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Allen-Bradley
Very High
Speed Counter
Module
(Cat. No. 1794-VHSC)
User
Manual
–1
Allen-Bradley Spares
Important User Information Because of the variety of uses for the products described in this publication, those responsible for the application and use of this control equipment must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards.
The illustrations, charts, sample programs and layout examples shown in this guide are intended solely for example. Since there are many variables and requirements associated with any particular installation,
Allen-Bradley does not assume responsibility or liability (to include intellectual property liability) for actual use based upon the examples shown in this publication.
Allen-Bradley publication SGI–1.1, “Safety Guidelines For The
Application, Installation and Maintenance of Solid State Control”
(available from your local Allen-Bradley office) describes some important differences between solid-state equipment and electromechanical devices which should be taken into consideration when applying products such as those described in this publication.
Reproduction of the contents of this copyrighted publication, in whole or in part, without written permission of Allen–Bradley Company, Inc.
is prohibited.
Throughout this manual we make notes to alert you to possible injury to people or damage to equipment under specific circumstances.
!
ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss.
Attention helps you:
• identify a hazard
• avoid the hazard
• recognize the consequences
Important: Identifies information that is especially important for successful application and understanding of the product.
Important: We recommend you frequently backup your application programs on appropriate storage medium to avoid possible data loss.
FLEX I/O, DeviceNet, DeviceNetManager, and RediSTATION are trademarks of Allen-Bradley Company, Inc.
PLC, PLC–2, PLC–3, and PLC–5 are registered trademarks of Allen-Bradley Company, Inc.
All other brand and product names are trademarks or registered trademarks of their respective companies.
Purpose of This Manual
This manual shows you how to use the Very High Speed Counter module with an Allen-Bradley programmable controller. It helps you install, program, and troubleshoot your module.
Audience
You must be able to program and operate an Allen-Bradley programmable controller (PLC) to make efficient use of this module.
We assume that you know how to do this in this manual. If you do not, refer to the appropriate programming and operations manual for the associated programmable controller before you attempt to use this module.
Vocabulary
In this manual, we refer to:
• the Very High Speed Counter module as the “module,” the
“1794-VHSC” or the “VHSC module.”
• the programmable controller as the “controller,” or the “PLC.”
Manual Organization
This manual is divided into 5 chapters. The following chart shows each chapter with its corresponding title and a brief description of the topics covered in that chapter.
Chapter Title Topics Covered
1
2
3
4
5
Overview of the Very High Speed Counter Module
Installing the Very High Speed Counter Module
Explanation of modes, outputs, and how the module communicates with the processor.
How to install, key, connect wiring, ground and an explanation of the indicators on the module.
Programming Your Very High Speed Counter
Module
Input, Output and Configuration Files for the Very
High Speed Counter on ControlNet
Use RSLogics to program this module.
Identification and description of bit/words for input, output and configuration.
Troubleshoot the Very High Speed Counter Module
Using the indicators for troubleshooting and diagnostic codes.
Appendices
A Specifications Specifications for the 1794-VHSC module.
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Using This Manual
Related Products
Product Compatibility
Related Publications
You can install your input module in any system that uses
Allen-Bradley programmable controllers and the 1794 I/O structure.
Contact your nearest Allen-Bradley office for more information about your programmable controllers.
This module can be used with 1794-ACN15 series B and -ACNR15 series B or later ControlNet Adapters. Communication between the module and the processor is bidirectional. The PLC sends module information using ControlNet messages to the adapter. The PLC receives module status information through ControlNet messages from the adapter.
For a list of publications with information on Allen-Bradley programmable controller products, consult our publication index
SD499.
Publication 1794-6.5.10 – December 1998
Table of Contents
Overview of the Very High
Speed Counter Module
Chapter 1
Chapter Objectives
Module Description
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features of the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation in Encoder or Counter Mode . . . . . . . . . . . . . . . . . . . . .
Counter Mode
Encoder Mode
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preset Value
Rollover Value
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Software Reset
Gate/Reset Input
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation in Period/Rate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous/Rate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation in Rate Measurement Mode
Pulse Width Modulation
. . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enabling and Forcing Outputs . . . . . . . . . . . . . . . . . . . . . . . . . .
Assigning Outputs to Counter Windows
Operation of Outputs
. . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What the High Speed Counter Module Does
Chapter Summary
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2
How to Install Your Very
High Speed Counter Module
What This Chapter Contains
Before You Install Your Input Module . . . . . . . . . . . . . . . . . . . . . . .
European Union Directive Compliance . . . . . . . . . . . . . . . . . . . . . .
EMC Directive
Low Voltage Directive
Module Indicators
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Allen-Bradley Spares
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring the Terminal Base Units (1794-TB3G shown) . . . . . . . .
Installing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting the Terminal Base Unit on a DIN Rail . . . . . . . . . . . . .
Panel/Wall Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting the High Speed Counter Module on the
Terminal Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting Wiring for the High Speed Counter Module . . . . . . . . . .
Wiring connections for the 1794-VHSC High Speed
Counter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of Quadrature Encoder Wiring to a 1794-TB3G Terminal
Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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ii
Table of Contents
Programming Your Very
High Speed Counter Module
Input, Output and
Configuration Files for the
Very High Speed Counter on
ControlNet
Troubleshoot the Very High
Speed Counter Module
Specifications
Chapter 3
Programming Your High Speed Counter Module . . . . . . . . . . . . . . .
Chapter 4
Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
About the ControlNet Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Over the FLEX I/O Backplane
Scheduled Data-Transfer
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unscheduled Data-Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module I/O Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adapter Input Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safe State Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Fault Behavior
Idle State Behavior
. . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Data Behavior upon Module Removal . . . . . . . . . . . . . . . .
High Speed Counter Module (1794-VHSC) Image Table Mapping
Chapter 5
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Codes Returned by the Module . . . . . . . . . . . . . . . . . . .
Diagnostics Reported in Word 8 of BTR . . . . . . . . . . . . . . . . .
What’s Next . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix A
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Derating Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Publication 1794-6.5.10 – December 1998
Chapter
1
Overview of the Very High
Speed Counter Module
Chapter Objectives
Module Description
This chapter gives you information on:
• features of the 1794-VHSC module
• how the module communicates with programmable controllers.
• how the module operates
The VHSC module performs high speed counting for industrial applications. The module is an intelligent I/O module that interfaces signals with any Allen-Bradley programmable controller that has
ControlNet capability.
The VHSC module, once configured for its intended purpose, can continue to operate without flexbus power. (Note: Customer power is required for the module, inputs and outputs.) After scanning the inputs and updating the outputs, the input data is converted to a specified data type in a digital format to be transferred to the processor’s data table on request. Command and configuration data is sent from the programmable controller data tables to the module via ControlNet.
Features of the Module
The HSC module counts pulses from encoders (such as
Allen-Bradley Bulletin 845), pulse generators or mechanical limit switches, proximity switches, etc. and returns either a count or frequency in binary format.
The module’s features include:
•
2 counters configurable for 3 encoder modes, counter mode, period/rate mode, continuous/rate mode, rate measurement and pulse width modulation (PWM)
•
4 outputs, isolated in pairs
• outputs are current-sourcing at 5 or 12– 24V dc (0.5mA max. @
5V; 1A max. @ 12–24V)
• single-ended or differential inputs
•
2-phase encoder inputs up to a frequency of 250KHz (X 4 mode)
• single-phase counter inputs up to a frequency of 1MHz
• input voltage range of 5 or 24V dc
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Overview of the Very High Speed Counter Module
• returns input as count or frequency in binary format
• input counts as high as 16,777,215
• up to 1MHz in period/rate or rate measurement frequency modes
• outputs can be tied to any or all counter windows
• each output has a user-selectable on-off value
• outputs can be tied back to an input for cascading
• each counter has a user-selectable preset and rollover value
• totalization is provided in period/rate, continuous/rate and rate measurement modes
• module can continue counting without flexbus power (after configuration)
• outputs have safe state values which can be applied when there is a network failure or the PLC is switched to PROGRAM mode
• pulse width modulation (PWM) mode is available
Operation in Encoder or
Counter Mode
The 1794-VHSC module operates in the following modes:
• counter mode –
• encoder X1 mode
• encoder X2 mode
• encoder X4 mode
• period/rate mode
• continuous/rate mode
• rate measurement frequency mode
• pulse width modulation (PWM)
The operation of the module in these modes is described below.
The operation of encoder and counter modes is virtually identical.
The only difference between the two modes is in the type of feedback used.
Use the counter mode if you need the module to read incoming pulses from a maximum of 2 encoders (single-ended or differential), counters, pulse generators, mechanical limit switches, etc. and return them to the programmable controller as a binary number
(0-16,777,215).
Use the encoder modes if you need the module to read incoming quadrature pulses and return them to the programmable controller as a binary number (0-16,777,215). In these modes, the module accepts two-phase quadrature feedback and counts up or down depending upon the condition of the phase B input for each counter.
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Overview of the Very High Speed Counter Module
1–3
The operation of the module in the encoder/counter modes is as follows:
• counter mode - channel B is direction control (up or down).
Channel A input is used for pulse. The count is bidirectional with the direction determined by channel B.
• encoder X1 - This is a bidirectional count mode; counting up or down, using quadrature input signals.
• encoder X2 - This is a bidirectional count mode, using quadrature input signals, with 2 times the resolution of X1.
• encoder X4 - This is a bidirectional count mode, using quadrature input signals, with 4 times the resolution of X1.
Each of the counters in encoder/counter mode has values associated with it. These are:
• preset value
• rollover value
Counter Mode
The counter mode allows the module to read incoming pulses and return them to the programmable controller processor as a binary number (0-16,777,215).
In the counter mode, direction (up counting or down counting) is determined by the phase B input, which can be a random signal. If
Phase B is high, the counter will count down. If phase B is low or floating, (that is, not connected), the counter counts up.
If Phase B is:
High
Low or floating (not connected)
Counter will count (direction):
Down
Up
The module reads incoming pulses from a maximum of 2 encoders
(single-ended or differential), counters, pulse generators, mechanical limit switches, and so forth and returns a count to the programmable controller processor in a binary number (0-16,777,215).
The counter mode accepts only one phase feedback. This relationship is shown in figure 1.1.
