Publication 1764-UM001A-US-P
C-4
Troubleshooting Your System
Identifying Controller
Faults
While a program is executing, a fault may occur within the operating system or
your program. When a fault occurs, you have various options to determine what
the fault is and how to correct it. This section describes how to clear faults and
provides a list of possible advisory messages with recommended corrective actions.
Automatically Clearing Faults
You can automatically clear a fault by cycling power to the controller when the
Fault Override at Power-up bit (S:1/8) is set in the status file.
You can also configure the controller to clear faults and go to RUN every time the
controller is power cycled. This is a feature that OEMs can build into their
equipment to allow end users to reset the controller. If the controller faults, it can
be reset by simply cycling power to the machine. To accomplish this, set the
following bits in the status file:
•
S2:1/8 - Fault Override at Power-up
•
S2:1/12 - Mode Behavior
If the fault condition still exists after cycling power, the controller re-enters the fault
mode. For more information on status bits, refer to the
MicroLogix 1200 and
MicroLogix 1500 Instruction Set Reference Manual
.
Manually Clearing Faults Using the Fault Routine
The occurrence of recoverable or non-recoverable user faults can cause the user
fault subroutine to be executed. If the fault is recoverable, the subroutine can be
used to correct the problem and clear the fault bit S:1/13. The controller then
continues in the Run or test mode.
The subroutine does not execute for non-user faults. Refer to the
MicroLogix 1200
and MicroLogix 1500 Instruction Set Reference Manual
for information on creating a
user fault subroutine.
Fault Messages
Refer to the
MicroLogix 1200 and 1500 Instruction Set Reference Manual
for the
controller fault messages that can occur during operation of the MicroLogix 1500
programmable controllers. Each fault message includes the error code description,
the probable cause, and the recommended corrective action.
NOTE
You can declare your own application-specific major fault by
writing your own unique value to S:6 and then setting bit S:1/13
to prevent reusing system defined codes. The recommended
values for user defined faults are FF00 to FF0F.
Summary of Contents for micrologix 1500
Page 1: ...MicroLogix 1500 Programmable Controllers Bulletin 1764 User Manual AB Spares...
Page 6: ...Publication 1762 RM001A US P Preface P 4...
Page 52: ...Publication 1764 UM001A US P 3 16 Wiring Your Controller...
Page 78: ...Publication 1764 UM001A US P 5 10 Using Trim Pots and the Data Access Tool DAT...
Page 96: ...Publication 1764 UM001A US P B 6 Replacement Parts...
Page 102: ...Publication 1764 UM001A US P C 6 Troubleshooting Your System...
Page 132: ...Publication 1764 UM001A US P F 10 System Loading and Heat Dissipation...
Page 147: ...AB Spares...
Page 149: ...AB Spares...
