Rockwell Automation 1756-LSC8XIB8I User Manual
User Manual
ControlLogix Low-speed Counter Module
Catalog Number 1756-LSC8XIB8I
Important User Information
IMPORTANT
Solid-state equipment has operational characteristics differing from those of electromechanical equipment. Safety
Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication SGI-1.1
your local Rockwell Automation® sales office or online at http://www.rockwellautomation.com/literature/
important differences between solid-state equipment and hard-wired electromechanical devices. Because of this difference,
and also because of the wide variety of uses for solid-state equipment, all persons responsible for applying this equipment
must satisfy themselves that each intended application of this equipment is acceptable.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the
use or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and
requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or
liability for actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or
software described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation,
Inc., is prohibited.
Throughout this manual, when necessary, we use notes to make you aware of safety considerations.
available from
) describes some
WARNING: Identifies information about practices or circumstances that can cause an explosion in a hazardous environment,
which may lead to personal injury or death, property damage, or economic loss.
ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property
damage, or economic loss. Attentions help you identify a hazard, avoid a hazard, and recognize the consequence.
SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous
voltage may be present.
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reach dangerous temperatures.
Identifies information that is critical for successful application and understanding of the product.
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Table of Contents
Preface
Module Features
Module Operation
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 1
About the Counter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Proximity Sensor Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Module Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Additional I/O Module Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Parts Illustration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 2
Counters 0…7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
On/Off Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Rollover Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Counter Control Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Up/Down Count Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Count Enable Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Reset Count Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Preset Count Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Output Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Install the Counter Module
Configure the Module
Chapter 3
Install the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Key the Removable Terminal Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Connect the Wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
RTB Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
RTB Wiring Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Wire Terminations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Assemble the Removable Terminal Block and Housing. . . . . . . . . . . . . . 35
Install the Removable Terminal Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Remove the Removable Terminal Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Remove the Module from the Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter 4
ControlLogix Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Direct Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Local Chassis Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Remote Chassis Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Create a New Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Connection Formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Configure Connection Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Configure Counters 0…7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Configure Hardware Inputs 0…7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Download the Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 3
Table of Contents
Chapter 5
Troubleshoot the Module
Electronic Keying
Tag Definitions
Alternate Wiring for
Non-IEC Type 3 Sensors
Index
Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Software Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Fault Type Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Module Error Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Appendix A
Electronic Keying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Exact Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Compatible Keying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Disabled Keying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Appendix B
Configuration Tags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Input Tags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Output Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Appendix C
Module Input Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Choose a Pull-up Resistor for an Open Collector Sensor. . . . . . . . . . . . . 78
Open Collector Wiring without a Resistor . . . . . . . . . . . . . . . . . . . . . . . . . 78
4 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Preface
The ControlLogix® counter module counts incoming pulses and returns
accumulated count, instantaneous and average frequencies, and instantaneous
and average pulse width values. The module has two configurable On/Off
windows per counter that can be used to affect outputs on a 1756-OB16IEF
module in the same chassis.
The counter module requires the following:
• RSLogix™ 5000 software, version 18.02.00 or later
• The Add-on Profile (AOP) for the module available for download at
http://support.rockwellautomation.com/controlflash/LogixProfiler.asp
• Ability to program and operate an Allen-Bradley® ControlLogix controller
Additional Resources
These documents contain additional information concerning related products
from Rockwell Automation.
Resource Description
1756 ControlLogix I/O Modules Specifications
Technical Data, publication 1756-TD002
ControlLogix System User Manual,
publication 1756-UM001
ControlLogix Digital I/O Modules User Manual,
publication 1756-UM058
ControlLogix Analog I/O Modules User Manual,
publication 1756-UM009
ControlLogix Peer I/O Control Application Technique,
publication 1756-AT016
Industrial Automation Wiring and Grounding
Guidelines, publication 1770-4.1
Product Certifications website, http://www.ab.com Provides declarations of conformity, certificates, and other
Provides specifications for ControlLogix I/O modules.
Describes how to install and use traditional and extreme
environment ControlLogix controllers.
Describes how to install and use ControlLogix digital I/O
modules.
Describes how to install and use ControlLogix analog I/O
modules.
Describes typical peer control applications and provides details
about how to configure I/O modules for peer control operation.
Provides general guidelines for installing a Rockwell
Automation industrial system.
certification details.
