Rockwell Automation 1746-NR8 SLC 500 RTD/Resistance Input Module User Manual - Manual (Page 89)

Publication 1746-UM003A-EN-P
Module Diagnostics and Troubleshooting 6-5
If an open- or short-circuit is detected, the channel data word reflects input
data as defined by the broken input configuration bits (6 and 7) in the channel
configuration word.
Out-Of-Range Detection
Whenever the data received at the channel data word is out of the defined
operating range, an over-range or under-range error is indicated and bit 14 of
the channel status word is set.
For a review of the temperature range or resistance range limitations for your
input device, refer to the temperature ranges provided in Chapter 5 or the
user-specified range in configuration words 8 through 23 if proportional
counts is used.
Possible causes of an out-of-range condition include:
•
The temperature is too hot or too cold for the RTD being used.
•
Wrong RTD used for type/configuration selected.
•
Bad potentiometer or RTD.
•
Signal input from either potentiometer or RTD is beyond the user-set
scaling range.
Module Status LED (Green)
The module status LED is used to indicate module-related diagnostic or
operating errors. These non-recoverable errors may be detected at power-up or
during module operation. Once in a module error state, the RTD module no
longer communicates with the SLC processor. Channels are disabled and data
words are cleared (0).
Failure of any diagnostic test places the module in a non-recoverable state. To
exit this state, cycle power. If the power cycle does not work, then call your
local distributor or Rockwell Automation for assistance.
IMPORTANT
There is no under-range error for a direct resistance input
(default scaling).