Honeywell UMC800 User Manual

Page 90

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Diagnostics and Troubleshooting
Fault Detection and Troubleclearing

82

UMC800 Controller Installation and User Guide

Release F

4/01

Controller

Diagnostic Summary

(In the User Utility and Operator

Interface)

Controller

LED on CPU

Fault Detection / Troubleclearing

Menu

Item

Status

Possible Cause

Controller Action

User Action

SYSTEM

TASK FAULT

RUN LED
off.

And

POWER
LED flashes
3 times.

Software failure.

Function blocks are
not executed.

1.

Force a cold
start. (Toggle
controller mode
switch from
PGM to RUN.)

2.

Upgrade
controller
software.

3.

Replace CPU
board.

4.

Contact
Honeywell.

CPU

GOOD

none

CPU

WATCHDOG

POWER
LED flashes
3 times.

Watchdog reset
resulting from
software failure.

Executes normally.

1.

Force a cold
start. (Toggle
controller mode
switch from
PGM to RUN.)

2.

Upgrade
controller
software.

3.

Replace CPU
board.

4.

Contact
Honeywell.

CPU

BUS ERROR

POWER
LED flashes
4 times.

Bus Error
Detected.

Executes normally.

1.

Force a cold
start. (Toggle
controller mode
switch from
PGM to RUN.)

2.

Isolate system
from noise and
force a cold
start.

3.

Replace CPU
board.

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