You can view or download publications at
http:/www.rockwellautomation.com/literature/
. To order paper copies of
technical documentation, contact your local Allen-Bradley distributor or
Rockwell Automation sales representative.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 5
Preface
Notes:
6 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Chapter 1
Module Features
Top ic Pa ge
About the Counter Module 7
Proximity Sensor Compatibility 7
Module Features 8
Parts Illustration 10
About the Counter Module
Proximity Sensor Compatibility
The counter module is an eight counter, eight input point, 24V high-speed DC
isolated, sink/source input module. The counter module has eight dedicated,
40 kHz counters. Each counter returns accumulated count, instantaneous
frequency, average frequency, instantaneous pulse width, and average pulse
width. The module provides an additional eight inputs that you can assign to
counter control functions, including Up/Down Count, Count Enable, Reset
Count, and Preset Count, or use as standard hardware inputs.
Based on onboard comparisons of count or frequency values, each counter has
two configurable On/Off windows that are capable of controlling the On/Off
behavior of outputs on a 1756-OB16IEF module. The counter module is capable
of evaluating count values and activating outputs independent of the controller
for fast response time.
Inputs comply with the IEC 61131-2 directive for Type 3 sensors. Compatible
products include Allen-Bradley Bulletin 871, 872, and 875 proximity sensors.
To use the counter module with non-IEC Type 3 sensors, refer to Appendix
alternate wiring and recommendations.
C for
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 7
Chapter 1 Module Features
Module Features
The counter module provides the following features.
Table 1 - Counter Module Features
Feature Description
Dedicated counters Counters 0…7 on the module are dedicated to counting incoming
Configurable On/Off windows The module provides two configurable On/Off windows per counter
Real-time control over preset and rollover values Preset and rollover values for each counter are configurable via
Control of counter functionality via
hardware i nputs or outp ut tags
Peer-to-peer I/O control The module can be used in peer control applications in which input
pulses from a proximity sensor. Each counter returns these values:
• Accumulated count
• Instantaneous and average frequencies
• Instantaneous and average pulse width
For descriptions of each value, see Table 3 on page 12
for output control:
• Configure each window to use accumulated count,
instantaneous frequency, or average frequency.
• Define On/Off values via output tags.
For more about On/Off windows, see page 13
output tags for real-time control:
• For more about preset values, see page 21.
• For more about rollover values, see page 14
Counter control functions can be invoked by either of the following:
• The state of external input devices connected to the eight
standa rd hardware inpu ts on the mod ule.
• Output tags.
Counter control functions include Up/Down Count, Count Enable,
Preset Count, and Reset Count. For more information, see Counter
Control Func tions on page 15.
data is consumed by a1756-OB16IEF output module and used to
control outputs. For more information, see Output Control on
page 23 and the Peer I/O Control Application Technique, publication
1756-AT016.
.
.
.
Additional I/O Module Features
Ta b l e 2 lists additional features of all ControlLogix I/O modules, including the
counter module.
Table 2 - Digital I/O Module Features
Featu re Des cripti on
Configuration software RSLogix 5000 software has a custom interface to configure your module. All module features
Software configurable
filter times
Module fault reporting I/O modules provide both hardware and software indications when a module fault occurs.
Status indicators Status indicators on the front of the module report the operational status of the module.
8 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
can be enabled and disabled through the s oftware.
On to Off and Off to On filter times can be adjusted through RSLogix 5000 software for
ControlLogix input modules. These filters improve noise immunity within a signal. A larger
filter value affects the length of delay times for signals from input modules.
You can configure filter values for the eight hardware inputs and eight counters separately or
use no filtering.
Status indicators signal fault conditions. RSLogix 5000 software describes the fault message
so you know what action to take to resume normal operation.
Status indicators for counters 0…7 and counter control hard ware inputs 0…7 signal the
presence of voltage at each terminal.
Module Features Chapter 1
Table 2 - Digital I/O Module Features (continued)
Featu re Des cripti on
Producer/consumer
model
Electronic Keying Electronic keying prevents communication to a module that does not match the type and
RIUP RIUP is an abbreviation for removal and insertion under power. The module can be inserted
Logix5000 controllers let you produce (broadcast) and consume (receive) system-shared
tags. The module can produce data without having to be polled first by a controller. The
module produces the data, and any owner-controller device or 1756-OB16IEF peer output
module can consume it.
