03-21-2011 09:28 AM
Hi Folks -
The doc that used to exist for this, I think, #6048 seems to be 404. Point me to the new one, please !
I need to get a the whole SV structure , like 200 data items (no arrays, a couple short strings, the balance floats and ints) once per second. The SVE source is running on an XP box that's talking to a plc system over RS-232 (i.e. it is busy doing slow dumb things and I don't get to change how this operates), assorted other hosts in our system need to see its status on the one-or-two seconds sort of timescale. The number of others querying the controller, like a dozen, is seriously slowing down the operation of the control function, so we'd like to have one external computer getting all the variables once , and handling them separately for the others. The plc controlling program uses one network-published list for everything and I don't have control on how that program functions, I can only read what's there with the smallest overhead possible. The remote host reading the SVE has to be either linux or Mac , as we would prefer to serve this data back out to the other clients without shared variables anyway e.g. over a decently secure webserver .
We have tried publishing the whole thing regularly to a webserver with the export-to-xml vi, then write to a webserver, but it seems like it has big overhead.
So I can get one variable at a time with Data socket :psp//myserver/etc/etc but only one-at-a-time. How to get all the data at once ?
TIA
Alex
Solved! Go to Solution.
03-22-2011 04:37 PM
I'm looking into your issue, but while I do, what is the doc you're saying used to exist?
03-23-2011 09:30 AM
I searched the NI site on
"multiple data shared variables data socket mac linux " and got , among others,
Report Date: 08/24/2006
Last Updated: 09/11/2009
Document ID: 40NBECNO
which includes this link :
For an example of how to use the Datasocket API in LabVIEW please refer to Developer Zone Example: How to Access Multiple PSP Items Using the Datasocket API
http://zone.ni.com/devzone/cda/epd/p/id/6048
>No content exists for document id:6048
thanks for following up
03-23-2011 12:41 PM
Is this what you were looking for?
http://decibel.ni.com/content/docs/DOC-15102
"Access Multiple PSP Items using the Datasocket API"?
03-23-2011 01:07 PM
No,this was what I was trying to avoid.
The SV white sheet - "Using the LabView Shared Variable" Tests T5-T6 show and talk about overhead and # of variables. Since the SV _looks_ like it might be one object from (XP) Labview SV views, I was hoping there would be a way to get the whole thing in a go from the remote DataSocket. It looks from the previous existence of doc #6048 the NI had a method for doing this once, but that went away apparently. Maybe #6048 looped over the list of SVs also.
03-24-2011 11:57 AM
I imagine it did loop over them. I'm not aware of a way to do the whole thing at once easily. After much searching I haven't found a way to do what you're suggesting. I wonder what happened to that article you're referencing. It seems weird to remove it unless that method was no longer functional... If you'd like to tell me more about your set up, or perhaps describe the problem in another way, I'd be happy to try to come up with a workaround with you.
03-24-2011 12:06 PM
I'll find the items I really need and try looping over the subset. If the host slows down too much I'll be back.
thanks