18
…6.2
Self-tuning Page
…6
TUNING LEVEL
Self-tune High Limit
The process variable must be between the high and low
limits during the self-tuning process. If the process value
exceeds one of these, the self-tuning process is shut off
automatically by reverting to the Manual control mode and
returning the controller output to the value set when the
self-tuning was carried out. The high and low values are
the limits for cancelling self-tune execution.
Set the value required (in engineering units), the decimal
point is set automatically.
Self-tune Low Limit
If the process variable value exceeds this adjustable limit
during the self-tuning process, the self-tuning process is
stopped automatically. The display is in engineering units.
Control Terms
Select the Proportional, Integral and Derivative terms
required.
Control Type
A
for quickest response with
1
/
4
wave damping.
or
b
for quickest response with minimum overshoot.
Self-tune Mode Selection
With the self-tune mode enabled the 'ST' l.e.d. is illuminated
while the controller calculates the control terms, selected
above. On completion of the self-tune sequence the 'ST' l.e.d.
flashes. Select
ON
to enable,
OFF
to disable.
The time taken for completion of self-tuning is dependent
on the speed of response of the process being controlled.
If Self-tune is
OFF
return to the top of the
Self-tune Page
.
Wait for the 'ST' l.e.d. to flash.
Other pages can be accessed while the controller carries
out the self-tune sequence. The sequence is automatically
disabled on completion or can be manually disabled at any
time, i.e. by selecting
OFF
.
Advance to next parameter (view advisory values) or, if self-
tuning process not completed, return to top of
Self-tune Page
.
Continued on next page.
tYPE
A
S–tunE
OFF
AtSPt
A t S P t
ST
Self-tuning
not
completed
Self-tuning
completed
OFF
ON
St–HI
550
tErMS
PId
PI
P
St–LO
450
S t r t U P