The module produces count, frequency, and pulse width values at the RPI. In addition to the
RPI, the module also produces data whenever a Change of State (COS) occurs. A COS causes
an immediate production of data and is triggered by a change in value for these input tags:
• Pt[x].Data—Hardware input transitions On or Off.
• Counte r[x].InWindow0—Count or frequency value enters or exits window 0 parameters.
• Counte r[x].InWindow1—Count or frequency value enters or exits window 1 parameters.
revision expected. For more information, see Appendix
and removed from the chassis while power is applied. This flexibility allows you to maintain
the module, either removing or inserting, without disrupting the rest of the controlled
process.
A.
WARNING: When you insert or remove a module while backplane power is
applied, an electrical arc may occur. An electrical arc can cause personal injury
or property damage as a result of the following:
• Sending an erroneous signal to your system’s field devices causing unintended
machine motion or loss of process control.
• Causing an explosion in a hazardous environment.
Repeated electrical arcing causes excessive wear to contacts on both the module
and its mating connectors. Worn contacts may create electrical resistance that can
affect module operation.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 9
Chapter 1 Module Features
7
4
5
6
3
2
1
41623
Parts Illustration
Item Description
1 Backplane connector—The backplane interface for the ControlLogix system connects the module to
the backplane.
2 Top and bottom guides—Guides provide assistance in seating the removable terminal block (RTB)
onto the module.
3 Connector pins—Input/output, power, and grounding connections are made to the module through
these pins with the use of an RTB.
4 Status indicators—Indicators display the status of communication, module health, and presence of
input/output devices. Use these indicators to help in troubleshooting.
5 Locking tab—The locking tab anchors the RTB on the module and maintains wiring connections.
6 Slots for keying—The slots let you mechanically key the RTB to prevent inadvertently making the
wrong wire connections to your module.
7 Removable terminal block—The RTB lets you connect and house the wiring. The counter module
supports two types of RTBs:
• Cage clamp, catalog number 1756-TBCH
• Spring clamp, catalog number 1756-TBS6H
For wiring instructions, see Chapter 3.
10 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Chapter 2
11 µs
25 µs
Module Operation
Top ic Pa ge
Counters 0…7 11
Counter Control Functions 15
Output Control 23
Counters 0…7
Counters 0…7 on the module are dedicated to up and down counting of
incoming pulses. The module counts rising pulse edges at a maximum of 40 kHz.
However, the following limitations apply as shown in Figure 1
• The duration of a pulse cannot be less than 11 μs, which is the minimum
hardware delay time for a transition to be detected by an input.
• For repetitive counting, the total cycle time cannot be less than 25 μs.
Figure 1 - Pulse Cycle Limits
For complete specifications, refer to the 1756 ControlLogix I/O Modules
Specifications Technical Data, publication 1756-TD002
:
.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 11
Chapter 2 Module Operation
Each of the eight counters automatically returns the values described in Ta b l e 3 .
Table 3 - Counter Values
Value Data Type Description
Accumulated count DINT The total number of pulses. The module counts pulses on their rising edge. The module stores accumulated count in the Counter[x].Count
Instantaneous frequency REAL The frequency of the last pulse detected by a counter. The module calculates frequency by timing from rising edge to rising edge of the
Average frequency
(1)(2)
REAL The average frequency of pulses. The module calculates average frequency over the number of pulses defined in the
Instantaneous pulse width REAL The duration in microseconds of the last rising pulse edge to falling pulse edge. The accuracy of the instantaneous pulse width is always
(1)
Average pulse width
REAL The average width of pulses. The module calculates average pulse width over the number of pulses specified in the
input tag.
last two pulses (cycle time):
• If the cycle time is less than the frequency timeout (Counter[x].FreqTimeout) value, then instantaneous frequency = 1/cycle time.
• If the cycle time is greater than the frequency timeout (Counter[x].FreqTimeout) value, then instantaneous frequency = 0.
In instantaneous frequency calculations, the rising edge of the pulse that completes a cycle time is also the rising edge of the pulse that
starts the next cycle time.
