S7 315 CPU All Leds Flashing

Hello

We have an Siemens S7-315 CPU and several Sinamics CUs and drives. One of the drives have a fault and I was trying to figure out what the problem is. I was online with Simotion Scout then suddenly I dropped offline and when I checked out the panel I saw Sinamics have all leds red and 315 CPU's all leds flashes. Then in panic I switched 24V supply completly off waited 10 sec and then back on. Everything seemed OK except the faulty drive.

Now I am wondering what it means for Siemens S7-300 CPU to have all the leds flashing at the same time? I check out the web couldnt find any exact explanation. Something like CPU is defective is written but CPU works correctly right now. It is also said that CPU is in panic mode but dont know what it means
and dont know what caused this?

Do anyone have experience about it ? We are thinking it might be a power problem about 24V.

Thanks. Have a nice day.

I had such situaltion once, but swithcing on/off power supply, changing mode STOP/RUN did not help - CPU was malfunctioning and it had to be replaced. I still do not know what happened, but I know that new CPU solved that problem.

All LEDs flashing normally means a defective CPU.
It can be that the CPU has an intermittent hardware error, but it can also be the memory was corrupted because of electrical noise. If the CPU started with initial values in the DBs after the shutdown, then that is indicative of the latter.

I would check if there is a good ground everywhere, if screens of profibus and VFD cables are properly connected. Other than that, maybe have to replace the CPU.

In that "panic" mode I didnt checked the DBs nor the diagnostic buffer but I think I will have chance to have a look at the diagnostic buffer tomorrow. I think it is a strong option that it happened out of electrical noise because the Sinamics acted very strange all modules become faulty and over profibus it may affect the CPU. I will check the grounding of the panel carrefully. Not proper grounding might be the problem.

Also on net I found some other causes of that problem so will post here:

S7 CPU All Leds Flash

"This effect is called the status "DEFECTIVE" and is coming when the CPU don't know what to do with the situation it is in. After this message (all LEDs are blinking) you can't reach the CPU any more until you shut down the power and switch it on again.

It is important to save the Diagnostic Buffer and send that to your local Siemens Representative, to do so, please switch the CPU to STOP before you are powering down and directly after the power is switched on save the diagnostic buffer in ASCII and in HEX.

With that information Siemens can search for the status where the CPU was coming in where it don't get any way to come out. Normally you should say, why stopping and don't go any further when detected such a status?

That is because the CPU don't know the status any more and working further could be dangerous for mankind and equipment."

In this situation following is adviced:

1 - Check Grounding
2 - Check backplane pins of every module (pins can be harmed and dont conduct exactly)
3 - Update the firmware of the CPU

Thanks for the replies.

What version of Scout are you running? There is a known issue with 4.1.4.1 that will cause this - 4.1.5.3 is due out very soon and I suggest you update as soon as it's released.