ProSoft Technology MVI46-DNP - Manual (Page 58)

MVI46-DNP ♦ SLC Platform Reference
Master/Slave Communication Module
Page 58 of 143 ProSoft Technology, Inc.
August 23, 2007
5.2 Functional Overview
In order to implement a solution using the module, the SLC must be set up using
both program and data files. The data transfer interface requires ladder logic in
order to interface data in the module with that in the SLC. Data is transferred
between the module and the SLC through M-files located on the module. These
data areas are shared data regions available to both the processor and the
module. The ladder logic required is discussed in the ladder logic section. This
program interacts with the module by sending and receiving data, issuing
commands, and configuring the module.
Data files in the SLC contain the configuration and the data to be used by the
module.
Before you generate the program or layout the data files, you must first design
your system. Time spent doing system design at the outset of the project will
greatly enhance the success and ease of development of the project.
5.2.1 Module Power Up and Configuration
Configuration information is stored on the module's Compact Flash. Setup of the
module requires software configuration using the RSLogix 500 program and the
DNP.CFG configuration file on the Compact Flash. The easiest method to
implement the module is to start with the example provided with the module
(MVI46-DNP.RSS) and the example configuration file (DNP.CFG). Module
Configuration (page 17) describes how to use and/or modify the two files.
If the DNP master port is to be used, the module reads the slave configuration
information and builds the slave list during the configuration process. The module
also reads the command list from the M0: file. Valid commands will be added to
the command list. Binary input, counter and analog input objects will be added to
the point lists for each slave based on the commands processed. In addition, the
RBE (Report By Exception) flags for the binary and analog input points are set in
the RBE flag database.
The module next checks the DNP BO/AO (Binary Output / Analog Output) preset
flag to determine if the DNP binary and analog output data must be read from the
SLC. The option permits the SLC to set these read-only data at startup. There is
no static memory available on the module to remember the last values for these
data types. In order to prevent "shock" to the system at boot time, this option can
be used to set the module's database to the last transferred set of data. Ladder
logic must transfer the data to the module using the M1-file data area for these
data types.
The module now checks the IED (Intelligent Electronic Device) BI/AI/C (Binary
Input / Analog Input / Counter) preset flag to determine if the IED binary and
analog input and counter data must be read from the SLC. The option permits
the SLC to set these read-only data at startup. There is no static memory
available on the module to remember the last values for these data types. In
order to prevent "shock" to the system at boot time, this option can be used to set
the module's database to the last transferred set of data. Ladder logic must
transfer the data to the module using the M1-file data area for these data types.