... RS422/RS485(optional) WECON plc,programmable transistor control,replace FX2N plc Model LX2N-40MT-A(AC100 ... JEM-1021 standards,between power port and earth terminal. Insulation resistanceDC500V insulation tester test above 5MΩ, ... -1021 standards,between power port and earth terminal.Earth connectionThe third kind of earth connection(do ... 5kg WECON plc,programmable transistor control,replace FX2N plc