Hello Richard,
Micron is 1 million'th of a meter.
Millimeter is 1/1000 of a meter
millimeter to decimal is mm * 25.4 = 1.000 inch
so , if I did my math correctly (there is some doubt) 25,400 microns to the inch

PICs in P basic Pro only do Integer Math.
16 bit data bus only holds 65535 data bits.
Seems as though a PIC should hold about 2.58 inches worth

Do a search on DIV32, Darrel and some others have many threads and ideas.
JS