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Overview of the Very High Speed Counter Module
Figure 1.1
Block Diagram of Counter Mode
Single Phase Pulse Generator
A
B
Z (Store Count)
(Gate/Reset)
Count Up
Input A
Input B
Input Z
1794-VHSC
Count Down
A Input
B Input
Count
0 1
+
2
–
3 2
Outputs updated continuously
1 0
Encoder Mode
The encoder mode allows the module to read incoming pulses and return them to the programmable controller processor as a binary number (0-16,777,215).
In this mode, the module will accept two phase quadrature feedback.
The module senses the relationship between the 2 phases and counts up or down accordingly.
Encoder X1 mode – quadrature input signals count on the leading edge or the trailing edge of channel A for a bidirectional count. The phase relationship between Channel A and Channel B determines direction – channel A leading, and channel B floating, the count direction is up; channel A lagging, and channel B high, the count direction is down.
Encoder X2 mode – quadrature input signals count on the leading edge and the trailing edge of channel A for a bidirectional count.
Channel B determines direction – B low (floating), the count direction is up; B high, the count direction is down.
Encoder X4 mode – quadrature input signals count on the leading edge and the trailing edge of channel A and channel B for a bidirectional count. Channel B determines direction – B low
(floating), the count direction is up; B high, the count direction is down.
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Overview of the Very High Speed Counter Module
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Direction of Count
The module can count either up or down, depending upon the condition of the B input for each counter. In encoder applications, the counter will increment on the leading edge of input A, while input B determines the direction of the count.
You also have the option of X1, X2 and X4 multiplying of the input pulses. Figure 1.2 shows the relationships between inputs A and B for forward and reverse directions in encoder applications.
Quadrature Encoder
Forward Rotation
CCW Encoder Rotation
Figure 1.2 Phase Relationship for Forward or Reverse
Directions
High Speed Counter Module
A
B
Z (Store Count)
(Gate/Reset)
Input A
Input B
Input Z
1794-VHSC
Reverse Rotation
CW Encoder Rotation
A Input
B Input
1
X1
Count
2
3
1 2 3 4 5 6 7 8 9 10 11 12
X2
Count
1 2 3 4 5 6 7 8 9 10 11 12
X4
Count
2 1
0
12 11 10 9 8 7 6 5 4 3 2 1
0
12 11 10 9 8 7 6 5 4 3 2 1
0
The following paragraphs apply to both encoders and counters.
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Overview of the Very High Speed Counter Module
Preset Value
Each of the 2 counters has one preset value associated with it. In the encoder or counter modes, the preset value represents a reference point (or count) from which the module begins counting. The module can count either up or down from the preset value. Preset values are loaded into the count registers through the preset count bits. Preset values can range from 0 to 16,777,215 binary.
Rollover Value
Each of the 2 counters has one rollover value associated with it.
When the rollover value is reached by the encoder/counter, it resets to 0 and begins counting again. The rollover values range from 1 to
16,777,216 binary. The rollover value is circular (for example: if you program 360, the count will be from 358, 359, 0, 1 etc. in a positive direction and from 1, 0, 359, 358 etc. in a negative direction).
Software Reset
The counters can also be reset by the Reset Count bits found in Word
0, bits 0 and 4 of the Counter Control word. When one of these bits is set to 1, the associated counter is reset to zero and begins counting.
The module can also be reset with the gate/reset as explained below.
Refer to chapter 4 for further details.
Gate/Reset Input
There is one gate/reset input for each of the 2 counters. The gate/reset input, when active, will function in one of the 4 store count modes outlined below.
Scaling Input Count at the Gate/Reset Terminal
You can scale the incoming count at the gate/reset terminal. Scaling allows the incoming pulses at gate/reset to be divided by a number in the range of 1, 2, 4, 8, 16, 32, 64 and 128.
Store Count
The store count feature allows the module to store the current count value of the associated counter. The store count feature is triggered by the state of the gate/reset terminal on the module. The stored count of each counter is placed in a separate word in the Read Data file. The stored count value will remain in the Read Data file until a new trigger pulse is received at the Gate/Reset terminal. When a new trigger pulse is received, the old count value will be overwritten by the new value.
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Overview of the Very High Speed Counter Module
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In mode 1, store/continue (figure 1.3), the leading edge of a pulse input on input Z (gate/reset) terminal causes the current value in the counter to be read and stored. The counter will continue counting.
The stored count will be available in the Read Data file. The stored count information will remain in the block transfer read file until it is overwritten by new data.
Figure 1.3 Store/Continue
Read, Store Count and continue counting.
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In mode 2, store/wait/resume (figure 1.4), a rising edge of a pulse input on the Z input (gate/reset) terminal reads and stores the current counter value in the Read Data file, and inhibits counting while the gate/reset input is high. Counting resumes when the input goes low.
Mode 2 does not reset the counter, although it does store the count value. The stored count is available in the Read Data file. The stored count remains in the Read Data file until it is overwritten with new data.
Figure 1.4 Store/Wait/Resume
Store Count
Stop counting
Resume counting
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In mode 3, store-reset/wait/start (figure 1.5), the rising edge of the pulse on input Z (gate/reset) terminal causes the counter to stop counting, store the current count value in the Read Data file and reset the count to zero. The counter does not count while the Z input on the gate/reset terminal remains high. Counting resumes from zero on the falling edge of the pulse at the Z (gate/reset) terminal. The stored count is available in the Read Data file. The stored count remains in the Read Data file until it is overwritten with new data.
Figure 1.5 Store-Reset/Wait/Start
Counter has stopped counting
Stop count, store and reset to zero
Start counting from zero
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Overview of the Very High Speed Counter Module
In mode 4, store-reset/start (figure 1.6), on the rising edge of a pulse input at the Z (gate/reset) terminal causes the counter to store the accumulated count value in the Read Data file, and reset the counter to zero. The counter continues counting while the Z gate/reset input is high. The stored count is available in the Read
Data file. The stored count remains in the Read Data file until it is overwritten with new data.
Figure 1.6 Store-Reset/Start
Rising Edge
Falling Edge
Store Count, reset to zero, start counting.
Store Count, reset to zero, start counting.
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Figures 1.3 through 1.6 show the store count feature operating on the rising edge of the gate/reset pulse. The user has the option of selecting these same features using the falling edge of the gate/reset pulse. The gate invert bit is active in the store count, continuous/rate and period/rate modes.
Operation in
Period/Rate Mode
Use the period/rate mode to determine the frequency of input pulses by counting the number of internal 5MHz clock pulses over a user-specified number of input signal pulses. At the end of the specified number of pulses, the module returns the frequency and the total number of pulses received.
A channel configured for period/rate mode acts as a period rate counter. An internal 5MHz clock is used as a frequency reference.
This clock is gated by the incoming pulse train at the gate/reset input. The results of this gating action are the number of pulses or a frequency. The frequency is returned in input file words 0 (LSW) and 1 (MSW) for channel 0 and word 2 (LSW) and 3 (MSW) for channel 1. The total pulses received is stored in input file words 4
(LSW) and 5 (MSW) for channel 0 and words 6 (LSW) and 7
(MSW) for channel 1. Select the period/rate mode by setting the appropriate bits in word 0 of the configuration block.
1794-VHSC modules count the total number of pulses occurring at the Z (gate/reset) pin. This function is frequency-limited to 200Hz X the scaler value. You can reset this count by setting the VR bit.
Figure 1.7 shows a diagram of the module used in the period/rate mode.
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Overview of the Very High Speed Counter Module
Figure 1.7 Period/Rate Mode
A (not used)
B (not used)
Z (gate/reset)
Single Phase Pulse Generator
Input A
Input B
Input Z scaler
5MHz Clock
1794-VHSC
1–9
Incoming pulse train at Z
(gate/reset terminal)
5MHz internal clock
Accumulated Count
1 10 20
Frequency and Outputs updated here
Assumes symmetrical pulse, 50% duty cycle, so period = sample time on X 2 (on and off)
Frequency = 1/period
If count = 25, scaler = 1, and clock period = (1/5MHz)
Frequency = 1 / [(25/1) X (1/5MHz) X 2] = 100KHz
In Figure 1.7, the incoming pulse train from the gate/reset terminal is used to sample pulses from the 5MHz internal clock. As the frequency of the incoming pulse train at the gate/reset terminal increases, the number of sampled pulses from the 5Mhz clock decreases. This relationship is shown in NO TAG. Since accuracy is related to the number of pulses received over the sample period, the accuracy will decrease with increasing input frequencies at the
Gate/Reset terminal.
To some extent, the decrease in accuracy can be lessened by scaling the input frequency through the use of a scaler. A scaler value of 1 will only return an accurate input frequency if incoming pulses have a 50% duty cycle.
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Overview of the Very High Speed Counter Module
Table 1.A
Relationship Between Sampled Pulses and Input Frequency
Input Frequency at Z
(Gate/Reset)
Terminal in Hz
100
200
500
1KHz
2KHz
5KHz
10KHz
20KHz
50KHz
100KHz
10
20
2
5
50
Sampled Pulses for 1/2 Cycle of Z (Gate/Reset) Pulse
25K
12.5K
5K
2.5K
1.25K
500
250
125
50
25
1.25M
500K
250K
125K
50K
Operation of scaler
In period/rate mode, the scaler lets the incoming pulse train at the Z
(gate/reset) terminal be divided by a user defined number.
Acceptable values for the scaler are 1, 2, 4, 8, 16, 32, 64 and 128.
There is one scaler value for each counter.
!
ATTENTION: Sample period times scaler must be less than 6.71 seconds in order to avoid a zero frequency detect indication.
Connection to Counter Inputs
The only input to the module in the period/rate mode is made to the
Z (gate/reset) terminal. The counter inputs (channel A and B) are not used in the period/rate mode.
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Continuous/Rate Mode
The continuous/rate mode is similar to the period/rate mode previously described except the outputs in this mode are dynamic outputs. Use this mode to determine the frequency of input pulses by counting the number of internal 5MHz clock pulses over a user-specified number of input signal pulses. Each output is turned on as soon as the turn-on count is reached, and turned off as soon as the turn-off count is reached. As the internal 5MHz clock is counted, the outputs dynamically track the 5MHz count. This allows you to turn an output on a certain number of 5MHz counts after the gate/reset pin goes active, and turn it off a certain number of 5MHz counts later.
