Automatic test stop: Wait for STO to be deselected via SMM

What does A30788 mean?

The system is waiting for the Safe Torque Off (STO) function of the extended safety functions to be deselected via Safety Monitor Module (SMM) as part of an automatic test stop procedure. This can also indicate active safety messages preventing STO deselection.

• An automatic test stop procedure (e.g., periodic safety test, commissioning test) is currently in progress, initiated by the system.
• The Safety Monitor Module (SMM) has activated STO as part of its internal test sequence to verify functionality.
• System is waiting for the STO signal to be released by the SMM to continue operation after a temporary test.
• A condition requiring a safety test has been met, and the system is awaiting confirmation from the SMM.

Click steps to track your progress.

1. 1

   Confirm the Safety Monitor Module (SMM) status via its LED indicators (e.g., Green for RUN, Yellow for TEST) or diagnostic word (r0947.x).

2. 2

   Wait for the SMM to complete its internal test sequence; this process is typically automatic and requires no user intervention.

3. 3

   Verify that all conditions for STO deselection are met by the SMM, such as no active safety faults or pending acknowledgments.

4. 4

   Check if any external intervention (e.g., manual acknowledgement on HMI or Profisafe telegram reset bit) is required by the SMM to proceed with operation.