Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 311)

Introduction to Programming
Chapter 10
10-37
The B--word is commonly used when the number of M--codes is not
sufficient for the available number of miscellaneous functions. Any
alphabetic character which is not used for other functions may be used
instead of B by setting the proper AMP parameter. For details, refer to the
documentation prepared by your system installer, or your AMP reference
manual. This manual assumes the B--word is used to call second auxiliary
functions.
The B--word is designated by a two or three-digit numeric value following
address B. Unlike M--codes, each block can contain only one B--word.
Important: When the MISCELLANEOUS FUNCTION LOCK feature is
activated, the control displays M--, B--, S--, and T--words in the part
program with the exception of M00, M01, M02, M30, M98, and M99.
This feature is described in chapter 7.
Each block in a part program can be assigned up to a five-digit numeric
value following an N--address. These numbers are referred to as sequence
numbers and are used to distinguish one block from another.
Sequence numbers can be assigned at random to specific blocks or to all
blocks if desired. Blocks assigned sequence numbers can be called later by
referencing their sequence number. Sequence numbers are necessary to
make program jumps and to specify a block for subprogram calls and
returns.
The O-word is used to define a program name. To use an O--word as a
program name it must be the first block entered in a program. This block
can be used to identify a program when reading from a tape (when
program name is selected as “automatic” from the device setup menu).
This is useful when many programs are placed together on a single tape.
An O-word can have up to five numeric characters following it.
When the same series of blocks are repeated more than once it is usually
easier to program them using a subprogram.
Important: To make jumps, loops, or calculations within an executing
program or subprogram use any of the paramacro features as discussed in
chapter 28.
P--words in a subprogram call (M98) are used to designate the specific
program being called. The P--address is followed by the program name
being called.
10.5.7.1
Auxiliary Miscellaneous
Function (B- word)
10.5.8
N- words (Sequence
Numbers)
10.5.9
O- words (Program Names)
10.5.10
P ,L (Main Program Jumps
and Subprogram Calls)