YOKOGAWA UT750, Instruction Manual

Page: 61 / 108

<Toc> <4. Troubleshooting and Maintenance>
4-3
IM 05D01B02-41E
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Possible Errors during Operation
The following shows possible errors occurring during operations.
Description
of error
PV Control output
Alarm
output
Retransmis-
sion output
Commu-
nication
Remedy
RJC error
Measured
with RJC=0
Normal action
ADC error 105%
Faulty
Contact us for repair.
PV burnout error
Dependent on the
BSL parameter
Up-scale: 105%
Down-scale: -5%
In AUTO:
Preset value output
In MAN:
Normal action
Check wires and
sensor.
Excessive PV
Out of -5 to 105%
-5% or 105% Normal action Check process.
Auto-tuning
failure
(Time-out) Action with PID
existing before
auto-tuning
Faulty
communication
line
Check wires and
communication
parameters, and make
resetting. Recovery at
normal receipt
Check process. Press
any key to erase error
indication.
Normal
action
Normal action
Stopped
Normal
action
Normal
action
Normal
action
Normal
action
Runaway (due to
defective power
or noise)
Undefined
Faulty if power off/on
does not reset start
the unit. Contact us for
repair.
Power off None
0% or less or OFF OFF
0% or
less
Stopped
Check for abnormal
power.
Feedback resistor
breakdown Check the feedback
resistor.
Stopped
Display position
(Note)
2
1
-
3
Error indication
Displays “RJC” and
PV alternately
Left end of SP display
unit blinks.
Decimal point at right end
lights.
All indications off
E200
E300
OVER or -OVER
B.OUT
Setpoint display
Note 1: PV-indicating LED display
2: LCD
3: Display showing the PV of the loop in which the error has been caused
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Remedies if Power Failure Occurs during Operations
The operation status and remedies after a power failure differ with the length of power
failure time:
●
Instantaneous Power Failure of 20 ms or less
A power failure is not detected. Normal operation continues.
●
Power Failure of about 2 seconds or less
The following show effects caused in “settings” and “operation status.”
Alarm action Continues. Alarm with standby function will enter standby status.
Setting parameter Set contents of each parameter are retained.
Auto-tuning Cancelled.
Control action Action before power failure continues.
1st Edition : May 31,2000-00