Siemens SINUMERIK 840D Function Manual page 164

V1: Feedrates
5.4 Feedrate control
Activation
The dry run feedrate can be selected in the automatic modes and activated from the PLC or the
operator panel front.
When activated from the operator panel front, the interface signal:
DB21, ... DBX24.6 (dry run feedrate selected)
is set and transferred from the basic PLC program to the interface signal:
DB21, ... DBX0.6 (activate dry run feedrate).
When selected on the PLC, the interface signal DB21, ... DBX0.6 (activate dry run feedrate)
must be set from the PLC user program.
Effectiveness
As long as the "Activate dry run feedrate" interface signal is set, instead of the programmed
feedrate, the feedrate value set via SD42100 DRY_RUN_FEED is effective in the way specified
via SD42101 $SC_DRY_RUN_FEED_MODE (see parameterization):
The dry run feedrate is always interpreted as linear feedrate (G94).
Parameterization
Activation of dry run feedrate
The time of activation depends on the setting in the machine data:
MD10704 $MN_DRYRUN_MASK (activation of dry run feedrate)
Value
0
1
2
Changing the dry run feedrate
The feedrate for the dry run is entered in the setting data:
SD42100 $SC_DRY_RUN_FEED (dry run feedrate)
The setting data can be changed via the operator panel front in the "Parameters" operating
area.
If the selection has been accepted by the NC, the following NC/PLC interface signal is set:
DB21, ... DBX318.6 (dry run feedrate active)
164
Meaning
The dry run feedrate may only be switched on and off at the end of the block (default setting).
The dry run feedrate can also be activated during the program processing (in the part pro‐
gram block).
Notice:
Activation during processing triggers an internal reorganization operation on the controller
which causes the axes to be stopped for a short time. This can affect the surface finish of the
workpiece being machined.
The dry run feedrate can be activated/deactivated at any time without the axes being stop‐
ped. The function only takes effect with a block "later" in the program run.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA