open RSLogix 500.
2.
Select File.
3. New.
4.
Choose MicroLogix 1500 LRP series C.
5.
The screen capture below should match what you see on your computer.
In this example the name for this application is “TEMP”. In the
TEMP window you see everything associated with the application. Within the Controller folder you will see I/O
Configuration.
6.
Double click I/O Configuration .
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7-4 Using the 1769-SDN Scanner Module with MicroLogix Controllers
I/O Configuration Screen
The I/O configuration screen shows each of the controllers I/O slots.
For the MicroLogix 1500 controller, slot 0 contains the embedded I/O that is part of the MicroLogix 1500 base unit. Slots 1 through 16 are for
Compact I/O expansion modules (referred to as local I/O, because they are physically attached to the controller). Slots 9 through 16 are only available using a Series C processor with a Series B base unit
(1)
.
To have RSLogix 500 read the controller’s local I/O and configure the slots automatically, select the Read I/O Config button.
TIP
To manually configure the controller I/O, simply drag the appropriate modules from the available list
(right window), to the appropriate slot on the left.
Note, you cannot have open slots, modules must be contiguous from 1 to 16.
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(1)
Series B base units will be available late in 2001. Contact your local Allen-Bradley distributor for availability.
Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-5
Read I/O Configuration
The next screen that appears is a communications dialog that allows you to select a communication path using RSLinx to the MicroLogix controller.
If you have previously connected to a controller, the communications driver that you used before will be the active driver. This dialog screen provides the ability to change the driver or perform a Who
Active across a network to locate the specific MicroLogix controller.
If the driver and path are correct, select Read I/O Config .
Installed I/O
RSLogix 500 then displays all of the I/O modules that are attached to the MicroLogix controller.
In this example, there is a 1769-SDN scanner module at slot 1, and a
16-point discrete input module in slot 2.
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7-6 Using the 1769-SDN Scanner Module with MicroLogix Controllers
1769-SDN Scanner Module Configuration
To configure a specific module, simply double-click on the module.
To configure the scanner in this example, double-click on the module in slot 1 .
Input Words
This is the number of input words the controller assigns to the module. The first 66 words (0 to 65) are required by the scanner for status. DeviceNet slave input data words start at slot word 66. You can have a maximum of 180 input words for DeviceNet slave devices
(maximum slot amount for 1769-SDN scanner module inputs = 246).
See Configuring the I/O Devices section on page 4-10 and Chapter 5,
DeviceNet I/O Image, for more information related to mapping
DeviceNet Slave devices into the 1769-SDN’s scanlist.
Output Words
This is the number of output words the controller assigns to the module. The first 2 words (0 and 1) are required by the scanner for status. DeviceNet slave output data words start at slot word 2. You can have a maximum of 180 output words for DeviceNet slave devices
(maximum slot amount for scanner outputs = 182).
See Configuring the I/O Devices section on page 4-10 and Chapter 5,
DeviceNet I/O Image, for more information related to mapping
DeviceNet Slave devices.
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Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-7
Changing the 1769-SDN Configuration
Changing (adding or removing) the amount of data the controller has assigned to the scanner is done in the expansion module configuration screen. From within RSLogix 500, I/O configuration , open the 1769-SDN scanner module and change the input or output words as needed. Save the program and download to the Controller.
TIP
Reducing the number of words for either inputs or outputs will require a change in the 1769-SDN’s scanlist, which is done using RSNetWorx.
IMPORTANT
It is recommended that you NOT reduce the number of words assigned to a 1769-SDN’s scanlist once a system is operational. Changing the number of words may cause addressing problems on the controller side, and mapping changes on the
DeviceNet network.
Adding words to an existing system is relatively easy to do, because it doesn’t affect existing addresses or mapping. Simply add the number of additional words that are needed in the module (using the above example), and change the scanlist using
RSNetWorx.
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7-8 Using the 1769-SDN Scanner Module with MicroLogix Controllers
The configuration screen for the scanner is shown below.
Backplane Messaging
Ignore Configuration Error
Checking (enabling) this box instructs the module to ignore I/O size mismatches. If this is checked and the input/output scanlist configured by RSNetWorx (DeviceNet side of the 1769-SDN) does
NOT match the amount of I/O data assigned by the controller (0 to
180 words), the module will not generate an error.
