PLC Subroutines Manual
6FC5397-0FP40-0BA0, 08/2013
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You can right-click over an instruction or directly press the F1 key to view its help information. For example:
2.3
Data management
The data can be broken down into three areas:
●
non-retentive data
●
retentive data
●
machine data for the PLC (this machine data is all active at POWER ON)
Most data, such as the process image, timers, and counters are non-retentive and are cleared each time the control system
is restarted.
For the retentive data, there is a data range of 1400 0000 -1400 0127. This location can be used to save all the data which is
to remain valid after POWER OFF/ON.
With the aid of the PLC-MD (see user interface), you can pre-assign your program with data or parameterize various parts of
the program.
2.4
Program organization
When programming the PLC, you must structure your program into finished program parts (subroutines). The programming
language for S7-200 offers you the capability to set up your user program in a structured manner.
There are the following two types of programs:
●
The main program
●
The subroutine.
Eight levels of programming are possible.
