181
MG.10.J8.02 – VLT is a registered Danfoss trade mark
Programmable SyncPos motion controller
Start correction
only if SYNCMFTIME > 0
Start correction is the correction we have to realize
after start condition is fulfilled. That means either we
observed the first two markers (SYNCMSTART 1,6) or
we reached master velocity and have observed the
first two markers (SYNCMSTART 2,3,4,5). This start
correction is split in such a way, that it will be elimi-
nated after SYNCOFFTIME. (Actually its divided by
the amount of markers, which will be passed in
SYNCOFFTIME at the actual master velocity and
that value is added to the normal marker correction.
If SYNCOFFTIME == 0, Start correction will be
eliminated at once, which means that the correction
will be done in between two markers.
Marker correction
SYNCMFTIME > 0
From SyncPos PC-Software version 5.04 onwards:
First we take the marker error and subtract the
remaining start correction. Then we set correction
filtering time corresponding to the SYNCOFFTIME
(master velocity dependant see start correction
number of markers).
Now we put the sum of all marker distance errors
into a marker filter to calculate the filtered sum. Then
we subtract the filtered error sum from the unfiltered
one. This result is then used to correct the marker
correction.
This corrected correction is then given into the
correction filter. The result of this correction filter is
then stored (plus start correction part if necessary).
Then we try to spread this correction over one mar-
ker distance. This is done by dividing the correction
by the number of samples which will be necessary
to pass one marker distance at actual master speed.
This value is stored and will be used every sample
time to correct the calculated slave position.
Following SYNCMFPAR settings modify behavior:
SYNCMFPAR & 4
➜
correction time is used instead
of using SYNCOFFTIME.
SYNCMFPAR & 16
➜
We don’t make the correction
concerning the error of marker
distances.
Marker correction
SYNCMFTIME == 0
In the first case where marker correction > 0, we
spread the correction over a time of
(-SYNCVFTIME / 100) ms.
In the second case we add the correction to our
demand position at once.
The reaction of course is limited by the actual
acceleration and deceleration in every case.
Parameter Group
AXS Synchronization
(It is not yet in the parameter dialog window.)
Unit
1 ms
Value range
–MLONG … MLONG
★
0
0 = If SYNCVFTIME (65) is negative,
the marker correction is spread by
SYNCVFTIME /100
Parameter Reference
