Problematic Situations In The Determination; Of The Marker Distance - Danfoss VLT5000 SyncPos Operating Instructions Manual

■ ■ ■ ■ ■ Problematic situations in the determination of the
marker distance
If the marker is mounted so close to the proces-
sing point that there is no time left to correct the
synchronization after the marker has been detec-
ted, then you can remedy the problem only
through mechanical modification of the marker.
On the other hand, the same effect might also
occur if the marker distance is larger than the
master cycle length and if an insufficient distance
likewise remains after the subtraction of this value,
for example:
The value is entered into the buffer when the
marker appears. The buffer is read out only when
the next marker is recognized. This means that the
marker is only "recognized" at the master position
900 and that there is little time left in our example
to correct the error. It is the same effect as if the
sensor had been mounted at the value (distance –
master cycle length) or (4100 – 4000), respectively,
i.e. only 10 mm in front of the processing point.
Thus, it would be better to install the sensor in
such a way that the distance to the processing
point is either smaller or substantially larger than
one master cycle length; here, for example, at a
distance of 3900. Then it is possible to correct
from 2500 to 1000.
44
Programmable SyncPos motion controller
Alternatively, the sensor could be installed further
away, for example at a distance of 7900; this has
the same effect as if the sensor had been installed
at distance – master cycle length (7900 – 4000),
i.e. 3900 in front of the processing point. This
allows enough time to correct the synchronization.
If this cannot be done mechanically, then the
values must be manipulated somewhat in order to
avoid the solution with the buffer. Please proceed
as follows:
Subtract a value x from the actual distance so that
the distance becomes < than the master cycle
length, for example 4100 – 200 = 3900. You also
subtract the value x from the master position, i.e.
Stamping roller = Slave
1000 – 200 = 800.
Conveyor belt = Master
Enter both values in the index cards →
Master positions (1/100 mm)
"SYNCHRONIZATION" and → "CURVE DATA":
Master Marker Distance
SYNCMPULSM(58) = 3900
Master Marker Position = 800
Since no buffer is generated now, it would be
possible to correct from 2500 to 800, for example.
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