Installation manual

Publication 1747-RM001G-EN-P - November 2008
Data File Organization and Addressing E-19
When entering values into an instruction or data table element, you can specify
the radix of your entry using the appropriate suffix. The radixes that can be
used to enter data into an instruction or data table element are:
• integer (D).
• binary (B).
• hexadecimal (H).
• octal (O).
Numeric constants are used in place of data file elements. They cannot be
manipulated by the user program. You must enter the offline program editor
to change the value of a constant.
M0 and M1 Data Files -
Specialty I/O Modules
M0 and M1 files are data files that reside in specialty I/O modules only. There
is no image for these files in the processor memory. The application of these
files depends on the function of the particular specialty I/O module. For some
modules, the M0 file is regarded as a module output file and the M1 file is
regarded as a module input file. In any case, both M0 and M1 files are
considered read/write files by the SLC 5/02 and higher processors.
M0 and M1 files can be addressed 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 that you keep the following in mind in creating and applying your
ladder logic.
TIP
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 M0 and M1 data, independent of the rung
logic applied during the scan.