Siemens S7-300 PLC lights up red and SF fault is eliminated

I was taking a regular nap at noon a week ago. I received a call from a former colleague who hadn’t been in contact for a long time. We used to get along pretty well and were considered half-teachers and half-friends. He told me that a set of 300 plc of a customer has been running normally for five or six years, but this morning it suddenly turned red without warning, the system was out of operation, and all the data of the host computer was shadowed and could not be connected to the PLC. The owner is very anxious, and the cost is easy to say, can he find someone to troubleshoot and let the system return to normal as soon as possible. After briefly introducing the situation, he asked me if I would like to take a trip. I honestly say that this kind of situation can be big and small, but it cannot guarantee 100% immediate results. Let alone someone else’s project, it’s a project I made myself. Sometimes there is no guarantee that the hand will be cured in a short period of time. The exchange continues. . . . . .

Now that I agreed and the owner emphasized that the sooner the better, I immediately booked a high-speed rail ticket. I thought about going back to the base in the town to prepare some spare parts without insurance and seeing enough time. Something is better than nothing. Sitting on the bus back to the town, I stroked the whole process, and also looked at the short videos and photos sent back from the scene. Maybe the owner was in a hurry, and I didn’t wake up and I was brought to the rhythm. I forgot to remind the other party if the system was all slumped, did you try to power it up again. According to my debugging experience, there are indeed inexplicable problems that can be eliminated by re-powering. I told the owner on WeChat to back up important data (even taking photos or screenshots are fine). After half an hour passed, the owner sent a message that the system has resumed operation by re-powering on, and it depends on whether the problem can be reproduced yesterday. Although the real reason has not been found out, it is a good choice to resume production first to see the after-effects.

Through this incident, I once again confirmed what a predecessor said to me: urgent matters should be dealt with later. It makes sense. Otherwise, the refund fee can also be added at night, hahaha. The attached picture looks a bit flustered.