Rockwell Automation GMLC Reference Manual - Manual (Page 830)

Publication GMLC-5.2 - November 1999
Understanding M Files 793
5. Select OK. The name of the new SLC Output Bit Group appears in
the Tag Window.
Understanding M Files
M files transfer large, non-time-critical groups of data—such as endpoints
and CAM tables—between the 1394 GMC Turbo and the SLC. M files
are updated whenever they are accessed during read/write functions. Each
M file is 1024 bytes long and can consist of one of the following:
• All integers.
• All floating points.
• A combination of both.
Total Signals in
Group Type the number of consecutive bits in the
group.
Note:
This number must include all bits in the
sequence—bits you will write to, as
well as bits in the sequence you will not
write to.
Use Bit Mask To exclude (mask) one or more signals in the
group, type a binary value representing the bits
whose signals you will write to.
See Bit Masks in the Expression Builder chapter
of this manual for more information on bit
masks.
Field Description
If an M File contains all: The maximum number of elements is:
Integer elements 512 (each integer element is 16 bits (one word)).
Floating point elements 256 (each floating point element is 32 bits (two words)).