Spectrum Controls 1756-CTR8 User manual

Owner’s Guide 0300310-02A

ii ControlLogix™ CTR8 Counter Module
Owner’s Guide 0300199-01 Rev. D
Important Notes
Please read all the information in this owner’s guide before installing the product.
The information in the guide applies to hardware version A and firmware version
2.0 or later.
This guide assumes that you have a full working knowledge of the relevant
processor.
Notice
The product and services described in this owner’s guide are useful in a wide
variety of applications. Therefore, you and others responsible for applying the
products and services described herein are responsible for determining their
acceptability for each application. While efforts have been made to provide
accurate information within this owner’s guide, Spectrum Controls, Inc. assumes
no responsibility for the accuracy, completeness, or usefulness of the information
herein.
Under no circumstances will Spectrum Controls, Inc. be responsible or liable for
any damages or losses, including indirect or consequential damages or losses,
arising out of either the use of any information within this guide or the use of any
product or service referenced herein.
No patent liability is assumed by Spectrum Controls, Inc. with respect to the use
of any of the information, products, circuits, programming, or services referenced
herein.
The information in this owner’s guide is subject to change without notice.
Limited Warranty
Spectrum Controls, Inc. warrants that its products are free from defects in
material and workmanship under normal use and service, as described in
Spectrum Controls, Inc. literature covering this product, for a period of 1 year.
The obligations of Spectrum Controls, Inc. under this warranty are limited to
replacing or repairing, at its option, at its factory or facility, any product which
shall, in the applicable period after shipment, be returned to the Spectrum
Controls, Inc. facility, transportation charges prepaid, and which after
examination is determined, to the satisfaction of Spectrum Controls, Inc., to be
thus defective.
This warranty shall not apply to any such equipment which shall have been
repaired or altered except by Spectrum Controls, Inc. or which shall have been
subject to misuse, neglect, or accident. In no case shall the liability of Spectrum
Controls, Inc. exceed the purchase price. The aforementioned provisions do not
extend the original warranty period of any product which has either been repaired
or replaced by Spectrum Controls, Inc.

