ProSoft Technology MVI46-103M - Manual (Page 17)

Functional Overview MVI46-103M ♦ SLC Platform
IEC 60870-5-103 Master Communication Module
ProSoft Technology, Inc. Page 17 of 187
September 12, 2006
3.1.4 Backplane Data Transfer
The MVI46-103M module is unique in the way it utilizes the SLC backplane. All
data for the module is contained in the module's M1 file. Data is moved between
the module and the SLC processor across the backplane using the module's M1
file. The SLC scan rate and the communication load on the module determine the
update frequency of the M1 file. The COP instruction can be used to move data
between user data files and the module's M1 file.
The following illustration shows the data transfer method used to move data
between the SLC processor, the MVI46-103M module and the IEC 60870-5-103
network.
As shown in the previous diagram, all data transferred between the module and
the processor over the backplane is through the M1 file. Ladder logic must be
written in the SLC processor to interface the M-file data with data defined in the
user-defined data files in the SLC. All data used by the module is stored in its
internal database. Data contained in this database is constantly updated with the
M1 file data by the module and requires no SLC ladder logic to implement. The
user database resides in the M1 file at addresses 0 to 3999. Addresses above
3999 are used for special block control of the module.
3.1.5 Data Types and Mapping
When interfacing data in the processor to that of the IEC 60870-5-103 protocol, it
is important that the user understand the mapping of the data types to their
corresponding representation in the modules database. The table that follows