How do large AC power switching surges affect the Duet board?

Nagoya-Kougei

We operate a tool change system using duet 3 mini 5+ and 4×1LCs.
The other day, there was a power outage at the factory while the 3D printers were still on. It seems that the printer's breaker was still on when the problem was restored. At this time, I think an opening/closing surge occurred and caused a failure in the board.

What I am currently finding fault with is the following:
・His OUT0 FET of mini5+ broke down.
・12864LCD backlight no longer shines (display side is not broken)
・The temperature sensor (pt1000) of T3 connected with 1LC is broken and the resistance becomes infinite ohms even when measured.

These problems were temporarily resolved by replacing the mini5+ and temperature sensor.

After the repair, when I executed a print job that took about 26 hours, an error like the one shown in the image occurred and the machine stopped in an emergency.

When I searched the forum for similar errors ,it was said that the problem was caused by SSR noise. I use an SSR with a zero cross function, so I had never encountered this error before this failure occurred.

It is unclear whether 1LC was also damaged by the surge.
Does this error occur not due to SSR noise but also due to a failure or heating error in the 1LC itself?
I would like some help as there is not much explanation about this error.

About the device configuration
Main board: duet3 mini5+ firmware: 3.4.5
Distribution board: Yes
Tool board: 1LC × 4
Operates on Raspberry Pi 4
Power supply: 24v & 5v
power environment : Single phase AC 100V 60Hz
Switching power supplies do not have surge absorber varistors.

droftarts

@Nagoya-Kougei There's no real surge protection on Duet boards. There is some protection for over-current, which it sinks through the stepper driver FETs, but this is for short and small over-current and over-voltage events, or wiring the power incorrectly. Realistically, surge protection and conditioning on the power supply is preferable. It's quite possible the toolboards have been damaged too, especially given the failure of the PT1000.

If you have replaced the Mini 5+, is the firmware version the same as the 1LC boards? Send M122 to check the firmware on the main board, and M122 B# where # is the CAN address of each 1LC board. Mismatched firmware versions can cause issues with toolboard control, though I would think the heaters wouldn't turn on in the first place.

Ian

Nagoya-Kougei

@droftarts
I had never heard of such surges occurring at installation sites, so it was unexpected.
I plan to replace all the tool boards I use.

I think the firmware version of the 1LC was 3.4.4.
1LC should not have had 3.4.5.
sorry. I can't confirm it right away because I don't have the equipment at hand.

I think additional surge protection should be added to the AC circuit.
Is a protective component like a varistor necessary on the DC side as well?