Search WeChatElectrical Engineering LearningThis article will introduce the detailed steps of Modbus communication between the S7-1200 PLC and the V20 inverter.1. Find an S7-1200 PLC with an RS485 communication module and a V20 inverter.2. Connect the RS485 module to the V20 inverter. The wiring method is to connect the red wire to P+ and the green wire to N-.3. Set the parameters of the V20 inverter.4. Create a TIA Portal project and upload the hardware configuration of the S7-1200 PLC.5. Set the parameters of the RS485 module. The communication parameters of the module must match those set on the V20. Here, I set it to 9600, 8, even.6. Add Modbus communication instructions.7. Modify the mode parameter in the background DB of the initialization instruction to 4.8. Program testing, the motor starts and stops normally. The Modbus address 40101 is the command source, 047E is stop, 047F is forward, 0C7F is reverse, and the address 40100 is the frequency source. 16#0-16#4000 corresponds to 0Hz-50Hz.9. You can observe the communication indicator lights on the module to check if the communication is successful. If TX and RX flash alternately, the communication is successful.
