Controller Failure Symptoms; Table 7-4 Controller Failure Symptoms - Honeywell UDC2500 Product Manual

Troubleshooting/Service

7.6 Controller Failure Symptoms

Introduction
In addition to the error message prompts, there are failure symptoms that can be
identified by noting how the controller displays and indicators are reacting.
Symptoms
Compare your symptoms with those shown in Table 7-4.
Upper
Display Display
Upper
Display Display
Blank
OK
Displayed
OK
disagrees
with Controller
OK
OK
OK
Display does not change when a key is pressed
Controller fails to go into "Slave" operation during communications
OK Displayed
disagrees with
Auxiliary Output
Other symptoms
If a set of symptoms or prompts other than the one you started with appears while
troubleshooting, re-evaluate the symptoms. This may lead to a different troubleshooting
procedure.
164

Table 7-4 Controller Failure Symptoms

Lower Indicators
Lower Indicators
Blank Off
OK
OK
Output
Output
OK
OK
OK OK
OK
Output
UDC2500 Universal Digital Controller Product Manual
Controller Probable
Output Cause
Controller Probable
Output Cause
None Power Failure
Current
Proportional Output
Controller
Three Position
Output
Step Control
disagrees
Output
with Displayed
Output
Time Proportional
Output
Current/Time
Proportional Output
External Alarm Malfunction in
function does alarm output
not operate
properly
Keyboard
Malfunction
Communications
Failure
Controller
Auxiliary Output
Auxiliary Output
disagrees
with Displayed
Auxiliary Output
Trouble-
shooting
Procedure
Trouble-
shooting
Procedure
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