ABB ACS 800 Series, Firmware Manual

Page: 104 / 340

Program features
104
The position can be moved to a predefined value using the Homing sequence . An
initial position value in mm can be entered in Par. 78.10 HOME POSITION to
initialize the actual position to the predefined value. The actual position is initialized
in the respective drives on completion of the homing sequence. Homing is possible
from EXT1 control location only. Therefore, after the homing sequence is done, the
control should be moved to EXT2 and a Synchro command given using Par.
10.14 .
Before the Synchro command is given, parameter 78.12 SYNC CORR MODE has to
be selected.
If an offset of position is required in the Follower, set parameter 78.12 to OFFSET
and activate the Synchro command in the Follower when it is at the required
position. The difference in the position between the Master and the Follower when
the Synchro command is activated is taken as a constant offset in this case.
If an offset is not required in the Follower, set parameter 78.12 to DIRECT and
activate the Synchro command in the Follower. The difference in the position
between the Master and Follower when the Synchro command is activated is taken
as the position error in this case. The position error will be calculated with the new
position value with respect to the actual Master position.
Example : Actual position value 02.21 is initialized with 1000 mm after a homing
sequence, and the drive is then moved to EXT2 control for synchronisation.
Consider the Master actual position received by Follower drive as 5000 mm. After a
Synchro command is given with parameter
78.12 SYNC CORR MODE as DIRECT,
the 02.23 SYNC POS ERROR will be (5000 … 1000) 4000 mm. If a Synchro
command is given with parameter 78.12 SYNC CORR MODE as OFFSET, the 02.23
SYNC POS ERR will be 0 mm, and the difference (5000 … 1000) 4000 mm will be
considered a permanent offset.