Position Correction - ABB ACSM1 Firmware Manual

56
Stop: linear axis
60.02 POS AXIS MODE
The figure shows how the dynamic limiter works
together with the position profile generator when the
drives are stopped: Before the stop command of the
master, the speed of the follower is limited by the
dynamic speed limiter
results in a position error. When the master starts to
decelerate, the follower uses positioning deceleration,
and, eventually, positioning speed to overcome the
position error.

Position correction

Homing
If an incremental encoder is used in position feedback, the drive actual position is set
to zero at power-up. Normally, before first homing, the actual position of the driven
machinery does not correspond to the internal zero position in the drive position
control. Homing establishes a correspondence between these two positions.
Because all homing functions use the same latching function, only one can be
performed at a time.
Homing is implemented according to the CANopen Standard Proposal 402 for
Device Profile Drives and Motion Control. The profile includes 35 different homing
sequences (see the following homing mode table and chapter
modes). The start direction and used latch signals depend on the selected homing
mode.
Homing sequence can be executed only in the homing control mode when the drive
is modulating. When homing is activated by the homing start signal, the drive
accelerates according to the active ramp time* to homing speed 1. The start
direction depends on the selected homing method and the status of an external latch
signal (home switch signal). During homing the direction can be changed by an
external latch signal. Homing speed 1 is maintained until an external latch signal for
homing speed 2 or for the home position is received. Homing is stopped with an
index pulse or switch signal from an external latch and drive actual position is set as
the zero position (or the user defined home position).
* Acceleration and deceleration ramp times are defined by the active position
reference set (see parameter group
Drive control and features
is set to (0) LINEAR.
(70.04 POS SPEED LIM), which
Speed
Master speed
STOP
Follower speed
A
70.04 POS SPEED LIM
Master speed
65 PROFILE REFERENCE
A = B
65.05 POS SPEED 1
65.13 POS SPEED 2
B
t
65.07 PROF DEC 1 /
65.15 PROF DEC 2
Appendix C – Homing
on page 204).
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