CCU_SR Safety Power Supply Not Present

What does PWRS/3.3V Off mean?

The PWRS/3.3V Green LED is OFF, indicating an absence of supply voltage for the safety-related 3.3V rail. This condition points to a power supply issue to the CCU_SR module or a fault within the module itself, specifically impacting critical safety functions that rely on this voltage.

• The safety power supply (PWRS/3.3V) for the safety circuit is not present.
• The 3.3V power rail dedicated to safety functions is off.
• Loss of power to the safety control unit (CCU_SR) safety supply.

Click steps to track your progress.

1. 1

   Check fuse F17.3 on the CCU_SR for continuity and proper rating.

2. 2

   If the PWR/3.3V LED (Item 6) lights up, indicating the main 3.3V power is present, but the PWRS/3.3V is off, exchange the CCU_SR module as the safety power rail is internally faulty.