Allen-Bradley SLC 500 Service manual

Publication 1746-IN012B-EN-P - May 2001
Installation Instructions
SLC 500™ RTD/Resistance Input Module
(Catalog Number 1746-NR4)
Inside…............................................................................................page
Hazardous Location Considerations ........................................................ 2
Environnements dangereux ..................................................................... 2
Overview .................................................................................................. 3
Required Tools and Equipment ................................................................ 4
Electrostatic Damage............................................................................... 5
NR4 Power Requirements........................................................................ 5
Modular Chassis Considerations............................................................. 5
Fixed Expansion Chassis Considerations................................................. 6
General Considerations ........................................................................... 6
Module Installation and Removal............................................................ 7
Terminal Block Wiring and Removal ........................................................ 8
Wiring Considerations ............................................................................. 9
Wiring Resistance Devices (Potentiometers) to the NR4 Module ........ 12
Wiring Input Devices to the NR4 Module ............................................. 14
Module Addressing................................................................................ 15
Channel Configuration ........................................................................... 16
Specifications ........................................................................................ 18
For More Information............................................................................. 24

2SLC 500™ RTD/Resistance Input Module
Publication 1746-IN012B-EN-P - May 2001
Hazardous Location Considerations
This equipment is suitable for use in Class I, Division 2, Groups A, B, C, D or
non-hazardous locations only. The following WARNING statement applies to use in
hazardous locations.
Environnements dangereux
Cet équipement est conçu pour être utilisé dans des environnements de Classe I,
Division 2, Groupes A, B, C, D ou non dangereux. La mise en garde suivante
s’applique à une utilisation dans des environnements dangereux.
WARNING
!
EXPLOSION HAZARD
•Substitution of components may impair suitability for Class
I, Division 2.
•Do not replace components or disconnect equipment
unless power has been switched off or the area is known to
be non-hazardous.
•Do not connect or disconnect components unless power
has been switched off or the area is known to be
non-hazardous.
•All wiring must comply with N.E.C. article 501-4(b).
WARNING
!
DANGER D’EXPLOSION
•La substitution de composants peut rendre cet équipement
impropre à une utilisation en environnement de Classe I,
Division 2.
•Ne pas remplacer de composants ou déconnecter
l'équipement sans s'être assuré que l'alimentation est
coupée.
•Ne pas connecter ou déconnecter des composants sans
s'être assuré que l'alimentation est coupée.

SLC 500™ RTD/Resistance Input Module 3
Publication 1746-IN012B-EN-P - May 2001
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 20 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 Rockwell Automation.

4SLC 500™ RTD/Resistance Input Module
Publication 1746-IN012B-EN-P - May 2001
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
CHL 1
SHIELD
SHIELD
CHL 0
RTD
SHIELD
MODULE STA TUS
0
1
2
3
CHANNEL
STATUS
RTD/resistance
RT D
CHL 0
SENSE CHL
1
SENSE
CHL 0
RETRN CHL
1
RETRN
SHIELD
CHL
3
CHL 2
RTD
RT D
CHL
2
SENSE CHL
3
SENSE
CHL
2
RETRN CHL
3
RETRN
SHIELD
SHIELD
Door Label
Channel Status LEDs
(Green)
Module Status LED
(Green)
Removable Terminal
Block
Cable Tie Slots

SLC 500™ RTD/Resistance Input Module 5
Publication 1746-IN012B-EN-P - May 2001
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 about
module compatibility in a 2-slot fixed expansion chassis on page 6.
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.
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

6SLC 500™ RTD/Resistance Input Module
Publication 1746-IN012B-EN-P - May 2001
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 -

SLC 500™ RTD/Resistance Input Module 7
Publication 1746-IN012B-EN-P - May 2001
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

8SLC 500™ RTD/Resistance Input Module
Publication 1746-IN012B-EN-P - May 2001
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 to 0.9 Nm (6 to 8 in-lb.).
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.
Terminal Block Spare Part
Catalog Number 1746-RT25G
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)
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

SLC 500™ RTD/Resistance Input Module 9
Publication 1746-IN012B-EN-P - May 2001
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.
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

10 SLC 500™ RTD/Resistance Input Module
Publication 1746-IN012B-EN-P - May 2001
2-Wire RTD Interconnection
3-Wire RTD Interconnection
4-Wire RTD Interconnection
Cable Shield
Add Jumper
Return Return
Belden #9501 Shielded Cable
RTD RTD
Shield
CH 0 RTD
CH 0 Sense
CH 0 Return
Cable Shield
Return Return
Belden #9501 or #9533 Shielded Cable
RTD RTD
Shield
CH 0 RTD
CH 0 Sense
CH 0 Return
Sense Sense
Shield
CH 0 RTD
CH 0 Sense
CH 0 Return
Cable Shield
Return
RTD
Sense
RTD
Sense
Return
Belden #9501 or #9533 Shielded Cable
Belden #9501 or #9533
Shielded Cable
Leave one sensor wire open.