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