Powermeter fast-fault edits

[KaushikMalapati]

Description

Only fast-fault if ppm is not out or moving

Motivation and Context

Power meters in rix are fast faulting even when beam energy should not be high enough to trigger them.

How Has This Been Tested?

Where Has This Been Documented?

Pre-merge checklist

• Code works interactively
• Code contains descriptive comments
• Test suite passes locally
• Libraries are set to Always Newest version (Library, *)
• Committed with pre-commit or ran pre-commit run --all-files

[KaushikMalapati]

I tried adding a simple way of only triggering the fault if the energy is persistently over what's allowable, but I am completely open to doing it another way.

[ZLLentz]

I like the counter approach here because it's easy to understand and doesn't do anything overly complex. This is what we want for a robust PLC program.

25 cycles at 10ms per cycle = 250ms = quarter of a second
I'm not exactly sure what the "most optimal" count would be but this seems reasonable and will definitely cull the false positives.

[KaushikMalapati]

If bOverAllowableEnergy switches between True and False frequently, it could take up to 50 cycles or half a second to trigger the fault. (+2 * 50) + (-1 * 50) = 50, (+2 * 49) + (-1 * 51) = 47. As long as half of the cycles or more are over, it will trigger, but the higher the proportion the less time it takes, maxing at a quarter second. Like you said, these are all magic numbers that I just think seemed reasonable

[ZLLentz]

I'm trying to get into the habit of verbosely double-checking fast faults now:

Fault is OK if:

• PPM is out
• OR counter is under 50

Therefore, the beam turns off when both:

• PPM is at one of the known target or an unknown state or in motion
• AND the counter is at least 50 (counter caps out at 50)

This is totally reasonable logic and I endorse it

Some might argue that e.g. the YAG states should also be exempt from these faults, but there is some judgement call to be made because what if the beam is actually hitting the power meter somehow in these states? And what if the state positions other than "OUT" are wrong? I think there's a philosophical discussion to be had here.

[ZLLentz]

I forgot to come back and re-approve, I like this

[ghalym]

LGTM

[KaushikMalapati]

Maggie helped me test this. We checked that the fault would not occur unless the PPM position was at the power meter and the energy was above the threshold, so I think this is good to merge