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Reading/Writting multiple items on trigger/event

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01 May 2014 15:39 #1918 by support
OK, let me know if there is still something that I need to answer.

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01 May 2014 13:25 #1916 by masa
I don't want to use Live Binding in this application. Just manually coded call to WriteMultipleItems.

I am performing measurements and at the end of these operations I would like to send set of parameters to single OPC server.

I have known about WriteMultipleItems, but I was not sure what is behind this function. It sounds great that it is performing just single OPC Write operation and not multiple OPC Write ones.

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01 May 2014 12:21 #1915 by support
First thing that needs to be determined is whether you want to use Live Binding, or just a "manually" coded call to WriteMultipleItems (or a combination of them).

Live Binding is meant only for visual applications with Windows Forms, where the forms contain controls that should update according to OPC values, and/or contain values that need to be written to an OPC server. Is this your case?

If not, I will recommend an approach without the Live Binding model. - but we need to establish this first.

It is true that when properly set, Live Binding will use a single call to WriteMultipleItems when you invoke the writing.

It is also true that with WriteMultipleItems, only a single OPC Write operation will be made, containing all the items you specified (actually, first the input items will be split according to which OPC server they address, but if you have just a single server, then this is irrelevant).
The following user(s) said Thank You: masa

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30 Apr 2014 17:03 #1911 by masa
Hi,

I am receiving and sending set of parameters to and from my measurement PC application. Using OPC DA, QuickOPC.NET and VB.NET. I really like the idea of Live binding demo with BindingGroup where is a group of parameters send to server as atomic transaction.

My idea is to perform reading/writing set of parameters on base of some trigger. Probably an Event. I would like to be sure that all of my parameters (e.g. 70 tags) are consistent and no item is delayed using just simple WriteMultipleItems command.

Could you please suggest me the way how to achieve that?

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