• Jasmine
• 2023-12-27 13:51:19

Modbus newsletter, understand in five minutes

As a common connection between industrial electronic devices, the Modbus communication protocol can facilitate the connection between different devices and is an indispensable and important tool in industrial automation systems. This article will introduce the detailed steps of Modbus communication between S7-1200 PLC and V20 inverter.

Steps

• Find an S7-1200 PLC with an RS485 communication module and a V20 inverter, the motor used in this picture is a small diamond motor.
• Connect the RS485 module to the V20 inverter, and the wiring is done by connecting the red wire to P+ and the green wire to N-.
• Set the inverter parameters of V20.
• Create a Protherm project and upload the hardware configuration of S7-1200 PLC.
  
  
  
• Set the parameters of the RS485 module, the communication parameters of the module should be consistent with the communication parameters set by V20, which I set here as 9600, 8, and even.
• Add Modbus communication instructions.
• Modify the mode parameter in the background DB of the initialization instruction to 4.
• Program test, motor normal start-stop, which Modbus address for 40101 address for the command source, 047E for stop, 047F for forward rotation, 0C7F for reverse rotation, address for 40100 address for the frequency source, 16 # 0-16 # 4000 corresponds to 0Hz-50Hz.
• You can observe the module's communication indicator can see whether the communication is successful, if TX and RX alternately flash that is, communication is successful.

Conclusion

Modbus is a powerful communication protocol. Understanding and implementing the Modbus communication protocol is essential for smooth communication between electronic devices and improved system performance. With these steps, you can use this powerful tool without any problems.