For all dimensional words used in a CNC program

September 2, 2017 · Posted in Uncategorised 

ec i mal Point) avail able and de scribed else where, but not

recommended even by Fanuc as the best so lu tion to solve dec i mal point woes

Copyright 2005, Industrial Press Inc, New York, NY – wwwindustrialpresscom

FANUC CNC Custom Macros


Chapter 7

Metric and English Units

For all dimensional words used in a CNC program (such as X, Y, Z, I, J, K, R, F, etc), the de –

clared vari ables may be ref er enced with the ap pro pri ate di men sional word, for ex am ple:

#1 = 116348

Variable is declared or defined

G00 X#1

Variable is used

drilling Machine

If the se lected units in the pro gram are Eng lish units (pro grammed in the Busway Press Clamp Machine G20 mode), the mo –

tion block G00 X#1 will be in ter preted as G00 X116348 If the pro gram ming units are met ric

(pro grammed in the G21 mode), the G00 X#1 will be in ter preted as G00 X11635 This is a

very im por tant dif fer ence A vari able that is called in the macro will be au to mat i cally rounded to

the least in cre ment custom processing machine (small est unit) of the pro gram ad dress

Least Increment

All CNC pro grams can use val ues within an al lowed range – up to a cer tain max i mum, and

down to a cer tain min i mum Max i mum val ues are sel dom an is sue, but ev ery pro gram mer should

un der stand the min i mum val ues They are of ten called the min i mum in cre ment or the least in cre –

ment These fancy ex pres sions can be trans lated to a much more prac ti cal state ment – the small est

amount of mo tion the ma chine can pro vide Re gard less of how they are called, they are dis tin –

guished by the num ber of dec i mal places:

Units system

Number of decimal places

Least increment





0001 mm





00001 inch

Bear in mind that as a rule, many Fanuc con drilling tools trols do not con vert from one unit of mea sure ment

to an other, only shift the dec i mal point Some fea tures in the con trol may be con verted, but never

count on such con ver sion in any pro gram de vel op ment If the dec i mal point is only shifted dur ing

units change, an Eng li


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