GS20 Fault E.CF — Communication Fault
What This Fault Means
E.CF triggers when the drive loses communication with the master device (PLC or HMI) over Modbus RTU or Modbus TCP for longer than the configured communication timeout.
Common Causes
- RS-485 cable disconnected or damaged
- PLC communication program stopped or faulted
- Baud rate or parity mismatch between drive and master
- Network collision from too many devices on the RS-485 bus
- Communication timeout (P09.01) set too tight
Recommended Fix
- Verify the PLC communication program is running and actively polling the drive.
- Check RS-485 wiring: shield grounded at one end only, A↔A and B↔B, 120Ω termination at both ends of the bus.
- Confirm baud rate (P09.00) and data format (P09.04) match the PLC configuration.
- Increase the communication timeout (P09.01) if the PLC poll cycle is slow.
- For Modbus TCP, verify the IP address, subnet mask, and gateway in P09.30–P09.33.
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