Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual - Manual (Page 65)

Publication 1746-UM008B-EN-P - December 2006
Channel Configuration, Data, and Status 65
6. If the channel is configured for RTD inputs and engineering
units data format, determine if you want the channel data word
to read in ° C or ° F and enter a one or a zero in bit 8
(Temperature Units) of the configuration word.
If the channel is configured for a resistance input, this field is
ignored.
7. Determine the desired input filter frequency for the channel and
enter the two-digit binary code in bit field 9 and 10 (Filter
Frequency Selection) of the channel configuration word.
A lower filter frequency increases the channel update time, but
also increases the noise rejection and channel resolution. A
higher filter frequency decreases the channel update time, but
also decreases the noise rejection and channel resolution.
8. Place a one in bit 11 (channel Enable) if the channel is used or
place a zero in bit 11 if the channel is not used.
9. Place a zero in bit 12 for an excitation current of 2.0 mA or place
a one in bit 12 for 0.5 mA.
Select the excitation current value based on RTD vendor
recommendations and the Input Specifications table, on
page 118.
10. If you have chosen proportional counts data format, select
whether you want the module-defined default scaling selected
for each channel or if you want to define the scaling range
yourself. Use bits 13 and 14 (user-set scaling) for this setting. If
you choose to define the scaling range for proportional counts
data format, make sure to enter the lower and upper limits in
words 4 and 5 (defines range 0) or 6 and 7 (defines range 1).
11. Place a zero is in bit 15 because this bit is not used.
12. Build the channel configuration word using the configuration
worksheet on page 128 for every channel on each RTD module
repeating the procedures given in steps 1…11.
Enter the Configuration Data
Follow the steps outlined in Chapter 2, Quick Start Guide;
Chapter 6, Ladder Programming Examples; or Appendix D, Channel
Configuration, Data, and Status.
Enter your configuration data into your ladder program and copy it to
the RTD module.