AUTO function for dew heaters

[Panoptes53]

High PA,
I don’t own any PA equipment yet, but I am considering purchasing UPBv3 with external environmental sensor. It has a formidable set of capabilities and would certainly meet most, if not all, of my needs. One of my primary concerns is how to control dew. I noticed that UPBv3 has 3 outputs for dew heaters; the amount of heat generated by heaters is PWM controlled. There’s also an AUTO function, which is described as almost some sort of magic capable of automatically determining activation and tuning of the heaters, but without details of how that’s done.

I am a bit puzzled with this AUTO function. It is easy to calculate dew point from temperature and RH data which PA environmental sensor provides, but you’d also need to know what temperature your e.g. lens is at, to be able to provide adequate heat and ensure the lens is a few degrees above the dew point. There’s no mention in any of PA manuals I read of any temperature probe attached to protected parts, so it seems that UPBv3 is somehow guessing the right settings.

Looking through messages in this forum I found one where I learned that in Unity software there’s a “button” for how aggressive dew control is, between 1 and 10. I assume that this button, and human feedback that controls it, is the means through which dew heater operation is tuned so that dew is eliminated. But that’s not an automated process, if I understand it correctly. And it probably takes some non-trivial time and a number of iterations to get to the right setting of this button. Such system is probably somewhat wasteful of precious power if you are working in some remote location.

So, my first question is if this understanding is correct, or I am missing something important. My apologies if it’s obvious how this loop works, and I don’t see it, but it bugs me, so I decided to ask.

The second question is why PA didn’t decide to use temperature probe that would be attached to the part where dew is to be eliminated? That would be a simple and relatively accurate feedback, which would probably provide more objectivity than a heuristic “aggressiveness” button. It would also absorb many uncertainties, obvious ones being the amount of heat different dew strips generate, radiative cooling, wind, etc.
Or the idea was to absorb all these uncertainties into the software button and provide control via a human?

And finally, I’d be very grateful if I can get some information on how well this works in practice. How effective it is, and how quickly one can eliminate dew by tweaking the software button and PWM settings.
Cheers…