6.9 Redundant encoder
It is possible to set the position difference between the positioning encoder and a
redundant encoder. To do this, the channel of the redundant position encoder must
be specified in P 524[0] - ENC_EncRedPos and the maximum position tracking error
must be specified, in increments, in P 597[0] - ENC_RedPos_DiffMax. Monitoring is
not active if P 524[0] = 0 and the drive has been referenced. It is reset when the
associated error is acknowledged or homing is executed again.
P No.
Index Name
Unit Description
524
0
ENC_EncRedPos
Selection of the channel (1-3) with which the
position encoder is to be evaluated.
597
0
ENC_RedPos_DiffMax
inc
Maximum position tracking error setting
Table 6.34: Parameters for monitoring the position difference
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
100
6 Encoder
6.10 Axis correction
The position value delivered by the encoder system and the actual position value on
the axis may vary for a number of reasons. Such non-linear inaccuracies can be
compensated by axis error correction (using position- and direction-dependent
correction values). For this, a correction value table is filled with values for each of
the two directions. The respective correction value is produced from the current axis
position and the direction of movement by means of cubic, jerk-stabilized
interpolation. The position value is adapted on the basis of the corrected table. Both
tables contain 250 interpolation points.
The correction range is within the value range delimited by parameters
P 591 -
ENC_ACOR_PosStart
"Start position" and
P 592 - ENC_ACOR_PosEnd
"End
position correction". The start position is preset on the user side; the end position is
determined on the drive side.
Possible cause of deviations
l
Inaccuracy of the measuring system
l
Slack in mechanical elements such as the gearing, coupling, feed spindle
etc.
l
Thermal expansion of machine components.
