Rockwell Automation 1747-SDN SLC 500 DeviceNet Scanner Module User Manual - Manual (Page 126)

Publication 1747-UM655B-EN-P - June 2007
126 Configuring the M0/M1 Files by Using RSLogix 500 Software
The COP instruction below copies six words of data from an M1 data
file in a module positioned in slot four to an integer file (N1:0). This
technique is used to monitor the contents of an M0 or M1 data file
indirectly, in a processor data file. An update of these six words is
made for each SLC program scan.
Reduce Scan Time
In the equivalent rungs below, XIC instruction M1:2.1/1 is used only
in rung 1, reducing the scan time by approximately 1 ms.
TIP
To reduce processor scan time, use discretion when you use
instructions addressing the M0 or M1 files. For example, XIC
instruction M1:2.1/1 is used in rungs 1 and 2 below, adding
approximately 2 ms to the scan time if you are using an 5/02,
series B processor.
COP
COPY FILE
Source
Dest
Length
#M1:4.3
#N10:0
6
] [
M1:2.1
1
( )
B3
10
] [
B3
12
] [
M1:2.1
1
( )
B3
14
1
2
XIC instructions in rungs 1 and 2 are addressed to the M1 data file. Each
of these instructions adds approximately 1 ms to the scan time
(SLC 5/02, series B processor).
M1:2.1
1
( )
B3
10
] [
B3
12
] [
B3
10
( )
B3
14
1
2
] [
These rungs provide equivalent operation to those of the previous diagram by
substituting XIC instruction B3/10 for XIC instruction M1:2.1/1 in rung 2. Scan
time is reduced by approximately 1 ms (SLC 5/02 series B processor).