Owner’s Guide 0300199-01 Rev. D
Table of Contents
IMPORTANT NOTES ............................................................................................................................................... II
TABLE OF CONTENTS............................................................................................................................................. III
PREFACE ................................................................................................................................................................V
CHAPTER 1 MODULE OVERVIEW......................................................................................................................... 1-1
SECTION 1.1 GENERAL DESCRIPTION ........................................................................................................................ 1-1
SECTION 1.2 INPUT TYPES ...................................................................................................................................... 1-1
SECTION 1.3 HARDWARE FEATURES ......................................................................................................................... 1-1
SECTION 1.4 DIAGNOSTIC LEDS.............................................................................................................................. 1-2
SECTION 1.5 SYSTEM OVERVIEW ............................................................................................................................. 1-2
SECTION 1.6 SYSTEM OPERATION ............................................................................................................................ 1-2
SECTION 1.7 MODULE OPERATION .......................................................................................................................... 1-2
SECTION 1.8 CABLES ............................................................................................................................................. 1-3
CHAPTER 2 INSTALLING THE CONTROLLOGIX 1756SC-CTR8 MODULE ................................................................2-1
SECTION 2.1 BEFORE YOU BEGIN............................................................................................................................. 2-1
SECTION 2.2 COMPLIANCE TO EUROPEAN DIRECTIVE................................................................................................... 2-2
SECTION 2.3 EMC DIRECTIVE ................................................................................................................................. 2-2
SECTION 2.4 ATEX DIRECTIVE ................................................................................................................................ 2-2
SECTION 2.5 LOW VOLTAGE DIRECTIVE..................................................................................................................... 2-2
SECTION 2.6 CONFORMAL COATING STANDARD ......................................................................................................... 2-3
SECTION 2.7 IMPORTANT POWER REQUIREMENTS INFORMATION................................................................................. 2-3
SECTION 2.8 REMOVABLE TERMINAL BLOCK AND HOUSING ......................................................................................... 2-3
SECTION 2.9 INSTALLING THE MODULE .................................................................................................................... 2-3
SECTION 2.10 KEYING THE REMOVABLE TERMINAL BLOCK ............................................................................................ 2-5
SECTION 2.11 WIRING THE REMOVABLE TERMINAL BLOCK ........................................................................................... 2-6
SECTION 2.12 PREPARING AND WIRING THE CABLES .................................................................................................... 2-7
SECTION 2.13 WIRING SINGLE-ENDED INPUTS ........................................................................................................... 2-8
SECTION 2.14 WIRING BI-DIRECTIONAL OR QUADRATURE INPUTS ................................................................................. 2-8
CHAPTER 3 OPERATION WITHIN THE CONTROLLOGIX SYSTEM ...........................................................................3-1
SECTION 3.1 OWNERSHIP AND CONNECTIONS............................................................................................................ 3-1
SECTION 3.2 USING RSNETWORX AND RSLOGIX 5000............................................................................................... 3-1
SECTION 3.3 DIRECT CONNECTIONS ........................................................................................................................ 3-2
SECTION 3.4 MODULE OPERATION .......................................................................................................................... 3-2
SECTION 3.5 MODULES IN A LOCAL CHASSIS ............................................................................................................. 3-3
SECTION 3.6 REAL TIME SAMPLE (RTS) ................................................................................................................... 3-3
SECTION 3.7 REQUESTED PACKET INTERVAL (RPI)...................................................................................................... 3-3
SECTION 3.8 MODULES IN A REMOTE CHASSIS .......................................................................................................... 3-4
SECTION 3.9 LISTEN-ONLY MODE............................................................................................................................ 3-4
SECTION 3.10 MULTIPLE OWNERS OF INPUT MODULES................................................................................................. 3-5
SECTION 3.11 CONFIGURATION CHANGES IN AN INPUT MODULE WITH MULTIPLE OWNERS................................................. 3-6
CHAPTER 4 PROGRAMMING YOUR MODULE ...................................................................................................... 4-1
SECTION 4.1 MODULE INSTALLATION ....................................................................................................................... 4-1
SECTION 4.2 ADDING YOUR MODULE TO A PROJECT ................................................................................................... 4-1

