Siemens SINUMERIK 840D Function Manual page 808

S1: Spindles
18.4 Configurable gear adaptations
Bit 1 = 1
DryRun, program testing and SERUPRO
Bit 2 = 0
Bit 2 = 1
Sequence
If a gear stage change is suppressed, if necessary, the interpolator will limit the programmed
spindle speed to the permissible speed range of the active gear stage.
NC/PLC interface signals 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 stage change is suppressed, no new gear stage setpoint
(DB31,... DBX82.0-82.2) is output to the PLC.
The gear stage change request DB31, ... DBX82.3 (change gear) is also suppressed.
This ensures that no gear stage change information has to be processed by the PLC program.
Determining the last active gear stage
System variable $P_GEAR returns the gear stage 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 stage from the part
program, synchronized actions and at the user interface.
Behavior after deselection
The DryRun function can be deselected within a running part program. Once it has been
deselected, the correct gear stage 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 stage has been activated. Any necessary gear stage change is performed in the
system REPOS started on deselection if the spindle is in speed control mode. A complete gear
stage change dialog takes place with the PLC and the last programmed gear stage is activated.
If, for REPOS, there is a mismatch between the gear stage programmed in the part program
and the actual gear stage supplied via the NC/PLC interface, then no gear stage change takes
place.
The same applies to the SERUPRO function.
For further explanations regarding the block search SERUPRO, see:
Further information
G2: Velocities, setpoint / actual value systems, closed-loop control (Page 31)
808
For active program test / SERUPRO function - for part program blocks - a gear stage
change is suppressed with M40, M41 to M45, programming via FC18 and synchronized
actions.
Gear stage change for programmed gear stage is not performed subsequently on REPOS
after deselection of functions DryRun, Program Test and SERUPRO.
Gear stage change for programmed gear stage is performed after deselection of functions
DryRun and SERUPRO if possible.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA