Position Control; Synchron Control; Homing Control - ABB ACSM1 Firmware Manual

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Position control

In position control, the load is positioned along a single axis from the start position to
the defined target position. A position reference is given to the drive to indicate the
target position. The path to the target position is calculated by the position profile
generator, controlled by position reference sets.
Position feedback (encoder or resolver) must always be used in position control to
determine the actual position of the load. The same encoder can also be used to
provide speed feedback. It is also possible to have separate encoders for the load
(position feedback) and motor sides (speed feedback).
Note: It is emphasised that all position relevant parameters are load side related,
e.g. the setting of parameter
limitation) of 300 rpm denotes that, with a load gear ratio of 1:10, the motor can run
at up to 3000 rpm.
If the actual position exceeds the defined minimum and maximum position limits,
fault POSITION ERROR MAX / POSITION ERROR MIN is created. The actual
position monitoring is active in position, synchron, homing and profile velocity modes
if the drive is enabled.

Synchron control

Synchron control is used to synchronise several mechanical systems (axes). The
control is similar to position control, but in synchron control the position reference is
taken from a moving target via an encoder, the master drive, the PLC, or from the
virtual master function.
Position feedback (encoder or resolver) must always be used in synchron control to
determine the actual position of the load.
Mechanical slippage etc. can be compensated using the cyclic correction functions.
Note: Synchron control is not available in local control mode.
Virtual master function
With the virtual master function, a physical master drive or PLC is not needed in a
synchron-controlled follower. The follower will generate its own synchron reference
by converting the speed reference selected by parameter
M into a position reference by integration.

Homing control

Homing establishes a correspondence between the actual position of the driven
machinery and the drive internal zero position.
An encoder must always be used in homing control.
See section
Note: Homing control is not available in local control mode.
Drive control and features
70.04 POS SPEED LIM
Position correction on page 56.
(dynamic limiter speed
67.02 SPEED REF VIRT