Operating Manual CMGZ 622
25
Note
If the controller is disabled while the material is running, the drive unit will stop
immediately. This may cause material crack. Therefore, the controller should be
disabled only if the machine is no longer running.
9.8
Additional settings
PI or PID configuration
The Tension Controller can be operated as PI or as PID controller (with unwind brake,
PI only). FMS recommends operating as PI controller because this setup is much
easier to handle, and the controller dynamics are sufficient for most applications (refer
also to „5. Controller theory“):
Characteristics of PI controller
Characteristics of PID controller
+
Easier to adjust than a PID controller
+
Quite good behaviour
+
Is very suitable where great inertia
moments make the D component
ineffective
+
Behaviour is more dynamically than
that of a PI controller (PID controller
are used where the dynamics of a PI
controller is not enough)
−
The D component causes greater
tendency to instable behaviour than
using a PI controller!
The parameter
PID-configuration
is set to
PI
or
PID
, depending on required operation
mode.
Setting of the lowpass filters
The electronic unit provides 2 lowpass filters independently adjustable from each
other. They are used to prevent noise which is added to the signals. Signal variations
which are faster than the cut-off frequency are then suppressed. The lower the cut-off
frequency, the more sluggish the output signal will be.
The lowpass filters are configured by setting its cut-off frequency to an appropriate
value. The cut-off frequency is set in the parameter
Lowpass display
and
Lowpass
feedback
(ref. to „14. Parametrisation“).
Note
If the cut-off frequency is set to a value too low, the output signal will become
sluggish. It may be that the feedback value is no longer suitable for control loop
applications. You have to pay attention that the cut-off frequency is set to a suitable
value.
