Over Or Under Range Detection; Open Circuit Detection; Non-Critical Vs; Errors - Spectrum Controls 1769 User Manual

Section 5.5

Non-critical vs.

Critical Module

Errors

User's Manual Pub. 0300241-01 Rev. A
Chapter 5: Diagnostics and Troubleshooting
Whenever a channel configuration word is improperly defined, the module reports an
error. See pages 5-3 to 5-5 for a description of module errors.

5.4.2 Over or Under Range Detection

Whenever the data received at the channel word is out of the defined operating range, an
over-range or under-range error is indicated in input data word 7.
Possible causes of an out-of-range condition include:
•
The temperature is too hot or too cold for the type of RTD being used.
•
The wrong RTD is being used for the input type selected, or for the
configuration that was programmed.
•
The input device is faulty.
•
The signal input from the input device is beyond the scaling range.

5.4.3 Open Circuit Detection

On each scan, the module performs an open-circuit test on all enabled channels.
Whenever an open-circuit condition occurs, the open-circuit bit for that channel is set in
input data word 6.
Possible causes of an open circuit include:
•
The input device is broken
•
A wire is loose or cut
•
The input device is not installed on the configured channel
•
A RTD is installed incorrectly
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.
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 or
program mode of operation until the error can be dealt with. Critical module errors are
indicated in Table 5-3 Extended Error Codes on page 5-5.
5-3