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5.
Principle of Operation
5.1.
Synchronization
The Synchro controller receives full positional information about the master axis by means of
the Master encoder. This incremental information can be scaled by means of the
Master Scaling Factor (subsequently named Factor1). From this information the unit can
calculate an analog speed output signal which is necessary to make the Slave axis exactly
follow to the Master.
The feedback of the actual position of the Slave axis is given by the Slave encoder. This
information uses a separate impulse scaling by means of the Slave Scaling Factor
(subsequently named Factor2).
Master position and Slave position are compared continuously, and the analog output is
updated correspondingly within very short cycle times of only about 100 µs. As a result, both
positions can be kept inside an error window of typ/- 5 encoder increments (e.g. the
Slave may lead or lag the Master by a few encoder increments, but will never loose position)
It is easy to understand, that this kind of positional and angular synchronization includes at the
same time error-free speed synchronization of Master and Slave.
When we move the Master forward or reverse by a distance “d
Master
”, at the same time the
Slave will move forward or reverse by a distance “d
Slave
”, under consideration of the impulse
scaling factors Factor1 and Factor2. In general Factor1 is the parameter to change the speed
ratio, and Factor2 is considered as a machine constant.
With most of the applications it is desirable to have proportional characteristics of Factor1, i.e.
we like to increase the Slave speed when we increase Factor1.
Some application however may require reciprocal characteristics (e.g. when we use the unit for
a rotary cutter application where Factor1 is used to set the cutting length. In this case, higher
setting requires lower Slave speed, i.e. Factor1 has to operate reciprocally.
Both, proportional and reciprocal characteristics can be selected by parameter. Depending on
these settings, the distances (and also the speeds) follow to one of the formulae below:
Proportional Operation:
Reciprocal Operation:
