Siemens 020-011 用户手册

Industry Sector, IA&DT

SCE Training Curriculum

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To be used only in Educational and R&D Facilities

TIA Portal Module 020-011, Edition 04/2014

SCE_EN _020-011_R1404_Startup Programming with SIMATIC S7-1500

5.7

What do logic operations look like in the PLC program?

Logic operations are used to specify conditions for switching an output.
In the PLC program, these conditions can be generated with the programming languages ladder

diagram (LAD) or function block diagram (FBD).

For reasons of clarity, we are using the FBD.

A large number of logic operations is available that can be used in PLC programs.

The AND as well as the OR logic operation and the NEGATION of an input are primarily used and will be

briefly explained below using examples.

Note: Information regarding additional logic operations is available quickly and clearly arranged in Online

Help.

5.7.1 AND Logic Operation

Example of an AND logic operation:

A lamp is to be lit when two switches are operated simultaneously as NO contact.

Circuit diagram:

Explanation:

The lamp is lit exactly when both switches are operated; i.e., if switches S1 and S2 are operated, lamp

P1 is lit.

24V