iv ControlLogix™ CTR8 Counter Module
Owner’s Guide 0300199-01 Rev. D
SECTION 4.3 CONFIGURING MODULE ATTRIBUTES:CONFIGURATION TAGS .................................................................... 4-6
SECTION 4.4 CHANNEL-SPECIFIC TAGS ..................................................................................................................... 4-6
SECTION 4.5 DATA TAGS........................................................................................................................................ 4-7
SECTION 4.6 STATUS TAGS ..................................................................................................................................... 4-8
CHAPTER 5 CONFIGURATION, DATA, AND STATUS TAGS .................................................................................... 5-1
SECTION 5.1 SEND CONFIGURATION DATA TO THE MODULE ......................................................................................... 5-1
SECTION 5.2 CONFIGURATION TAGS......................................................................................................................... 5-2
SECTION 5.3 CHANNEL SPECIFIC SETTINGS................................................................................................................. 5-2
SECTION 5.4 UNI-DIRECTIONAL............................................................................................................................... 5-3
SECTION 5.5 BI-DIRECTIONAL ................................................................................................................................. 5-3
SECTION 5.6 X1 QUADRATURE ENCODER.................................................................................................................. 5-3
SECTION 5.7 X4 QUADRATURE ENCODER.................................................................................................................. 5-3
SECTION 5.8 STORAGEMODE[X]0-4 INT (C) ............................................................................................................ 5-4
SECTION 5.9 OUTPUT TAGS.................................................................................................................................... 5-7
SECTION 5.10 INPUT TAGS ....................................................................................................................................... 5-8
CHAPTER 6 PROGRAMMING EXAMPLES ............................................................................................................. 6-1
SECTION 6.1 INITIAL PROGRAMMING ....................................................................................................................... 6-1
SECTION 6.2 USING THE GATE STORAGE MODE......................................................................................................... 6-3
SECTION 6.3 INSTALLATION RECOMMENDATIONS ....................................................................................................... 6-4
HIGH IMPEDANCE INPUTS............................................................................................................................................. 6-4
FILTER FREQUENCY SETTINGS LOW VOLTAGE DIRECTIVE..................................................................................................... 6-4
Debounce Filter.................................................................................................................................................. 6-4
METER PROVING ........................................................................................................................................................ 6-4
CHAPTER 7 TROUBLESHOOTING ......................................................................................................................... 7-1
SECTION 7.1 USING MODULE INDICATORS TO TROUBLESHOOT ..................................................................................... 7-1
SECTION 7.2 USING RSLOGIX 5000 TO TROUBLESHOOT YOUR MODULE........................................................................ 7-2
SECTION 7.3 DETERMINING FAULT TYPE ................................................................................................................... 7-3
SECTION 7.4 MODULE CONFIGURATION ERRORS ....................................................................................................... 7-3
SECTION 7.5 GLOBAL ERRORS ................................................................................................................................. 7-4
CHAPTER 8 MAINTAINING YOUR MODULE AND ENSURING SAFETY ................................................................... 8-1
SECTION 8.1 PREVENTIVE MAINTENANCE.................................................................................................................. 8-1
SECTION 8.2 SAFETY CONSIDERATIONS .................................................................................................................... 8-1
SECTION 8.3 TECHNICAL ASSISTANCE ....................................................................................................................... 8-3
SECTION 8.4 DECLARATION OF CONFORMITY ............................................................................................................. 8-3
APPENDIX A MODULE SPECIFICATIONS...............................................................................................................A-1
PHYSICAL SPECIFICATIONS............................................................................................................................................ A-1
ENVIRONMENTAL SPECIFICATIONS ................................................................................................................................. A-2
INPUT SPECIFICATIONS................................................................................................................................................. A-2
REGULATORY COMPLIANCE........................................................................................................................................... A-3
ACCURACY ................................................................................................................................................................ A-3
APPENDIX B PROGRAMMING YOUR MODULE ....................................................................................................B-1
PROGRAMMING YOUR MODULE.................................................................................................................................... B-1
MODULE INSTALLATION ............................................................................................................................................... B-1
ADDING YOUR MODULE TO A PROJECT .......................................................................................................................... B-1
INDEX ..................................................................................................................................................................I-1

ControlLogix™ CTR8 Counter Module v
Owner’s Guide 0300199-01 Rev. D
Preface
NOTE This is a re-issue of an existing manual, with some corrections, and
updated Certification information.
Read this introduction to familiarize you with the rest of the owner’s guide. This
preface covers the following topics:
•Who should use this manual
•How to use this manual
•Rockwell Automation technical support
•Documentation
•Conventions used in this manual
Who Should
Use This Manual
You must be able to program and operate an Allen-Bradley ControlLogix™ 1756
Controller to efficiently use your input modules. We assume that you know how
to do that in this manual. If you do not, refer to the appropriate Allen Bradley
manual for the associated AB controller.
How to Use
This Manual
Use this guide to install, configure, and troubleshoot your ControlLogix 1756sc-
CTR8 module. The 1756sc-CTR8 Module mounts to an Allen-Bradley
ControlLogix 1756 Controller chassis. The module uses a Removable Terminal
Block (RTB) to connect all field-side wiring.
Before you install your module you should have already:
•Installed and grounded a 1756 chassis and power supply.
•Ordered and received an RTB and its components for your application.
The table below provides a listing of publications that contain important
information about Allen-Bradley PLC systems.
Allen-Bradley Refer to this Document Allen-Bradley
Pub. No.
1756-PA72, -PB72
1756-A4, -A7, -A10, -A13, -
A17
ControlLogix Power Supply
Installation Instructions
Control Logix Chassis
Instructions
1756-5.1
1756-5.2
1756 Series
ControlLogix Module
Installation Instructions
(Each module has separate
document for installation)
1756-5.5, -5.42
1756-L1, -LIM1, -LIM2 Logix5550 Controller User
Manual
1756-6.5.12

