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Press and (the Setpoint Select button)
simultaneously to begin the Auto Tune.
The Actual display will flash “At” and the current process
temperature to indicate that an Auto Tune is underway.
If Auto Tune is successful, the controller automatically
starts controlling using the new PID parameters.
If you press the STOP button or a fault occurs during the
Auto Tune, the control enters stop mode and Auto Tuning
immediately terminates. The actual display stops flashing
“At.” If a fault occurred, the control will display the appro-
priate error message.
PERFORMING AN
AUTO TUNE
UGH004/0999 microKool Portable Chillers
OPERATION 4-9
Run
ERROR MESSAGE ERROR DESCRIPTION
Insufficient setpoint/process deviation.
If the absolute value of (setpoint - process
value) is less than 25° F. The Auto Tune can-
not be started until the temperature
difference is at least 25° F.
Auto Tune timed out. Auto Tune will time out
if a stable process value cannot be obtained
5 minutes into the tune, or if the tuning
process takes longer than 30 minutes. If this
error occurs, verify that you followed every
requirement under “To ensure a successful
Auto Tune” and perform a second tune.
Invalid PID constants were generated.
The most likely causes of this error is a tune
started inappropriately or an external ele-
ment (i.e., loose thermocouple) that upset
the process while tuning was in progress.
Verify that you followed every requirement
under “To ensure a successful Auto Tune”
and perform a second tune.
dEvAt
tI
At
badAt
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