Rockwell Automation 1762-IR4 RTD/Resistance Input Module - Manual (Page 72)

Publication 1762-UM003A-EN-P - February 2003
4-4 Diagnostics and Troubleshooting
Possible causes for an out-of-range condition include:
•
The temperature is too hot or too cold for the RTD being used.
•
The wrong RTD is being used for the input type selected, or for
the configuration that you have programmed.
•
The input device is faulty.
•
The signal input from the input device is beyond the scaling
range.
Open-Wire or Short-Circuit Detection
The module performs an open-circuit or short-circuit input test on all
enabled channels on each scan. Whenever an open-circuit or
short-circuit condition occurs, the broken input bit for that channel is
set in input data word 4.
Possible causes of a broken input condition include:
•
the input device is broken
•
a wire is loose or cut
•
the input device is not installed on the configured channel
•
an RTD is internally shorted
•
an RTD is not installed correctly
Non-critical vs. Critical
Module Errors Non-critical module errors are typically recoverable. Channel errors
(over-range or under-range errors) are non-critical. Non-critical error
conditions are indicated in the module input data table. Non-critical
configuration errors are indicated by the extended error code. See
Table 4.3 Extended Error Codes on page 4-7.
Critical module errors are conditions that may prevent normal or
recoverable operation of the system. When these types of errors
occur, the system typically leaves the run mode of operation until the
error can be dealt with. Critical module errors are indicated in Table
4.3 Extended Error Codes on page 4-7.
TIP
See Open-Circuit Flag Bits (OC0 to OC3) on page
3-4.