User guide

28
Chapter
28–1
Troubleshooting Faults
This chapter:
• lists the major error fault codes
• indicates the probable causes of faults
• recommends corrective action
Chapter 27 also lists the error codes, under word S:6.
The following general information applies to troubleshooting.
User Fault Routine Not in Effect
You can clear a fault by one of the following methods:
• Manually clear minor fault bits S:5/0 – S:5/7 and the major fault bit
S:1/13 in the status file, using a programming device or DTAM. The
processor then enters the Program mode. Correct the condition causing
the fault, then return the processor to the Run or Test mode.
• Set the Fault Override at Powerup Bit S:1/8 in the status file to clear the
fault when power is cycled, assuming the user program is not corrupt.
• Set one of the autoload bits S:1/10, S:1/11, or S:1/12 in the status file of
the program in an EEPROM to automatically transfer a new non-faulted
program from the memory module to RAM when power is cycled.
Refer to chapter 27 for more information on status bits S:1/13, S:1/8,
S:1/10, S:1/11, and S:1/12.
Application Note: You can declare your own application-specific major
fault by writing your own unique value to S:6 and then setting S:1/13.
User Fault Routine in Effect – SLC 5/02 Processors Only
When you designate a subroutine file for your user fault routine, the
occurrence of recoverable or non-recoverable user faults will cause the
designated subroutine to be executed for one scan. If the fault is recoverable,
the subroutine can be used to correct the problem and clear the fault bit
S:1/13. The processor will then continue in the Run mode. If the fault is
non-recoverable, the subroutine can be used to send a message via the
Message instruction to another DH–485 node with error code information
and/or do an orderly shutdown of the process.
The subroutine does not execute for non-user faults. The user fault routine is
discussed in chapter 29.
Troubleshooting Overview