Siemens S7-300/S7-400 Function Block Diagram Programming Reference Manual

About this manual

This manual provides a complete guide to creating user programs with the Function Block Diagram (FBD) language for Siemens S7-300 and S7-400 programmable logic controllers. It is intended for S7 programmers, operators, and maintenance personnel who are familiar with automation technology and Windows‑based STEP 7 software.

The document includes a full list of FBD instructions, programming examples, safety information, online‑help usage, and contact details for technical support. It also references the applicable IEC 1131‑3 standard and the required STEP 7 version (5.3). This manual is written in Chinese.

What's inside

• Safety Guidelines
• Purpose and Scope
• Basic Knowledge Requirements
• Supported PLC Models
• STEP 7 Version Requirements
• Instruction Overview
• Programming Examples
• Online Help Integration
• Technical Support and Service

Specifications

Frequently asked questions

Which Siemens PLC models does this manual cover?

It covers the S7‑300 and S7‑400 programmable logic controllers.

What STEP 7 software version is required to use this manual?

The manual is intended for STEP 7 version 5.3.

Who is allowed to install and operate the equipment described in the manual?

Only qualified personnel who are authorized to follow safety practices may install and operate the equipment.

What standard defines the Function Block Diagram language used in this manual?

The FBD language is defined by IEC 1131‑3.