SST SST-ASI-SLC, User Manual

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The following data is based on information in the SLC 500 Instruction Set
Reference Manual , Allen-Bradley publication 1747.6.15, and is provided
here for reference.
M0 and M1 files are files that reside in specialty I/O modules only. There is
no image for these files in the processor memory. This means that when an
application running on the SLC accesses the data, the SLC must go out to
the module and read the data. The application of these files depends on the
function of the particular specialty I/O module. Both M0 and M1 files are
considered read/write files by the SLC processor. On the SST-ASI-SLC,
you cannot write to the M files.
M0 and M1 files can be addresses in your ladder program and they can also
be acted upon by the specialty I/O module, independent of the processor
scan. It is important to keep the following in mind when creating and
applying your ladder logic.
During the processor scan, M0 and M1 data can be changed by the
processor according to ladder diagram instructions addressing the M0 and
M1 files. During the same scan, the specialty I/O module can change the
M0 and M1 data, independent of the rung logic applied during the scan.
A
M0 and M1 Files