If this box is not checked, the number of data words on the controller side must match the number of words configured by RSNetWorx. The default condition is unchecked (report an error on mismatch).
Series/Major Rev/Minor Rev
You will need this information if you contact Rockwell Automation
Technical Support. (phone 440-646-5800)
The MicroLogix 1500 1764-LRP processor and the 1769-SDN scanner module also support backplane messaging. This new level of functionality allows the processor to read (get) or write (set) data to other devices on DeviceNet. This is also referred to as Explicit
Messaging .
You can use two different types of messages to exchange information with the DeviceNet device. The type of message used is determined by the destination device. You can generate a PCCC message or a CIP message.
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Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-9
PCCC Messaging
PCCC stands for “Programmable Controller Communications
Commands”. PCCC provides point to point and master/slave communications between devices. PCCC is an open protocol that is built into all Allen-Bradley controllers, and many other Allen-Bradley and third-party products.
PCCC messaging has been used for many years on DH-485, DH+ and
Ethernet networks, and for point-to-point communications between
Allen-Bradley controllers. PCCC messaging allows program upload/download to occur over DeviceNet, and allows users to message across DeviceNet, just like they did using DH-485 or DH+.
There are a number of devices that support PCCC messaging over
DeviceNet, including the 1761-NET-DNI (DNI), 1203-GU6 interface, and RSLinx. If the DeviceNet network has DNI’s, either device can initiate a PCCC message.
CIP Messaging
Program Upload/Download
Before performing a program upload/download through the scanner, be sure that the module is properly installed in the system, and that a terminator is present at the end of the Compact I/O expansion bus.
IMPORTANT
DeviceNet networks can operate at 125K, 250K or
500K baud. Depending on network size and communication activity, performing program upload and/or download operations while the network is controlling an application may impact control system performance. It is up to the user to know and understand how upload/download will impact their operations.
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7-10 Using the 1769-SDN Scanner Module with MicroLogix Controllers
To perform program upload/download using RSLogix 500, select
Comms . From the drop-down menu, select System Comms .
System Comms will generate an RSLinx screen similar to the example below.
In this example, the DeviceNet interface is a 1770-KFD module.
Selecting the 1770-KFD driver will show the devices on the DeviceNet network.
In this example, upload/download can be performed with the devices at nodes 5, 6, 7 and 32. Node 32 is a 1769-SDN. Simply highlight the
1769-SDN and then click on either the upload or download button on the right side of the screen.
Publication 1769-UM009B-EN-P - May 2002
Configuring a Local
DeviceNet Message
Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-11
This section describes how to configure a local message using the scanner and a MicroLogix 1500 1764-LRP processor.
Message Setup Screen
Rung 0 shows a standard RSLogix 500 message (MSG) instruction preceded by conditional logic.
1.
Access the message setup screen by double-clicking Setup
Screen .
2.
The RSLogix 500 Message Setup Screen appears. This screen is used to setup or monitor message parameters for “This
Controller”, “Target Device”, and “Control Bits”. Descriptions of each of these sections follow.
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7-12 Using the 1769-SDN Scanner Module with MicroLogix Controllers
“This Controller” Parameters
Channel
The 1764-LRP supports three different pathways for messaging, channels 0 and 1 are RS-232 ports and are functionally identical to
MicroLogix 1200 and MicroLogix 1500 1764-LSP controllers. The
1764-LRP also supports backplane communications through the
Expansion Communication Port (ECP) as illustrated below.
When ECP is chosen, you are able to select which slot position (1 to
16) the scanner resides in. The 1764-LRP processor can support up to two 1769-SDN scanner modules with full messaging functionality.
Publication 1769-UM009B-EN-P - May 2002
TIP
You can use multiple 1769-SDN scanner modules in a MicroLogix 1500 system, but you can only message through the first two. Any other 1769-SDN scanner can only be used for I/O scanning.
Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-13
Communication Command
The 1764-LRP processor supports the six standard types of communications commands (same as all other MicroLogix 1200 and 1500 controllers) and CIP Generic. When any of these six standard commands are chosen, you can initiate standard messages to destination devices connected to DeviceNet products that support
PCCC messaging (including MicroLogix and SLC controllers using
1761-NET-DNI’s, other MicroLogix 1500 controllers using 1769-SDN scanner modules, etc.). You can initiate reads, writes, program upload/download and online monitoring across DeviceNet. This is functionally identical to DH-485 and DH+ networking.
