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  multiple realtime chart problem
Posted by Timo Becker on Aug-08-2011 16:06
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Hello dear support Team,

im using chartdirector in many of my projects and it always worked very well for my
requirements. Now i started a new project in that i have to draw multiple realtime charts (5
- 10 on one single site). The Charts get their data from an OPC Server and refresh every 5
seconds. This works well if just one client is viewing the page. If a second client starts to
view the Page he only gets 4-5 charts of 10 drawed. the other charts are displayed with a
red cross (broken link) while the first client's page still works fine.

Is there a limit for realtime charts to be used at the same time?

Please see attached some example screenshots from client 1 and client 2. the more clients
access the website the less charts are being drawn.

i would be happy if you could give me some advise..

Greetz

Timo
client1.png
client2.png

  Re: multiple realtime chart problem
Posted by Peter Kwan on Aug-09-2011 01:09
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Hi Timo,

There is no built-in limit to the number of realtime charts used.

For your case, to diagnose the problem, you may try to get the error message inside the "red X" (the broken image symbol). If you are not aware how to do this, see:

http://www.chartdir.com/forum/download_thread.php?site=chartdir&bn=chartdir_faq&thread=1117817200

You may also try to check the server access log, error log and event log, to see if there are any cue there.

Are you testing on a "real server" (eg. Windows 2008 server or Windows 2003 server), or is it an IIS on a desktop Windows computer (Windows 7, Vista, XP)? The IIS on a desktop Windows has a 10 concurrent session limit, and it is possible your application may exceed the limit. (On the other hand, the IIS on a "real server" has a much higher limit.) Many desktop windows also have a 10 TCP inbound connection limit for each TCP port.

You mentioned your data are obtained from an OPC Server. You may also want to check if there is a concurrent limit on the OPC Server.

When you update the charts, are you updating them all at once (that is, wait for 5 seconds, then send 10 updates)? You may consider to update them one by one (update one chart every 0.5 seconds, so that all 10 charts are updated in 5 seconds). Spreading out the HTTP requests may help to reduce concurrent TCP connections.

Please kindly let me know of the results.


Regards
Peter Kwan

  Re: multiple realtime chart problem
Posted by Timo Becker on Aug-09-2011 13:55
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Hey, thanks for your quick reply.

I just checked the image url in google chrome...wasn't a good idea i think. Chrome shows
the image correctly if i copy its link into another browser window. Then i tryed to copy the
image link into an ie browser window. the internet explorer shows: HTTP 403.9 Access
forbidden - to many users... For developement i'm using a local iis on an windows xp prof
machine. the live system is a windows 2003 server so i think i should try to publish the site
on the live system first. Also your suggestion with maximum TCP ports is interesting - i will
check this out, too.

Our OPC-Servers have no user limitation tough.

ill report again after i have checked all those possible issues :) Thanks in advance.

Timo

  Re: multiple realtime chart problem
Posted by Timo Becker on Aug-09-2011 19:11
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Hey Peter,

setting up the max connection limit of the iis fixed the problem (adsutil set w3svc/MaxConnections 40). Many thanks for that tip. I also implemented your advice to refresh the charts one by one - not in a stack. This increased the application performance as well.

Thanks!

Timo