Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual - Manual (Page 18)

Publication 1746-UM008B-EN-P - December 2006
18 Overview
System Overview The RTD module communicates to the SLC 500 processor through the
parallel backplane interface and receives +5V dc and +24V dc power
from the SLC 500 power supply through the backplane. No external
power supply is required. You may install as many RTD modules in
your system as the power supply can support.
RTD Module Configuration
Each individual channel on the RTD module can receive input signals
from two, three or four wire RTD sensors or from resistance input
devices. You configure each channel to accept either input. When
configured for RTD input types, the module converts the RTD
readings into linearized, digital temperature readings in °C or °F.
When configured for resistance inputs, the module provides a linear
resistance value in ohms.
IMPORTANT
The RTD module is designed to accept input from RTD sensors
with up to three wires. When using 4-wire RTD sensors, one of
the two lead compensation wires is not used and the 4-wire
sensor is treated like a 3-wire sensor. Lead wire compensation
is provided via the third wire.
See NR4 Wiring Considerations on page 40 for more
information.
RTD Modules
SLC Processor