Siemens SINUMERIK 840D sl Commissioning Manual page 164

NCK start-up
10.5 Parameterize axis data
Determining the absolute offset
To determine the absolute offset between the measuring system zero point and the machine
zero, the following procedure is recommended:
1. Determining the actual position of the measuring system
● MD34090 REFP_MOVE_DIST_CORR = 0
1. Determine the absolute machine actual position
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
164
After two reference marks following one after the other (synchronized) have been
overtraveled, the actual position of the length measuring system can be read on the user
interface at "Actual position".
The absolute offset must be zero at this time:
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.
Commissioning Manual, 07/2007, 6FC5397-2AP10-3BA0
IBN CNC: NCK, PLC, drive