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This driver was created to connect
a very old plc Amper plc 68K with a modern
scada. Due to the lack of a scada application
ready driver for this plc many components
had to be implemented in a single driver in
order to be operational.
The development of this driver made possible
the Public Power Corporation (PPC) of Greece
witch allowed us to test this driver in their
facilities. In order to design this application
we had to begin from the very start with reverse
engineering of the Amper plc serial protocol,
then a multithreaded core was designed in
order to manipulate the plc's needed and finally
the DDE and ADO interface of the driver in
order to communicate with other applications..
The development tool used for the development
of this driver was Visual C++ .NET. During
the field testing of the driver we implemented
the driver some useful features such as:
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| Features |
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- DDE Request and Advanced request transactions
- DDE Hot link support AREQ
- DDE bit request for each topic
- Amper plc flag memory interface
- Multithreaded application
- Real time clock and watch dog timer
- Net DDE Hot link support
- User friendly GUI
- Auto memory clean up (memory friendly)
HASP Protected
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| Parameters |
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Configuration menu:
- PLC name to DDE Topic
- Autostart in case of communication failiure
- DDE tag update
- up to 30 plc
- Demo Operation
- Configurable timeouts
- Database connetion via ODBC or ADO
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| Topology |
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This
is a typical connection tested between the
HMI (Human Machine Interface) and the field
( plc ).
In the schematic someone can see the interconnection
of the scada application an the driver developed,
ether via Ethernet or locally using dde or
netDDE. The connection of the driver with
the plc is established with the use of some
Ethernet to rs232 devices. These devices can
be used either as a virtual rs232 device or
as a raw socket to rs232 device. In our tests
we used both methods with good results but
we ended up using the virtual rs232 method
due to PPC request. With the development of
this tool we practically created a multifunctional
tool which can connect any device with a scada
system or a database.
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