Siemens SINUMERIK 840D sl Function Manual page 1757

2.3.5 Dry run feedrate
Application
The dry run feedrate is used when testing part programs without machining the workpiece in
order to allow the program or program sections to execute with an increased path feedrate,
for example.
"Dry run feedrate selected" DB21, .... DBX24.6
The dry run feedrate can be activated from the PLC or the operator panel.
When activated from the operator panel, interface signal "Dry run feedrate selected" (DB21,
... DBX24.6) is set and transferred by the PLC basic program to interface signal "Activate dry
run feedrate" (DB21, ... DBX0.6).
When selected on the PLC, the "Activate dry run feedrate" interface signal is required to be
set by the PLC user program.
The execution of the program is triggered with G94.
The dry run feedrate also takes precedence over the feedrates for G93,G95 and
G33,G34,G35.
In this case, the programmed feedrate is compared to the dry run feedrate in:
SD42100 DRY_RUN_FEED
and the axis is then traversed at the higher of the two feedrates.
Dry run feedrate change "Dry run feedrate active" DB21, .... DBX318.6.
The dry run feedrate (SD42100 DRY_RUN_FEED = 1) can be changed via the operator
panel in the operating area "Parameters".
The interface signal "Dry run feedrate active" (DB21, ... DBX318.6) is set if the selection has
been accepted by the NCK. DRY is displayed in the operator panel status bar to indicate an
active dry run feedrate if
• selection takes place when the program stops at the end of a block or if the machine data
• MD10704 DRY_RUN_MASK = 1 has been set during execution of the program.
If MD10704 DRYRUN_MASK = 0 has been set a dry run feedrate may only be activated/
deactivated at the end of a block.
If the dry run feedrate is no longer selected, the interface signal "Dry run feedrate active"
(DB21, ... DBX318.6) is reset.
Basic logic functions: Feeds (V1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.3 Feedrate control
41