10.5.12.3 Absolute Encoders - Siemens SINUMERIK 804D sl Commissioning Manual

2. Calculating the absolute offset
• MD34090 REFP_MOVE_DIST_CORR (reference point/absolute offset)
Literature
Function Manual Basic Functions; Reference point approach: Referencing with length
measuring systems with distancecoded reference marks

10.5.12.3 Absolute encoders

Absolute encoders
Initial referencing of the measuring system of a machine axis with absolute encoder is
performed by calibrating the encoder.
Follow-up referencing
Follow-up referencing of a machine axis is performed automatically while the NC starts up
without axis movement. The following conditions must be fulfilled:
• The measuring system of the machine axis active after the booting of the NC works with
• The absolute encoder is calibrated:
Calibration
To calibrate the absolute encoder, the actual value of the encoder is matched with the
machine zero once and then enabled.
CNC Part 1 (NCK, PLC, drive)
Commissioning Manual, 11/2006, 6FC5397-2AP10-2BA0
Determining the absolute machine actual position, e.g., can be performed by traversing
the machine axis to a known position (fixed stop). Alternatively, it can be measured at any
position (laser interferometer).
Linear measurement system non-inverse to machine system:
Absolute offset = machine actual position + actual position of the measuring system
Linear measuring system inverse to machine system:
Absolute offset = machine actual position - actual position of the measuring system
Warning
After you have determined the absolute offset and made an entry in
• MD34090 REFP_MOVE_DIST_CORR (absolute offset)
the position measuring system must be re-referenced.
the absolute value encoder
MD34210 ENC_REFP_STATE[n] = 2 (absolute value encoder is calibrated)
NCK start-up
10.5 Parameterize axis data
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