F7C3

Arrival Monitoring Timeout (No Resends)

Mitsubishi Electric · MELSEC Q-series MELSECNET/H

What does F7C3 mean?

An arrival monitoring timeout occurred while waiting for a response, and the resend count was set to 0. This can happen with RECV instructions if another station is sending, or if the host is executing the instruction without a response.

Common Causes

  • RECV instruction timing out when another station is executing a SEND instruction
  • Host station is the instruction execution station, but a response is not received
  • RECV instruction executed without the RECV instruction execution request flag turned ON
  • Network communication issues or target station problems

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Increase the value of the arrival monitoring time in the system settings

  2. 2

    Verify the RECV instruction execution request flag is turned ON before executing the RECV instruction

  3. 3

    If the error persists, conduct a thorough check of the network infrastructure and the target stations

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Verified technical data. Last updated: March 2026

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Source: Mitsubishi Electric MELSEC Q-series MELSECNET/H