F7C4
No Communication After Resends
Mitsubishi Electric · MELSEC Q-series MELSECNET/H
What does F7C4 mean?
Communication failed persistently even after executing the designated number of resends. This indicates a fundamental communication breakdown that retries cannot overcome.
Common Causes
- Persistent network communication failure
- Issues with the target station
- Insufficient arrival monitoring time
Repair Steps & Checklist
Click steps to track your progress.
- 1
Increase the value of the arrival monitoring time in the system settings
- 2
Conduct a thorough check of the entire network infrastructure for physical faults or misconfigurations
- 3
Verify the operational status and configuration of the target stations
Verified technical data. Last updated: March 2026
Related Faults
Source: Mitsubishi Electric MELSEC Q-series MELSECNET/H