Siemens SINUMERIK 840C - Manual (Page 854)

11.92 12 Functional Descriptions
12.11.1 SIPOS absolute encoder up to SW 4
Comments
• NC MD 1808* bit 3: – Software limit switch and leadscrew error compensation are
enabled.
– The leadscrew error between the reference point and the
absolute position are included in the calculation.
• Reference point approach with a SIPOS absolute encoder is only possible when NC MD
1808* bit 3 has been reset.
• Information as to whether the SIPOS absolute encoder is in the same or opposite
direction as the machine system is required by the control for calculating the absolute
value without reference point approach. Once the SIPOS absolute encoder has been
synchronized it is very easy to determine the direction of the SIPOS absolute encoder.
This is done by traversing the axis concerned to any desired position and starting up the
control.
If, after setting up, positive approach and POWER ON, a larger absolute encoder value is
displayed, the system is in the same direction and does not have to be corrected. If a
smaller absolute encoder value is displayed, NC MD 1808* bit 2 = 1 must be set. The
correct position is then displayed after the next POWER ON.
• If the mechanical traverse direction is changed with NC MD 564*, NC MD 1808* bit 2
must also be adapted correspondingly.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–79
SINUMERIK 840C (IA)