SIMATIC Function Block Diagram (FBD) for S7-300 and S7-400 Programming - Reference Manual - Bit Logic Instructions 1

Oct 26, 2026

Manual for creating and programming user programs using the Function Block Diagram (FBD) language for SIMATIC S7-300 and S7-400. Provides a reference section covering syntax and functions of FBD language elements, plus guidance on required basic knowledge and software release scope. Includes safety and legal notices, defines warning grades, and specifies proper use of Siemens products and trademark/liability information, supporting consistent and safe application in automation programming environments.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages208

Reading Time8 h 44 min

AccessFree to download

Legal information

Warning notice system

Qualified Personnel

Proper use of Siemens products

Trademarks

Disclaimer of Liability

Preface

Purpose

Basic Knowledge Required

Scope of the Manual

Compliance with Standards

Reference sections and navigation

Bit Logic Instructions

Comparison Instructions

Conversion Instructions

Counter Instructions

Data Block Instructions

Jump Instructions

Integer Math Instructions

Floating-Point Math Instructions

Move Instructions

Program Control Instructions

Shift and Rotate Instructions

Status Bit Instructions

Timer Instructions

Word Logic Instructions

Overview of All FBD Instructions

Programming Examples

Working with Function Block Diagram

SIMATIC Function Block Diagram (FBD) for S7-300 and S7-400 Programming Reference Manual This manual is part of the documentation package with the order number: 6ES7810-4CA10-8BW1 05/2010 A5E02790131-01 Bit Logic Instructions 1 | Comparison Instructions |

2 | | --- | --- | | Conversion Instructions |

3 | | Counter Instructions |

4 | | Data Block Instructions |

5 | | Jump Instructions |

6 | | Integer Math Instructions |

7 | | Floating-Point Math
Instructions |

8 | | Move Instructions |

9 | | Program Control Instructions |

10 | | Shift and Rotate Instructions |

11 | | Status Bit Instructions |

12 | | Timer Instructions |

13 | | Word Logic Instructions |

14 | | Overview of All FBD
Instructions |

A | | Programming Examples |

B | | Working with Function Block Diagram |

C | Legal information Warning notice system This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are graded according to the degree of danger. |
DANGER | | --- | | indicates that death or severe personal injury will result if proper precautions are not taken. | | WARNING | | --- | | indicates that death or severe personal injury may result if proper precautions are not taken. | | CAUTION | | --- | | with a safety alert symbol, indicates that minor personal injury can result if proper precautions are not taken. | | CAUTION | | --- | | without a safety alert symbol, indicates that property damage can result if proper precautions are not taken. | | NOTICE | | --- | | indicates that an unintended result or situation can occur if the corresponding information is not taken into account. | If more than one degree of danger is present , the warning notice representing the highest degree of danger will be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to property damage. Qualified Personnel The product/system described in this documentation may be operated only by personnel qualified for the specific task in accordance with the relevant documentation for the specific task, in particular its warning notices and safety instructions. Qualified personnel are those who, based on their training and experience, are capable of identifying risks and avoiding potential hazards when working with these products/systems. Proper use of Siemens products Note the following: | WARNING | | --- | | Siemens products may only be used for the applications described in the catalog and in the relevant technical documentation. If products and components from other manufacturers are used, these must be recommended or approved by Siemens. Proper transport, storage, installation , assembly, commissioning, operation and maintenance are required to ensure that the products operate safely and without any problems. The permissible ambient conditions must be adhered to. The information in the relevant documentation must be observed. | Trademarks All names identified by ® are registered trademarks of the Siemens AG. The remaining trademarks in this publication may be trademarks whose use by third parties for their own purposes could violate the rights of the owner. Disclaimer of Liability We have reviewed the contents of this publication to ensure consistency with the hardware and software described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the information in this publication is reviewed regularly and any necessary corrections are included in subsequent editions. Siemens AG Industry Sector Postfach 48 48 90026 NÜRNBERG GERMANY A5E02

FAQs

What is the purpose of this FBD programming reference manual?

It serves as a guide to creating user programs in the Function Block Diagram (FBD) programming language and provides a reference section describing syntax and functions of FBD language elements.

Who is the manual intended for?

It is intended for S7 programmers, operators, and maintenance/service personnel, requiring general knowledge of automation technology.

What software scope and standards does the manual cover?

It is valid for release 5.5 of the STEP 7 programming software package and states that FBD corresponds to the IEC 1131-3 Function Block Diagram language.

Oct 26, 2026

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