6-1-1-1

Max Internal Temperature Exceeded

Beckhoff · EL1904 Digital Input Terminal

What does 6-1-1-1 mean?

The EL1904 terminal has detected that its internal temperature has exceeded the maximum permissible value. This often indicates that the ambient temperature around the terminal is too high, leading to overheating. Prolonged operation in this state can reduce terminal lifespan or cause component failure.

Common Causes

  • Internal sensor reading exceeds predefined thermal limit.
  • Cooling system malfunction or insufficient airflow to components.
  • High ambient operating temperature impacting equipment performance.
  • Overload condition causing excessive power dissipation.
  • Faulty temperature sensor providing inaccurate readings (P1-10).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the ambient temperature around the EL1904 terminal using a calibrated thermometer.

  2. 2

    Compare the measured ambient temperature to the permissible operating temperature range specified in the terminal's technical data sheet.

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Verified technical data. Last updated: March 2026

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Source: Beckhoff EL1904 Digital Input Terminal