vi ControlLogix™ CTR8 Counter Module
Owner’s Guide 0300199-01 Rev. D
Rockwell
Automation
Technical
Support
For technical support, please contact your local Rockwell Automation
TechConnect Office for all Spectrum products. Contact numbers are as follows:
•USA (1) 440-646-6900
•United Kingdom (44) 01908 635230
•Australia 1800-809-929
•Mexico 001-888-365-8677
•Brazil (55) 11 3618 8800
•Europe [phone]
or send an email to
[e-mail]
Documentation
If you would like a .PDF version of a manual, you can download a free electronic
version at www.spectrumcontrols.com.
Conventions
Used in This
Manual
The following conventions are used throughout this manual:
•Bulleted lists (like this one) provide information not procedural steps.
•Numbered lists provide sequential steps or hierarchical information.
•Italic type is used for emphasis.
•Bold type identifies headings and sub-headings.
WARNING
Identifies information about practices or circumstances that can lead to
personal injury or death, property damage, or economic loss. These
messages help you to identify a hazard, avoid a hazard, and recognize the
consequences.
ATTENTION
Actions ou situations risquant d’entraîner des blessures pouvant être
mortelles, des dégâts matériels ou des pertes financières. Les messages «
Attention » vous aident à identifier un danger, à éviter ce danger et en
discerner les conséquences.
Allen-Bradley Refer to this Document Allen-Bradley
Pub. No.
1756-ENET
ControlLogix Ethernet
Communication Interface
Module User Manual
1756-6.5.1

ControlLogix™ CTR8 Counter Module vii
Owner’s Guide 0300199-01 Rev. D
NOTE
Identifies information that is critical for successful application and
understanding of the product.

viii ControlLogix™ CTR8 Counter Module
Owner’s Guide 0300199-01 Rev. D

Owner’s Guide 0300199-01 Rev. D
Chapter 1
Module Overview
This chapter describes the 1756sc-CTR4 and 1756sc-CTR8 and the conformally
coated 1756sc-CTR4/1756sc-CTR8K counter modules and explains how the
ControlLogix controller reads analog input data from the modules. Other than the
conformal coating, the modules are identical so all information applicable to the
earlier modules applies to the K versions. Read this chapter to familiarize
yourself further with counter module. This chapter covers:
•General description and hardware features.
•An overview of system and module operation.
This module is designed exclusively for use in the Allen-Bradley ControlLogix
1756 I/O rack systems. The module reads AC and DC pulse information from
external sensors and stores the data in its image table for retrieval by all
ControlLogix processors.
Following is a list of features available on the CTR8 module that allow their use
in a wide variety of applications:
•Removal and insertion under power (RIUP)−a system feature that allows you
to remove and insert modules while chassis power is applied.
•Producer/consumer communications−an intelligent data exchange between
modules and other system devices in which each module produces data
without having been polled.
•System timestamp of data–64-bit system clock places a timestamp on the
transfer of data between the module and its owner-controller within the local
chassis.
•IEEE 32-bit floating point format.
•On-Board Features, such as custom User Scaling, Analog and Digital
Filtering, and Under/Over Detection.
The 1756-CTR supports both AC and DC input signal types. The module input
type is configured on a channel-pair basis. Each pair must be configured for the
same input type.
The module fits into any single slot for I/O modules in a ControlLogix modular
system. The module has a unique generic profile which may be configured using
your RSLogix 5000 programming software. The module uses one removable
terminal block that provides connections for the eight input channels. The

1-2 Chapter 1: Module Overview
Owner’s Guide 0300199-01 Rev. D
module is configured through RSLogix 5000 software, defining input type,
counter control, and signal filtering.
Table 1-1. Hardware Features
Hardware
Function
OK LED Displays communication and fault
status of the module.
Cal LED Displays a fault condition.
Side Label (Nameplate) Provides module information.
Removable Terminal Block Provides electrical connection to input
devices.
Door Label
Permits easy terminal identification.
Self-Locking Tabs Secure module in chassis slot.
Terminal Block Switch Locks the RTB to the module.
The module contains diagnostic LEDs that help you identify the source of
problems that may occur during power-up or during normal operation. Power-up
and diagnostics are explained in Chapter 7, Troubleshooting.
The module communicates with the ControlLogix processor and receives +5
VDC and +24 VDC power from the system power supply through the parallel
backplane interface. You may install as many counter modules in the system as
the power supply can support.
Channels (0 through 7) can receive AC or DC input signals. Input types must be
configured in channel pairs. Each channel reports both count data and rate data in
independent registers. Extended status information is also available for each
channel.
At power-up, the module checks internal circuits, memory, and basic functions.
During this time, the SYS LED remains on. If the module does not find any
faults, it turns off the SYS LED.
After completing power-up checks, the module waits for a connection to an
owner-controller, then valid channel configuration data from your ladder logic
program. After channel configuration data is transferred, and one or more
channels are enabled, the module continuously converts the inputs to floating
point data for use in your ladder program.
Each time the module reads an input channel, the module tests that data for a
fault, i.e., signal mismatch, or out-of-range condition. If it detects an error
condition, the module sets a unique bit in the status tags.
The module’s input circuitry consists of eight, single-ended inputs, routed into an

Chapter 1: Module Overview 1-3
Owner’s Guide 0300199-01 Rev. D
FPGA. The FPGA reads the input signals and converts them to counter and rate,
and then presents them in floating point values. The input circuitry also supports
gate inputs, allowing you to disable and control counter operation.
Cable length should be kept to a minimum. Use the lowest capacitance shielded
cable available. We recommend that you use Belden #9501 (or equivalent).
Table 1-2. Cable Specifications
Description Belden #9501
When used? AC/DC inputs.
Conductors
2, #24 AWG tinned
copper (7×32)
Shield
Belden foil
aluminum polyester
shield with copper
drain wire.
Insulation
PVC
Jacket Chrome PVC
Agency Approval NEC Type CM
Temperature Rating 80 °C

1-4 Chapter 1: Module Overview
Owner’s Guide 0300199-01 Rev. D

Owner’s Guide 0300199-01 Rev. D
Chapter 2
Installing the ControlLogix
1756sc-CTR8 Module
Use this guide to install and wire your ControlLogix 1756sc-CTR8 module. The
1756sc-CTR8 Module mounts to an Allen-Bradley ControlLogix 1756 Controller
chassis. The module uses a Removable Terminal Block (RTB) to connect all
field-side wiring.
Before you install your module, you should have already:
•Installed and grounded a 1756 chassis and power supply.
•Ordered and received an RTB and its components for your application.
WARNING
Electrostatic discharge can damage integrated circuits or
semiconductors if you touch backplane connector pins.
To prevent damage, follow these guidelines when you handle the module:
•Touch a grounded object to discharge static potential.
•Wear an approved wrist-strap grounding device.
•Do not touch the backplane connector or connector pins.
•Do not touch circuit components inside the module.
•If available, use a static-safe workstation.
•When not in use, keep the module in its static-shield box.
WARNING
Hazard of electrical arcing when removing or inserting the module
while power is applied to the rack.
This module is designed so you can remove and insert it under backplane
power and field-side power. When you remove or insert a module while
field-side power is applied, you may cause an electrical arc. An electrical
arc can cause personal injury or property damage because it may:
•Send an erroneous signal to your system’s field devices, causing
unintended machine motion or loss of process control.
•Cause an explosion in a hazardous environment.
•Repeated electrical arcing also causes excessive wear to contacts on
both the module and its mating connector. Worn contacts may create
electrical resistance.

