Siemens SINUMERIK 840D sl Function Manual page 1452

Detailed description
2.12 Block descriptions
Auxiliary functions
Generally, high-speed or acknowledging auxiliary functions are processed with or without
interrupt control independently of any assignment.
Basic-program parameters in FB 1 can be set to define which auxiliary functions (T, H, DL)
must be processed solely on an interruptdriven basis by the user program.
Functions which are not assigned via interrupts are only made available by the cyclic basic
program as in earlier versions. The change signals of these functions are available in a PLC
cycle.
Even if the selection for the auxiliary function groups (T, H, DL) is made using interrupt
control, only one interrupt can be processed by the user program for the selected functions.
A bit is set channelspecifically in the local data "GP_AuxFunction" for the user program (if
"GP_AuxFunction[1]" is set, then an auxiliary function is available for the 1st channel).
The change signals and function value are available to the user in the associated channel
DB. The change signal for this interruptdriven function is reset to zero in the cyclic basic
program section after the execution of at least one full OB1 cycle (max. approx. two OB1
cycles).
Tool change
With the tool-management option, the tool-change command for revolver and the tool
change in the spindle is supported by an interrupt. The local data bit "GP_TM" in OB 40 is
set for this purpose. The PLC user program can thus check the tool management DB (DB 72
or DB 73) for the tool change function and initiate the tool change operation.
Position reached
In the bit structure, "GP_InPosition" of the local data of OB 40 is specific to the machine axis
(each bit corresponds to an axis/spindle, e.g., GP_InPosition[5] corresponds to axis 5).
If a function has been activated via FC 18 (spindle control, positioning axis, indexing axis) for
an axis or spindle, the associated "GP_InPosition" bit can be used to implement
instantaneous evaluation of the "InPos" signal of the FCs listed above. This feature can be
used, for example, to obtain immediate activation of clamps for an indexing axis.
Declaration
FUNCTION FC 3 : VOID
//No parameters
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Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0