Program Testing - Bosch CL300 Manual

Software Description
Ladder Diagram LD
5.5.3

Program Testing

Forcing
5−28
If required, the IL can be printed with symbol or line annotations or both.
Derived from the circuit diagram, the ladder diagram is a graphic repre
sentation of the program. The connections between input and output
signals are shown by means of contact symbols.
The ladder diagram is subdivided into program branches. Each program
branch can have any number of texts allocated to it. Following each ter
minating operation, a new branch is opened.
Signal flow is from left to right. Up to 7 contact symbols may be used in
series.
Program testing is performed directly on the CL300 Programmable Con
troller.
Program testing permits to check the link conditions of the individual cir
cuit paths for their logic function through the status indications of the in
put and output signals.
The interrupt stack allows extensive diagnostic functions to be per
formed.
The test mode allows forcing of inputs/outputs and of interface inputs/
outputs.
Forcing is performed with the programming unit. It is signalized by the
special marker SM 31.4 and can be evaluated in the controller program.
The selected signal is allocated a defined state of 1" or 0", independent
of its state.
As long as a signal is forced, the LED display FIX" of the ZE front panel
lights.
The complete forcing mask on the central processing unit is cleared and
the forcing markers are reset by pressing the Reset Fix" button on the
central processing unit.
Flexible Automation