2-2 Chapter 2: Installing a ControlLogix 1756sc-CTR8-SC Module
Owner’s Guide 0300199-01 Rev. D
If this product bears the CE marking, it is approved for installation within the
European Union and EEA regions. It has been designed and tested to meet the
following directives.
This product is tested to meet Council Directive 2014/30/EU Electromagnetic
Compatibility (EMC) and the following standards, in whole or in part,
documented in a technical construction file:
•EN 61000-6-4 Electromagnetic compatibility (EMC)–Part 6-4: Generic
standards–Emission standard for industrial environments.
•EN 61000-6-2 Electromagnetic compatibility (EMC)–Part 6-2: Generic
standards–Immunity for industrial environments.
UKCA Electromagnetic Compatibility Regulations 2016
•BS EN 61131-2, BS EN 61000-6-4, BS EN 61000-6-2.
This product is intended for use in an industrial environment.
This product is tested to meet Council Directive 2014/30/U/ATEX, and the
following standards, in whole or in part, documented in a technical construction
file:
•EN 60079-0 Explosive atmospheres–Part 0: Equipment – General
requirements.
•EN 60079-7 Explosive atmospheres–Part 7: Equipment protection by
increased safety "e".
This module also meets the standards for the United Kingdom Equipment and
Protective Systems Intended for use in Potentially Explosive Atmospheres
Regulations 2016:
•BS EN 60079-0.
•BS EN 60079-7.
This product is tested to meet Council Directive 2014/35/EU Low Voltage, by
applying the safety requirements of EN 61010-2-201 Safety Requirements for
Electrical Equipment for Measurement, Control, and Laboratory Use - Part 2-
201: Particular Requirements for Control Equipment.
For specific information required by EN 61010-2-201, 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.

Chapter 2: Installing a ControlLogix 1756sc-CTR8-SC Module 2-3
Owner’s Guide 0300199-01 Rev. D
This equipment is classified as open equipment and must be installed (mounted)
in an enclosure during operation as a means of providing safety protection.
The conformally coated versions of the module meet or exceed the ANSI/ISA
71.04.2013 G3 Environment standard.
This module receives power through the 1756 chassis backplane from the fixed
or modular +5 VDC and +24 VDC chassis power supply.
5 VDC
24 VDC
230 mA 75 mA
Add this current to the requirements of all other modules in this chassis to
prevent overloading the chassis backplane.
A ControlLogix I/O module mounts in a ControlLogix chassis and uses a
Removable Terminal Block (RTB) to connect all field-side wiring. RTBs are not
included with your purchase.
When ordering RTBs, specify Allen Bradley Part Number:
•1756-TBCH 36-pin Screw terminal RTB
•1756-TBS6H 36-pin Spring clamp RTB
You receive the following components with your RTB:
•1756-TBH standard-depth RTB housing.
•Wedge-shaped keying tabs and U-shaped keying bands.
•A generic RTB door label.
Use these components in all module applications. Use an optional extended-
depth cover (1756-TBE) or applications requiring heavy gauge wiring.
When installing the module in a chassis, it is not necessary to remove the
terminal blocks from the module. However, if the terminal blocks are removed,
use the write-on label located on the side of the terminal blocks to identify the
module location and type.

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Owner’s Guide 0300199-01 Rev. D
WARNING
Hazard of electrical arcing when removing or inserting the module
while power is applied to the rack.
This module is designed so you can remove and insert it under backplane
power and field-side power. When you remove or insert a module while
field-side power is applied, you may cause an electrical arc. An electrical
arc can cause personal injury or property damage because it may:
•Send an erroneous signal to your system’s field devices, causing
unintended machine motion or loss of process control.
•Cause an explosion in a hazardous environment.
•Repeated electrical arcing also causes excessive wear to contacts on
both the module and its mating connector. Worn contacts may create
electrical resistance.
WARNING
Counter input isolated secondary circuits must be energy limited and
limited to not source more than 5.8 Amps into either the Counter inputs or
the Gate inputs in the event of a component failure.
WARNING
The 1756sc-CTR8 is to be used only with the Allen-Bradley 1756
ControlLogix System.
You can install the module while chassis power is applied. To insert your module
into the rack, align the circuit board of your module with the card guides at the
top and bottom of the chassis as shown below:

Chapter 2: Installing a ControlLogix 1756sc-CTR8-SC Module 2-5
Owner’s Guide 0300199-01 Rev. D
Key the RTB to prevent inadvertently making the wrong wire connections to
your module. Use a unique keying pattern for each module. You can use a
minimum of one key.
When the RTB mounts onto the module, keying positions will match up. For
example, if you place a U-shaped keying band in position #4 on the module, you
cannot place a wedge-shaped tab in #4 on the RTB or your RTB will not mount
on the module.
We recommend that you use a unique keying pattern for each slot in the chassis.
1. Key the module. Insert the U-shaped band with the longer side near the
terminals. Push the band onto the module until it snaps into place.
2. Key the RTB in positions that correspond to un-keyed module positions.
Insert the wedge-shaped tab on the RTB with the rounded edge first.
3. Push the tab onto the RTB until it stops.
4. Reposition the tabs to rekey future module applications.

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Owner’s Guide 0300199-01 Rev. D
Follow these guidelines to wire your input signal cables:
•Power, input, and output (I/O) wiring must be in accordance with Class I,
Division 2 wiring methods [Article 501-4(b) of the National Electrical Code,
NFPA 70] and in accordance with the authority having jurisdiction.
•Peripheral equipment must be suitable for the location in which it is used.
•Route the field wiring away from any other wiring and as far as possible
from sources of electrical noise, such as motors, transformers, contactors,
and ac devices. As a general rule, allow at least 15.2 cm (about 6 in.) of
separation for every 120 V of power.
•Routing the field wiring in a grounded conduit can reduce electrical noise
further.
•If the field wiring must cross ac or power cables, ensure that they cross at
right angles.
•To limit the pickup of electrical noise, keep thermocouple, RTD, millivolt,
and milliamp signal wires as far from power and load lines as possible.
•Ground the shield drain wire at only one end of the cable. The preferred
location is at the shield connections at the ControlLogix chassis. (Refer to
IEEE Std. 518, Section 6.4.2.7 or contact your sensor manufacturer for
additional details.)
•Keep all unshielded wires as short as possible.
•To limit overall cable impedance, keep input cables as short as possible.
Locate your I/O chassis as near the RTD or thermocouple sensors as your
application will permit.
•Tighten screw terminals with care. Excessive tightening can strip a screw.
The RTB terminations can accommodate 2.1…0.25 mm2(14…22 AWG)
shielded wire and a torque of 0.5 N•m (4.4 lb•in.).
•Follow system grounding and wiring guidelines found in your ControlLogix
Installation and Operation Manual.
•Wire the RTB before installing it onto the module. Use a 1/8-inch (3.2 mm)
maximum flat-bladed screwdriver.
NOTE
Before wiring, pull the housing off the RTB.

Chapter 2: Installing a ControlLogix 1756sc-CTR8-SC Module 2-7
Owner’s Guide 0300199-01 Rev. D
To prepare and connect cable leads and drain wires, follow these steps:
1. At each end of the cable, strip some casing to expose individual wires.
2. Trim signal wires to 5-inch lengths beyond the cable casing. Strip about
3/16 inch (4.76 mm) of insulation to expose the ends of the wires.
3. At the module-end of the cables (see figure above):
•Extract the drain wire and signal wires.
•Remove the foil shield.
•Bundle the input cables with a cable strap.
4. Connect pairs of drain wires together, Channels 0 and 1, Channels 2 and
3, Channels 4 and 5, Channels 6 and 7. Keep drain wires as short as
possible.
5. Connect the drain wires to the grounding lug on the PLC chassis.
6. Connect the signal wires of each channel to the terminal block.
NOTE
IMPORTANT: Only after verifying that your connections are correct for
each channel, trim the lengths to keep them short. Avoid cutting leads too
short.
7. At the source-end of cables from devices:
•Remove the drain wire and foil shield.
•Apply shrink wrap as an option.
•Connect to mV devices keeping the leads short.
NOTE
Important: If noise persists, try grounding the opposite end of the cable,
instead. (Ground one end only.)

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Owner’s Guide 0300199-01 Rev. D
The following figure shows the general terminal block layout. The input signal
type determines which pins are used: