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Entry type: Application example Entry ID: 109476801, Entry date: 09/21/2018

Controlling several fans (ebm-papst) using the SIMATIC S7-1200 via Modbus RTU

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This application example describes how to connect your EC fans from ebm-papst to a SIMATIC S7-1200 via Modbus RTU and how to monitor and control it from an operator panel.
ebm-papst offers a varied product range of Green Tech EC fans for virtually any application.
These fans are equipped with an integrated RS485 interface and will be connected to a SIMATIC PLC via Modbus RTU, monitored and controlled.

A SIMATIC S7-1200 CPU with firmware >= V4.2.1 is used as the controller.
It exchanges the motor data with the ebm-papst fans sequentially using the serial communication board CB 1241 RS485 via the Modbus RTU data protocol.
To operate and monitor the motor data, a SIMATIC HMI KTP900 BASIC (or its simulation in the TIA Portal) is used.
Configuration is performed with STEP 7 V15.

Display 01


This application example offers the following advantages:
  • Input and output of the parameters with the correct unit and meaning through the KTP900 Basic PN operator panel
  • Sequential cyclic reading of the key input registers of all fans
  • Overview of all fans (default: 4) with bar graph display of the current modulation level
  • Automatic retrieval of the most common holding registers after selection and subsequent editing of all fans
  • Collective retrieval of device-specific input registers and non-writable holding registers of all fans upon request
  • Access to the register of each fan via the control program
  • Communication can be expanded to up to 32 fans

Current version 2.0 for controlling several fans
  Documentation V2.0 (2.5 MB)
 Registration required  TIA Portal V15 project V2.0 for S7-1200 from firmware V4.2.1 (2.8 MB)

Older version 1.0 for controlling a fan
  Documentation V1.0 (2.0 MB)
 Registration required  TIA Portal V13 SP1 project V1.0 for S7-1200 from firmware V4.1.1 (4.3 MB)

Additional Information
How can you read input words in the address range from 9999 to 65535 with the SIMATIC S7-1200 via Modbus RTU? 
How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200?
Updates for STEP 7 V15 and WinCC V15
Firmware updates for SIMATIC S7-1200 CPUs
Manual: SIMATIC S7-1200 Automation system
Ebm-papst website

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