Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 295)

Programming Reference
B–7
Address Bit Classification Description
S:1/13 Major Error
Halted Dynamic
Configuration This bit is set by the controller any time a major
error is encountered. The controller enters a
fault condition. Word S:6, the Fault Code will
contain a code that can be used to diagnose
the fault condition. Any time bit S:1/13 is set,
the controller:
•
either places all outputs in a safe state
(outputs are off) and energizes the fault
LED,
•
or enters the user-fault routine with
outputs active (if in REM Run mode),
allowing the fault routine ladder logic to
attempt recovery from the fault condition.
If the user-fault routine determines that
recovery is required, clear S:1/13 using
ladder logic prior to exiting the fault
routine. If the fault routine ladder logic
does not understand the fault code, or if
the routine determines that it is not
desirable to continue operation, the
controller exits the fault routine with bit
S:1/13 set. The outputs are placed in a
safe state and the FAULT LED is
energized.
When you clear bit S:1/13 using a
programming device, the controller mode
changes from fault to Remote Program. You
can move a value to S:6, then set S:1/13 in
your ladder program to generate an application
specific major error. All application generated
faults are recoverable regardless of the value
used.
Note: Once a major fault state exists, you
must correct the condition causing the fault,
and you must also clear this bit in order for the
controller to accept a mode change attempt
(into REM Run or REM Test). Also, clear S:6
to avoid the confusion of having an error code
but no fault condition.
Note: Do not re-use error codes that are
defined later in this appendix as application
specific error codes. Instead, create your own
unique codes. This prevents you from
confusing application errors with system errors.
We recommend using error codes FFOO to
FFOF to indicate application specific major
errors.
Reference