Technical data

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MG.10.Q1.5B – VLT is a registered Danfoss trade mark
VLT 5000/5000 FLUX SyncPos Quick-Setup
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■ Commissioning Guideline
When the APOS user program is written and it is
time to impelment it in a given application it is a
godd idea to have a plan of attack. Below is a list
with 10 steps to success with SyncPos. It does
not make sense to download the APOS user
program and run the machine before the VLT and
SyncPos parameters are correctly set. If
something goes wrong during commissioning the
troubleshooting guideline can be used to assist in
the faultfinding.
1. Setup of VLT parameters (AMA)
2. SyncPos PC software installation and starting
3. Setup of serial communication
4. Setup of SyncPos parameters
5. Check encoder connection and direction of
rotation
6. Execute testrun via SyncPos PC software
7. Optimise PID controller of SyncPos
8. Install software (APOS user program)
9. Test functionality of user program
10. SUCCESS
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■ How the control process works
The "TESTRUN" explained in the chapter
PC Software Interface of the SyncPos manual
found on the CD can be used as a tool to opti-
mize the SyncPos controller settings, thereby
optimizing your system performance. To do that
you only need to know a few things about the
control scheme of SyncPos:
The SyncPos position controller has two parts:
1. The Setpoint Generator interprets the various
positioning commands in SyncPos and gene-
rates a series of setpoint positions that even-
tually ends with the desired position.
Normally, all positioning processes have a
trapeze-shaped velocity curve. That means
that after a phase of constant acceleration
there is a phase with constant velocity and
finally a phase with constant deceleration,
which ends at the desired target position.
2. The PID controller receives the setpoint posi-
tions from the Setpoint generator and in turn
calculates the speed reference needed for
the motor to follow the current setpoint
position.
By setting the PID control parameters you
can directly influence to what degree and ■
Significance and influence of the control
parameters
quickly a deviation from a theoretical set path (as
specified by the setpoint series) should be
counteracted.
The following behavior indicate that the control para-
meters are not optimally adjusted:
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• Drive vibrates
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• Drive is loud
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• Frequent occurrence of position errors
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• Poor control accuracy
NB!
The control parameters are load-dependent.
Thus the drive must be optimized under the
actual conditions of use.
In exceptional cases it may be necessary to deter-
mine various sets of control parameters while wor-
king with heavily changing load conditions and to re-
program them in subsequent application programs
depending on the motion process.
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■ Significance and influence of the control
parameters
The PID control unit of the SyncPos option transfers
the necessary output frequency via an internal
speed reference to the VLT. This set value is periodi-
cally re-calculated with an interval of one millisecond
(interval is programmable by the TIMER parameter).
The SyncPos option is by default set with soft 'fit for
all' controller parameters.
The PID filter works according to the following
formula:
① = FFVEL * (Setpoint velocity)
② = FFACC * (Setpoint acceleration)
③ = KPROP * (Position deviation)
④ = KINT * (Sum of all previous position devia-
tions) (limited by KILIM)
⑤ = KDER * (Velocity of position deviation)
⑥ = ③ + ④ + ⑤
(limited by BANDWIDTH)
10 steps to optomise the PID loop