Power cycle diagnostics, Channel diagnostics, Non-critical versus critical module errors – Rockwell Automation 1769-OF4 Compact Analog Output Module User Manual
Page 45: Power cycle diagnostics channel diagnostics, Output clamp detection

Publication 1769-UM020A-EN-P - December 2009
45
Module Diagnostics and Troubleshooting Chapter 4
Power Cycle Diagnostics
When you cycle power to the module, a series of internal diagnostic
tests are performed. These diagnostic tests must be successfully
completed or the module status indicator remains off and a module
error results and is reported to the controller.
Channel Diagnostics
When any channel is enabled, the module performs a diagnostic
check to see that the channel has been properly configured. In
addition, the module checks each channel during every conversion
cycle for over-range (high clamp) and under-range (low clamp)
conditions.
Output Clamp Detection
Whenever data is sent to an output that meets or exceeds that
channel’s configured clamp limits, an over-range (high clamp) or
under-range (low clamp) error is indicated in the Input Data file.
Non-critical versus Critical
Module Errors
Non-critical module errors are typically recoverable. Channel errors
(over-range or under-range errors) are non-critical. Non-critical errors
are indicated in the module input data table.
Critical module errors are conditions that 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
.
Module Status
Indicator
Condition
Corrective Action
On
Proper Operation
No action required.
Off
Module Fault
Cycle power. If condition persists, replace the
module. Call your local distributor or Rockwell
Automation for assistance.