Rockwell Automation Logix5000 Controllers Major, Minor, and I/O Faults Programming Manual - Manual (Page 25)

Major faults Chapter 1
Identify when the controller is in prescan
In the main routine of your program, enter the following rung as the first rung in
the main routine of the program.
The fault routine of this program uses the status of this bit to determine if the
fault occurred during prescan or normal scan of the logic.
• During prescan, this bit is off. During prescan, the controller resets all bits
that are referenced by OTE instructions.
• When the controller begins to run the logic, the CPU_scanning bit is
always on.
Get the fault type and code
Enter the following rung in the fault routine for the program.
The GSV instruction:
• Accesses the MajorFaultRecord attribute of this program. This attribute
stores information about the fault.
• Stores the fault information in the major_fault_record (of type
FAULTRECORD) tag. When you enter a tag that is based on a structure,
enter the first member of the tag.
Rockwell Automation Publication 1756-PM014G-EN-P – October 2014 25