Can this PID library include a function to accelerate from 0 to SetSpeed and continue at that speed until the SetPoint is reached (because it will automatically decelerate before reaching the SetPoint)?
I have tried to do a function that accelerates until Speed = SetSpeed and only then activate the PID controller, but sometimes I need to make small corrections so the Speed never reaches SetSpeed. Can this be done in the PID controller?
I don't think so. the pid is a "simple" control element whose job is to make Input = Setpoint. once you want to do more complicated things, you'll need to make the pid part of a larger control strategy. it sounds like that's what you're trying to do anyway, so let's talk about that.
First, I'm not sure I completely understand your application. You use both SetSpeed and SetPoint in your question. I'm would assume that Speed is the output from the pid, and Setpoint is the value you want the PID Input to achieve. I'm not sure though.
I don't want to give you bad advice at this point. Could you give a description of what it is you're trying to do in the real world (i.e. "I've got this thermonuclear jetpack, and I'm tyring to control take-off velocity. my inputs and outputs are...") I'll be able to give better advice once I know what it is you're trying to do.
Brett