Functions Of The Basic Program Called From The User Program - Siemens SINUMERIK 840D sl Function Manual

P3: Basic PLC program for SINUMERIK 840D sl
13.10 Structure and functions of the basic program
13.10.7

Functions of the basic program called from the user program

General
In addition to the modules of the basic program, which are called at the start of OB1, OB40
and OB100, functions are also provided which have to be called and supplied with parameters
at a suitable point in the user program.
These functions can be used, for example, to pass the following jobs from the PLC to the NCK:
● Traversing concurrent axes (FC18)
● Start asynchronous subprograms (ASUBs) (FC9),
● Select NC programs (FB4)
● Control spindle (FC18),
● Read and write variables (FB2, FB3)
Note
Checking and diagnostics of a function call of the basic PLC program
To simplify the checking and diagnostics of a function call (FB or FC) of the basic PLC
program that is controlled via a trigger (e.g. via Req, Start parameters) and that provide an
execution acknowledgement as output parameter (e.g. via Done, NDR, Error parameters),
proceed as follows.
A variable compiled of other signals which produce the trigger for the function call should
be set. Start conditions may be reset only as a function of the states of parameters Done,
NDR and Error.
The appropriate control mechanism can be placed in front of or behind the function call. If
the mechanism is placed after the call, the output variables can be defined as local variables
(advantage: Reduction of global variables, markers, data variables and time-related
advantages over data variables).
The trigger parameter must be a global variable (e.g. marker, data variable).
Jobs that are still active must be reset from the user program in OB100 (Req, Start,
parameters,
etc. from TRUE ⇒ FALSE). A POWER OFF/ON could result in a state in which jobs are still
active.
Concurrent axes
The distinguishing features of concurrent axes are as follows:
● They must be defined as such via the NC machine data.
● They can be traversed either from the PLC or from the NC by means of the JOG keys.
● Starting from the PLC is possible in the NC operating modes MDI and AUTOMATIK via FC.
● The start is independent of NC block boundaries.
Function calls are available for positioning axes, indexing axes and spindles (FC18).
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions