Clear a major fault during prescan, Clear the fault, Clear a major fault – Rockwell Automation Logix5000 Controllers Major, Minor, and I/O Faults Programming Manual User Manual

Page 24

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Chapter 1 Major faults

Item

Description

The second CLR instruction sets to zero the value of the fault code in the major_fault_record tag.

Clear the fault

The SSV instruction writes:

The new values to the MajorFaultRecord attribute of this program.

The values contained in the major_fault_record tag. Because the Type and

Code member are set to zero, the fault clears and the controller resumes

execution.

If the controller faults immediately after you switch it to the Run mode, examine

the prescan operation for the fault. Depending on the revision of your controller,

an array subscript that is beyond the range of the array (out of range) during

prescan might cause a fault.

If controller is revision

Then

11.x or earlier

During prescan, an array subscript that is beyond the range of the array (out of

range) produces a major fault.

12.x

See the release notes for the firmware of your controller.

13.0 or later

During prescan, the controller automatically clears any faults due to an array

subscript that is beyond the range of the array (out of range).

See the following procedures to clear a major fault that occurs during prescan.

Identify when the controller is in prescan on 25

Get the fault type and code on page 25

Check for a specific fault on page 26

Clear the fault on page 26

Important: It is good programming practice to check for a specific fault before clearing that fault.

Clear a major fault during
prescan

24

Rockwell Automation Publication 1756-PM014G-EN-P – October 2014

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