Honeywell UMC800 - Page 90

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.