Re: Drive Straight C Code using Encoders without PID?
 

Yes. #defines are handled by the pre-processor before the file ever gets compiled. So what really happens is that the preprocessor finds all occurances of the #defined name and replaces it with whatever it was #defined to, and then runs the compiler on the result. The compiler never even sees the names you've assigned to your #defines.

Re: Drive Straight C Code using Encoders without PID?
 

And compiler error messages reflect that: the compiler will point to a line of code and object to some text that isn't in that line of code -- it's in the #define
If the compiler quotes the code it doesn't like, it will quote "3.14.159", not "PI" while referring to the line "circum = PI * dia;". That's because it doesn't see "PI", only "3.14.159".

Re: Drive Straight C Code using Encoders without PID?
 

Just another Idea:
Did you play arround with the Code Optimizing Features that the C18 Compiler has? I know you can get at least 10-15% more Space using that but I've also heard it could cause weird errors. But if you ask some people that used that before they can probably tell you what's safe to turn on and what you have to keep unoptimized ...