Allen-Bradley SLC 500 1746-NR4 User manual

SLC 500™ RTD/Resistance Input
Module
(Catalog Number 1746-NR4)
Installation Instructions
Inside… page
Important User Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
For More Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Required Tools and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrostatic Damage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
NR4 Power Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Modular Chassis Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Fixed Expansion Chassis Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Module Installation and Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Terminal Block Wiring and Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Wiring Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Wiring Resistance Devices (Potentiometers) to the NR4 Module . . . . . . . . . . . . . . 13
Wiring Input Devices to the NR4 Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Channel Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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2SLC 500™ RTD/Resistance Input Module
Publication 1746-5.17
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 purposes of 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 that 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 these installation instructions we use notes to make you aware of
safety considerations:
Attention statements help you to:
• identify a hazard
• avoid the hazard
• recognize the consequences
!ATTENTION: Identifies information about practices or
circumstances that can lead to personal injury or death, property
damage or economic loss.
Important: Identifies information that is critical for successful application and
understanding of the product.

SLC 500™RTD/Resistance Input Module 3
Publication 1746-5.17
For More Information
As part of our effort to preserve, protect, and improve our environment, Allen-
Bradley is reducing the amount of paper we use. Less paper means more options
for you. In addition to traditional printed publications and CD-ROM versions, we
now offer on-line manuals with the most up-to-date information you can get. We
recommend that you read the related publications listed below before starting up
your control system.
Related Publications
How to Get More Information
If you would like a manual, you can:
•download a free electronic version from the internet at
www.theautomationbookstore.com
•purchase a printed manual by:
—contacting your local distributor or Rockwell Automation
representative
—visiting www.theautomationbookstore.com and placing your order
—calling 1.800.963.9548 (USA/Canada) or 001.330.725.1547 (Outside
USA/Canada)
For Refer to this Document Pub. No.
A more detailed description on how to install
and use your RTD/Resistance Input Module. SLC 500™RTD/Resistance Input Module User Manual 1746-6.7
A more detailed description on how to install
and use your modular SLC 500 system. SLC 500™Modular
Hardware Style Installation
and Operation Manual 1747-6.2
A more detailed description on how to install
and use your fixed SLC 500 system. SLC 500™Fixed Hardware
Style Installation and
Operation Manual 1747-6.21
A reference manual that contains status file
data, instruction set, and troubleshooting
information.
SLC500™andMicroLogix™
1000 Instruction Set
Reference Manual 1747-6.15
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4SLC 500™RTD/Resistance Input Module
Publication 1746-5.17
Overview
The RTD module receives and stores digitally converted analog data from RTDs
or other resistance inputs such as potentiometers into its image table for retrieval
by all fixed and modular SLC 500 processors. An RTD consists of a temperature-
sensing element connected by 2, 3 or 4 wires that provide input to the RTD
module. The module supports connections from any combination of up to four
RTDs of various types (for example: platinum, nickel, copper, or nickel-iron) or
other resistance inputs. See the input specifications beginning on page 21 for
RTD types, their associated temperature ranges, and the analog input signal
ranges that each 1746-NR4 channel will support. Each input channel is
individually configurable for a specific input device. Broken sensor detection
(open- or short-circuit) is provided for each input channel. In addition, the
module provides indication if the input signal is out-of-range.
The module contains a removable terminal block providing connection for any
mix of four RTD sensors or resistance input devices. There are no output
channels on the module. Module configuration is done via the user program.
There are no DIP switches.
Channel Status LEDs
Channel status LEDs indicate the status for channels 0 through 3. Related error
information is contained in the channel status word. This includes conditions
such as:
•normal operation
•channel-related configuration errors
•open circuit errors
•out-of-range errors
All channel errors are recoverable errors.
Module Status LED
The module status LED shows diagnostic or operating errors related to the
module. These non-recoverable errors may be detected during power up or
during operation. Once an error has been detected, the module no longer
communicates with the SLC processor. Channel states are disabled, and data
words are cleared (0). Failure of any diagnostic test results in a non-recoverable
error and requires the assistance of your local distributor or Allen-Bradley.

SLC 500™RTD/Resistance Input Module 5
Publication 1746-5.17
Required Tools and Equipment
Have the following tools and equipment ready
•medium blade screwdriver
•medium cross-head screwdriver
•RTD module (1746-NR4)
•RTD sensor or resistance input
•appropriate cable (if needed)
•programming equipment
INPUT
CHL1
SHIELD
SHIELD
CHL0
RTD
SHIELD
MODULE STATUS
0
12 3
CHANNEL
STATUS
RTD/resistance
RTD
CHL0
SENSE CHL1
SENSE
CHL0
RETRN CHL1
RETRN
SHIELD
CHL3
CHL2
RTD
RTD
CHL2
SENSE CHL3
SENSE
CHL2
RETRN CHL3
RETRN
SHIELD
SHIELD
Door Label
Channel Status
LEDs (Green)
Module Status
LED (Green)
Removable
Terminal Block
Cable Tie Slots
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6SLC 500™RTD/Resistance Input Module
Publication 1746-5.17
Electrostatic Damage
Electrostatic discharge can damage semiconductor devices inside this module if
you touch backplane connector pins or other sensitive areas. Guard against
electrostatic damage by observing the following precautions.
•Wear an approved wrist strap grounding device when handling the module.
•Touch a grounded object to rid yourself of electrostatic charge before
handling the module.
•Handle the module from the front, away from the backplane connector. Do
not touch backplane connector pins.
•Keep the module in its static-shield bag when not in use, or during
shipment.
NR4 Power Requirements
The RTD module receives its power through the SLC 500 chassis backplane from
the fixed or modular +5V dc/+24V dc chassis power supply. The maximum
current drawn by the module is shown in the table below.
When you are using a modular system configuration, add the values shown in the
table above to the requirements of all other modules in the SLC chassis to
prevent overloading the chassis power supply.
When you are using a fixed system controller, refer to the important note page 7
about module compatibility in a 2-slot fixed expansion chassis.
!ATTENTION: Electrostatic discharge can degrade performance
or cause permanent damage. Handle the module as stated below.
5V dc Amps 24V dc Amps
0.050 0.050

