Why servo drive cannot communicate with PLC?
Last modified by Wecon on 2025/09/03 21:03
| Question | Reason | Solution |
|---|---|---|
| Drive cannot communicate With Master | Communication parameter setting error | Servo drive only support Modbus RS485, please check whether the communication parameter is wrong such as baud rate, station number, stop bit. |
| Communication port selection error | VD2 series use CN5/CH6 port and VD2F(need to set P12-05 as 1) series use CN3/CN4 port. | |
| Communication cable failure | (1) Check whether the wiring is correct according to the pin definition. | |
| Wiring method error | Please use a hand-in-hand communication structure, and do not use a star structure or a bifurcated structure. | |
| Some addresses cannot communicate | Modbus address wrong | Please check the Modbus address of parameter in manual |
| Didn't change endianness when read 32bit address | Change endianness with PLC program or set servo P12-06 as 1. | |
| PLC RS instruction directly uses constant assignment | Using registers for assignment. | |
| Modbus function code wrong |  |