OpenOPC for Python was specially designed as an easy-to-use and Open Source OPC (OLE for Process Control) library.
The OpenOPC project also includes a Windows gateway service allowing non-Windows clients to also access OPC-DA calls.
Here are some key features of "OpenOPC":
Easy to use:
· Because the OpenOPC library implements a minimal number of Python functions which may be chained together in a variety of ways, the library is simple to learn and easy to remember. In its simplest form, you can read and write OPC items as easily as any variable in your Python program.
Cross platform support:
· OpenOPC works with both Windows and non-Windows platforms. It has been tested with Windows, Linux, and Mac OS X.
Functional programming style:
· OpenOPC allows OPC calls to be chained together in an elegant, functional programming style. For example, you can read the values of all items matching a wildcard pattern using a single line of Python code!
Designed for dynamic languages:
· Most OPC toolkits today are designed for use with static system languages (such as C++ or C#), providing a close mapping to the underlying Win32 COM methods. OpenOPC discards this cumbersome model and instead attempts to take advantage of the dynamic language features provided by Python.
· OpenOPC is also one of the very few OPC-DA toolkits available for any dynamic language, and future support is planned for Ruby.
Requirements:
· Python
What's New in This Release: [ read full changelog ]
· In previous versions of OpenOPC the Gateway Service would sometimes fail
· to bind to a TCP port, thus causing the service to not listen for incoming
· connections. This would only occur on systems containing multiple ethernet
· interfaces and the failure would not be consistent or predictible.
· In such situations you can now tell the Gateway Service which ethernet
· interface to bind to by setting the OPC_GATE_HOST system enviornment
· variable equal to the IP address of the desired ethernet interface.
· It is recommended that this setting be made on all computers with more
· than one active ethernet interface. System enviornment variables can
· be set using the "System" applet inside the Windows Control Panel.
· In some cases the opc.read() function would attempt to automatically
· destoy an OPC group that no longer existed. This would result in an
· exception being thrown. This bug has been fixed.
· The OpenOPC installer has been updated to check for multiple versions
· of Python when installing th...
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