To determine the accuracy of the instantaneous frequency value, use this formula:
0.0011 x Counter[x].Frequency value
For example, a 1 kHz input frequency has a worst case instantaneous frequenc y value of ±1.1%.
The module stores instantaneous frequency in the Counter[x].Frequency input tag.
Counte r[x].FreqAveragePulseCount configuration tag. You can configure this number of pulses on the Counter Configuration tab of the
Module Properties dialog box.
The module calculates average frequency as follows.
1. Starts timing on the first rising pulse edge and stops timing on the Counter[x].FreqAveragePulseCount rising pulse edge.
2. Calculates frequency based on the total time from step 1 and multiplies the Counter[x].FreqAveragePulseCount value by the pulse
count.
For example, if Counter[x].FreqAveragePulseCount = 10 and the calculated frequency = 1 Hz, the average frequency = 10 Hz (10 pulses/
1 second).
If Counter[x].FreqAveragePulseCount = 10, the module updates average frequency values as follows:
• From pulses 0…9, the module does not calculate average frequency and returns a value of zero.
• From pulses 10…19, the module calculates and updates the average frequency for pulses 0…9 at pulse 10.
• From pulses 20…29, the module calculates and updates the average frequency for pulses 10…19 at pulse 20, and so on.
The module stores the average frequency in the Counter[x].FreqAverage input tag.
± -11s regardless of the actual pulse width. The module stores instantaneous pulse width in the Counter[x].PulseWidth input tag.
Counte r[x].FreqAveragePulseCount configuration tag. Frequency timeouts do not affect the pulse width average. If the input is high or
low for a long period of time, the average pulse width is not updated until the number of pulses in the
Counte r[x].FreqAveragePulseCount tag occurs.
The module calculates average pulse width as follows.
1. Stores each instantaneous pulse width for the number of pulses in the Counter[x].FreqAveragePulseCount tag.
2. Calculates the total of all pulse widths stored in step 1 and divides the total by the value in the Counter[x].FreqAveragePulseCount
tag.
If Counter[x].FreqAveragePulseCount = 10, the module calculates average pulse width as follows:
• From pulses 0…9, the module does not calculate average pulse width and returns a value of zero.
• From pulses 10…19, the module calculates average pulse width for pulses 0…9 at pulse 10.
• From pulses 20…29, the module calculates average pulse width for pulses 10…19 at pulse 20, and so on.
The accuracy of the average pulse width is always ± - 11 s/Counter[x].FreqAveragePulseCount regardless of the actual pulse width.
The module stores average pulse width in the Counter[x].PulseWidthAverage input tag.
(1) The average frequency and average pulse width may not be calculated on the same pulse due to frequency timeouts.
(2) Frequency timeouts may cause the accuracy of average frequency calculations to vary.
12 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
IMPORTANT
On/Off Windows
Each counter has two configurable On/Off windows that compare the
accumulated count or frequency of incoming pulses to user-defined On/Off
values. When the count or frequency values are within the user-defined window
parameters, the module sets the corresponding bit in the Counter[x].InWindow0
or Counter[x].InWindow1 input tag.
The module produces data to the system on the rising and falling edge of each
On/Off window. A rising edge occurs when a count or frequency value enters the
window, and a falling edge occurs when a count or frequency value exits a
window.
You define each On/Off window by using these parameters:
• Comparison method—Defines whether the On/Off window uses
accumulated count, instantaneous frequency, or average frequency. You
define the comparison method for a window on the Counter
Configuration tab of the Module Properties dialog box.
• On and Off values—Defines the count or frequency value that results in
an On/Off status for the window. On and Off values represent counts or
frequency depending on the window’s comparison method. You define
these values in a set of output tags for each window:
– Counter[x].Window0On and Counter[x].Window0Off
– Counter[x].Window1On and Counter[x].Window1Off
Keep in mind the following when using frequency as a window comparison
method:
• When configured to compare frequency values, window On/Off values are
still DINT (32-bit signed integers) while the returned frequency values are
REAL (32-bit IEEE float). As a result, the frequency triggers for On/Off
windows can only be defined in 1 Hz increments.
• Fluctuations in high frequency values across window parameters could
cause the window to transition on each pulse if the input frequency is at a
window parameter and you are using instantaneous frequency as the
comparison method. In this case, the module will produce a COS message
on the backplane with each input. This high traffic could result in system
communication issues.
