Siemens / TIA

S7-1500 watchdog after a TIA V19 download — cell stays in STOP

Marcus Hale · Controls engineer · body shop

Press shop, S7-1500, TIA Portal V19. After a small OB1 edit the CPU comes up then drops to STOP with a diagnostic buffer pointing at a cycle watchdog. No new hardware. Anyone seen this on a Comfort Panel HMI that still talks V17 tags?

Priya Shah · Integrator
Check the HMI connection resources and any cyclic WinCC script you added in V19. We had a tag group set to 10 ms that ate the scan. Bump the cycle watchdog in the CPU properties only after you find the extra traffic — don't just raise it and walk away.