ProSoft Technology MVI46-DNP - Manual (Page 19)

Configuring the Module MVI46-DNP ♦ SLC Platform
Master/Slave Communication Module
ProSoft Technology, Inc. Page 19 of 143
August 23, 2007
The commands are also used to define the point mapping of IED response data
to the DNP database. These mappings are used for IED generated event
messages. When an IED unit generates an event message, the module must be
informed what point in the database to associate with the event. When the
command list is read during initialization, the data point mapping is determined
for each slave. Mappings are generated for binary input, analog input and
counter points. A separate set of lists is maintained for each slave defined for the
master port. The following illustration shows the storage of the data in the
module.
DI Pnts are generated for each command with an object type of 1. AI Pnts are
generated for each command with an object type of 30. Cntr Pnts are generated
for each command with an object type of 20 or 21.
When a master port receives a poll response or an unsolicited response
message, the points in the message are mapped to the IED and/or DNP
databases using the point lists. For example, when a master port receives a
value for binary input point 10 from slave unit 14, the module performs the
following steps:
1 The module searches the slave list to make sure slave 14 is valid for the
module. If the slave is not found, the message is ignored. If the slave is
found, the module saves the pointer to the binary input point list.
2
Point number 10 is searched for in the binary input point list. If the point is
found in the DNP point list, the new value is stored at the correct offset in the
DNP database. If the point is found in the IED point list, the new value is
stored at the correct offset in the IED database. If the point is not found in
either point list, it is ignored.
Note: Data can be placed in both the DNP and IED databases if the point number is
found in both searches. This would cause the value to be stored for use by the remote
DNP master unit and the SLC ladder logic.
Each node in the point lists contains the start-stop IED point ranges and the IED
and DNP database offset values. These values are read by the module from the
command list each time the module performs the restart operation. If the IED or
DNP database value is set to –1 or 65535, the database is not used for the
specified point range.