Guys, many thanks for your answers and I admire your patience. My thinking got twisted after a response about position vs velocity back in the other forum.
@IRStuff, your comment has straightened all this out: " Your problem seems to stem from the concept, "whenever the PID gives an output of...
My apologies if I misled anyone, that wasn't my intention. I think my confusion has been evident from the very start and can be summed up by these lines from my posts:
"I don't understand what is meant by positional. Does it mean that one extreme of the PID output (say -3V) represents actuator...
I re-read your post xnuke a few times, and I've realized something else. Going back to the point in my scenario above where the P contribution has taken the window to just below the SP. As I said earlier, it can't open the window to the zero (no error/window half open) actuator position...
@xnuke: sorry just saw your comment about doing this using the ATTiny. Well, yes, that would make sense, but lets face it, this is all about education. If I had any cop-on I'd just go and open the window myself. The thing is, I'm a software guy by trade, so programming uP's is in my comfort...
@waross, your answers are definitely bringing me closer to figuring this out. I'll re-state what I think you've said in your last two posts and you can let me know if I'm there.
So, firstly - and lets forget about PID and assume you were doing this yourself: sunny; 25degrees SP; you move the...
Thanks for sticking with this waross, I appreciate it. As you describe it then, zero output from the pid would be 3/6 or 50% which would mean the window is half open. And since zero output from the PID means no error you're saying that you expect the temperature(PV) to equal the SP when the...
Aha, waross, I think I'm starting to see the solutions now! It's funny, but the suggestion at the end of your last post was exactly what I had in mind when I asked the question on the SE forum. That's what I meant when I posted "One idea I had was to slow down the command delivery by sampling...
Hi djs, the actuator is one I've built myself. You can see it in the stackexchange thread (see link above), it's basically a wooden box with an m6 threaded rod for a lead screw pushing an aluminium bar. It's simple, but it works pretty well (a little noisy maybe). The motor is a gear motor I...
Thanks Bill, well actually you may have guessed that this isn't a life or death project. It's another foray into the murky world of electronics albeit one with some utility. If all that happens at the end of all this is that I learn a few things, I'll be happy enough.
I have disabled the I...
Hi, first time poster - so go easy:-) and I'm relatively new to control systems and electronic engineering, so noddy answers are actually appreciated.
I'm going to post a link to the question I posted on another site to save me typing in all the detail again. I've decided to ask here because...
