Applicable Systems
GOT2000 Series
Symptoms
GOT2000 shows 'PLC No Response' (err. 401) on the system alarm window.
Possible Causes
- RS-422 cable between GOT and FX5U/Q CPU disconnected or broken wire.
- GOT standard monitor driver does not match the connected PLC series.
- PLC communication port already occupied by another GOT or programming tool.
Troubleshooting Steps
- Step 1: Check the RS-422 cable with a multimeter for continuity on all 4 signal pairs.
All pairs show <1 Ohm continuity and >1 MOhm isolation to shield. - Step 2: Open GT Designer3, verify the controller type in the project settings.
Controller type matches the actual PLC model (e.g., MELSEC-FX5U). - Step 3: Disconnect other devices from the PLC programming port and reset the GOT.
GOT establishes connection within 10 seconds after exclusive access is ensured.
How to Reset
Repair or replace the RS-422 cable, match the PLC driver in GT Designer3, and ensure exclusive port access.
Common Replacement Parts
- RS-422 communication cable GT01-C30R4-8P: RS-422 communication cable GT01-C30R4-8P
Source: Mitsubishi GOT2000 Series Connection Manual
Category: HMI