24
Pb–INt
HI– LMt
SP tOO
CLOSE
INCrSE
StEP
SLO
PrCESS
NOISY
CLOSE
SP tOO
PrCESS
INPUt
Abort
USEr
LIMItS
UPdAtE
OUt
tIME
Error
A–tUNE
CAUtN
A–tUNE
FAIL
Flashing
with
or
or
Flashing
with
or
or
or
or
or
or
Message
Explanation
Action
The process is too slow for the auto
tuning to work correctly.
The input failure level has been
exceeded, possibly due to a broken
sensors or the process has exceeded
one of the auto-tune limits.
With '
At Set Point'
tuning, the ratio of
process oscillation to hysteresis value is
too small for best results.
The auto-tune process has selected a
proportional band or integral action time
above the high limits of these parameters
so the high value has been used.
Because of the process
characteristics, re-trying the auto-
tuning process is unlikley to improve
the calculated control parameters.
Restart auto-tune with a larger output
step size or a smaller hysteresis value.
Hysteresis must be at least equal to
and preferably greater than process
noise.
If possible, use a larger output step
value.
Check input wiring to find the cause of
the failure or restart auto-tuning with a
smaller output step size.
The process variable signal is
excessively 'noisy'.
Check input wiring to try and find the
source of the problem. If the process
is changing rapidly then allow it to
settle before re-trying the auto-tuning
process.
With '
Start-up'
tuning, the process
variable is <10% of the display range,
below the control set point.
Allow the process variable to move
further below the control set point
before re-trying '
Start-up
' auto-tuning.
Alternatively, use the '
At Set Point
'
auto-tune facility.
With '
Start-up'
tuning, although the control
set point was >10% of the display range
above the process variable, it may still be
too close to allow the auto-tune facility to
determine the process characteristics
accurately.
If desired, allow the process variable
to move further below the control set
point (by changing the control output
in the manual control mode) before
re-trying '
Start-up
' auto-tuning.
Alternatively, use the '
At Set Point
'
auto-tune facility.
Operator has stopped auto-tune
process.
None.
Non-volatile memory failure while
updating control parameters.
Re-try auto-tune, if error persists
contact local Service Organization.
The auto-tune process is too slow.
If possible, use a larger output step
value. Otherwise, for '
Start-up'
auto-
tuning, move the process closer to the
set point, or, for '
At Set Point
'
auto-tuning, reduce the hysteresis value.
5.8
Auto-tune Diagnostic Messages
…5 CONTROL OPERATION
Table 5.1 Auto-tuning Error and Diagnostic Messages
Summary of Contents for COMMANDER 1900 Series
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