Siemens SINUMERIK 840Di Function Manual page 1083

NC process alarms
If the interrupt is triggered by the NC (possible in each IPO cycle), a bit in the local data of
OB 40 ("GP_IRFromNCK") is set by the basic program. (only if FB 1 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, job-
controlled processing of the user program for the machine, the following NC functions are
available in the interrupt processing routine (OB 40 program section) for the PLC user
program with SW 3.2 and higher:
• Selected auxiliary functions
• Tool-change function for tool-management option
• Position reached for positioning axes, indexing axes and spindles with activation via PLC
• Block transfer to FM (function available soon)
The functions listed above can or must be evaluated by the user program in OB 40 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 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 interruptcontrolled function is reset to zero in the cyclical
basic program section after the execution of at least one full OB1 cycle (max. approx. two
OB1 cycles).
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Detailed description
2.12 Block descriptions
2-171