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7-14 Using the 1769-SDN Scanner Module with MicroLogix Controllers
CIP Generic
CIP stands for “Control & Information Protocol”. CIP is a newer and more versatile protocol than PCCC. It is an open protocol that is supported by newer Allen-Bradley controllers and third-party products.
CIP messaging is the native messaging format for DeviceNet. All
DeviceNet devices are compliant with CIP messaging. The MicroLogix
1500 1764-LRP processor (Series C) has an enhanced message instruction that provides simple, easy to use CIP messaging.
Selecting CIP Generic configures the message instruction to communicate with DeviceNet devices that do not support PCCC messaging. When CIP Generic is chosen, you will notice that a number of message parameters change and many new ones become available depending upon the service selected.
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Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-15
Data Table Address (Receive and Send)
This value identifies the data file location within the 1764-LRP controller that will receive data from the DeviceNet device, and/or the starting data file location that will be sent to the destination DeviceNet device.
Size in Bytes (Receive and Send)
Since all data transmitted on DeviceNet is byte based, you must enter the number of bytes that will be received and sent. You must make sure that enough memory is available in the destination device. Word elements within 1764-LRP controllers contain 2 bytes each. These include Bit and Integer data files. Long word and Floating point elements contain 4 bytes each.
For receive, the Size in Bytes entered must be greater than or equal to the number of bytes than the DeviceNet device will return. DeviceNet devices return a fixed number of bytes depending on the Class and
Service. If more data is returned than expected, the message will error and no data will be written. If less data is returned than expected, the data will be written and the remainder of the bytes will be filled with zeros.
In the example screen shown below, N7:0 will receive 2 bytes (1 word) of data.
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7-16 Using the 1769-SDN Scanner Module with MicroLogix Controllers
Target Device
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Message Timeout
Message timeout is specified in seconds. If the target does not respond within this time period, the message instruction will generate a
specific error (see MSG Instruction Error Codes on page 7-18). The
amount of time that is acceptable should be based on application requirements and network capacity/loading.
Target Type
You can select either Module or Network Device . If you need to message to a device on DeviceNet, select Network Device. If you need to message to a DeviceNet parameter on the scanner, select
Module. This allows the control program access to module
parameters. Some of the parameters are shown in Appendix B,
1769-SDN DeviceNet Class Codes.
TIP
Note, many module parameters are not editable, and some can only be edited when the module is in Idle
Mode.
Using the 1769-SDN Scanner Module with MicroLogix Controllers 7-17
Local Node address
This is the target device’s DeviceNet node number.
Service
DeviceNet uses services to provide specific messaging functions. A number of standard services with their corresponding parameters have been preconfigured for ease of use.
If you need to use a service that is not available, select one of the
Generic services. The Generic service allows you to enter specific service code parameters. Information on what services a target device supports is usually provided in the device’s documentation.
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7-18 Using the 1769-SDN Scanner Module with MicroLogix Controllers
MSG Instruction Error
Codes
When the processor detects an error during the transfer of Expansion
I/O Communication Module message data, the processor sets the ER bit and writes an error code at MG file subelement #18 that you can monitor from your programming software.
Table 7.1 1769-SDN Module Error Code
Error Code
E0H
Description
Expansion I/O Communication Module Error.
The processor also writes general status information related to this error at the high byte of MG file subelement #22 that can be monitored from your program.
Table 7.2 Error Status Information
11H
13H
14H
15H
16H
19H
20H
28H
08H
09H
0BH
0CH
0EH
10H
General Status Description
01H Illegal or Unsupported Service Parameter
02H
04H
07H
Resource Unavailable
Segment Type Error in IOI
Connection Lost
Service Not Supported
Invalid Attribute Value
Already in Requested Mode/State
Object State Conflict
Attribute Not Setable
Device State Conflict
Reply Data Too Large
Not Enough Data
Attribute Not Supported
Too Much Data
Object Does Not Exist
Store Operation Failure
Invalid Parameter
Invalid Member ID
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Key features
- Connects up to 64 DeviceNet slave devices
- Provides a gateway between CompactLogix controllers and DeviceNet devices
- Uses the RSNetWorx for DeviceNet software for configuration
- Supports both explicit and implicit messaging
- Provides diagnostic information for troubleshooting
- Has a built-in watchdog timer to ensure reliable operation