Load ON with External Power Supply Only (Transistor Output)

What does LOAD-ON-PSU-ONLY mean?

A load connected to a transistor output module operates solely when the external power supply is turned on, without the transistor output being actively commanded ON. This fault occurs because the external power supply is connected with reversed polarity, allowing current to flow via the output element's internal protection diode directly into the load.

• External power supply is connected with its polarity reversed.
• The reversed polarity allows current to flow through the output element's protection diode, bypassing the transistor switch and energizing the load.

Click steps to track your progress.

1. 1

   Verify and correct the polarity of the external power supply connection to the transistor output module.