The peripheral outputs are forced byte by byte.
In multiprocessor operation, you can force all peripheral outputs
(regardless of the peripheral assignment in DB 1).
Timeout errors that occur are detected when outputs are changed (PG
message "I/O module does not exist").
Terminating the function
You can terminate the function by pressing the <BREAK> key on the
PG. The disable output command signal is active again (i.e., the
"BASP" LED is on). The function also ends if the CPU goes into the
RUN mode between calling the function and actually forcing outputs.
Force variables
You can call the "force variables" function to look at the values of
operands (process variables) in the process image table and change
them. You can use this function in the RUN and soft STOP modes and
within the "program test" function. You can display the following
process variables: inputs, outputs, flags, timers, counters and data
words.
Special features
Any change becomes effective at the next system checkpoint, i.e.
regardless of the system checkpoint (start of cycle or end).
Note that the forced values can be overwritten again (e.g. by the user
program or by the process image updating).
Note
The PG forces process variables in bytes.
If you are forcing several operands, the bytes are changed in
memory one after the other distributed over several cycles.
PG Functions
CPU 948 Programming Guide
C79000-G8576-C848-04
11 - 15
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