Rockwell Automation 1203-SM1 SLC to SCANport Communication Module - Manual (Page 63)

M0, M1, and G Files A–7
Publication 1203–5.9 –– October 1996
SLC 5/03 Processor Example
The SLC 5/03 access times depend on the instruction type. Consult
the previous table for the correct access times to add. As an
example, if you use a COP to M file instruction like the one shown,
add 772
µ
s plus 23
µ
s per word. This adds 1554
µ
s to the SLC 5/03
scan time due to the COP instruction.
Minimizing the Scan Time
To keep the processor scan time to a minimum, reduce the use of
instructions addressing the M0 or M1 files. For example, XIC
instruction M0:2.1/1 is used in rungs 1 and 2 of the following
example, adding approximately 2 ms to the scan time if you are
using a SLC 5/02 Series B processor.
XIC instructions in rungs 1 and 2 are addressed to the M0 data file. Each
of these instructions adds approximately 1 ms to the scan time (SLC 5/02
Series B Processor).
M0:2.1 B3
1 10
( ) ] [
1
B3 B3
12 14
( ) ] [
2 M0:2.1
1
] [
In the equivalent rungs shown below, XIC instruction M0:2.1/1 is
used only in rung 1, reducing the SLC 5/02 scan time by
approximately 1 ms.
These rungs provide equivalent operation to those of figure A by substituting
XIC instruction B3/10 for XIC instruction M0:2.1/1 in rung 2. Scan time is
reduced by approximately 1 ms (Series B processor).
M0:2.1 B3
1 10
( ) ] [
1
B3 B3
12 14
( ) ] [
2 B3
10
] [