Hopefully one of the electrical experts can chime in. I would think all controllers need to be tuned. And for someone to do that for you they'd have to fill it with water and run the cycle. And then dry it and package it. I can't see anyone doing that.
Edit - FWIW, to tune a PID you fill with water, pick a water temperature, then press and hold one button until a certain light turns on. That's it. Hardest part is reading the manual while using your phone.
Not an electrical expert, but I did take a process control class in college and work with process control engineers on a somewhat frequent basis to help figure out the best way to control process systems. Here's what I THINK I know...
With a PID control loop, the optimal parameters for P, I and D are very specific to that system. And when I say system, in this context I mean not only your equipment (dimensions, wetted surface area per volume,etc.), but also the volume of water used, the amount of grain used, the type of grain used, the rate of circulation, length of hoses, atmospheric temperature, wind speed, maybe others.
When your grain bill changes, the optimal values for P, I and D change. When you different amounts of water and different water/grist ratios, same thing. When it's especially cold/hot/windy outside, if you have lower circulation rates during the mash (I run my pump throttled way back).
But, what most folks do in the home brewing world is run the auto-tune feature using only water, most likely with their pumps running wide open, maybe even in their climate controlled kitchen. The controller does its thing and assigns the values based on that. And it would control beautifully if that's how we brewed beer.
Technically, optimal P, I and D values are different for each brew session. But hopefully the values arrived at during the auto-tune, with water only, will get us close enough so that we don't over/under shoot the temps we want. We can get closer to optimal P, I and D values by running the auto-tune feature during a brew session with a "typical" grain bill. Again, it won't be perfect for every brew session, but it would be closer than just using water and running everything wide open!
Hopefully this helps. And hopefully someone with more expertise than me will chime in if I've said anything that's off base.
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