Tormach PCNC 440 - 7.2.7 Additional G-code Formatting Notes; 7.2.7.1 Repeated Items; 7.2.7.2 Order of Execution

Chapter 7
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UM10372_PCNC440_Manual_0221A
PROgRAMMiNg
7.2.7 Additional G-code Formatting Notes
7.2.7.1 Repeated Items
A line may have any number of G words, but two G words from the same modal group may not
appear on the same line. For more informaon, see Modal Groups later in this chapter.
A line may have zero to four M words. Two M words from the same modal group may not appear
on the same line.
For all other legal leers, a line may have only one word beginning with that leer.
If a parameter seng of the same parameter is repeated on a line, #3=15 #3=6, for example, only the
last seng takes eect. It is illogical but not illegal to set the same parameter twice on the same line.
7.2.7.2 Order of Execution
The order of items on a line does not determine the order of execuon on the commands. For more
informaon, see table Order of Execuon later in this chapter.
The three types of items whose order may vary on a line (as given at the beginning of this secon)
are word, parameter seng, and comment. Imagine that these three types of items are divided into
three groups by type.
The rst group (the words) may be reordered in any way without changing the meaning of the line
which is as dened above.
If the second group (the parameter sengs) is reordered, there is no change in the meaning of
the line unless the same parameter is set more than once. In this case, only the last seng of the
parameter takes eect. For example, aer the line:
#3=15 #3=6
has been interpreted, the value of parameter 3 is 6. If the order is reversed to
#3=6 #3=15
and the line is interpreted, the value of parameter 3 is 15.
If the third group (the comments) contains more than one comment and is reordered, only the last
comment is used. If each group is kept in order or reordered without changing the meaning of the
line, then the three groups may be interleaved in any way without changing the meaning of the line.
For example, the line:
G40 G01 #3=15 (foo) #4=-7.0
has ve items and means exactly the same thing in any of the 120 possible orders, such as #4=-
7.0 G01 #3=15 g40 (foo), for the ve items. The order of execuon of items on a line is
crical to safe and eecve mill operaon. If items occur on the same line, they are executed in a
parcular order. For more informaon, see Order of Execuon table later in this chapter.