Operating instructions

04/08 Application manual Positioning 85
4.7 Electronic gear
Electronic gears are used in many plants where a synchronous operation, either
continuous or for a limited period of time, of several drives is required. The function
includes:
−
Activation/deactivation of synchronization of several drives at any time during
operation.
−
Adjustable ratio of different gear factors between master and slave.
− Parameterizable signals for feedback "In Gear".
− Synchronization of slave drive with master drive via system bus or encoder in-
puts.
−
Combination of electronic gear with positioning modes possible
Note: If two encoders (motor encoder and position encoder) are used, the
function "Electronic Gear" can only be used via system bus.
Typical applications include:
−
Belt conveyors
Example: Several belt conveyors are connected in series mechanically. The mate-
rial is transferred from one conveyor to the next which conveys it at the same
speed. The different motor gears are compensated in the internal calculation in
the slave.
−
Hoisting applications
Example: A material elevator is driven by 2 motors on the left and right side. For
safety reasons (redundancy) and in order to save space and reduce costs, two
identical small motors are used instead of one large motor. Synchronous opera-
tion prevents tilting of the platform.
4.7.1 Master position source
The following operation modes are available for selecting the source of the signal for
positioning in combination with the electronic gear function. Via parameter
Master
Position Source
1122, the operation mode is selected.
Master Position Source
1122
Function
0 - Off No source selected.
1 - Encoder 1
The current speed and position of the master drive is
taken over from encoder input 1.
2 -
Encoder 2 /
Resolver
The current speed and position of the master drive is
taken over from encoder input 2 or resolver.
11 -
RxPDO1.Long1
extrapolated
The current position of the master drive is taken over by
the process data channel RxPDO1.Long1 of the system
bus. Additionally, the data received are extrapolated,
even for slow settings of TxPDO Time of the master.
Depending on the application, select a setting of the cor-
responding TxPDO.Long of the master:
−
"606 – Act. Position (16/16)", mechanical position of
master drive.
−
"620 – motion profile gen.: Ref. Position", reference
position of master drive; advantage: improved control-
ler properties
Application manual Positioning 8504/08