| The OPC server adds
an additional component to the open architecture of SYSTEM-90E. The OPC server is a software
interface enabling standardized access to data of various characteristics and origin.
In this case it is unimportant whether this data is transferred via application programs
or interfaces. The OPC server sees to it that this data is made uniformly available, and
the OPC client need not be concerned with transmission details. |
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| Open standard |
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Since OPC is a widely accepted standard which is supported by many software vendors, a broad range
of OPC servers is available for the most diverse tasks and these servers are compatible at the OPC
interface. |
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| Easy linkage to visualization systems |
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Many manufacturers of visualization tools use the OPC standard for coupling to various
applications and interfaces. Since programming is done with a uniform interface, creating
user interfaces is considerably simplified. As an alternative, of course, one can also use a
programming language such as Visual Basic or Visual C++ to access an OPC server.
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| Networkwide access |
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An additional important advantage of the OPC technology is that an OPC server provides
its data networkwide. If for example an OPC server is running on a computer and exchanging
data with a field unit, any computer in the network can access this data provided by the
OPC server.
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| Easy to connect via pNET protocol |
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Physically connecting the OPC server to SYSTEM-90E is done via a
serial RS232 interface in conjunction with the pNET protocol.
During the implementation phase special attention was paid to achieving as high a data
transfer rate as possible; at a baud rate of 115000 up to 1000 transfers per second
are achieved. |
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| Inside a computer, several
OPC servers connected to various control units can be operated simultaneously.
Cascading servers is of course also possible here to increase the data throughput. |
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| A configuration file read in when booting up the OPC server is used for assigning
the OPC variables to SYSTEM-90E's multi-port registers. This makes
visualization programming completely independent of the concrete location of the variables;
besides, modifications of the assignments may be made without having to adapt the visualization. |
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