Technical data

VLT 5000/5000 FLUX SyncPos Quick-Setup
MG.10.Q1.5B – VLT is a registered Danfoss trade mark14
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■ Optimizing your controller settings
step-by-step
For best results use the functions in the
testruntestrun
testruntestrun
testrun
menu for this purpose; these help you to evaluate
and optimize the PID controller on the basis of
graphs of the set and actual curves.
However, we recommend only changing one value
at a time and subsequently determining the im-
provement with a testrun
..
..
.
Click on "CONTROLLER" → "PARAMETER" →
"AXIS" and select the VLT, of which you are
currently adjusting the settings.
Setting controller behavior
Before you adjust the controller parameters it is
important to determine which controller behavior
should be achieved.
NB!
The drive elements must never be operated
outside of the technical specifications. Thus
the maximum acceleration is determined by the
“weakest” drive element.
• “Stiff” axis: the fastest reaction possible is
mainly influenced by the
Proportional factorProportional factor
Proportional factorProportional factor
Proportional factor.
You can judge the results on the basis of the
velocity graph.
• Damping of vibrations are mainly influenced
by the
Derivative factorDerivative factor
Derivative factorDerivative factor
Derivative factor. The results can best
be assessed in the velocity graph.
• Temporary (static) deviations in position are
mainly reduced by the
Integral factorIntegral factor
Integral factorIntegral factor
Integral factor and
can best be judged on the basis of the posi-
tioning graph.
Ten steps to optimise the PID loop
The following procedure will optimize your control-
ler settings in most applications:
1. Make sure that you have specified correct
values for VLT parameter #205, as well as the
SyncPos parameters VELMAX (1), ENCODER
(2) and RAMPMIN (31). If you change these
settings again at a later point you may need to
optimize the controller again.
2. Set the POSERR (15) parameter to a very high
value e.g. 1000000 to avoid getting the option
error no. 8 during the following tests.
NB!
To avoid damaging the system, make sure, that
you set the POSERR within the limits of the
system.
3. Optimize the
Velocity feed-forwardVelocity feed-forward
Velocity feed-forwardVelocity feed-forward
Velocity feed-forward control:
Auto feed-forward calculation:
The FFVEL can be calculated hence it is not
needed to perform a testrun to optimise the
FFVEL. For VLT 5000 process the following
formula applies:
FFVEL = (62914560000 * P104) / (Vnom * Eres
* Tsample * P205)
P104: Denotes the value of the VLT 5000
parameter 104 (nameplate motor frequency)
P205: Denotes the value of the VLT 5000
parameter 205 (maximum reference)
Vnom: Is the nominal encoder velocity at
nominal motor frequency. The unit is RPM.
Eres: Is the number of quad-counts per
encoder revolution. If an absolute encoder is
used the unit is steps (positions) per revolution.
Tsample: Is the PID controller sampling interval
(TIMER).
For VLT 5000 Flux the following formula
applies:
FFVEL = (62914560000 / Eres * Tsample *
Vmax)
Eres: Is the number of quad-counts per
encoder revolution. If an absolute encoder is
used the unit is steps (positions) per revolution.
Tsample: Is the PID controller sampling interval
(TIMER).
10 steps to optimise the PID loop