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Omron CP1H “Modbus RTU” PowerFlex525 VFD

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Hi. The Allen Bradley PowerFlex 525 inverter is an extremely modern and easy to use inverter. It supports many communication standards such as Modbus-RTU, Modbus-TCP, Ethernet/IP…

Today will guide you to use Omron PLC, specifically CP1H to control PowerFlex 525 inverter via Modbus RTU.

Wiring Diagram

PowerFlex525 Communication Configurator

To configure the inverter to be able to communicate with Modbus-RTU, we need to set the following parameters:

Register Control Address

+ Register Control Address = 2000 (Hex)
>>> Set Word 2000 = 18: Motor Forward Run
= 34: Motor Reverse Run
= 1: Motor Stop
= 8: VFD Reset Error

+ Register Setting Frequency Address = 2001 (Hex)

Register Monitoring Address

CP1H Communication Setting

We need to configure the communication parameters of the PLC to be the same as the Allen Bradley PowerFlex 525

CP1H Modbus Programming

+ Initialize the VFD when the PLC starts running

+ Transmission Distribution

+ Frequency Setting

+ Control Run Command

+ Read Data Response

+ Data Monitoring

Project Video Tutorial


Recommended software and documentation:

+ CX Programmer for PLC Omron Programming

+ PowerFlex 525 VFD Manual PDF Download (Password Extract:

If you have any difficulty in connecting Omron PLC with PowerFlex525, please comment below the article, will answer you as soon as I read the article.

Best Regards!

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