1794-VHSC modules count the total number of pulses occurring at the Z (gate/reset) terminal. This function is frequency-limited to
200Hz X the scaler value. This total count is returned in input file words 4 (LSW) and 5 (MSW) for channel 0 and 6 (LSW) and 7
(MSW) for channel 1. You can reset this count by setting the VR bit.
Figure 1.8 Period/Rate and Continuous/Rate Output
Operation with Scaler of 1
A (not used)
Encoder/Pulse Generator
B (not used)
Z
(Gate/Reset)
Input A
Input B
Input Z scaler
5MHz Clock
1794-VHSC
Incoming pulse train at Z
(gate/reset terminal)
5MHz internal clock
1 10 20
Accumulated Count
Outputs updated continuously
Assumes symmetrical pulse, 50% duty cycle, so period = sample time on X 2 (on and off)
Frequency = 1/period
If count = 25, scaler = 1, and clock period = (1/5MHz)
Frequency = 1 / [(25/1) X (1/5MHz) X 2] = 100KHz
Frequency updated here
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Overview of the Very High Speed Counter Module
Operation in Rate
Measurement Mode
Use the rate measurement mode to count incoming pulses for a user-specified time interval. At the end of the interval, the module returns a value representing the sampled number of pulses and a value indicating the incoming frequency. When the count and frequency are updated, any associated outputs are checked against their associated presets.
The value representing the total number of pulses is returned in input file words 4 (LSW) and 5 (MSW) for channel 0 and 6 (LSW) and 7
(MSW) for channel 1, and the value indicating the incoming frequency is returned in words 0 (LSW) and 1 (MSW) and 2 (LSW) and 3 (MSW). The total count equals the running sum of the number of pulses received during the sample period. The operation of rate measurement mode is shown below in Figure 1.9.
Figure 1.9
Operation of the Rate Measurement Mode
A Input
Encoder/Pulse Generator
B (not used)
Z (not used)
(Gate/Reset)
Input A
Input B
Input Z
Time base
1794-VHSC
A Input (pulse)
Internal Sampling Gate
1 2 3
Accumulated Count
Frequency calculated, outputs updated here
If sample period is 50ms, and count = 3, then frequency = 3/50ms = 60Hz
Example:
In figure 1.9, three counts have been accumulated during the user-selected time period. If you had selected 50 milliseconds as the sample period, the frequency returned to the programmable controller processor would be:
Frequency = Counts/Sample period = 3 counts/50 milliseconds =
60Hz
Publication 1794-6.5.10 – December 1998
Pulse Width Modulation
Outputs
Overview of the Very High Speed Counter Module
1–13
Sample Period
You can set the sample period used in the frequency calculation in the rate measurement mode. Allowable values are 10 milliseconds to
3 seconds in 10 millisecond increments. The default value is 1 second.
Connection to Counter Inputs
The only user connections used in the rate measurement mode are to phase A of the module. The Z (gate/reset) and channel B terminals are not used in this mode.
The module can generate a pulse width modulation signal that may be tied to any output. By specifying a period (configuration word 2) and gate interval (configuration word 2 or 3) together with the PWM configuration word 2 or 3, a counter and its first ON/OFF window comparator is assigned and the signal generated. The actual duty cycle is specified by output words 2 and 3.
The VHSC module has 4 outputs, isolated in groups of 2. Each of the outputs is capable of sourcing current and will operate between 5 and 24 volts dc. You must connect an external power supply to each of the outputs. The outputs can source 1A dc alone or in combination. The outputs are hardware-driven and will turn on in about 25
µ s when the appropriate count value has been reached.
Enabling and Forcing Outputs
Outputs may be forced on or off independent of count or frequency value. To force the outputs, they must first be enabled. Enabling the outputs is done through a data table word 1, bits 1, 5, 9 and 13 (refer to chapter 4). Once the outputs have been enabled, they may be forced on by setting bits 0, 4, 8 or 12 in word 1. The outputs can be forced off by setting the enable bit to 0.
Assigning Outputs to Counter Windows
By setting bits in the configuration block, you can assign the outputs on the module to any of the various counter windows. You can assign any output to any count window with no restrictions.
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Overview of the Very High Speed Counter Module
Operation of Outputs
When the outputs for the VHSC module are enabled and assigned to a counter window they operate in an ON-OFF fashion. For example, assume that the module were programmed to turn ON an output when a count value of 2000 was reached. Further, assume that the user desired to have the output remain energized for a period of 3000 counts and then turn OFF. The end result would be that the outputs would turn ON at count of 2000, would remain energized for 3000 additional counts, and would turn OFF at 5000 counts. The ON and
OFF values are circular around zero. Refer to figure 1.10.
Figure 1.10 On-Off Operation of Output
Output remains energized for 3000 additional counts
Output turns on at count value of 2000
Output turns off at count value of 5000
10686-I
Refer to figure 1.11. Using output 0 as an example, when the value in Counter ON Value is less than the value in Counter OFF Value, the output turns on at 2000 and off at 5000. If the value in Counter
ON Value is greater than the value in Counter OFF Value, the output turns off at 2000 and on at 5000.
Figure 1.11 Effect of Values in On/Off Operation
Output turns ON at count of 2000.
Output remains energized for 3000 additional counts.
Output turns OFF at count of 5000.
Output turns OFF
at count of 2000.
Output turns ON
at count of 5000.
When values in Counter ON Value are less than values in Counter OFF Value.
When values in Counter ON Value are greater than values in Counter OFF Value.
10687-I
Isolation of Outputs
The module provides 850V dc isolation between each of the outputs and the flexbus.
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Overview of the Very High Speed Counter Module
1–15
Connecting Outputs to Counters
You can connect any of the outputs to any of the counter inputs. In this way, it is possible to use the outputs to reset a counter or to cascade counters. If using the outputs this way, make certain that the output voltage is compatible with the chosen input.
What the Very High Speed
Counter Module Does
The very high speed counter module performs high-speed scaling calculation operations for various industrial applications. The module interfaces with a FLEX I/O family ControlNet 1794-ACN15 series B or -ACNR15 series B or later adapter which then communicates with a programmable controller processor.
The adapter/power supply transfers data to and from the module over the flexbus. Instructions in the PLC facilitate this communication and let you write output values and configure the module’s mode of operation. The following illustration describes the communication process.
1
The adapter transfers your configuration data to the module.
2
External devices transmit frequency signals to the module.
Flexbus
4
The adapter transfers the data over the flexbus.
Allen-Bradley
1794–VHSC
ÎÎÎÎÎ
OK
1
5
The adapter and module determine that the transfer was made without error and input values are within a specified range.
3
The module converts frequency signals into integer format and stores these values until the adapter requests their transfer.
6
ControlNet transfers the data to the programmable controller data table.
1. The adapter transfers your configuration data and commands to the module.
2. External devices generate input signals that are transmitted to the module.
3. The module converts these signals into binary format, and stores these values and controls their output until the adapter requests
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Overview of the Very High Speed Counter Module
4. The adapter transfers the data over the flexbus.
5. The adapter and module determine that the transfer was made without error and inputs values are within a specified range.
6. ControlNet transfers the data to the PLC data table.
Chapter Summary
In this chapter you learned how your module operates, and how your module communicates with the programmable controller.
Publication 1794-6.5.10 – December 1998
What This Chapter
Contains
Before You Install Your
Input Module
European Union Directive
Compliance
Chapter
2
How to Install Your Very High
Speed Counter Module
In this chapter, we tell you:
For information on See page
Before You Install Your Module . . . . . . . . . . . . . . . . . . . . . . . 2–1
European Union Directives . . . . . . . . . . . . . . . . . . . . . . . . . . 2–1
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
Installing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–4
on a DIN rail . . . . . . . . . . . . . . . . . . .
on a wall/panel
on the terminal base
Connecting Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–9
Module Indicators . . . . . . . . . . . . . . . . . .
Before installing your 1794-VHSC very high speed counter module:
You need to:
Calculate the power requirements of all modules in this FLEX system.
Position the keyswitch on the terminal base
As described under:
Installing the Module, page 2–4
If this product has the CE mark it is approved for installation within the European Union and EEA regions. It has been designed and tested to meet the following directives.
EMC Directive
This product is tested to meet Council Directive 89/336/EEC
Electromagnetic Compatibility (EMC) and the following standards, in whole or in part, documented in a technical construction file:
•
EN 50081-2EMC – Generic Emission Standard, Part 2 –
Industrial Environment
•
EN 50082-2EMC – Generic Immunity Standard, Part 2 –
Industrial Environment
This product is intended for use in an industrial environment.
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How to Install Your Very High Speed Counter Module
Low Voltage Directive
This product is tested to meet Council Directive 73/23/EEC
Low Voltage, by applying the safety requirements of EN 61131–2
Programmable Controllers, Part 2 – Equipment Requirements and
Tests.
For specific information required by EN 61131-2, see the appropriate sections in this publication, as well as the following Allen-Bradley publications:
•
Industrial Automation Wiring and Grounding Guidelines For
Noise Immunity, publication 1770-4.1
•
Automation Systems Catalog, publication B111
This equipment is classified as open equipment and must be mounted in an enclosure during operation to provide safety protection.
Power Requirements
The wiring of the terminal base unit is determined by the current draw through the terminal base. Make certain that the current draw does not exceed 10A.
!
ATTENTION: Total current draw through the terminal base unit is limited to 10A. Separate power connections may be necessary.
Publication 1794-6.5.10 – December 1998
How to Install Your Very High Speed Counter Module
Methods of wiring the terminal base units are shown in the illustration below.
Wiring the Terminal Base Units (1794-TB3G shown)
!
ATTENTION: Do not daisy chain power or ground from the terminal base unit to any ac or dc digital module terminal base unit.
2–3
Daisy-chaining
Frequency Input
Module
VHSC
Module
VHSC
Module
VHSC
Module
24V dc
Individual
Note: Do not use any digital modules in this configuration.
Wiring when total current draw is less than 10A
Digital Input
Module
VHSC
Module
Digital Input
Module
Digital Output
Module
24V dc
24V dc
24V dc
Note: Use this configuration if using any digital output modules that could couple transients to the 24V supply.
VHSC Module wiring separate from digital wiring.
Wiring when total current draw is greater than 10A
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How to Install Your Very High Speed Counter Module
Installing the Module
Installation of the very high speed counter module consists of:
• mounting the terminal base unit
• installing the VHSC module into the terminal base unit
• installing the connecting wiring to the terminal base unit
If you are installing your module into a terminal base unit that is already installed, proceed to “Mounting the High Speed Counter
Module on the Terminal Base” on page2–8.
