Learn how easy it is to sync an existing GitHub or Google Code repo to a SourceForge project! See Demo

Close

Reading remote group always returns same valu

Help
2012-03-15
2013-05-30
  • Andy Lawton
    Andy Lawton
    2012-03-15

    here is the code:

    opc = OpenOPC.open_client("remote_pc")
                opc.connect('Matrikon.OPC.Simulation')
                rtags =
                print opc.read(rtags, group='rtest')
                time.sleep(2)
                print opc.read(group='rtest')
                time.sleep(2)
                print opc.read(group='rtest')
                time.sleep(2)
                print opc.read(group='rtest')
                time.sleep(2)
                print opc.read(group='rtest')
                time.sleep(2)
                print opc.read(group='rtest')
                time.sleep(2)
                opc.remove('rtest')
                opc.close()

    Connecting to a remote PC returns the same values for every read of the group. Connecting to localhost returns random values (as expected) for each read. I'm using the latest version of OpenOPC. Tested on Windows 7, two separate remote PC's.

     
  • try windows 9 - that'll help (just kidding).

    ugh - i long for the day when barry finally commits the ua implenation and we're free of windows all together. 

    that said, i got nothin' - that is a very odd behavior you have described, almost like it's caching data somewhere. 

     
  • Andy Lawton
    Andy Lawton
    2012-03-17

    As I can't seem to edit my post, here's an update. The same thing happens if you connect to localhost. The reason values were changing (I think) is that I had the Matrikon OPC Explorer running, looking at the same OPC variables. As soon as I shut the Explorer down, I got the same effect.