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OpenOPC for Python 1.3.0

Copyright (c) 2007-2012 Barry Barnreiter (barry_b@users.sourceforge.net)
Copyright (c) 2014 Anton D. Kachalov (mouse@yandex.ru)
Copyright (c) 2017 José A. Maita (jose.a.maita@gmail.com)
Copyright (c) 2017 Cédric Hernalsteens (cedric.hernalsteens@gmail.com)

http://openopc.sourceforge.net/
https://github.com/ya-mouse/openopc
http://github.com/chernals/openopc

Notes about version 1.3.0

TODO

Post installation

Please go through the following post installation steps and functional checks to verify your installation of OpenOPC for Python is working correctly.

  1. Get a listing of the available OPC servers on your computer by going to the command prompt and entering:

opc -q

  1. Set your prefered OPC server as the default by setting the system wide enviornment variable OPC_SERVER. (On Windows you can do this by going to Control Panel > System > Advanced > Environment Variables)

OPC_SERVER=Matrikon.OPC.Simulation

  1. Test your Win32 COM connection to the OPC server by entering the following at the command prompt:

opc -i

  1. Test to see if the OpenOPC Gateway Service is functioning by entering:

opc -m open -i

  1. Test some of the other commands available using the OPC Command Line Client. To get started, try entering the opc command without any arguments in order to see the help page:

opc

To read an item from your OPC server, just include the item name as one of your arguments. For example, if you're using Matrikon's Simulation server you could do:

opc Random.Int4

To read items from a specific OPC server you have installed, include the -s switch followed by the OPC server name. For example:

opc -s Matrikon.OPC.Simulation Random.Int4

If you experience any unexpected errors during these tests, please check the FAQ on http://openopc.sourceforge.net for additional help.

If after reading through the FAQ you still require additional help, then the author of this package would be happy to assist you via e-mail. Please see the project website for current contact information.

Software Developers

If you elected to install the OpenOPC Development library during the installation process, then you'll need to also download and install the following packages in order to develop your own Python programs which use the OpenOPC library:

  1. Python 3.4+ http://www.python.org/download/

  2. Python for Windows Extensions (pywin32) http://sourceforge.net/projects/pywin32/

  3. Pyro4 https://github.com/irmen/Pyro4

Of course, Python is necessary on all platforms. However the other packages may be optional depending on your configuration:

  1. Win32 platform, using the OpenOPC Gateway Service

Pywin32: optional Pyro4: required

  1. Win32 platform, talking to OPC Servers directly using COM/DCOM

Pywin32: required Pyro4: optional

  1. Non-Windows platform (use of Gateway Service is mandatory)

Pywin32: not applicable Pyro4: required

In order to get the most from the OpenOPC package, Windows developers are encouraged to install both Pywin32 and Pyro. Using Pyro to talk to the Gateway Service provides a quick and easy method for bypassing the DCOM security nightmares which are all too common when using OPC.

Documentation

A PDF manual for OpenOPC is included in this installation inside the "doc" folder. Users are encouraged to also look at the OpenOPC web site for additional usage examples that may not be contained in the manual.

A note for *nix users

Note that when using OpenOPC on a non-Windows system you must be running the OpenOPC Gateway Service (OpenOPCService.py) on a Windows box somewhere on your network. The OpenOPC Gateway Service then acts as a proxy for all your OPC calls.

For example, if your Windows node which is running the Gateway Service had the IP address of 192.168.1.20 then you would use the OpenOPC command line client like this:

opc.py -H 192.168.1.20 -s Matrikon.OPC.Simulation -r Random.Real4

Or when using the OpenOPC.py module inside your own Python code, you would create your opc object like this:

import OpenOPC opc = opc.open_client('192.168.1.20') opc.connect('Matrikon.OPC.Simulation')

The above examples all assume that the OPC server and the OpenOPC Gateway Service are both installed on the same box. This is the recommended configuration in order to avoid any DCOM security issues.

If you downloaded this source code only version of OpenOPC for Unix, it is recommended you also download one of the win32 labeld downloads and use the pre-complied OpenOPCService.exe executable for Windows. This file is self contained and does not require that Python be installed on your Windows box.

Technical Support

If you have any questions, bug reports, or suggestions for improvements please feel free to contact the author at:

barry_b@users.sourceforge.net

While I cannot always guarantee a quick response, I eventually respond to all e-mails and will do my best to slove any issues which are discovered.

Thanks for using OpenOPC for Python!