Mounting the Terminal Base Unit on a DIN Rail
!
ATTENTION: Do not remove or replace a terminal base unit when power is applied. Interruption of the flexbus can result in unintended operation or machine motion.
1. Remove the cover plug (if used) in the male connector of the unit to which you are connecting this terminal base unit.
2. Check to make sure that the 16 pins in the male connector on the adjacent device are straight and in line so that the mating female connector on this terminal base unit will mate correctly.
3. Position the terminal base on the 35 x 7.5mm DIN rail A (A-B pt.
no. 199-DR1).
B
C
A
A
Position terminal base at a slight angle and hooked over the top of the DIN rail.
4. Make certain that the female flexbus connector C is fully
retracted into the terminal base unit.
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How to Install Your Very High Speed Counter Module
2–5
Slide the terminal base unit over tight against the adapter.
Make sure the hook on the terminal base slides under the edge of the adapter and the flexbus connector is fully retracted.
Press down on the terminal base unit to lock the terminal base on the DIN rail. If the terminal base does not lock into place, use a screwdriver or similar device to open the locking tab, press down on the terminal base until flush with the DIN rail and release the locking tab to lock the base in place.
30077–M
Gently push the flexbus connector into the side of the adapter to complete the backplane connection.
5. Repeat the above steps to install the next terminal base.
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How to Install Your Very High Speed Counter Module
Panel/Wall Mounting
Installation on a wall or panel consists of:
• laying out the drilling points on the wall or panel
• drilling the pilot holes for the mounting screws
• mounting the adapter mounting plate
• installing the terminal base units and securing them to the wall or panel
If you are installing your module into a terminal base unit that is already installed, proceed to “Mounting the High Speed Counter
Module on the Terminal Base” on page2–8.
Use the mounting kit Cat. No. 1794-NM1 for panel/wall mounting.
1.4
(35.5)
1794-NM1 Mounting Kit
Contents:
1 – Mounting Plate for Adapter
2 – 18 #6 self-tapping screws
(2 for the adapter, and 2 each for up to 8 modules)
1
2
Adapter Module
(not included)
Terminal Base Unit
(not included)
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.83 (21)
Inches
(Millimeters)
How to Install Your Very High Speed Counter Module
1.4
(35.5)
To install the mounting plate on a wall or panel:
1. Lay out the required points on the wall/panel as shown in the drilling dimension drawing.
Drilling Dimensions for Panel/Wall Mounting of FLEX I/O
2.3
(58.5)
1.4
(35.5)
2.3
(58.5)
1.4
(35.5)
2–7
More
2. Drill the necessary holes for the #6 self-tapping mounting screws.
3. Mount the mounting plate (1) for the adapter module using two
#6 self-tapping screws (18 included for mounting up to 8 modules and the adapter).
Important:
Make certain that the mounting plate is properly grounded to the panel. Refer to “Industrial Automation
Wiring and Grounding Guidelines,” publication
1770-4.1.
4. Hold the adapter (2) at a slight angle and engage the top of the mounting plate in the indention on the rear of the adapter module.
5. Press the adapter down flush with the panel until the locking lever locks.
6. Position the terminal base unit up against the adapter and push the female bus connector into the adapter.
7. Secure to the wall with two #6 self-tapping screws.
8. Repeat for each remaining terminal base unit.
Note: The adapter is capable of addressing eight modules. Do not exceed a maximum of eight terminal base units in your system.
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How to Install Your Very High Speed Counter Module
Mounting the High Speed Counter Module on the Terminal
Base Unit
The 1794-VHSC module mounts on a 1794-TB3G or TB3GS terminal base unit.
1. Rotate the keyswitch (1) on the terminal base unit (2) clockwise to position 1 as required for this module.
7
3
1
2
6
4
5
2. Make certain the flexbus connector (3) is pushed all the way to the left to connect with the neighboring terminal base/adapter.
You cannot install the module unless the connector is fully extended.
3. Make sure that the pins on the bottom of the module are straight so they will align properly with the connector in the terminal base unit.
!
ATTENTION: Remove field-side power before removing or inserting the module. This module is designed so you can remove and insert it under
backplane power. When you remove or insert a module with field-side power applied, an electrical arc may occur. An electrical arc can cause personal injury or property damage by:
• sending an erroneous signal to your system’s field devices causing unintended machine motion
• causing an explosion in a hazardous environment
Repeated electrical arcing causes excessive wear to contacts on both the module and its mating connector.
Worn contacts may create electrical resistance.
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2–9
4. Position the module (4) with its alignment bar (5) aligned with the groove (6) on the terminal base.
5. Press firmly and evenly to seat the module in the terminal base unit. The module is seated when the latching mechanism (7) is locked into the module.
6. Repeat the above steps to install the next module in its terminal base unit.
Connecting Wiring for the
High Speed Counter
Module
Wiring to the high speed counter module is made through the terminal base unit on which the module mounts.
Compatible terminal base units are:
1794-TB3G
Module
1794-VHSC
1794-TB3G
Yes
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A 0 –15 A
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
B
16–33
B
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
C 34–51 C
1794-TB3GS
Yes
1794-TB3GS
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
Label placed at top of wiring area.
34 and 50 = 24V dc
35 and 51 = common
16 and 33 = chassis ground
40 thru 45 = chassis ground
34 and 50 = 24V dc
35 and 51 = common
16 and 33 = chassis ground
40 thru 45 = chassis ground
Connecting Wiring using a 1794-TB3G and -TB3GS Terminal Base
Units
1. Connect the individual signal wiring to numbered terminals on the 0–15 row (A) for +24V inputs (terminals 0–5 and 8–13) and
17–32 row (B) for +5V inputs (terminals 17–22 and 25–30).on
the terminal base unit. Connect the input devices as shown in the wiring table on page 2–12.
!
ATTENTION: Do not connect 24V signals to the 5V input terminals. Permanent damage to the module will result.
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How to Install Your Very High Speed Counter Module
2. Connect individual output wiring to terminals 6, 7 and 14, 15 on the 0–15 row (A) and terminals 23, 24 and 31, 32 on the 16–32 row (B) on the terminal base unit. Connect output return wiring for channels 0, 1, 2, and 3 to terminals 23, 24 31 and 32 respectively. Connect the output devices as shown in the wiring table on page 2–12.
3. Terminate any shield to terminals 16 or 33 on row B, or 40 through 45 on row C.
4. Connect +24V dc to terminal 34 on the 34-51 row (C), and 24V common to terminal 35 on the 34-51 row (C).
!
ATTENTION: To reduce susceptibility to noise, power VHSC modules and digital modules from separate power supplies. Do not exceed a length of 33 ft (10m) for dc power cabling.
5. If daisy chaining the +24V dc power to the next base unit, connect a jumper from terminal 50 (+24V) on this base unit to terminal 34 and from terminal 51 (24V dc common) to terminal
35 on the next base unit.
6. Connect output power wiring to terminals 37 (+) and 39 (–) for outputs 0 and 1, and terminals 46 (+) and 48 (–) for outputs 2 and 3.
!
ATTENTION: Do not daisy chain power or ground from the VHSC terminal base unit to any ac or dc digital module terminal base unit.
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How to Install Your Very High Speed Counter Module
0 1 2 3
Connections for Terminal Base 1794-TB3G shown
4 5 6 7 8 9 10 11 12 13 14 15
2–11
16
A
17
A B
24V Inputs
18 19
B Z
20 21
Z O0 O1
22 23 24
A
25
A B B Z
26
24V Inputs
27 28 29
Z O2 O3
30 31 32 33
A A B
Chassis Gnd
34 35
5V Inputs
36 37
B Z Z
38 39
R0 R1
40 41 42
A A B B Z
43 44
5V Inputs
45 46 47
Z R2 R3
48 49
Chassis Gnd
50 51
+24V COM
24V dc
Base Power
+V –V
6 Chassis Ground for Shields
+V
Where: A, A – incremental encoder input A (+5 or +24V dc)
B B – incremental encoder input B (+5 or +24V dc)
Z, Z – incremental encoder input Z (+5 or +24V dc)
O = sourcing outputs
R = returns for sourcing outputs
+V = +5 or +24V dc isolated power externally supplied for outputs (1A max.)
–V = negative isolated power connection (1A max.)
+24V dc = 24V dc terminal base power for module
COM = return for +24V dc terminal base power for module
Chassis Gnd = chassis ground for input or output cable shields
–V +24V COM
24V dc
Base Power
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How to Install Your Very High Speed Counter Module
Wiring connections for the 1794-VHSC High Speed Counter Module
Incremental
Input A
Input A
Input B
Input B
Input Z
Input Z
Input A
Input A
Input B
Input B
Input Z
Input Z
Channel 0
Terminal Base Units
1794–TB3G, –TB3GS
Channel 1
+24V Inputs
0 8
1
2
9
10
3
4
5
Channel 0
17
18
+5V Inputs
11
12
13
Channel 1
25
26
19
20
21
22
27
28
29
30
Outputs
Output
O0
O2
+24V dc base power
+24V dc COM
+5V or +24V
Output Pwr
–V Output Pwr
Chassis GND
Sourcing Out Return Output
6
14
23
31
O1
O3
Sourcing Out Return
Terminals 34 and 50
7
15
24
32
Terminals 35 and 51
Terminals 37 and 46
Terminals 39 and 48
Terminals 16, 33, and 40 thru 45
!
ATTENTION: Total current draw through the terminal base unit is limited to 10A. Separate power connections to the terminal base unit may be necessary.
Publication 1794-6.5.10 – December 1998
How to Install Your Very High Speed Counter Module
Example of Quadrature Encoder Differential Wiring to a
1794-TB3G Terminal Base Unit
2–13
A
B
Z (Store Count)
(Gate/Reset)
Quadrature Encoder
(ex. 845H–SJ__24DRY__ )
Mechanical Switch
16
0
0
17
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
2 3 4 5 6 7 8 9 10 11 12 13 14 15
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
1794-TB3G
0 –15
16–33
34–51
A
B
C
24V Base Power
12V
+
–
Solenoid
Attention: Keep exposed area of inner conductor as short as possible.
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How to Install Your Very High Speed Counter Module
Module Indicators
The high speed counter module has one red/green status indicator
(OK) that is on when power is applied to the module and one yellow indicator for each input and output.
Allen-Bradley
VERY HIGH SPEED COUNTER MODULE
1794–VHSC
B
Z
Indicator
A
OUT 0, 1, 2, 3
A
0
B Z 0
OUT
1 A
1
B Z
OUT
2 3
C B A
A = Power/status indicator – indicates power applied to module and status of module.
B = Insertable label for writing individual I/O assignments.
C = Status Indicators –
A = Status of input A
B = Status of input B
Z = Status of gate input Z
OUT = Output indicators, 1 for each output
Indication
Yellow
Off
Yellow
Off
Yellow
Off
Yellow
Off
Explanation
Input A active
Input A not active
Input B active
Input B not active
Input Z active
Input Z not active
Output is on
Individual output is off
Publication 1794-6.5.10 – December 1998
Chapter Summary
How to Install Your Very High Speed Counter Module
2–15
Indicator
OK
Indication
Red (solid)
Red (flashing)
Green (solid)
Green (flashing)
Explanation
•
Hardware diagnostic error, TF set to 1 and module/channel status contains error code.
•
Hardware runtime failure (i.e. watchdog timeout), module communication ceases.
•
Module is configuring hardware, NR is set to 1.
•
Module in test mode (bits 15–8 of counter control word are non–zero), TF set to 1
•
Module is active and operating normally.
•
Module is not configured.
•
Programming error, PE is set to 1 and error code is supplied in bits 11–0 of module/channel status word.
•
Field power fault, FP set to 1.
•
Adapter powered down, and module local power still active.
•
ControlNet cable disconnected.
•
PLC in PROG mode.
When an input indicator (yellow) is lighted, it indicates that a valid signal (active high or active low) is present at one of the Input terminals.
In this chapter, we told you how to install your input module in an existing programmable controller system and how to wire to the terminal base units.
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How to Install Your Very High Speed Counter Module
Publication 1794-6.5.10 – December 1998
Chapter
3
Programming Your Very High
Speed Counter Module
To initiate communication between the very high speed counter module and your PLC processor, you must use RSLogix 5 software.
Refer to the RSLogix software manuals for information on communicating with this 1794-VHSC very high speed counter module.
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Programming Your Very High Speed Counter Module
Publication 1794-6.5.10 – December 1998
Chapter
4
Input, Output and
Configuration Files for the
Very High Speed Counter on
ControlNet
Chapter Objectives
In this chapter you will learn about:
•
ControlNet Adapter
•
I/O structure
• safe state data
• communication fault data
• idle state behavior
• input data behavior upon module removal
About the ControlNet
Adapter
This module must be used with the FLEX I/O ControlNet adapters
(cat. no. 1794–ACN15 series B and –ACNR15 series B or later) which support extended data transfer (EDT). These adapters interface up to 8 FLEX I/O modules and a ControlNet processor or scanner. The adapter can support ControlNet real–time data connections to individual modules or module groups. Each connection is independent of the others and can be from different processors or scanners.
Communication Over the
FLEX I/O Backplane
Read
One 1794-ACN15/B and -ACNR15/B ControlNet adapter can interface up to eight terminal base units with installed FLEX I/O modules, forming a FLEX I/O system of up to eight slots. The adapter communicates to other network system components
(typically one or more controllers or scanners, and/or programming terminals) over the ControlNet network. The adapter communicates with its I/O modules over the backplane.
I/O Module
0
Inputs
I/O Module
Inputs
I/O Module
Inputs
Status
Read
Words
Status Status
ControlNet
Adapter
Network
Write
Outputs
Configuration
15
Slot 0
Write
Words
Outputs
Configuration
Slot 1
Outputs
Configuration
Slot 7
Data is exchanged scheduled (when mapped) or unscheduled (using
Allen-Bradley Spares
4–2
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Scheduled Data-Transfer
Scheduled data transfer:
• is continuous
• is asynchronous to the ladder-logic program scan
• occurs at the actual rate displayed in the Actual Packet Interval field on the programming software ControlNet I/O mapping
(monitor) screen
Unscheduled Data-Transfer
Unscheduled operations include:
• unscheduled non-discrete I/O data transfers—through ControlNet
I/O Transfer (CIO) instructions
• peer-to-peer messaging—through Message (MSG) instructions
• messaging from programming devices
Unscheduled messaging on a ControlNet network is non-deterministic. Your application and your configuration—number of nodes, application program, NUT, amount of scheduled bandwidth used, etc.—determine how much time there is for unscheduled messaging.
Module I/O Mapping
The I/O map for the VHSC module is divided into read words and write words. Read words consist of input and status words, and write words consist of output and configuration words. The number of read words or write words can be 0 or more. The length of each I/O module’s read words and write words vary in size depending on module complexity. Each I/O module will support at least 1 input word or 1 output word. Status and configuration are optional, depending on the module. The VHSC module has 9 input words, no status words, 4 output words and 56 configuration words.
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I/O Structure
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Output data is received by the adapter in the order of the installed
I/O modules. The Output data for Slot 0 is received first, followed by the Output data for Slot 1, and so on up to slot 7.
The first word of input data sent by the adapter is the Adapter Status
Word. This is followed by the input data from each slot, in the order of the installed I/O modules. The Input data from Slot 0 is first after the status word, followed by Input data from Slot 2, and so on up to slot 7.
Network READ
ControlNet Adapter
Read Data
Adapter Status
Slot 0 Input Data
Slot 1 Input Data
Slot 7 Input Data
Output Data
Slot 0 Output Data
Slot 1 Output Data
Read
Write
I/O Module
Slot 0
I/O Module
...
Slot 1
I/O Module
Slot 7
Network WRITE
Slot 7 Output Data
Adapter Input Status Word
Bit:
The input status word consists of:
•
I/O module fault bits – 1 status bit for each slot
• node address changed – 1 bit (created by PLC–5 controller)
•
I/O status – 1 bit (created by PLC–5 controller)
15 10 through 15 9 8 7 6
I/O Module Fault Bits
5 4 3 2 1 0
Not Used
Created by PLC–5 controller
I/O State Bit
Node Address Changed Bit
The adapter input status word bit descriptions are shown in the following table.
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Bit Description
Node Address Changed
(Created by PLC–5 controller.)
I/O State (Created by
PLC–5 controller.)
Bit
5
6
7
2
3
0
1
4
Explanation
This bit is set (1) when an error is detected in slot position 0.
This bit is set (1) when an error is detected in slot position 1.
This bit is set (1) when an error is detected in slot position 2.
This bit is set (1) when an error is detected in slot position 3.
This bit is set (1) when an error is detected in slot position 4.
This bit is set (1) when an error is detected in slot position 5.
This bit is set (1) when an error is detected in slot position 6.
This bit is set (1) when an error is detected in slot position 7.
8
This bit is set (1) when the node address switch setting has been changed since power up.
9
Bit = 0 – idle
Bit = 1 – run
10 thru 15 Not used – set to 0.
Safe State Data
Device Actions
Possible causes for an I/O Module Fault are:
• transmission errors on the FLEX I/O backplane
• a failed module
• a module removed from its terminal base
• incorrect module inserted in a slot position
• the slot is empty
• the slot contains a non–discrete module
The ControlNet adapter does not provide storage for alternate module output data during communication faults or processor idle state. This “safe state data” is stored in the VHSC module and may be defined using configuration software. Safe state data assures that a known output will be applied to the output devices to maintain a previously designated safe operating condition during the previously mentioned failure modes. This data is sent in the configuration block
(see Image Table Mapping later in this chapter).
Device actions include:
• communication fault behavior
• idle state behavior
• input data behavior upon module removal
Publication 1794-6.5.10 – December 1998
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Communication Fault Behavior
You can configure the VHSC response to a communication fault.
Upon detection of a communication fault, the module can:
• leave the module output data in its last state (hold last state)
• reset the module output data to zero (reset)
• apply safe state data to the module output
4–5
Idle State Behavior
The VHSC module responds to idle state (PLC in PROGRAM mode) according to the Communication Fault Behavior described above. The module can:
• leave the module output data in its last state (hold last state)
• reset the module output data to zero (reset)
• apply safe state data to the module output
Input Data Behavior upon Module Removal
I/O module input data sent by the adapter upon module removal is configurable. The adapter can:
• reset the module output data to zero (reset)
• leave the module output data in the last state before module removal (hold last state)
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ControlNet Files
Input File Size
1 to 9 Words
Output File Size
0 to 4 Word
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
High Speed Counter Module (1794-VHSC) Image Table Mapping
Module Image
Channel 0 Current Count (least significant word)
Channel 0 Current Count (most significant word)
Channel 1 Current Count (least significant word)
Channel 1 Current Count (most significant word)
Channel 0 Stored/Accumulated Count (least significant word)
Channel 0 Stored/Accumulated Count (most significant word)
Channel 1 Stored/Accumulated Count (least significant word)
Channel 1 Stored/Accumulated Count (most significant word)
PE FP NR TF OS OS OS OS C1 C0 ZF ZS C1 C0 ZF ZS
0 LC OE
Reserved
FO 0 LC OE FO
0
0
VR CP CR
LC OE
Channel 0 PWM Output Value (0–95.00%)
Channel 1 PWM Output Value (0–95.00%)
FO
0 VR CP CR
0 LC OE FO
Configuration File Size
56 Words
Counter Configuration
Filter Selection
Time Base Value/PWM Period
Channel 0 Gate Interval
Channel 1 Gate Interval
Reserved
Channel 0 Rollover Value (least significant word)
Channel 0 Rollover Value (most significant word)
Channel 1 Rollover Value (least significant word)
Channel 1 Rollover Value (most significant word)
Channel 0 Preset Value (least significant word)
Channel 0 Preset Value (most significant word)
Channel 1 Preset Value (least significant word)
Channel 1 Preset Value (most significant word)
Channel 0 Scaler
Channel 1 Scaler
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Configuration File Size
56 Words
0
0
0
0
0 0
0 0
0 0
0 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
S4
S4
S4
S4
S3
S3
S3
S3
S2
S2
S2
S2
S1
S1
S1
S1
F4
F4
F4
F4
First Counter 1st On Value (least significant word)
F3
F3
F3
F3
F2
F2
F2
F2
F1
F1
F1
F1
First Counter 1st On Value (most significant word)
First Counter 1st Off Value (least significant word)
First Counter 1st Off Value (most significant word)
First Counter 2nd On Value (least significant word)
First Counter 2nd On Value (most significant word)
First Counter 2nd Off Value (least significant word)
First Counter 2nd Off Value (most significant word)
First Counter 3rd On Value (least significant word)
First Counter 3rd On Value (most significant word)
First Counter 3rd Off Value (least significant word)
First Counter 3rd Off Value (most significant word)
First Counter 4th On Value (least significant word)
First Counter 4th On Value (most significant word)
First Counter 4th Off Value (least significant word)
First Counter 4th Off Value (most significant word)
Second Counter 1st On Value (most significant word)
Second Counter 1st Off Value (least significant word)
Second Counter 1st Off Value (most significant word)
Second Counter 2nd On Value (least significant word)
Second Counter 2nd On Value (most significant word)
Second Counter 2nd Off Value (least significant word)
Second Counter 2nd Off Value (most significant word)
4–7
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Configuration File Size
(continued)
56 Words
Second Counter 3rd On Value (least significant word)
Second Counter 3rd On Value (most significant word)
Second Counter 3rd Off Value (least significant word)
Second Counter 3rd Off Value (most significant word)
Second Counter 4th On Value (least significant word)
Second Counter 4th On Value (most significant word)
Second Counter 4th Off Value (most significant word)
Counter Control Safe State
Output Control Safe State
Channel 0 PWM Safe State
Channel 1 PWM Safe State
Input Word
Word 0
Word 1
Word 2
Word 3
Word 4
Word 5
Bit
00–15
(00–17)
00–15
(00–17)
00–15
(00–17)
00–15
(00–17)
00–15
(00–17)
00–15
(00–17)
Definition
Channel 0 current count – The current count consists of 2 words (32 bits)
4 enco er PW or t e re uenc in erio rate continuou rate rate measurement.). The range of values is (0 < value < 16,777,215).
