Rockwell Automation 1203-SM1 SLC to SCANport Communication Module - Manual (Page 64)

M0, M1, and G Files A–8
Publication 1203–5.9 –– October 1996
The following figure shows another economizing technique. The
COP instruction addresses an M1 file, adding approximately 4.29 ms
to the scan time if you are using a SLC 5/02 Series B processor.
Scan time economy is realized by making this rung true only
periodically, as determined by clock bit S:4/8. (Clock bits are
covered in chapter 1 of the Advanced Programming Software
Reference Manual, Publication 1747–6.11.) A rung such as this
might be used when you want to monitor the contents of the M1 file,
but monitoring need not be on a continuous basis.
S:4/8 causes the #M1:4.3
file to update the #N10:0
file every 2.56 seconds.
COP
Copy FILE
Source
#M1:4.3
Dest #N10:0
Length 6
S:4
8
] [
B11
0
]OSR[
Capturing M0–M1 File Data
The first two ladder diagrams in the previous section show a
technique that lets you capture and use M0 or M1 data as it exists at
a particular time. In the first figure, bit M0:2.1/1 could change state
between rungs 1 and 2. This could interfere with the logic applied in
rung 2. The second figure avoids the problem. If rung 1 is true, bit
B3/10 captures this information and places it in rung 2.
In the second example of the last section, a COP instruction is used
to monitor the contents of an M1 file. When the instruction goes
true, the six words of data in file #M1:4.3 is captured as it exists at
that time and placed in file #N10.0.
Some specialty I/O modules use G (confiGuration) files (indicated in
the specific specialty I/O module user’s manual). You can think of
the files as the software equivalent of DIP switches.
You can access and edit the content of G files offline from the I/O
Configuration function. You cannot access G files under the Monitor
File function. Data you enter into the G file is passed to the specialty
I/O module when you download the processor file and enter the
REM Run or any one of the REM Test modes.
G Files