Program Controller SE-707
© 2018 by STANGE Elektronik GmbH
Subject to technical modifications
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2.)
Disturbance by opening the plant
If the plant is opened during a hold phase, e.g. to take out parts or add new parts, then a strong actual value reaction is
caused thereby (e.g. break-down of the temperature about 20 K) which results in a strong regulating procedure with
substantial overshooting. The plant heats with full strength against it and the operating point changes although it is not
necessary.
The method of resolution for this is the X-tracking: It avoids, that the controller notices a large control deviation and leads
the controller set value softly to the target value again.
The X-tracking is started retriggerable over the control zone tolerance.
The following graph displays the regulation of two disturbances in the hold phase. It can be seen that the X-tracking is
retriggered in each case.
Configuration notes see below!
Configuration in the device
The following configuration points were created for the two examples above.
When the X-tracking is released must then only be defined in the PLC statement list.
Control zones:
e
.g.:
Function
Input
X-tracking time base
1/minute
X-tracking gradient
1.0
X-tracking progression interval
20.0
X-tracking progression factor Min
0.05
X-tracking progression factor Max
20.0
I-Brake (overshoot damping)
On
The control zona tolerance value might be selected e.g. to 0.5 %, in case of a temperature range of 1200 °C that corresponds to a deviation
of 6 K.
Tolerance:
e.g.:
Function
Input
Tolerance code
Av – TargetSv
External activation
No (always active)
Operand number 1
01 (same actual value, like the control zone)
Operand number 2
01 (same set value, like the control zone)
Plus-Tolerance
+ 50.0
Minus-Tolerance
- 50.0
