3.4.1. Overview of the program components

The STEP7 program of the S7 controller consists of the program components:

Both program components are always loaded during measurement.

Measuring program

The measuring program is composed of:

Load program

The load program does not perform specific tasks, it is only used for loads for the S7 controller. Different load programs cause different cycle times of the S7 controller.

The following table gives an overview of the elements belonging to STEP 7 program:

STEP 7 program component Tasks in the sending station Tasks in the receiving station
Measuring program Communication program Sending of data (in OB1) Receiving of data (in OB1)
Acquisition program for measured values - Waiting for the start signal
- Measuring the cycle time
- Measuring the cycle time
- Generating the ready signal
Load program No concrete task; is used for loads for the S7 controller (in OB1) No concrete task; is used for loads for the S7 controller (in OB1)

 

Composition of the cycle time

The figure below shows the structure of the STEP7 programs and the cycle time in the S7 CPU: