Block Rules - Siemens SINUMERIK 840D sl Programming Manual

Fundamentals
2.2 Fundamental Principles of NC Programming
2.2.2.2

Block rules

Start of block
NC blocks can be identified at the start of the block by block numbers. These consist of the
character "N" and a positive integer, e.g.
N40 ...
The order of the block numbers is arbitrary, however, block numbers in rising order are
recommended.
Note
Block numbers must be unique within a program in order to achieve an unambiguous result
when searching.
End of block
A block ends with the character LF (LINE FEED = new line).
Note
The LF character does not have to be written. It is generated automatically by the line change.
Block length
A block can contain a maximum of 512 characters (including the comment and end-of-block
character LF).
Note
Three blocks of up to 66 characters each are normally displayed in the current block display on
the screen. Comments are also displayed. Messages are displayed in a separate message
window.
Order of the statements
In order to keep the block structure as clear as possible, the statements in a block should be
arranged in the following order:
N... G... X... Y... Z... F... S... T... D... M... H...
Address
N
G
X,Y,Z
F
S
46
Meaning
Address of block number
Preparatory function
Positional data
Feedrate
Speed
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming