PC rebooted and wrote zeros to PLC

[EE_Kraig]

Last week the PC running AHMI was in the process of installing updates and rebooting and for some time it was on the "please don't turn off" Win10 screen. Somewhere during that process, it set all the PLC registers that the app writes to, to zero. Trying to understand why/when it wrote zeros and if it's a bug, intended, etc.

[Archie]

Do you have code in your application that writes to the PLC?

[EE_Kraig]

Yes and no. I have two DPMs that only write to the PLC from the control. I have three AnalogValueDisplays that write from the control and in code I do write to the same values on an event, e.g. ButtonClick.

I should add this is ModbusTCP

[Archie]

To my knowledge, there are only 2 possibilities for something to write to the PLC on startup without user interaction. Those would be user code or the Analog Input Controls expansion pack.

[EE_Kraig]

I don't think it was actually on startup but rather on shutdown. I'm guessing the PC closed the app before it tried to shutdown, or maybe it didn't and then the modbus driver freaked? Just wanted to mention it in case I was missing something.