• For example, if you set a window Off value at 18 kHz, and the input is at
18 kHz, the instantaneous frequency calculation could result in frequency
fluctuations for each pulse between 17998.0 Hz and 18002.0 Hz. This
fluctuation would cause a COS message to be sent every 55 µs. If this
situation occurs for all eight counters, the module can generate a large
amount of backplane traffic possibly resulting in system communication
issues.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 13
Chapter 2 Module Operation
Counte r[x].Window0On tag = 2000
Counte r[x].Window0Off tag = 5000
Counte r[x].InWindow0
turns On at count 2000.
Counte r[x].InWindow0
remains On for 3000 counts.
Counte r[x].InWindow0
turns Off at count 5000.
On Value < Off Value
Counte r[x].Window1On = 5000
Counte r[x].Window1Off = 2000
Counte r[x].InWindow1
remains Off for 3000 counts.
Counter[x].InWindow1
turns Off at count 2000.
Counte r[x].InWindow1
turns On at count 5000.
On Value > O ff Value
EXAMPLE
Figure 2 compares two On/Off windows by using the Accumulated Count
comparison method. In the first window, the On value is less than the Off value.
In the second window, the On value is greater than the Off value.
Figure 2 - Window States Based on Accumulated Count
The Counter[x].InWindow0 and Counter[x].InWindow1 input tags can be
consumed by a controller or a 1756-OB16IEF peer output module and used to
affect outputs. For more information about using peer modules, see the
ControlLogix Peer I/O Control Application Technique, publication
1756-AT016
.
Rollover Values
A rollover value determines how many counts accumulate before the count rolls
over to zero. The count rolls over to zero on the rollover value. Each counter can
have one rollover value.
A rollover value of 100 produces the following count sequences:
• Increasing count sequence: 98, 99, 0, 1, 2…
• Decreasing count sequence: 2, 1, 0, 99, 98…
For real-time control, you define a rollover value in the Counter[x].Rollover
output tag. The following criteria applies to a rollover value:
31
• The default rollover value is a maximum count of 2
• A rollover value must be a positive DINT value. If an invalid rollover value
31
is defined, the module will use a value of 2
.
.
14 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
Counter Control Functions
The counter module provides four counter control functions:
• Up/Down Count
• Count Enable
• Reset Count
• Preset Count
The module provides two methods to invoke counter control functions:
• Hardware inputs—You can tie counter control functions to standard
hardware inputs 0…7 to let the state of external input devices directly
control the functionality of a designated counter. To configure this
method, you use the Input Configuration tab within the module’s
properties to set up ties as shown in Figure 3 on page 16
• Output tags—The output tag method enables you to programmatically
control the counter functions via the module’s output tags. This method
offers the most flexibility in invoking counter control functions. However,
the response time is limited due to the time required for the controller to
process your application routine.
Keep in mind the following when tying hardware inputs to counter control
functions:
.
• A single input can control functionality for multiple counters. For
example, you can tie input 3 to the Up/Down Count function for all eight
counters.
• Only one type of counter control function can be tied to a single input. For
example, you cannot tie both the Count Enable and Reset Count
functions to the same input.
• If you do not require hardware inputs 0…7 to support counter control
functionality, you can use the inputs as general purpose On/Off inputs
without timestamping.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 15
Chapter 2 Module Operation
Up/Down Count function for counter 1
is tied to hardware inp ut 3.
Up/Down Count Function
The Up/Down Count function causes a counter to increment or decrement
accumulated count or changes the direction bit for frequency values.
To invoke the Up/Down Count function for a counter by using the hardware
input method, tie the function to a hardware input on the Input Configuration
tab of the Module Properties dialog box as shown in Figure 3
Figure 3 - Up/Down Count Function Controlled by Hardware Input
.
When tied to a hardware input, this function is level-sensitive resulting in a
change of status when the input is either low or high:
• By default, the count direction goes up when the input is low and down
when the input is high.
• When the function is inverted, the count direction goes up when an input
is high and down when the input is low.
16 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
IMPORTANT
0 = Count direction is up,
level-sensitive.
1 = Count direction is down,
level-sensitive.
