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Cancellation of adaption: The operator can cancel the adaption attempt at any time.
For this, key H must be pressed. The controller continues operating with the old
parameters.
Adaption problems
If process or control conditions occur preventing a successful
adaption, the controller cancels the adaption attempt.
The display is as shown here.
The controller outputs are switched off, to prevent from set-point overshoots. After
acknowledgement with H, process control is continued with the old parameters.
Optimizing problems
Problem: Self-tuning cancelled immediately, display: AdF
Inverse controllers: process value too high and set-point W must be increased or
direct controller: process value too low and set-point W must be reduced.
Problem: Self-tuning cancelled after switching on the energy, display: AdF
Wrong action direction and the instrument must be reconfigured (inverse i direct) or
the difference X i W is too small and X
* must be reduced.
h
For single cooling control, the heating function of a 2-point controller with direct action
must be used. If the cooling function of a 3-point controller is used instead, the same
problem occurs.
Problem: Self-tuning cancelled after approx. 1 hour, display: AdF
The process value X does not react. Check sensors, connections and process.
Problem: With self-tuning, energy is not switched on, display: AdA i X
The difference X i W does not increase sufficiently and W
* must be reduced or
h
the process value X is continuously unstable and the process must be checked
(disturbances, correcting variable).
Problem: Line-out too slow
Pb1 and/or ti too high (r Optimizing aid).
Problem: Control oscillates too much around set-point / actuator opens and closes continuously
Pb1 and/or ti too small (r Optimizing aid). For motor actuators, 3-point stepping
controllers must be used, 2- or 3-point controllers cannot be used.
Problem: Control oscillates before reaching the set-point
td too high. Proceed further according to the table of Optimizing aid.
Problem: Control sensitivity too low with 3-point stepping controller
Because of switching rate, the trigger point separation Sh has been adjusted too
high. We recommend to adjust the value to an optimum of switching rate (wear of
actuator) and control sensitivity.
= SPH - SPL (set-point range), X
= InH - InL (control range)
* W
h
h
15
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