I can't seem to find anything, I'm trying to come up with a justification for how many decimal places to display on this Ignition SCADA system I'm building for a client. The answer might simply be that there is no industry standard, I'm just not sure.
This depends, keep enough decimal places that the user can discern the difference between a bunch of items easily.
But if you need a standard to go by, this paper suggests that you use 2 decimal places
Personally, I've noticed that 2 is very common. I know it's a rule in currencies and of course finance/accounting fields that work with currencies. But the article above really helps solidify this idea. I've only schemed through what I needed for this answer, but I'm sure the author goes into more detail. Hopefully enough to convince you to stick to 2 for now.