Process Voltage Too Low

What does 16139 mean?

This error indicates that the measured process voltage supplied to the safety I/O module or its channels has dropped below the minimum permissible operating limits. Insufficient voltage can lead to unreliable operation or complete failure of the module and connected components, compromising safety functions.

• The process voltage supplied to the safety I/O module's power terminals (e.g., L+ and M) has dropped below the module's minimum operating rating (e.g., <18VDC).
• Malfunction of the external power supply unit (PSU), causing it to output an undervoltage.
• Excessive load on the power supply, leading to a voltage drop across the supply lines.
• High resistance or a partial open circuit in the process voltage supply wiring to the module.
• Significant voltage drop across long supply cables due to insufficient wire gauge.

Click steps to track your progress.

1. 1

   1. Immediately measure the voltage at the process voltage input terminals (e.g., L+ and M) of the safety I/O module with a multimeter.

2. 2

   2. Check the output voltage of the power supply unit (PSU) feeding the safety I/O module under load.

3. 3

   3. Verify the integrity and continuity of the wiring from the PSU to the safety I/O module.

4. 4

   4. Calculate the total current draw of all devices connected to the PSU and ensure the PSU is adequately sized.

5. 5

   5. Inspect the gauge of the supply wiring and consider upgrading to a larger wire size if excessive voltage drop is calculated.