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Subscribing to a non-existent item
08 Jul 2021 08:21 #9950
by support
Replied by support on topic Subscribing to a non-existent item
Hello.
I am not sure if you have sent me the right code.
When I run your program, I get this form:
with the values in the uppermost edit box quickly changing.
This, in my understanding, *is* the expected behavior with the code in the program, which looks like this (shortened):
Edit1 is changing because the server sends no errors, good quality Byte-typed updates for the 'Random.UInt1' item.
Edit2 keeps its original text because the server returns an error for this item, EventArgs.Succeeded is false, and the "if" statements do not thus make any update.
Edit3 changes to 'Edit3 text changed unexpectedly', because (I have mentioned in my previous post), the server sends a string value for this item, although it is not configured.
I do not see any signs of the problem you reported, i.e. that the program blocks somewhere, or stops. But, this is not the same code you had included with that report.
Regards
I am not sure if you have sent me the right code.
When I run your program, I get this form:
with the values in the uppermost edit box quickly changing.
This, in my understanding, *is* the expected behavior with the code in the program, which looks like this (shortened):
procedure TForm1.FormCreate(Sender: TObject);
begin
OPCDAClient := CoEasyDAClient.Create ;
OPCDAClient.PullItemChangedQueueCapacity := 1000 ;
OPCDAClient.SubscribeItem('', 'Matrikon.OPC.Simulation.1', 'Random.UInt1', 50) ;
OPCDAClient.SubscribeItem('', 'Matrikon.OPC.Simulation.1', 'SomeUnknownItem', 50) ;
OPCDAClient.SubscribeItem('', 'Matrikon.OPC.Simulation.1', 'Bucket Brigade.UIntqa', 50) ;
end;
procedure TForm1.Timer1Timer(Sender: TObject);
Var i : Integer ;
EventArgs: _EasyDAItemChangedEventArgs ;
Begin
Repeat
EventArgs := OPCDAClient.PullItemChanged(5) ;
If EventArgs <> nil Then
If EventArgs.Succeeded Then
If EventArgs.VTQ.HasValue and EventArgs.VTQ.Quality.IsGood Then
Begin
If EventArgs.Arguments.ItemDescriptor.ItemId = 'Random.UInt1' Then
Edit1.text := EventArgs.VTQ.Value ;
If EventArgs.Arguments.ItemDescriptor.ItemId = 'SomeUnknownItem' Then
Edit2.text := 'Edit2 text changed unexpectedly' ;
If EventArgs.Arguments.ItemDescriptor.ItemId = 'Bucket Brigade.UIntqa' Then
Edit3.text := 'Edit3 text changed unexpectedly' ;
End;
Until EventArgs = nil ;
End;Edit1 is changing because the server sends no errors, good quality Byte-typed updates for the 'Random.UInt1' item.
Edit2 keeps its original text because the server returns an error for this item, EventArgs.Succeeded is false, and the "if" statements do not thus make any update.
Edit3 changes to 'Edit3 text changed unexpectedly', because (I have mentioned in my previous post), the server sends a string value for this item, although it is not configured.
I do not see any signs of the problem you reported, i.e. that the program blocks somewhere, or stops. But, this is not the same code you had included with that report.
Regards
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