81004 : Stop/abort event error analysis via STEP 7 required

a) From archieve v reloaded PLC archieve, machine became alright

b)After 10 days, again error 81004, we moved S4 from 0 to 2, 2 to 3, 3to 2, 2 to 0 , with this PLC came to run mode and PS red on NCU went off, again reloaded PLC archieve to control (Menu Select - Data In - Archieve - Control)
Machine was ok for 5 days, again error 81004

Kindly advice why PLC going to stop mode so often even after taking above steps

Regards,

M. Rishikesh