The PLC is in Service mode. But it cannot be reset with power cycling back to RUN. Only think that recovers the PLC is fresh installation (remotely I do mostly USB installation).
To me it seems like the CF card gets corrupted. It happened multiple times and now I tried to replicate the issue by removing supply in booting phases, while CF is reading, multiple times without waiting and I am simply not able to replicate the issue. The PLC boots fine.
Its worth mentioning that the issue is happening mostly if the whole factory has some supply failure. So might it be connected with some power peak?
Did it happen to you too?
Do you have any ideas to troubleshoot that?
If the PLC is in Service mode, the best way to diagnose is to connect to it and view the Logger. There will be messages which tell you why it booted into Service mode, and that is a good place to start.
It does seem interesting that the issue only happens on the machine, and not on your test bench. Next time the issue happens, I also suggest checking the 24V supply to the PLC to make sure that this is stable.
Hello Marcus,
thanks for reply. I did all the basic checks of power supply voltage, fuses, etc…
The issue is I dont always have access to the PLC logger remotely. It depends on the network setup. When I faced this issue I downloaded the whole content of CF (basically made 1:1 copy) and sent it to B&R but no luck troubleshooting that unfortunately.
Sorry for taking so long to reply. I’ve had this in the back of my mind, but unfortunately, I do not have any ideas. Hopefully my reply bumps this post and someone else has some ideas.
As far as I know, the CF shouldn’t get corrupted like that due to a power loss. A recipe file (for example) may get corrupted if there is a power loss during writing, but I don’t know why the entire application would get corrupted, especially since you cannot reproduce it and it sounds like the logs didn’t have much information.
It’s possible the CF card is failing. Have you tried replacing it? Perhaps the difference between your machine and test setup is the card itself.
Hi @Ondrej_Petr
I already see something like this but not on the same hardware. Here is what I’ve already experiment:
1 APC 3100
UPS
Somes drives using powerlink
UPS is shutdown after 2s on battery
When I shutted down the cabinet, the APC go in SERV and keep power on the UPS during all the night (because he was in SERV no program is executed).
After checking the profiler stored on the APC (one is store when the PLC goes SERV), there is a specific task related to motion in mappMotion (I didn’t found back the task name) in cyclic #1.
I ask my local B&R office for this and it appear that a function block (MC_ReadActualTorque) that we was using was switch between enable:=TRUE and enable:=FALSE every cycle due to wrong programming not checking communication OK with the axis.
So the APC goes in SERV mode during powerfail because we lost the powerlink communication and the APC still power up by the UPS. During the time on the UPS, a high CPU load result in a “Stack overflow” or “Page Fault”, then goes in SERV mode.
It’s maybe not related but I hope it could maybe help!
Hello, @marcusbnr Thanks for reply, we tried to replace the CF card. It happened multiple times with different customers all around the world. So I assume its not only one CF card specific.
@florent.boissadier Thanks for reply. Do I get right that high CPU load is caused since the comm with APC is missing while power loss? I assume because of trying to establish connection or something like that.
@Ondrej_Petr yeah the APC3100 CPU was overload due to powerlink communication down and the function block was call with enable so he try to do something with the communication and this was every 4ms so.
One hint I could tell you, as you didn’t have access to the logger remotely. You could check or ask your client to use the SDM, when a PLC crash there is a profiler store on the PLC :