To invoke the Up/Down Count function by using the output tag method, use the
Counter[x]CountDown output tag to define the direction of Counter[x] as
shown in Figure 4
Figure 4 - Counter[x]CountDown Output Tag
. By default, the count direction is up.
The Counter[x].CountDown output tag is active only if the Up/Down Count
function is not tied to Counter[x] via a hardware input. If a hardware input is
tied to Counter[x], the hardware input overrides the value of the
Counter[x].CountDown output tag.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 17
Chapter 2 Module Operation
Up/Down Control Sensor
Count U p
Count Dow n
1756-LSC8XIB8I
Counte r x
Counter Control
Hardware Input x
Counti ng Senso r
Counter Control Hardware In put
+
–
3
0
1
2
Counti ng Senso r
1
2
Count Total in Counter[x].Count Tag
Frequency in Counter[x].Frequency Tag
Count Direction in Counter[x].Direction Tag
Pulse Width in Counter[x].PulseWidth Tag
New Frequency
Valu e
New Frequency
Valu e
New Frequency
Valu e
New Frequency
Valu e
New Frequency
Valu e
New Frequency
Valu e
1 1 0
0
0
1
New Pulse
Width Valu e
New Pulse
Width Valu e
New Pulse
Width Valu e
New Pulse
Width Valu e
New Pulse
Width Valu e
Figure 5 illustrates the input tag values returned when the Up/Down Count
function is tied to an input via a hardware input.
Figure 5 - Example of Up/Down Count Function
18 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
Count Enable function for counter 2
is tied to hardware input 4.
0 = Counting occurs,
level-sensitive.
1 = Counting is disabled,
level-sensitive.
Count Enable Function
The Count Enable function serves as a gate input that controls when counting
starts and stops.
To invoke the Count Enable function for a counter by using the hardware input
method, tie the function to a hardware input on the Input Configuration tab of
the Module Properties dialog box as shown in Figure 6 on page 19
Figure 6 - Count Enable Function Controlled by Hardware Input
.
When tied to a hardware input, this function is level-sensitive resulting in a
change of status when the input is either low or high:
• By default, counting starts only when the input is high and stops when the
input is low.
• When the function is inverted, counting starts only when the input is low
and stops when the input is high.
To invoke the Count Enable function by using the output tag method, use the
Counter[x].DisableCount output tag as shown in Figure 7
Figure 7 - Counter[x]DisableCount Output Tag
.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 19
Chapter 2 Module Operation
IMPORTANT
Reset Count function for counter 3
is tied to hardware input 5.
Note that the module continues to calculate frequency and pulse width values
even if you disable counting via the Count Enable function.
Either the Count Enable hardware input or the corresponding bit in the
Counter[x]DisableCount output tag can determine whether counting is
enabled or disabled.
Counting is enabled under the following conditions:
• Counter[x].CountEnTieToPt configuration tag = -1 (no tie) or 0…7 and the
corresponding hardware input is non-inverted and high or inverted and
low (level-sensitive)
and
• Counter[x]DisableCount output tag = 0 (level-sensitive)
Counting is disabled under these conditions:
• Counter[x].CountEnTieToPt configuration tag = 0…7 and the
corresponding hardware input is non-inverted and low or inverted and
high (level-sensitive)
or
• Counter[x]DisableCount output tag = 1 (level-sensitive)
Reset Count Function
The Reset Count function resets the count to zero.
To invoke the Reset Count function for a counter by using the hardware input
method, tie the function to a hardware input on the Input Configuration tab of
the Module Properties dialog box as shown in Figure 8
Figure 8 - Reset Count Function Controlled by Hardware Input
.
When tied to a hardware input, this function is edge-sensitive resulting in a reset
when the designated input transitions low or high:
• By default, counting resets to zero on a rising pulse edge.
• When the function is inverted, counting resets to zero on a falling pulse
edge.
20 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
IMPORTANT
EXAMPLE
0 = Tag-based reset is not
active.
1 = Count transitions to zero
on a rising edge.
To invoke the Reset Count function by using the output tag method, use the
Counter[x].ResetCount output tag as shown in Figure 9
Figure 9 - Counter[x]ResetCount Output Tag
.
Either the Reset Count hardware input or the corresponding bit in the
Counter[x]ResetCount output tag can determine whether the count is reset.
