Program Execution - ABB 07CR41 Operating Manual

1.3.2

Program execution

Advant Controller AC 31 / Issued: 01.99
The basic unit microprocessor ensures the cyclic execution of the user program as shown in
Figure 4.
The internal processing:
- PLC monitoring and control
- operating and test functions
is executed in parallel with the previously described cycle.
The execution duration of a cycle (bus cycle + program cycle) is controlled by the basic unit.
Any excess of the cycle time defined by the user is signaled by the ERR LED at the front of the
basic unit.
Read inputs
RUN
Program processing
Write outputs
Communication along the
CS31 system bus
Figure 4: The program execution cycle
STOP
Forcing the outputs
to 0
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