Channel 1 current count – The current count consists of 2 words (32 bits)
4 enco er PW or t e re uenc in erio rate continuou rate rate measurement.). The range of values is (0 < value < 16,777,215).
Channel 0 stored/accumulated count – These are 32–bit long word values representing the stored count of the counter at the time of some specified event.
These words are not updated in counter modes (counter, X1 encoder, X2 encoder, X4 encoder) without store modes selected. With store modes selected, it is the counter value at the time of the specified Z input event.
In PWM configuration, it is the counter value at the end of the period specified by the product of the time base times gate interval. pulses (i.e. if scaling is set to 128, the accumulator will increase by 128 counts). The maximum frequency that accumulation can follow is (200Hz X
Scaler value).
In rate measurement, it is the total number of pulses seen at the A input accumulated over each period as specified by the product of time base times gate interval. The range of values occupy the entire 32–bit size from 0
< value < 4,294,967,295. These words are not cleared by changing the configuration.
Publication 1794-6.5.10 – December 1998
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Input Word Bit Definition
Word 6
Word 7
Words 8
00–15
(00–17)
00–15
(00–17)
00
01
02, 03
Channel 1 stored/accumulated count – These are 32–bit long word values representing the stored count of the counter at the time of some specified event.
These words are not updated in counter modes (counter, X1 encoder, X2 encoder, X4 encoder) without store modes selected.With store modes selected, it is the counter value at the time of the specified Z input event.
In PWM configuration, it is the counter value at the end of the period specified by the product of the time base times gate interval. pulses (i.e. if scaling is set to 128, the accumulator will increase by 128 counts). The maximum frequency that accumulation can follow is (200Hz X
Scaler value).
In rate measurement, it is the total number of pulses seen at the A input accumulated over each period as specified by the product of time base times gate interval. The range of values occupy the entire 32–bit size from 0
< value < 4,294,967,295. These words are not cleared by changing the configuration.
Module Channel Status Word
Zero input status bit (ZS) for Channel 0– This bit represents the present status of the Z input.
0 = Off
1 = Input on
This bit is uneffected by Z invert, ZI, in the counter configuration word.
Zero frequency detected bit (ZF) for Channel 0 – Only used during frequency configurations (period/rate, continuous/rate, and rate measurement). In period/rate and continuous/rate, counts are acquired during on state of the Z input. At very low frequencies, the counter saturates, indicating a zero frequency detect. The time it takes to determine a zero frequency in these 2 configurations can be as long as 6.7s (16,777,215 counts X 1/5MHz X 2 half cycles of Z). In rate measurement, pulses on Z are counted over a sample interval specified by the product of time base X gate interval. The time to detect a zero frequency is determined by the sample interval (example: time base = 0.100s, gate interval = 3 is 300ms to determine ZF).
Stored/data count bit (C0, C1) for Channel 0 – This count cycles thru 00,
01, 10, 11, 00... Each time the stored/accumulated count words are updated,
C(0,1) is incremented. The PLC sample rate, including network delay and program scan, must be as fast or faster than the frequency of the event which updates.
04
Zero input status bit (ZS) for Channel 1 – This bit represents the present status of the Z input.
0 = Off
1 = Input on
Word 8 continued
05
Zero frequency detected bit (ZF) for Channel 1 – Only used during frequency configurations (period/rate, continuous/rate, and rate measurement). In period/rate and continuous/rate, counts are acquired during on state of the Z input. At very low frequencies, the counter saturates, indicating a zero frequency detect. The time it takes to determine a zero frequency in these 2 configurations can be as long as 6.7s (16,777,215 counts X 1/5MHz X 2 half cycles of Z). In rate measurement, pulses on Z are counted over a sample interval specified by the product of time base X gate interval. The time to detect a zero frequency is determined by the sample interval (example: time base = 0.100s, gate interval = 3 is 300ms to determine ZF).
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Input Word
continued
Bit
06, 07
08–11
(10–13)
12 (14)
13 (15)
14 (16)
15 (17)
Definition
Stored/data count bit (C0, C1) for Channel 1 – This count cycles thru 00,
01, 10, 11, 00... Each time the stored/accumulated count words are updated,
C(0,1) is incremented. The PLC sample rate, including network delay and program scan, must be as fast or faster than the frequency of the event which updates.
Output status indicators (OS) – Bit 08 corresponds to output 0, bit 09 to output 1, bit 10 to output 2, and bit 11 to output 3.
0 = output Off
1 = output On
Test/fail bit (TF) – If the flexbus power or terminal base power is applied and the module fails during hardware tests, a fatal error occurs. The TF bit is asserted and the red module indicator turns on. An error code will be set in the module/channel status word which can be read using a CIO instruction.
The TF bit is also asserted if the upper byte of the counter control word is not zero.
Not ready status bit (NR) – Whenever 24V dc power is applied to the module, the hardware must be initialized. The NR bit will be asserted and the red module indicator will flash. If the red indicator continues flashing, and the green indicator momentarily turns on, the 24V dc power is below the module minimum.
Field power fault bit (FP) – If the 24V dc module power drops, the FP bit is asserted, the green module indicator flashes, the module outputs turn off, and the module enters an idle state reporting status as it waits for power to be restored. Note: this bit does not indicate status of either output customer power supply.
Programming error bit (PE) – This bit is asserted if incomplete, incorrect or conflicting set of configuration parameters are sent to the module. The green module status indicator will flash and an error code will be placed in bits 11:0 of the module/channel status word. The module will not enter a normal operating state. Bit definitions are shown in Chapter 5.
Publication 1794-6.5.10 – December 1998
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Output Word Bit Definition
Counter Control Word
00–15
(00–17)
00
01
02
03
04
05
06
Channel 0 Counter reset bit (CR) – A 0 to 1 transition of this bit clears the counter. Outputs are adjusted according to the window compare values.
Channel 0 Counter preset bit (CP) – A 0 to 1 transition of this bit sets the counter to the value specified by the preset words. Outputs are adjusted according to the window compare values.
Channel 0 Value reset bit (VR) – A 0 to 1 transition of this bit clears the stored/accumulated count words.
This bit is always 0.
Channel 1 Counter reset bit (CR) – A 0 to 1 transition of this bit clears the counter. Outputs are adjusted according to the window compare values.
Channel 1 Counter preset bit (CP) – A 0 to 1 transition of this bit sets the counter to the value specified by the preset words. Outputs are adjusted according to the window compare values.
Channel 1 Value reset bit (VR) – A 0 to 1 transition of this bit clears the stored/accumulated count words.
This bit is always 0.
07
08–15
(10–17)
00–15
(00–17)
Reserved for factory use.
Output Control Word
00
01
02
03
04
05
Output 0 Force output bit (FO) – When set to 1, output is turned on if OE is
1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.
Output 0 Output enable bit (OE) – When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When
OE = 0, the associated output is turned off.
Output 0 Local control bit (LC) – When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)
When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.
Not used – set to 0.
Output 1 Force output bit (FO) – When set to 1, output is turned on if OE is
1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.
Output 1 Output enable bit (OE) – When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When
OE = 0, the associated output is turned off.
06
Output 1 Local control bit (LC) – When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)
When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Output Word
Word 2
Word 3
Bit
07
08 (10)
09 (11)
10 (12)
11 (13)
12 (14)
13 (15)
14 (16)
15 (17)
00–15
(00–17)
00–15
(00–17)
Definition
Not used – set to 0.
Output 2 Force output bit (FO) – When set to 1, output is turned on if OE is
1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.
Output 2 Output enable bit (OE) – When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When
OE = 0, the associated output is turned off.
Output 2 Local control bit (LC) – When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)
When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.
Not used – set to 0.
Output 3 Force output bit (FO) – When set to 1, output is turned on if OE is
1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.
Output 3 Output enable bit (OE) – When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When
OE = 0, the associated output is turned off.
Output 3 Local control bit (LC) – When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)
When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.
Not used – set to 0.
Channel 0 PWM Output value – When the module is configured for PWM, the time base is enabled, the counter for the respective channel, its gate interval, rollover and 1st on and 1st off value are used. Ties can be used to direct the PWM signal to any or all outputs. The range of the PWM values is
0 < value < 9500 decimal (i.e. 0.00% < value < 95.00%). The actual duty cycle at the output depends on the turn on and turn off times of the
MOSFET, energy storage capability of the cable/load and the resistance from output to return.