Counting is reset to zero under the following conditions:
• Counter[x].ResetTieToPt configuration tag = 0…7 (rising edge-sensitive)
or
• Counter[x]ResetCount output tag = 1 (rising edge-sensitive)
Preset Count Function
A preset value determines the starting value for a count. Each counter can have
one preset value defined in the Counter[x].Preset output tag.
A preset value of 99 produces the following count sequences:
• Increasing count sequence: 99, 100, 101, …
• Decreasing count sequence: 99, 98, 97, …
The following criteria applies to a preset value:
• The default preset value is zero.
• A preset value must be a non-negative DINT value.
• A preset value must be less than the rollover value. If the preset value is
greater than or equal to the rollover value, then the module uses the
requested rollover value and the default preset value of zero rather than the
invalid preset value.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 21
Chapter 2 Module Operation
Preset Count function for counter 4
is tied to hardware input 7.
0 = Tag-based preset not
active.
1 = Count transitions to the
preset value on a rising edge.
To invoke the Preset Count function for a counter by using the hardware input
method, tie the function to a hardware input on the Input Configuration tab of
the Module Properties dialog box as shown in Figure 10
Figure 10 - Preset Count Function Controlled by Hardware Input
.
When tied to a hardware input, this function is edge-sensitive resulting in a preset
when the designated input transitions low or high:
• By default, the count is set to the preset value on a rising pulse edge.
• When the function is inverted, the count is set to the preset value on a
falling pulse edge.
To invoke the Preset Count function by using the output tag method, use the
Counter[x].PresetCount output tag as shown in Figure 11
Figure 11 - Counter[x]PresetCount Output Tag
.
22 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Module Operation Chapter 2
IMPORTANT
Either the Preset Count hardware input or the corresponding bit in the
Counter[x]PresetCount output tag can determine whether the count is preset.
The count is preset to the Counter[x].Preset value under the following
conditions:
• Counter[x].PresetTieToPt configuration tag = 0…7 (rising edge-sensitive)
or
• Counter[x]PresetCount output tag = 1 (rising edge-sensitive)
Output Control
Inputs from the counter module can affect outputs on a 1756-OB16IEF module.
The output module consumes data from these input tags on a peer module:
• Pt[x]Data—Indicates the current On/Off value of the corresponding
hardware input.
• Counter[x]InWindow0—Indicates whether the accumulated count or
frequency value of Counter[x] is within the parameters defined by the
Counter[x].Window0On and Counter[x].Window0Off output tags. A
change in window status triggers a Change of State (COS) message to be
sent to the owner-controller or peer module.
• Counter[x]InWindow1—Indicates whether the accumulated count or
frequency value of Counter[x] is within the parameters defined by the
Counter[x].Window1On and Counter[x].Window1Off output tags. A
change in window status triggers a Change of State (COS) message to be
sent to the owner-controller or peer module.
You can define the output behavior on the 1756-OB16IEF module by applying
Boolean logic to the On/Off windows, inputs, and any bits from the controller.
To establish communication with an input module, the output module sends a
Listen-only connection request to the input module. Once the connection is
established, the output module can consume data directly from the input
module.
For more information about peer control, refer to the Peer I/O Control
Application Technique, publication 1756-AT016
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 23
.
Chapter 2 Module Operation
Notes:
24 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Chapter 3
Install the Counter Module
Top ic Pa ge
Install the Module 27
Key the Removable Terminal Block 29
Connec t the Wires 30
Wire Terminations 33
Assemble the Removable Terminal Block and Housing 35
Install the Removable Terminal Block 36
Remove the Removable Terminal Block 38
Remove the Module from the Chassis 39
ATTENTION: Environment and Enclosure
This equipment is intended for use in a Pollution Degree 2 industrial environment, in overvoltage Category II applications (as
defined in IEC 60664-1), at altitudes up to 2000 m (6562 ft) without derating.
This equipment is considered Group 1, Class A industrial equipment according to IEC/CISPR 11. Without appropriate
precautions, there may be difficulties with electromagnetic compatibility in residential and other environments due to
conducted and radiated disturbances.
