Bradley Smoker PLC-5 user manual Preparing Fault Routines, Responses to a Major Fault

Chapter 15

Preparing Fault Routines

Using This Chapter

For Information About	See Page
Understanding the fault routine concept	15-1
Understanding controller-detected major faults	15-2
Defining a fault routine	15-4
Defining a watchdog timer	15-5
Programming a fault routine	15-6
Monitoring faults	15-11

Understanding the Fault Routine Concept

Fault routines execute when a PLC-5 controller encounters a major fault during program execution.

Use a fault routine to specify how you want the controller to respond to a major fault. If your controller experiences a fault during program execution, you can tell the controller to interrupt the current program, run your fault routine, and then continue processing the original program.

A fault routine processes the major fault bit found in S:11 and determines the course of program execution based on the fault bit present. Fault routines provide a means to either:

•systematically shut down a process or control operation

•log and clear the fault and continue normal operation

For a detailed list of the words in the controller status file, see Appendix B.

Responses to a Major Fault

When the controller detects a major fault, the controller immediately interrupts the current program. If a fault routine exists (i.e., program file is specified in S:29 as a fault routine), the controller runs that fault routine program for recoverable faults. Depending on the type of fault, the controller then:

Publication 1785-UM012D-EN-P - July 2005