BY12512d_e.doc / Mai-08
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2.
Principle of operation
All operation is based on setting an "analogue synchronization" between the drives first. This
can be achieved by feeding a common speed reference voltage to the drives and tuning the
drive speeds in order to get them into an approximate synchronism. A ratio adaptation may be
necessary for the Slave drive, as shown in figure 1. This analogue pre-synchronization can
match the two speeds within an error range of approx. 1%.
Ratio Adjust
Master
Drive
Speed Reference
Slave
Drive
P1
P2
Fig 1
The digital synchronization now has to compensate for the analogue speed errors in order to
get an absolute, angular and positional synchronization with no drift and no cumulative
displacement of the motor shafts. This needs a digital feedback of the angular shaft position of
the drives. In general, incremental shaft encoders or equivalent signals (e. g. encoder
simulation from a resolver system) are used.
Encoder
Speed Reference
P1
V in
Master
Slave
Encoder
0-10V
0-10V
V out
A D
E1
E2
Fig 2
