Rockwell Automation 1746-INT4 Thermocouple/MV Isolated/ User Manual - Manual (Page 68)

Publication 1746-UM614B-EN-P - September 2007
68 Module Diagnostics and Troubleshooting
Out-of-range Detection (Bit 13 for under-range, bit 14 for over-range)
The module tests all enabled channels for an out-of-range condition
each time it scans its inputs. Possible causes of an out-of-range
condition include the following:
•
The temperature is too hot or too cold for the thermocouple
being used.
•
A type B thermocouple may be registering a °F value in EU x1
beyond the range allowed by the SLC processor (beyond 32,767)
for the data word.
•
A CJC thermistor may be damaged or the temperature within the
cabinet containing the module may be outside the CJC
thermistor range limits.
Invalid Channel Configuration (Bit 15)
The module sets this fault bit when it detects any of the following
invalid configurations:
•
Configuration bits 0…3: invalid input type = 1 1 0 0 , or 1 1 0 1,
or 1 1 1 0
•
Configuration bits 6…7: invalid code for open circuit mode = 1 1
•
Configuration bits 9…10, and 12…15: invalid non-zero bit
setting
Module-status LED (green) Indicator
The module-status LED indicator shows when the module detects a
non-recoverable fault when power is cycled or during operation. For
this type of fault, the module:
•
no longer communicates with the SLC processor.
•
disables all channels.
•
clears all data and status words.
A module failure is non-recoverable and requires the assistance of
your local distributor or Allen-Bradley Support Services (see Preface).