ProSoft Technology InRax MVI71-DNPSNET, Руководство пользователя

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Reference MVI71-DNPSNET ♦ PLC Platform
Distributed Network Protocol Interface Module
ProSoft Technology, Inc. Page 79 of 100
September 22, 2008
All data for these data types is derived from the processor and is passed to the
module over the backplane. The module will constantly monitor for changes in
this data and generate event messages when point values change. For binary
input points, events will be generated on any state change. For analog input
points, events will be generated for points that have a current value outside of the
user-set deadband based on the last value used for an event.
The following illustration shows the interaction of the counter points with the
databases.
This data is constantly sourced from the processor and placed in the module's
internal database. This information is available to the remote master for
monitoring. When the module receives a freeze command from the master unit, it
will copy the current counter values into the frozen counter database area. The
remote master can then monitor this information. If the module receives a
counter freeze with reset command, the current counter values will be passed to
the frozen counter database and only the module's values will be set to 0.
Note: This data is not sent to the controller, and the zero data be overwritten by the counter data
contained in the controller. Therefore, the freeze with reset should not be used with this module.
The results will not be as expected. There is no way to guarantee that counts will not be lost during
the reset step in the module and controller. As a result, this feature was not implemented in the
module.
The following illustration shows the interaction of the binary and analog output
points with the databases.
Output data is sourced from the controlling master station and passed to the
processor over backplane from the module. These data are used in the ladder
logic to control operations and I/O in the processor.