Position-Controlled Spindle Mode (Spcon, Spcof) - Siemens Sinumerik 840D sl Programming Manual

Feed control

8.3 Position-controlled spindle mode (SPCON, SPCOF)

Block step enable or program execution is not affected by POSA. The movement to the end
position can be performed during execution of subsequent NC blocks.
Travel with POS
The next block is not executed until all axes programmed under POS reach their end positions.
Wait for end of travel with WAITP
After a WAITP, assignment of the axis to the NC program is no longer valid; this applies until
the axis is programmed again. This axis can then be operated as a positioning axis through
the PLC, or as a reciprocating axis from the NC program/PLC or HMI.
Block change in the braking ramp with IPOBRKA and WAITMC
An axis is only decelerated if the wait marker has not yet been reached or if another end-of-
block criterion is preventing the block change. After a WAITMC, the axis starts immediately if
no other end-of-block criterion is preventing the block change.
8.3 Position-controlled spindle mode (SPCON, SPCOF)
Position-controlled spindle mode may be advisable in some cases, e.g. in conjunction with
large-pitch thread cutting with G33, where better quality can be achieved.
The SPCON NC command is used to switch over to position-controlled spindle mode.
Note
SPCON requires a maximum of three interpolation cycles.
Syntax
SPCON/SPCON(<n>)/SPCON(<n>,<m>, etc.)
...
SPCOF/SPCOF(<n>)/SPCOF(<n>,<m>, etc.)
Meaning
SPCON:
SPCOF:
108
Activate position-controlled mode
The specified spindle is switched over from speed control to position control.
SPCON s modal and is retained until SPCOF.
Deactivate position-controlled mode
The specified spindle is switched over from position control to speed control.
Number of the spindle to be switched over.
<n>:
If a spindle number is not specified, SPCON/SPCOF will be applied
to the master spindle.
SPCON or SPCOF can even be used to switch over multiple spin‐
<n>,<m>, etc.:
dles in one block.
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals