Siemens S7 1200 “Modbus RTU” Siemens Sinamics V20 Tutorial

Siemens S7-1200 PLC and Sinamics V20 inverter are devices commonly used in many machines around the world. Today plc247.com will guide you to control Sinamics V20 VFD through Modbus RTU (RS485) Communication.

Sinamics V20 has a built-in RS485 port, and for S7-1200 we need to use an additional expansion module S7-1200 CB1241 (or CM1241).

Siemens S7-1200 & Sinamics V20 “Wiring Diagram”

Siemens Sinamics V20 Modbus RTU Setting

In order for the Siemens Sinamics V20 inverter to communicate with Modbus RTU, we set the following communication parameters:

Registers for Control

Note: S7-1200 Modbus Address
= “VFD Address (dec) + 40001”

>>> Motor Control Address = 40001 + 99 = 40100

+ Set Word 40100 = 1151 >>> Forward Run
= 3199 >>> Reverse Run

+ Set Word 40100 = 1150 >>> Stop

+ Set Word 40100 = 1278 >>> VFD Reset

>>> Frequency Reference Address = 40001 + 100 = 40101

Register for Monitoring

+ Frequency Output Address = 40024

+ Speed Output Address = 40025

+ Current Output Address = 40026

Siemens S7-1200 Modbus RTU Configuration

+ S7 1200 CB1241 Parameters Settings

+ Create Data Types

+ Create Modbus Block

PLC Programming

+ Automatic Read/Write Distribution

+ Communication Configuration

+ Frequency Setting Command

+ Motor Control Command

+ Read Data Response

Detailed Instruction Video

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Required software and documentation

+ Download TIA Portal V15.1 for S7-1200 Programming

+ Siemens Sinamics V20 Manual PDF Download (Password Extract: plc247.com)

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