Channel 1 PWM Output value – When the module is configured for PWM, the time base is enabled, the counter for the respective channel, its gate interval, rollover and 1st on and 1st off value are used. Ties can be used to direct the PWM signal to any or all outputs. The range of the PWM values is
0 < value < 9500 decimal (i.e. 0.00% < value < 95.00%). The actual duty cycle at the output depends on the turn on and turn off times of the
MOSFET, energy storage capability of the cable/load and the resistance from output to return.
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
4–13
Configuration
Word
Configuration
Bit Definition
Bits 00–03
Bits 08–11
(10–13)
Bits 04–07
Bits 12–14
(14–16)
Bit 15 (17)
0
0
0
0
0
Counter Configuration – The upper byte of this word configures counter 1, the lower byte counter 0.
03 02 01 00 Counter 0
11
(13)
0
10
(12)
0
09
(11)
0
08
(10)
0
Counter 1
Counter
0
0
0
1
1
0
1
1
0
0
1
1
Encoder
0 Encoder X2
1 PWM
0 Encoder X4
Period/Rate
14
(16)
0
0
0
0
06
1 1
0 1
Mode Selection
1
0
1
Continuous/Rate
Rate Measurement
05 04 Counter 0
0
1
13
(15)
12
(14)
Counter 1
0
0
1
1
0
0 Store count disabled
1
0
1
Mode 1 – store/continue
Mode 2 – store/wait/resume
Mode 3 – store;reset/wait/start
0 Mode 4 – store;reset/start
Invert the Z signal – 0 = Z not inverted; 1 = Z inverted
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Configuration
Word
Word 1
Word 2
Word 3
Word 4
Word 5
Word 6 and 7
Word 8 and 9
Word 10 and
11
Word 12 and
13
Bit Definition
Bits 00–03
Filter Selection – Only 1 filter selection can be chosen at a time. Frequency = 50% duty cycle.
03 02 01 00 Counter 0
Bits 08–11
(10–13)
11
(13)
0
0
0
0
10
(12)
09
(11)
08
(10)
Counter 1
0 0
0
0
1
0
0
1
0
0
0 No filter
1 50kHz (10
µ s + 0
µ s/–1.6
µ s)
0 5kHz (100
µ s + 0
µ s/–13.2
µ s)
0 500Hz (1.0ms + 0ms/–1.25
µ s)
0 50Hz (10.0ms + 0ms/–1.25ms) 1
Bit 12 (14) Input A filter bit (AF) – 0 = not filtered; 1 = apply filter to input
Bit 13 (15) Input B filter bit (BF) – 0 = not filtered; 1 = apply filter to input
Bit 14 (16) Input Z filter bit (ZF – 0 = not filtered; 1 = apply filter to input
Bit 15 (17) Set to 0.
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Time base – Sets the fundamental time base for both counters. Resolution in ms, with a minimum of 10ms intervals (10ms = 10; 1s = 1000). Time base must be entered when
PWM and rate measurement are configured. The maximum programmed value is
3000.
Channel 0 Gate interval – Sets the individual counter gate interval using the time base setting as its time unit. Actual gate interval is time base X gate interval (i.e. time base of 10
X gate interval of 5 = 50ms). Maximum value is 3s. Gate interval must be entered when
PWM and rate measurement are configured.
Channel 1 Gate interval – Sets the individual counter gate interval using the time base setting as its time unit. Actual gate interval is time base X gate interval (i.e. time base of 10
X gate interval of 5 = 50ms). Maximum value is 3s. Gate interval must be entered when
PWM and rate measurement are configured.
Bits 00–15
(00-17)
Do not use – reserved.
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Channel 0 Rollover – Sets the number of counts the counter accumulates before rolling over. For example, a setting of 1000 produces a count sequence of 998, 999, 0, 1, 2... while incrementing; and 2, 1, 0, 999, 998... while decrementing. Rollover is a 32–bit number with a usable range of 16,777,216. In PWM, this value is zero; in count, X1 encoder, X2 encoder and X4 encoder configurations, it must be some specified nonzero number. The value doesn’t matter in period/rate, continuous/rate and rate measurement configurations.
Channel 1 Rollover – Sets the number of counts the counter accumulates before rolling over. For example, a setting of 1000 produces a count sequence of 998, 999, 0, 1, 2... while incrementing; and 2, 1, 0, 999, 998... while decrementing. Rollover is a 32–bit number with a usable range of 16,777,216. In PWM, this value is zero; in count, X1 encoder, X2 encoder and X4 encoder configurations, it must be some specified nonzero number. The value doesn’t matter in period/rate, continuous/rate and rate measurement configurations.
Channel 0 Preset – This word sets the preset value the counter is loaded with when CP is asserted. This number has a range of 0 < value < 16,777,216.
Channel 1 Preset – This word sets the preset value the counter is loaded with when CP is asserted. This number has a range of 0 < value < 16,777,216.
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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
4–15
Configuration
Word
Bit Definition
Words 16 to 19
02
03
04
05
00
01
06
07
04
05
06
07
02
03
00
01
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Bits 00
01
02
03
04
05
06
07
Bits 08–15
(10–17)
Channel 0 Scaler – This word scales the Z signal in period/rate and continuous/rate
modes. If the filter is applied, the filtered Z signal is scaled. Set only 1 bit of the Scaler.
Selecting a Scaler causes accumulated counts to be adjusted accordingly (i.e. selecting a
Scaler of 128 increases the accumulated count by 128 after 128 Z pulses have been received). We recommend using the filter to reduce erroneous frequency readings
any time you use the Scaler on the Z input.
Z Fmins (frequency at which the 24-bit counter overflows) = 0.149Hz
Z/2 Fmins (frequency at which the 24-bit counter overflows) = 0.298Hz
Z/4 Fmins (frequency at which the 24-bit counter overflows) = 0.596Hz
Z/8 Fmins (frequency at which the 24-bit counter overflows) = 1.192Hz
Z/16 Fmins (frequency at which the 24-bit counter overflows) = 2.384Hz
Z/32 Fmins (frequency at which the 24-bit counter overflows) = 4.768Hz
Z/64 Fmins (frequency at which the 24-bit counter overflows) = 9.537Hz
Z/128 Fmins (frequency at which the 24-bit counter overflows) = 19.073Hz
Channel 1 Scaler – This word scales the Z signal in period/rate and continuous/rate
modes. If the filter is applied, the filtered Z signal is scaled. Set only 1 bit of the Scaler.
Selecting a Scaler causes accumulated counts to be adjusted accordingly (i.e. selecting a
Scaler of 128 increases the accumulated count by 128 after 128 Z pulses have been received). We recommend using the filter to reduce erroneous frequency readings
any time you use the Scaler on the Z input.
Z Fmins (frequency at which the 24-bit counter overflows) = 0.149Hz
Z/2 Fmins (frequency at which the 24-bit counter overflows) = 0.298Hz
Z/4 Fmins (frequency at which the 24-bit counter overflows) = 0.596Hz
Z/8 Fmins (frequency at which the 24-bit counter overflows) = 1.192Hz
Z/16 Fmins (frequency at which the 24-bit counter overflows) = 2.384Hz
Z/32 Fmins (frequency at which the 24-bit counter overflows) = 4.768Hz
Z/64 Fmins (frequency at which the 24-bit counter overflows) = 9.537Hz
Z/128 Fmins (frequency at which the 24-bit counter overflows) = 19.073Hz
Output Ties – These bits connect the specified output to the appropriate compare window.
There are 8 windows, 4 per counter. Each output can be connected to any number of windows, from 1 ot 8.
F1 = Tie output to first counter 1st window
F2 = Tie output to first counter 2nd window
F3 = Tie output to first counter 3rd window
F4 = Tie output to first counter 4th window
S1 = Tie output to second counter 1st window
S2 = Tie output to second counter 2nd window
S3 = Tie output to second counter 3rd window
S4 = Tie output to second counter 4th window
Set to 0.
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Publication 1794-6.5.10 – December 1998
4–16
Input, Output and Configuration Files for the Very High Speed Counter on ControlNet
Configuration
Word
Bit Definition
Words 20 to 51
Words 52 to 55
Bits 00–15
(00-17)
Bits 00–15
(00-17)
Counter On and Off – These words program each of the 4 counter’s (first and second counter) on and off values. The first compare window for each counter is used in PWM, and when programmed for PWM, the associated compare window should remain at 0. The range of each entry is 0 < value < 16,777,215. When a tie is connected to a window comparator, that window must be specified. These windows are always interpreted as counts, regardless of the configuration setting, and can be computed as follows: counts = (Scaler X 2.5E6)/desired frequency (for period/rate and continuous/rate) counts = time base X desired frequency (for rate measurement)
Safe State Values – When the PLC transitions to PROG mode or a communication fault occurs, the module copies the safe state words into its real time working buffer. The definitions are identical to the those in the counter control word, except entering a PWM safe state value outside the range 0–9500 results in a Hold Last State.
Word 52 is Counter Control Safe State; word 53 is Output Control Safe State; word 54 is Channel 0 PWM Safe State word 55 is Channel 1 PWM Safe State.
Publication 1794-6.5.10 – December 1998
What This Chapter
Contains
Status Indicators
Chapter
5
Troubleshoot the Very High
Speed Counter Module
Use this chapter to troubleshoot the very high speed counter module by interpreting the indicators.
The module contains indicators for each of the following:
Allen-Bradley
VERY HIGH SPEED COUNTER MODULE
1794–VHSC
A
0
B Z 0
OUT
1 A
1
B Z
OUT
2 3
C B A
A = Power/status indicator – indicates power applied to module and status of module.
B = Insertable label for writing individual I/O assignments.
C = Status Indicators –
A = Status of input A
B = Status of input B
Z = Status of gate input Z
The indicators are multiplexed in 2 groups (A0, B0, Z0, O0/O1; and
A1, B1, Z1, O2/O3) at a frequency of 488Hz. If inputs or outputs change at or near that frequency, the associated indicator will vary in brightness.
Indicator Indication Explanation
A
B
Z
Yellow
Off
Yellow
Off
Yellow
Off
Yellow
Input A active
Input A not active
Input B active
Input B not active
Input Z active
Input Z not active
Output is on
OUT 0, 1, 2, 3
Off
Individual output is off
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Publication 1794-6.5.10 – December 1998
5–2
Troubleshoot the Very High Speed Counter Module
Indicator
OK
Indication
Red (solid)
Red (flashing)
Red (flashing) with occasional flashing Green
Green (solid)
Green (flashing)
Explanation
•
Hardware diagnostic error, TF set to 1 and module/channel status contains error code.
