Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 648)

Miscellaneous Parameters
Chapter 37
37-8
Function
This parameter specifies the letter that is used to call the second auxiliary
function which is commonly used when the number of M-codes is not
sufficient for the available number of miscellaneous functions. The system
installer determines what second auxiliary function words call what
auxiliary functions in PAL.
Axis Parameter
Number
All [443]
Range
Selection Result Selection Result
(a) A (f) W
(b) B (g) X
(c) C (h) Y
(d) U (i) Z
(e) V (j) none
Notes
This is a global parameter; the value entered here applies to all axes
and processes.
37.8
Secondary Auxiliary
Function Word