We added a new feature to our popular universal motor driver PoStep60-256.

A MODBUS communication over RS485 peripheral.

In addition to the existing USB and I2C bus, now you can configure and monitor the driver also using a standard robust industrial  Modbus communication protocol over RS485 bus. Now we can use the driver with PLC or other devices which supports Modbus RTU communication.  Above all, a wide range of commands allows users to control most of the driver functions including position control on board.

 

PoStep60-256 motor driver: Modbus over RS485

PoStep60-256 connection to Modbus over  RS485

 

The physical RS485  layer options  can be quickly and easy set in PoStep60 v1.20 application. We have prepared the Modbus configuration option select box . That way, the device can be accessed with baud rate 9600 or 19200 using None, Even or Odd parity check. Moreover, each PoStep60 motor driver connected to the same modbus client can be set with ID address number in range from 0x01 to 0x7F.

 

motor driver PoStep60-256: Modbus configuration

Modbus configuration options; using PoStep60 v1.20 application

 

PoStep60 Modbus communication supports a modbus RTU frame format. The new firmware allows three main function calls (FC) for writing and reading the PoStep60 registers.

Supported FC are:

  • Reading multiple holding registers (0x03)
  • Writing single holding register (0x06)
  • Writing multiple holding registers (0x10)

We have described in detail all the commands for PoStep60 Modbus communication in the PoStep60 User Manual (Chapter 9). For you, we also prepared an Arduino example code for easy start with PoStep60 Modbus communication. We will describe the example in one of our next PoBlog article.

However, you can free download the new version PoStep60 application from motor driver product page. All PoStep60- 256 motor driver boards revision 1.2 or newer (boards with RS485 connector) can existing users upgrade with new firmware version 1.20. Even more, the only restriction is that the board has integrated RS485 connector.

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