FMS CMGZ411, Operating Manual

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Operating Manual CMGZ411/421
20
10 Initial operation of PID controller
10.1 Parametrization of the PID controller
•
Set the parameters „Machine configuration“ and
„Output configuration“ as needed
Reference value given by potentiometer
(analogically)
•
Connect potentiometer or other source as shown in
the wiring diagram
•
Set parameter „scale poti reference“ referring to the
needed nominal force at 10V
Winder/Unwinder with 10V input for line speed
•
Input rotations per volt of the tacho generator to
parameter „Line speed tacho“
•
Input diameter of the tacho roller to parameter „Tacho diameter“
•
Input rotations per volt of the controlled drive to parameter „Winder drive“
•
Input minimum roller diameter to parameter „Center diameter“
•
Input maximum roller diameter to parameter „Max. diameter“
Tension reduction
If a reference tension reduction is needed, all settings have to be made as described under
„Winder/Unwinder“. In addition, the parameter „tension reduction“ stores the needed configuration, and the
parameter „reduction value“ stores the reduction factor.
Controller with line drive
•
Input the percentage quota of the PID controller which is added to the line speed to parameter „Line
speed overlay“.
10.2 Determination of PID control parameters
Mathematic determination of control parameters
To calculate the parameters for the controller, the well-known equations of Bode, Ziegler-Nichols or others
can be used. The values calculated by the appropriate formulas can be entered under the parameters PID-
configuration, Proportional component P, Integral component I, Derivative component D. After that, the
controller is fine-tuned under operating conditions.
Experimental determination of control parameters (recommended)
In the case of a control loop with unknown behaviour, tuning is done by means of a systematic approach.
•
Set parameter „PID-Configuration“ to PI
•
Set Parameter “Integral component I
″
very high
•
Set Parameter
″
Proportional component
″
small
•
enable controller
•
If loop is instable: Decrease Parameter
„Proportional component P“
•
If loop is stable: Increase Parameter „Proportional
component P“
•
Repeat this procedure until the loop is stable, but
is just not oscillating. This setting allows the loop
to be stable, but as long as there is no I
component, there will be a steady error.
•
If the loop is stable with only P component,
decrease the I component until the steady error
disappears. If the I component is too small, the
loop will once again become instable.
diagram: The controller has to be set in a way
that the feedback value will reach the
reference value as fast as possible.