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Using QuickOPC with Vee Pro (Keysight/Agilent/Hewlett-Packard)

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20 Jan 2015 06:46 #2619 by veecan
Thank you for the answer.
I have written my own sorting routines.

Just a bit fun as NI Field Point have "non sortable names". But it´s done.

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19 Jan 2015 16:00 #2616 by support
OPC specifications do not give any meaning to the order of the branches/leaves. They do not tell the servers in which order to provide the nodes, and they do not tell the clients to keep the order in which the nodes are coming.

It is assumed that when some order is needed, the client will sort the nodes (e.g. alphabetically). That can easily be done in most programming languages.

See also: stackoverflow.com/questions/26341994/sorting-items-in-opc-server

Best regards

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19 Jan 2015 07:33 #2614 by veecan
Hallo
Thank you. Yes that solves that problem.
I have another issue.
Why is it that when I have four elements in my FieldPoint, when I ask for a list (branch) these elements are returned in an random order.
Same goes when I come to the leafs. They also comes i random order.

regards René

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19 Jan 2015 07:22 #2613 by support
OPC data come in in form of a triple - Value, Timestamp, and Quality (VTQ).

The ReadItemValue waits until the Quality becomes Good, and then only returns the Value. Therefore it can take long time, if the quality is not Good initially.

You can use ReadItem instead. This will return the whole VTQ object, as soon as it is received from the server - even if the quality is Bad.

If ReadItem takes long as well, then it is the OPC server that causes it.

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16 Jan 2015 09:56 - 16 Jan 2015 11:30 #2612 by veecan
I think it is all about understanding the method. And your manual.
Really needs some examples.
At the moment I have a problem that I can't figure out how to solve.
I am talking to National Instruments FieldPoint OPC server.
As long as it is about Digital In and out there is no problem.
But I also have temperature points. And if a thermocouple is broken (this can easily be the case) then ReadItemValue is hanging for a very long time, and holding my program. Ending up with an error.
If I am not able to change this I am afraid I can't use the QuickOPC.
Any ideas ?
Last edit: 16 Jan 2015 11:30 by veecan.

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16 Jan 2015 08:48 #2611 by support
I am glad to hear this. Would you mind sharing what was the main obstacle and how it can be resolved?

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15 Jan 2015 09:04 #2610 by veecan
Halo Again
I have a motto in my company. Never give up.
I can tell you that you can now announce that the com version can be run from Vee Pro.

Regards René

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14 Jan 2015 16:31 #2607 by support
Unfortunately, we currently have no Vee Pro examples (and no customer has stated that he/she is using it, although it is possible).

I am quite willing to help you with this, as long as it will be within our capabilities. We are always interested in expanding the list of tools that are known to work with QuickOPC.

Can you please describe (and post code/project) what has you done so far (reading, writing)? And then, what is the nature of problem with browsing OPC servers and/or items?

I understand that there should be a free demo version of Vee Pro. I am not sure whether it's any good without having the hardware - do you know? If so, I should be able use it to try things on our side, too.

Best regards

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14 Jan 2015 16:13 #2606 by support
From: R.
Sent: Wednesday, January 14, 2015 10:13 AM
To: Zbynek Zahradnik
Subject: Re: OPC Labs Contact Form - License

Hallo Sir

I have now tried the basic functions as read and write to the OPC servers. It works fine for me.
I use the Vee Pro for programming. It is a Keysight (former Agilent ( former Hewlet-Packard)) product.
Do you by chance have any examples for Vee Pro or do you know of anybody using Vee with your Client software.

What I can't get working but really need is functions like Browse Servers and items.

I hope you can help me as I find your product will be the right choice for me.

regards R.

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