PaulS:
... none of my other function calls require me to include anything.
What other function calls are you referring to? ... Don't complain about having to include one lousy file...
My program is about 46,000 bytes, spread over 6 or 7 tabs in the IDE, so there are many other functions that are called from setup and/or loop. But they require zero (nil, zilch) #include statements (other than #includes for contributed libraries) so why should I have to start now, and it may only be required for this one only?!
PaulS:
I did try cut and paste recently but I get this error: 'FloatToString' was not declared in this scope??
So, we'd need to see how you did it. Generally, all ino files are merged for compilation as a single file. so the function should be in scope.
I'll attach the whole lot as a zip below, or later
PaulS:
... but so can google, so, I'll defer.
doh ... I should've thought of that! 
CJ_09.zip (18.2 KB)