I understand. In your earlier post, however, you have written

That PLC1 that is only available the first time I look for a tag.

After the first time it is nog shown and it gives an error.

Please provide the details of the error.

In the demo application, this behavior is by design, i.e. the value is written when the user presses the corresponding button. A source code of the demo application goes with the product, so if you need it differently, you can have a look at how it is done, and modify it.

Normally, the server should report an error when the write does not succeed, and QuickOPC transforms that error into an exception. It can be a server problem, and if your intuition is telling you that it has to do with data types/conversions, you may even be right; but it's impossible to tell without further analysis.

HOW do you test the Write? Is it e.g. with the Demo application that comes with QuickOPC, or do you have your own code? If you are doing it from code, definitively post it here, otherwise I won't be able to help.

Best regards

I have to admit that I understand you just partially. But I will try to do my best. What's most important, you need to describe precisely what you are seeing.

In your last post, you have written "...and it gives an error.". What was the error saying? Precisely please. You really need to post all possible details about the error here.

Value conversions: OPC servers normally provide values for a particular item using its so-called "canonical data type". So, in a reasonable server, an integer value would also be returned as an integer. In opposite direction (when writing) (at least according to the latest versions of the specs), the server is supposed to make the conversion whenever possible, so even if you write a string, a compliant server should (for an integer item) convert it to integer anyway.

There are ways to specify a concrete data type e.g. when subscribing. And there are way to make conversion yourself in your code (I am assuming you are using C# or .VB.NET - is that true?).

Either way, you need to show me first what precisely you want to achieve, and what you have tried already, and where it does not fulfill what you are looking for.

Best regards