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Ms. Tonya GarciaAug 2, 2025
What to do if all four LEDs on the Siemens Control Systems PLC flash?
- GGrace DavisAug 2, 2025
If all four LEDs on your Siemens Control Systems PLC are flashing, it indicates a system error. To address this, halt the PLC (set the 'PLC' switch to position 2) and perform a hardware reset. Use STEP 7 to read the diagnostic buffer and share this information with the Hotline / Development Service. If requested after the hardware reset, perform a general reset. After resetting or reloading the PLC program, normal operation may resume. Still, send the diagnostic buffer content to the Development Office.