Siemens SINUMERIK 840D sl Commissioning Manual page 166

NCK start-up
10.5 Parameterize axis data
3. Assumption of the reference position in the NC
4. Enabling encoder calibration
5. Activate changed machine data by NCK reset.
6. Completing encoder calibration
The NC then calculates the reference point offset and enters it in the machine data:
● MD34090 $MA_REFP_MOVE_DIST_CORR[n] (reference point offset)
● MD34210 $MA_ENC_REFP_STATE[n] = 2
● MD34100 $MA_REFP_SET_POS[n] (reference point value)
Calibrating several absolute encoders
For time-optimized calibration of the absolute encoders of several machine axes, the
following procedure is recommended:
1. Depending on the machine design, move all or several machine axes to their reference
position. See above: Points 1 to 4.
2. Perform an NCK reset. See above: Point 5.
3. Complete encoder calibration for all machine axes. See above: Point 6.
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NOTICE
To avoid the actual position of the machine axis being falsified by backlash in the
drive train, reference point approach must be performed at low velocity and always
from the same direction.
The reference position is entered in the machine data:
– MD34100 $MA_REFP_SET_POS[n] (reference point value)
Encoder calibration is performed in the machine data:
– MD34210 $MA_ENC_REFP_STATE[n] = 1
When the NC has started up, encoder calibration is completed in mode: JOG > REF for
the machine axis by once more pressing the direction key as described in point 2:
– Select JOG > REF mode
– Select machine axis
– Press traverse direction key
Note
Pressing the traverse direction key does not move the machine axis!
To indicate that calibration has been completed, the value in the machine data changes
from 1 = enable encoder calibration to 2 = encoder calibrated:
The value from the machine data is shown as the actual position of the machine axis for
the current machine position on the user interface:
Commissioning Manual, 07/2007, 6FC5397-2AP10-3BA0
IBN CNC: NCK, PLC, drive