This equipment is supplied as open-type equipment. It must be mounted within an enclosure that is suitably designed for those
specific environmental conditions that will be present and appropriately designed to prevent personal injury resulting from
accessibility to live parts. The enclosure must have suitable flame-retardant properties to prevent or minimize the spread of
flame, complying with a flame spread rating of 5VA or be approved for the application if nonmetallic. The interior of the
enclosure must be accessible only by the use of a tool. Subsequent sections of this publication may contain additional
information regarding specific enclosure type ratings that are required to comply with certain product safety certifications.
In addition to this publication, see the following:
• Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1
, for additional installation requirements.
• NEMA Standard 250 and IEC 60529, as applicable, for explanations of the degrees of protection provided by enclosures.
Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 25
Chapter 3 Install the Counter Module
North American Hazardous Location Approval
The following information applies when operating this equipment in
hazardous locations.
Products marked "CL I, DIV 2, GP A, B, C, D" are suitable for use in Class I Division 2 Groups
A, B, C, D, Hazardous Locations and nonhazardous locations only. Each product is supplied
with markings on the rating nameplate indicating the hazardous location temperature
code. When combining products within a system, the most adverse temperature code
(lowest "T" number) may be used to help determine the overall temperature code of the
system. Combinations of equipment in your system are subject to investigation by the
local Authority Having Jurisdiction at the time of installation.
Informations sur l’utilisation de cet équipement en environnements
dangereux.
Les produits marqués "CL I, DIV 2, GP A, B, C, D" ne conviennent qu'à une utilisation en
environnements de Classe I Division 2 Groupes A, B, C, D dangereux et non dangereux.
Chaque produit est livré avec des marquages sur sa plaque d'identification qui indiquent
le code de température pour les environnements dangereux. Lorsque plusieurs produits
sont combinés dans un système, le code de température le plus défavorable (code de
température le plus faible) peut être utilisé pour déterminer le code de température
global du système. Les combinaisons d'équipements dans le système sont sujettes à
inspection par les autorités locales qualifiées au moment de l'installation.
WARNING: EXPLOSION HAZARD
• Do not disconnect equipment unless power has
been removed or the area is known to be
nonhazardous.
• Do not disconnect connections to this
equipment unless power has been removed or
the area is known to be nonhazardous. Secure
any external connections that mate to this
equipment by using screws, sliding latches,
threaded connectors, or other means provided
with this product.
• Substitution of components may impair
suitability for Class I, Division 2.
• If this product contains batteries, they must only
be changed in an area known to be
nonhazardous.
European Hazardous Location Approval
The following applies when the product bears the Ex Marking.
This equipment is intended for use in potentially explosive atmospheres as defined by European Union Directive 94/9/EC and has been found to comply with the Essential Health and
Safety Requirements relating to the design and construction of Category 3 equipment intended for use in Zone 2 potentially explosive atmospheres, given in Annex II to this Directive.
Compliance with the Essential Health and Safety Requirements has been assured by compliance with EN 60079-15 and EN 60079-0.
WARNING: RISQUE D’EXPLOSION
• Couper le courant ou s'assurer que
l'environnement est classé non dangereux avant
de débrancher l'équipement.
• Couper le courant ou s'assurer que
l'environnement est classé non dangereux avant
de débrancher les connecteurs. Fixer tous les
connecteurs externes reliés à cet équipement à
l'aide de vis, loquets coulissants, connecteurs
filetés ou autres moyens fournis avec ce produit.
• La substitution de composants peut rendre cet
équipement inadapté à une utilisation en
environnement de Classe I, Division 2.
• S'assurer que l'environnement est classé non
dangereux avant de changer les piles.
ATTENTION: This equipment is not resistant to sunlight or other sources of UV radiation.
WARNING:
• This equipment must be installed in an enclosure providing at least IP54 protection when applied in Zone 2 environments.
• This equipment shall be used within its specified ratings defined by Rockwell Automation.
• Provision shall be made to prevent the rated voltage from being exceeded by transient disturbances of more than 40%
when applied in Zone 2 environments.
• This equipment must be used only with ATEX certified Rockwell Automation backplanes.
• Secure any external connections that mate to this equipment by using screws, sliding latches, threaded connectors, or other
means provided with this product.
• Do not disconnect equipment unless power has been removed or the area is known to be nonhazardous.
26 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
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