Siemens SINUMERIK 828D Function Manual page 635

Boundary conditions
Retracting the tool in JOG mode
Once the tool has been retracted in the JOG mode, axes whose positions have been restored are referenced.
For further details, see also machine data:
• MD20700 $MC_REFP_NC_START_LOCK
• MD34110 $MA_REFP_CYCLE_NR
Note
If machine data MD20700 $MC_REFP_NC_START_LOCK is set to a value of "2", then an
NC start is also possible with "restored" axis positions (in the MDI mode or when
overstoring).
Axes with incremental encoders and without actual value buffering
It is to be assumed that axes with incremental encoders and without actual-value buffering are clamped with
sufficient speed in the event of a power failure to prevent them drifting from their last position setpoint.
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
K1: Mode group, channel, program operation, reset response
9.14 System settings for power-up, RESET/part-program end
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