Siemens SINUMERIK 840D sl Function Manual page 1692

Detailed Description
2.5 Programming
Gear step change suppression
If a gear step change is suppressed, if necessary, the interpolator will limit the programmed
spindle speed to the permissible speed range of the active gear step.
NC/PLC IS:
DB31,... DBX83.2 (Setpoint speed increased)
and
DB31,...DBX83.1 (Setpoint speed limited) generated as a result of this limit
are suppressed.
Monitoring by the PLC program is not necessary during DryRun and in dry run feedrate.
When the gear step change is suppressed, no new gear step setpoint is output to the PLC
with NC/PLC IS:
DB31,...DBX82.0-82.2 (Gear step setpoint)
.
The gear step change request:
DB31,...DBX82.3 (Change gear)
is also suppressed.
This ensures that no gear step change information has to be processed by the PLC program.
Determining the last active gear step
System variable:
$P_GEAR
returns the gear step programmed in the part program (which may not have been output to
the PLC).
System variable:
$AC_SGEAR
can be used to read the last active gear step from the part program, synchronized actions
and operator panel interface.
The DryRun function can be deselected within a running part program. Once it has been
deselected, the correct gear step requested by the part program must be identified and
selected.
It cannot be assured that the remainder of the part program will run without errors until the
correct gear step has been activated. Any necessary gear step change is performed in the
system REPOS started on deselection if the spindle is in speed control mode. A complete
gear step change dialog takes place with the PLC and the last programmed gear step is
activated.
If there is a mismatch between the gear step programmed in the part program and the actual
gear step returned via the VDI interface with REPOS, no gear step change takes place.
The same applies to the SERUPRO function.
Further explanations regarding set search execution SERUPRO can be found under:
Literature:
/FB1/ Function Manual, Basic Functions; Mode group, Channel,
Program Mode (K1)
82
Basic logic functions: Spindles (S1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0