making a opc client in Python and use opc server Events

[jp.eugster at googlemail.com]

On 28 juin, 16:55, jp.eugs... at googlemail.com wrote:
> On 4 juin, 11:32, getelectro... at gmail.com wrote:
>
>
>
>
>
> > Hi all
> > I have a sample code to implement opc client in Python. i use a
> > file .py making by makepy with pythonwin for Com Interface.
> > i can get all server in machine, connect to server opc, disconnect,
> > add group, add item, read, write item in server opc.
>
> > import win32com.client  # librairie pour utiliser l'interface COM/DCOM
> > from win32com.client import gencache
> > gencache.EnsureModule('{DFB83232-A952-11D2-A46B-00C04F796375}', 0, 1,
> > 0)
>
> > for svr in opcserver.GetOPCServers():
> >     print svr
>
> > #connect to server OPC Demo Simulation from Matrikon
> > opcserver.Connect('Matrikon.OPC.Simulation.1')
>
> > # Instance object Groups
> > groups=opcserver.OPCGroups
> > #add group
> > group=groups.Add('Group1')
>
> > #instance onject Items
> > items=group.OPCItems
> > # add item in server opc
> > tem=items.AddItem('File1.item1',1)
>
> > #read item value
> > item.Read(win32com.client.constants.OPCDevice)
>
> > # write a new value
> > item.Write(100)
>
> > #read item value
> > item.Read(win32com.client.constants.OPCDevice)
> > #if no pb you have 100 :)
>
> > #Disconnect
> > #opcserver.Disconnect()
>
> > BUT, and BUT, i want to use a event from opc server for uodating item
> > value with this below class. And i don't konw how make it!!!!!!!!
> > help me plz
>
> > opcserver=win32com.client.Dispatch('OPC.Automation.1')
> > and now i want to use events from opc server. in a class:
> > class DIOPCGroupEvent:
> > class DIOPCGroupsEvent:
> > class DIOPCServerEvent:
>
> Try this:
>
> # Event Handlers
> class ServerEvent:
>         def __init__(self):
>                 print 'Init ServerEvent'
>
>         def OnServerShutDown(self, Reason):
>                 print 'OnServerShutDown', Reason
>
> class GroupEvent:
>         def __init__(self):
>                 print 'Init GroupEvent'
>
>         def OnAsyncCancelComplete(self, CancelID):
>                 print 'OnAsyncCancelComplete', CancelID
>
>         def OnDataChange(self, TransactionID, NumItems, ClientHandles,
> ItemValues, Qualities, TimeStamps):
>                 print 'OnDataChange', zip(ClientHandles, ItemValues, Qualities)
>
>         def OnAsyncReadComplete(self, TransactionID, NumItems, ClientHandles,
> ItemValues, Qualities,
>                                                  TimeStamps, Errors):
>                 print 'OnAsyncReadComplete', zip(ClientHandles, ItemValues,
> Qualities)
>
>         def OnAsyncWriteComplete(self, TransactionID, NumItems,
> ClientHandles, Errors):
>                 print 'OnAsyncWriteComplete', zip(ClientHandles, Errors)
>
> class GroupsEvent:
>         def __init__(self):
>                 print 'Init GroupsEvent'
>
>         def OnGlobalDataChange(self, TransactionID, GroupHandle, NumItems,
> ClientHandles, ItemValues,
>                                                  Qualities, TimeStamps):
>                 print 'OnGlobalDataChange', zip(ClientHandles, ItemValues,
> Qualities)
>
> opc = DispatchWithEvents('Matrikon.OPC.Automation.1', ServerEvent)
>
> groups = DispatchWithEvents(opc.OPCGroups, GroupsEvent)
> groups.DefaultGroupIsActive = True
> groups.DefaultGroupUpdateRate = 2000
>
> group1 = DispatchWithEvents(groups.Add('G1'), GroupEvent)
> group2 = DispatchWithEvents(groups.Add('G2'), GroupEvent)
> #etc ...
>
> It works for the GroupsEvents but I don't get the GroupEvent for each
> group, I may still do someting wrong..- Masquer le texte des messages précédents -
>
> - Afficher le texte des messages précédents -

In order to get the GroupEvent, you have to keep a reference to the
group you add
eg:
g1 = groups.Add('G1')
group1 = DispatchWithEvents(g1, GroupEvent)
etc...