topic Re: how to view mdsplus data using labview in Instrument Control (GPIB, Serial, VISA, IVI)

how to view mdsplus data using labview

inhp — Fri, 08 May 2009 22:55:01 GMT

I posted this question in the Labview board, but seems nobody replies it so far. I am not sure which board is the best place to post this question. So I just reposted here. Thanks a lot.

I am a newbie to Labview. I am trying to write some vi to view and write data to Mdsplus. I have downloaded Mdsplus(labview), and can find the Mdsplus functions, like mdsconnect, mdsput, ect, in the Call Library Function vi. But I have no ideal of how to use it. I tried to use Mdsconnect function to connect to some machine, but it always gives me an error message like, Labview: An exception occurred within the external code called by a call library function node....... I was searching for help documents on the internet, but couldn't find anything useful. Could you please help me for this problem? If you have any example of such vi, or teach me how to do it, that would be very helpful. I am using Labview 8 (windows). I would greatly appreciate your help! Looking forward for your reply.

Re: how to view mdsplus data using labview

Albert.Geven — Sat, 09 May 2009 12:16:56 GMT

MDSplus is datastorage in files in a special way.

So reading and writing files is the way to go

LabVIEW can support a lot of filetypes or you can read or write files.

The TDMS fileIO maybe supports also MDSplus otherwise it can be extended to such a system

Re: how to view mdsplus data using labview

gjhartwell — Mon, 11 May 2009 18:59:07 GMT

Hi,

We use LabVIEW 8.5.1 and communicate with an MDSPlus server on a regular basis, so we might be able to help. I've attached the VIs that we use to open a shot, read an array, and read a floating point.

Greg

Re: how to view mdsplus data using labview

gjhartwell — Mon, 11 May 2009 19:00:16 GMT

oops,

I didn't attach these correctly in the previous post.

Greg

Re: how to view mdsplus data using labview

inhp — Mon, 25 May 2009 21:42:37 GMT

Thanks a lot, Greg!

Re: how to view mdsplus data using labview

inhp — Tue, 26 May 2009 02:35:00 GMT

Greg, I checked the vi you attached. There are some sub-vi missing, such as Mdsconnect.vi, Mdsopen.vi, MdsGetInt.vi and Mdsclose.vi. Could you also please attach those vis? I think the Mdsconnect.vi and Mdsopen.vi are essential to me. Thank you so much!

Re: how to view mdsplus data using labview

gjhartwell — Tue, 26 May 2009 13:02:05 GMT

Hi inhp,

The missing sub-VIs that you mentioned should be in the mdsplus/labview download. Please check there first and if they are not there I will get them to you.

Thanks,

Greg

Re: how to view mdsplus data using labview

inhp — Wed, 27 May 2009 19:28:48 GMT

Thank you so much, Greg. I found those VIs.

Re: how to view mdsplus data using labview

gjhartwell — Wed, 27 May 2009 21:23:23 GMT

Hi inhp,

Great! I'm glad you got it. Let me know if I can be of further help.

Greg

Re: how to view mdsplus data using labview

Maxxi — Tue, 28 Jul 2009 23:39:36 GMT

Hi Greg,

I have labview 8.6 and couls not use those mdsplus vi's (not comaptible with labview 8.6). Do you know where to download the compatible mdsplus vi's??

Thanks

Maxxi

Re: how to view mdsplus data using labview

gjhartwell — Wed, 29 Jul 2009 00:00:43 GMT

No, I don't know where to find MDSplus VIs compatible with 8.6. We use 8.5.1 and have gone though at least one version upgrade with these VIs working in both. I don't recall having to do anything special to get them working after the last upgrade. I am surprised that these VIs are not compatible. Is the problem in the dll calls, or somewhere else in the routines?

Re: how to view mdsplus data using labview

Maxxi — Wed, 29 Jul 2009 00:08:51 GMT

when I open Exampl_Read_write_MDS_array.vi file, I got the following message:

"...the vi version is too old to convert to current Labview version..."

And could not find the following vi's:

MDSPLUS_error.vi

Read_write_MDS_IntArray.vi

Close_MDS_Shot.vi

Re: how to view mdsplus data using labview

gjhartwell — Wed, 29 Jul 2009 12:53:29 GMT

I have not tried upgrading these VIs to version 8.6, so I can only speculate that you may need to do something like recompile the dlls.

Have you downloaded the MDSPlus software? There is a LabVIEW library there and this is where you should find the routines that you mentioned being missing.The link is:

http://www.mdsplus.org/index.php?url=mdsplus/download.php&open=10371789941834252319&page=Software%2FDownloads

Greg

Re: how to view mdsplus data using labview

Maxxi — Wed, 29 Jul 2009 23:56:38 GMT

Thanks Greg,

Yes, I have downloaded the updated version of MDSPlus. How to recompile the dlls? Those vi files were not in mdsplus/labview directory. Is there any way for transforming old vi files to new vi files?

Maxxi

Re: how to view mdsplus data using labview

gjhartwell — Thu, 30 Jul 2009 01:33:10 GMT

Hmmm, don't know why those files would not be in the mdsplus/labview directory. We recently installed on a linux machine and they were there. Apparently we can only attach 3 files at a time on this forum and there are 21 files in the labview directory. If you are willing to post your email here (which I am not necessarliy advising) I will email you all of the files that I have.

Greg

Re: how to view mdsplus data using labview

inhp — Mon, 03 Aug 2009 23:17:35 GMT

Greg,

I have another problem. I can write integer number into Mdsplus, but have problems when I tried to write string into Mdsplus. I think there are something wrong in the set up of the call library function 'descr'. I am actually not sure what is the rule of setting up those parameters: dtype, descr1, endarg and the length of the string in the function 'descr' for string type. I attached my VI. Could you please take a look and let me know where I am wrong? Thank you so much!

Re: how to view mdsplus data using labview

gjhartwell — Tue, 04 Aug 2009 00:51:02 GMT

We also had some problems reading and writing strings. I've attached our solution. This vi reads or writes a comment depending on how an input flag is set. Try this and let me know if it works.

Greg

Re: how to view mdsplus data using labview

inhp — Wed, 05 Aug 2009 00:00:17 GMT

Thank you, Greg. Looks like you first convert a string to byte integer, then write that byte integer to Mdsplus. But for me I want to directly write a string to Mdsplus so that the string can also show up in traverser. I found out another solution and attach the VI here. It seems to work so far. You can also try it and let me know if you find any problem.

Thank you for your help all the time.

Re: how to view mdsplus data using labview

gjhartwell — Wed, 05 Aug 2009 13:13:00 GMT

Hey Inhp,

That is great! I've always hated our work-around to write alpha-numerics.

Thanks so much for posting this.

Greg

Re: how to view mdsplus data using labview

GretchenSkellyZimmer — Mon, 01 Aug 2011 19:26:00 GMT

Has anyone successfully written a VI to read a signal node? I can get the Y Values, but not the Time Axis values.

Gretchen