UA Expert client taking data from UA Gateway very slow

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amonllor@aplicon.es
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UA Expert client taking data from UA Gateway very slow

Post by amonllor@aplicon.es »

Hello,
I have installed the latest versions of UA Gateway and UA Expert. My intention is to test the efficiency of the software before making a multi-license purchase. I wanted to know the CPU load and refresh rate. The server is a Siemens WinCC 7.5 OPC DA. I need to read 15,000 tags. I have been creating configurations with 100 and 500 tags and it ends up reading fine. The problem is that opening and subscribing the variables takes a long time. When I put the 15.000 tags it took 10 minutes to make the first refresh to the UA Expert. After that it stays frozen until the next refresh, which can be every three or four minutes. I do not know if it is a problem of the DA WinCC OPC data server or a problem of the UA Expert performance with so much data. The client is a Windows 7 ultimate and the server is a windows server 2008 R2.
Tanks
Agustín

amonllor@aplicon.es
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Re: UA Expert client taking data from UA Gateway very slow

Post by amonllor@aplicon.es »

Sorry, I have idicated 15000 tags and really there are 1600.
I have left it running for a while and the scenario is as follows: if I do not touch the UA Expert the refresh of the variables on the screen is 4 seconds and corresponds to the configured; so far so good. If I move the vertical scroll bar of the UA Expert to see other tags, it freezes and takes 2 minutes to go down and refresh again. If I don't touch the bar it still refreshes fine. It gives the feeling that it is a UA Expert performance problem rather than a UA Gateway problem. I could try another UA client but I'm on site and they won't let me install just anything.

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Re: UA Expert client taking data from UA Gateway very slow

Post by Support Team »

Hi,

in general measuring performance by filling in tags into a GUI grid view control makes probably no sense, there would be no "real" application that is displaying several thousand tags in a grid. The UaExpert has extra plugin (PerformanceView) which you can use to measure performance. The GUI of UaExpert is rather clever showing/updating only what you see, even though the OPC UA Subscription in the background is requesting all the data (independent of whether it is shown in the grid or not).

A GUI Client like the UaExpert has several strategies to limit the returned data comming from the server into smaller portions, to not (or only minimal) freeze the GUI. E.g The UaExpert browses only 1000 tags at a time, and continues if there are more. Furthermore there are features running in the background, especially at startup that could create load on the server (e.g. browsing type dictionary). So question is are you going to measure the "startup phase" or the runtime operations?

In OPC UA there is "requested" update rate, a the hopeful wish of a client, and there is a "revised" update rate, what the server is realy willing to deliver. When being connected to an underlying classic DA server threre are some "expensive" calls (one call in OPC UA may end up in 5 calls into OPC DA), specially when first time adding the tags to the subscription, thereafter it should be all fine.

In my Read-Test I could read 15.000 tags through the UaGateway from an Underlying DA Server (Prosys.OPC.Simulation) within 140ms (average):
Read (NodeCount=15000, Cycles=50): Avg=139.08 Min=136.532 Max=186.461

when I register the tag before reading I goes even faster 100ms (average):
Read Registered (NodeCount=15000, Cycles=50): Avg=99.9494 Min=98.6349 Max=113.064
Best regards
Unified Automation Support Team

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