•
Hardware runtime failure (i.e. watchdog timeout), module communication ceases.
•
Module is configuring hardware, NR is set to 1.
•
Module in test mode (bits 15–8 of counter control word are non–zero), TF set to 1
•
Module 24V power is below minimum rating.
•
Module is active and operating normally.
•
Module is not configured.
•
Programming error, PE is set to 1 and error code is supplied in bits 11–0 of module/channel sttus word.
•
Field power fault, FP set to 1.
•
Adapter powered down, and module local power still active.
•
ControlNet cable disconnected.
•
PLC in PROG mode.
When an input indicator (yellow) is lighted, it indicates that a valid signal (active high or active low) is present at one of the Input terminals.
Diagnostic Codes
Returned by the Module
Read Word
Word 8
If an incomplete, incorrect or conflicting set of configuration parameters are sent to the module, the PE bit is asserted, the green module status indicator flashes, and an error code is displayed in bits
0–11 of the module/channel status word. These codes are identified below. Use a CIO instruction to access this information.
Diagnostics Reported in Word 8 of the Data Input File
Bit
Bit 00
Bits 01
Bits 02
Bit 03
Bit 04
Bit 05
Indication
A reserved configuration or mode was programmed
ZF/BF/AF were selected and no filter was programmed, or multiple filters were selected.
A timebase was entered that was not a multiple of 10, or the timebase is out of range > 3000, i.e. 3s).
A configuration requiring a timebase was selected and no gate interval was set, or the gate interval is out of range (> 3s) or the product of timebase and gate interval is greater than 3s.
A rollover of zero was programmed though PWM was not selected; a rollover was programmed and PWM was selected; or the rollover is out of range (1 < rollover < 16,777,216)
The preset (0 < preset < 16,777,215) is out of range.
Publication 1794-6.5.10 – December 1998
What’s Next
Troubleshoot the Very High Speed Counter Module
5–3
Read Word Bit
Bit 06
Bit 07
Bit 08
Indication
A configuration was selected that requires a scalar, and no scalar was programmed or multiple scalars were selected
A tie has been connected to an unprogrammed window
Counter 0 window ON and OFF values are equal and not zero or counter 0 window ON and OFF value greater than 16,777,215.
Counter 1 window ON and OFF values are equal and not zero or counter 1 window ON and OFF value greater than 16,777,215.
Bit 09
Bit 10
Bit 11
During hardware self-tests, when either flexbus power or terminal base power is first applied and a fatal error occurs, the TF bit is asserted and the red module status indicator turns on. An error code is placed in the lower byte of the module/channel status word to indicate the failed resource. Use a CIO instruction to access this information. When using a CIO instruction, this would be word 10.
Read Word
Word 8
Bit
Bits 00–07
0
0
02 01 00 Dec.
0 0 1 1 RAM test failed
Definition
1
1
1
0
0
1
2
3
ROM checksum test failed
EEPROM test failed
0 4 Programmable Gate Array loading failed
All other combinations not used
To find out more about the VHSC module:
See appendix A
Specifications
For
specifications on the 1794-VHSC module
Allen-Bradley Spares
Publication 1794-6.5.10 – December 1998
5–4
Troubleshoot the Very High Speed Counter Module
Publication 1794-6.5.10 – December 1998
Specifications – 1794-VHSC Very High Speed Counter Module
Input Specifications
Number of Counters
Input Voltage
Input Current (typical)
2
Number of Inputs per Counter 2 groups of A/A, B/B, and Z/Z pairs with 5V dc or 15-24V dc terminations
5V dc or 15-24V dc (determined on terminal base terminations)
5V dc terminations:
19.1mA @ 5V dc
25.7mA @ 6V dc
15-24V dc terminations:
6.1mA @ 15V dc
10.2mA @ 24V dc
Input Off-State Voltage 5V dc terminations: <1.25V dc
15-24V dc terminations: <1.8V dc
<0.250mA
Input Off-State Current
Input On-State Voltage 5V dc terminations: >2.6V dc
15-24V dc terminations: >12.5V dc
>5mA Input On-State Current
On-State Voltage Maximum 5V dc terminations: +6V
15-24V dc terminations: Refer to 24V Input
Derating curve below.
Input Frequency Maximum
Input Filter Selections
1.0MHz counter and encoder X1 (no filters)
500kHz encoder X2 (no filters)
250kHz encoder X4 (no filters)
5: Off, 10
µ s, 100
µ s, 1.0ms, 10.0ms per A/B/Z group
Specifications continued on the next page.
Allen-Bradley Spares
Publication 1794-6.5 10 – December 1998
A–2
Specifications
Specifications – 1794-VHSC Very High Speed Counter Module
Output Specifications
Number of Outputs 2 isolated groups of 2 (0.5A max. @ 5V dc;
1.0A max. @ 12–24V dc)
Output Control Outputs can be tied to 8 compare windows
Output Supply Voltage Range 5-7V dc; 10-31V dc
Off-State Leakage Current
On-State Voltage Drop
On-State Current Maximum
<0.3mA
5V dc terminations: 0.9V dc @ 0.5A
12-24V dc terminations: 0.9V dc @ 1.0A
5V dc terminations: 0.5A
12-24V dc terminations: 1.0A
Maximum Current per Output pair
Short Circuit Current
Delay Time
Isolation Voltage
Off to On
On to Off
5V dc terminations: 0.5A
12-24V dc terminations: 1.0A
5V dc terminations: 0.9A
12-24V dc terminations: 4.0A
Outputs are short circuit protected and turn off until power is cycled.
25
µ s (load dependent)
150
µ s (load dependent)
100% tested @ 850V dc for 1s between six isolated areas, including; flexbus module 24V dc power
A0/B0/Z0 inputs
A1/B1/Z1 inputs
O0/O1 and output power supply 1
O2/O3 and output power supply 2
75mA @ 5V dc (with terminal base power off)
5W maximum @ 31.2V dc
Flexbus Current
Power Dissipation
Thermal Dissipation
Indicators
Maximum 17.1 BTU/hr @ 31.2V dc
1 green/red power/status indicator
6 yellow input status indicators – logic side
4 yellow output status – logic side
Keyswitch Position 1
Specifications continued on the next page.
Publication 1794-6.5 10 – December 1998
Specifications
Specifications – 1794-VHSC Very High Speed Counter Module
General Specifications
Module Location Cat. No. 1794-TB3G or -TB3GS Terminal Base
Dimensions Inches
(Millimeters)
External dc Power
Supply Voltage
Voltage Range
Supply Current
1.8H x 3.7W x 2.1D
(45.7 x 94.0 x 53.3)
Refer to 24V Derating Curve below
24V dc nominal
19.2 to 31.2V dc (includes 5% ac ripple)
100mA @ 24V dc
Environmental Conditions
Operational Temperature
Storage Temperature
Relative Humidity
Shock Operating
Vibration
Nonoperating
Category
Agency Certification
(when product is marked)
User Manual
Installation Instructions
0 to 55 o
C (32 to 131 o
F)
–40 to 85 o
C (–40 to 185 o
F)
5 to 95% noncondensing (operating)
5 to 80% noncondensing (nonoperating)
30g peak acceleration, 11(+1)ms pulse width
50g peak acceleration, 11(+1)ms pulse width
Tested 5g @ 10–500Hz per IEC 68-2-6
12 gauge (4mm
2
) stranded maximum
3/64 inch (1.2mm) insulation maximum
2
1
•
CSA certified
•
CSA Class I, Division 2
Groups A, B, C, D certified
•
UL listed
•
CE marked for all applicable directives
Publication 1794-6.5.10
Publication 1794-5.67
1 Use this conductor category information for planning conductor routing . Refer to publication
1770-4.1, “Industrial Automation Wiring and Grounding Guidelines for Noise Immunity.”
24V Input Derating Curve
V in
On–state
20
Voltage
(V dc)
10
30
29
24.0
A–3
0
0 10 20
25
30 40
Ambient Temperature o
C
50 55 60
The area within the curve represents the safe operating range for the module under various conditions of user supplied 24V dc supply voltages and ambient temperatures.
This includes all possible mounting positions, including inverted horizontal.
Allen-Bradley Spares
Publication 1794-6.5 10 – December 1998
A–4
Specifications
Publication 1794-6.5 10 – December 1998
Index
Numbers
A
adapter input status word, 4–3
F
frequency input module, how it works, 1–15
G
C
CIOs. See ControlNet I/O Transfer instructions
compatible terminal bases, 2–9 connecting wiring, 2–9
considerations, pre–installation, 2–1
ControlNet I/O unscheduled non-discrete I/O data
unscheduled operations
messaging from programming devices,
4–2 peer-to-peer messaging, 4–2
ControlNet I/O Transfer (CIO) instructions,
counter mode
block diagram, 1–3 operation, 1–3
curent draw, through base units, 2–2
I
I/O, ControlNet unscheduled non-discrete I/O data
unscheduled operations messaging from programming devices,
4–2 non-discrete I/O data transfer, 4–2 peer-to-peer messaging, 4–2
indicators
installation
K
L
D
diagnostics, codes returned by module, 5–2
M
drilling dimensions, wall/panel mounting, 2–7
mapping
E
encoder, phase relationship, 1–5
encoder mode
operation, 1–3 encoder X4, 1–3
Allen-Bradley Spares
Publicati0on 1794-6.5.10 – December 1998
I–2
Index
mounting, on terminal base, 2–8
mounting kit, cat. no. 1794-NM1, 2–6
MSGs. See Message instructions
O
outputs
assigning to counters, 1–13 enabling and forcing, 1–13
P
period/rate mode, operation, 1–8
R
rate measurement, connection to counter
removing and replacing, under power
S
scaling input, 1–6 software reset, 1–6
store count
T
terminal bases, compatible, 2–9
U
unscheduled non-discrete I/O data transfer,
W
Publicati0on 1794-6.5.10 – December 1998
Pub. Name
Very High Speed Counter Module User Manual
Check Problem(s) Type: Describe Problem(s):
Technical Accuracy text illustration
Internal Use Only
Completeness
What information is missing?
procedure/step example explanation illustration guideline other definition feature info in manual
(accessibility) info not in manual
Clarity
What is unclear?
Sequence
What is not in the right order?
Other Comments
Use back for more comments.
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