Technical data

11.2 PG Functions
Note
The terms used in this section for the PG functions may in some
cases differ from the terms in your PG software.
Please refer to your STEP 5 manual.
Calling and using functions How to call and use the individual PG functions is described in the
STEP 5 manual.
Execution The PG functions are executed at defined points in the programmable
controller. There are points in the system program (= system
checkpoints) and points in the user program (= user checkpoints).
System checkpoints In the STOP mode there is the system checkpoint "stop" that is called
regularly.
In the RUN mode there is the system checkpoint "
cycle" that is called
at the end of the program processing level CYCLE before the process
image is updated.
If the CPU is in the WAIT state, the system checkpoint "
wait state" is
called regularly.
There is also a time-dependent system checkpoint "
asynchronous".
This system checkpoint is inserted asynchronously during program
execution.
User checkpoints In the test functions STATUS and PROGRAM TEST, user
checkpoints are used. A user checkpoint is called when a command is
executed that is marked accordingly by the PG.
11
PG Functions
CPU 928B Programming Guide
C79000-B8576-C898-01
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