SLC 500™RTD/Resistance Input Module 7
Publication 1746-5.17
Modular Chassis Considerations
Place your RTD module in any slot of an SLC 500 modular chassis (except slot
0) or a modular expansion chassis. Slot 0 is reserved for the modular processor or
adapter modules.
Fixed Expansion Chassis Considerations
General Considerations
Most applications require installation in an industrial enclosure to reduce the
effects of electrical interference. RTD inputs are susceptible to electrical noises
due to the small amplitudes of their signal.
Group your modules to minimize adverse effects from radiated electrical noise
and heat. Consider the following conditions when selecting a slot for the RTD
module. Position the module:
•in a slot away from power lines, load lines and other sources of electrical
noise such as hard-contact switches, relays, and AC motor drives
•away from modules which generate significant radiated heat, such as the
32-point I/O modules
Important: The 2-slot, SLC 500 fixed I/O expansion chassis (1746-A2)
supports many combinations of modules. The combinations that
are not supported by the fixed expansion chassis are shown in the
table below. For a complete listing of valid combinations using the
RTD module in a 2-slot expansion chassis with another SLC I/O or
communication module, refer to the table in the SLC 500™ RTD/
Resistance Input Module User Manual, publication 1746-6.7.
Invalid Combinations Using the RTD
Module in a Fixed Expansion Chassis 5V dc (Amps) 24V dc (Amps)
OW16 0.170 0.180
OB32 0.452 -
OB32 0.452 -
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8SLC 500™RTD/Resistance Input Module
Publication 1746-5.17
Module Installation and Removal
When installing the module in a chassis, it is not necessary to remove the
terminal block from the module.
Module Installation Procedure
1. Align the circuit board of the RTD module with the card guides located at
the top and bottom of the chassis.
2. Slide the module into the chassis until both top and bottom retaining clips
are secured. Apply firm even pressure on the module to attach it to its
backplane connector. Never force the module into the slot.
3. Cover all unused slots with the Card Slot Filler, Catalog Number 1746-N2.
Module Removal Procedure
1. Press the releases at the top and bottom of the module and slide the module
out of the chassis slot.
2. Cover all unused slots with the Card Slot Filler, Catalog Number 1746-N2.
Top and Bottom
Module Release(s)
Card
Guide

SLC 500™RTD/Resistance Input Module 9
Publication 1746-5.17
Terminal Block Wiring and Removal
The RTD module contains an 18-position, removable terminal block. The
terminal pin-out is shown below.
Terminal Wiring
Terminal screws accept a maximum of two #14 AWG (2 mm2) wires. Tighten
terminal screws only tight enough to immobilize wires. Maximum torque on
terminal screws is 0.7 - 0.9 Nm (6 - 8 in-lb.).
Terminal Block Removal
If the terminal block is removed, use the write-on label located on the side of the
terminal block to identify the module location and type.
To remove the terminal block:
1. Loosen the two terminal block release screws.
!ATTENTION: Disconnect power to the SLC before attempting
to install, remove, or wire the removable terminal wiring block.
To avoid cracking the removable terminal block, alternate the
removal of the terminal block release screws.
Release Screw
Max.Torque = 0.7- 0.9 Nm
(6 - 8 in-lbs)
Shield
Channel 1 RTD
Channel 1 Sense
Channel 1 Return
Shield
Channel 3 RTD
Channel 3 Sense
Channel 3 Return
Shield
Shield
Channel 0 RTD
Channel 0 Sense
Channel 0 Return
Shield
Channel 2 RTD
Channel 2 Sense
Channel 2 Return
Shield
Release Screw
Max Torque = 0.7 - 0.9 Nm
(6 - 8 in-lbs)
(Terminal Block Spare Part Catalog Number 1746-RT25G)
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10 SLC 500™RTD/Resistance Input Module
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2. Grasp the terminal block at the top and bottom and pull outward and down.
Wiring Considerations
Follow the guidelines below when planning your system wiring.
Since the operating principle of the RTD module is based on the measurement of
resistance, take special care in selecting your input cable. For 2-wire or 3-wire
configuration, select a cable that has a consistent impedance throughout its entire
length.
For a 3-wire configuration, the module can compensate for a maximum cable
length associated with an overall cable impedance of 25 ohms.
As shown in the figure on the next page, three configurations of RTDs can be
connected to the RTD module:
•2-wire RTD, which is composed of 2 RTD lead wires (RTD and Return)
•3-wire RTD, which is composed of a Sense and 2 RTD lead wires (RTD and
Return)
•4-wire RTD, which is composed of 2 Sense and 2 RTD lead wires (RTD and
Return). The second sense wire of a 4-wire RTD is left open. It does not
matter which sense wire is left open.
Configuration Recommended Cable
2-wire Belden™#9501 or equivalent
3-wire
less than 30.48 m (100 ft.) Belden #9533 or equivalent
3-wire
greater than 30.48 m (100 ft.) or high humidity
conditions Belden #83503 or equivalent