Specifications

PSU - 12 Positioning Drive Setup Ver. 0002
PSU.5.3 ABSOLUTE FEEDBACK
The absolute feedback on Fagor FXM motors registers the value of their angular position along
more than 4000 turns and it does not lose it when turning the machine off. Thus, the drive
knows from the very first instant which is the absolute position of that axis.
To place the machine zero at a particular point of the axis travel, proceed as follows:
• Take the axis to the point selected as zero.
• Read the PV51 -S51- PositionFeedback1 variable
• Set parameter PP177 -S177- AbsoluteDistance1 with the value read in PV51.
PSU.6 BALLSCREW BACKLASH COMPENSATION
When the position feedback is obtained on the motor shaft, the ballscrew backlash must be
compensated for.
Feedback on the motor.
The drive can compensate for any backlash between the load and the ballscrew by internally
acting upon the position command. Thus correcting the movement hysteresis originated when
reversing the direction of the axis.
Set this parameter:
PP58 -S58- Backlash
This ballscrew backlash compensation only takes place if:
• the Drive is in position control mode and
• there is no feedback on the load.
Warning: Both the drive and the CNC offer parameters setting the value of ballscrew
backlash. This value must ONLY be registered AT ONE OF THEM. The other
parameter must be set to "0".
Load
Ball-screw
Backlash