Post the job if you can.
We can try to program together!
No job posted, but let me show you something:
Step 1 - Define a B<variable number> for the number of jobs done counter.
Step 2 - After your weld instruction end, insert the command INCREMENT, like this: INC B<variable number>
Step 3 - After the INCREMENT code, insert an CALL JOB instruction like this: CALL JOB:NOZZLE_CLEAN IF B<variable number>=30
Step 4 - In the end of the cleaning job, insert a SET command to reset our counter, like this: SET B<variable number> 0