Huh, it was happened again: ADuM3160 USB isolator failed again:
Sorry for this somewhat late reaction..
Thinking about the failing ADuM 3160 isolator:
Normally the whole control section of the H24005, the arduino and so on, is totally isolated from the rest of the system. It is isolated by the ADuM 3160 USB isolator IC17 and control signal isolators IC19 - IC23. Power, 5V, comes from the TR1 supply module, the GND net of the control section is not connected to anything outside this section. So it looks like there is no path to prevent any buildup of a static charge.
In fact, when measuring voltage between PE and digital GND on point 8 of the left-hand auxiliary connector there is some voltage building up slowly. This happens while the H24005 is in standby as well as when switched on. Highest I have seen, after +/- 15 minutes was more than plus 10 Volts on a high impedance voltmeter. What is the cause? The meter, with its input open and nothing connected, has the habit of going to a negative indication. So it looks as if something else is loading the GND net positive referenced to PE. When switching the meter out of 'high-Z' to 10 Meg input the voltage drops to about zero.
I think there is nothing against connecting the control section GND net direct to PE with a piece of wire from point 6 to point 8 on the left-hand auxiliary connector. Just to provide a discharge path. Or a resistor 1 Meg or so? This will keep the 'inner' side of the isolator under control.
Another thing.. Also both power regulator sections are fully isolated and not protected against static. Shouldn't there be a (high) resistive discharge path as well? Or do the MeanWell supplies take care of that?
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PS. It looks like there is a typo in schematic 7/12 'Ethernet and USB PCB connectors' : near IC17 the GND symbols are wrongly identified as 'PGND', actually they are on the 'GND' net.