Fc3: Gp_Pral - Basic Program, Interruptdriven Section - Siemens SINUMERIK 840D sl Function Manual

P3: Basic PLC program for SINUMERIK 840D sl
13.17 Block descriptions
13.17.12

FC3: GP_PRAL - basic program, interruptdriven section

Function
Blocksynchronized transfers from the NCK to the PLC (auxiliary and G functions) are carried
out in the interruptdriven part of the basic program. Auxiliary functions are subdivided into
normal and highspeed auxiliary functions.
The highspeed functions of an NC block are buffered and the transfer acknowledged to the
NC. These are transferred to the application interface at the start of the next OB1 cycle.
Highspeed auxiliary functions programmed immediately one after the other, are not lost for the
user program. This is ensured by a mechanism in the basic program.
Normal auxiliary functions are acknowledged to the NC only after one completed cycle
duration. This allows the application to issue a read disable to the NC.
The G Functions are evaluated immediately and passed to the application interface.
NC process interrupts
If the interrupt is triggered by the NC (possible in each IPO cycle), a bit in the local data of
OB40 ("GP_IRFromNCK") is set by the basic program, when the FB1 parameter "UserIR": =
TRUE"). This data is not set on other events (process interrupts through I/Os). This information
makes it possible to branch into the associated interrupt routine in the user program in order
to initiate the necessary action.
To be able to implement highspeed, jobdriven processing of the user program for the machine,
the following NC functions are available in the interrupt processing routine (OB40 program
section) for the PLC user program:
● Selected auxiliary functions
● Tool-change function for tool-management option
● Position reached for positioning axes, indexing axes and spindles with activation via PLC
The functions listed above can or must be evaluated by the user program in OB40 in order to
initiate reactions on the machine. As an example, the revolver switching mechanism can be
activated when a T command is programmed on a turning machine.
For further details on programming hardware interrupts (time delay, interruptibility, etc.) refer
to the corresponding SIMATIC documentation.
Auxiliary functions
Generally, high-speed or acknowledging auxiliary functions are processed with or without
interrupt control independently of any assignment.
Basic-program parameters in FB1 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.
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions