Labview 6 & 7 DSC compatibility question

[Maxime]

Hi!

I have a question concerning Labview DSC, but first of all, I'll tell how things are presently.

Here, we have 2 computers. The first one is quite old and is running Labview 6.1 with DSC (won't be upgraded to LV7) and the other is quite recent, but it crashed recently. After formatting it, we installed Labview 7.1. Since that, some work has been done on this computer using Labview 7.1 (note:we have a cd of the DSC module). Now, I am asked to try to interact with the tags on the old computer using the most recent one, but I read that different versions of DSC would lead to compatibility issues. Is there a way to do this without having to install Labview 6.1 on the most recent computer? (we just don't have enough licences to have 2 versions of LV on a computer) Or is there a way to install an older version of DSC on the computer using Labview 7.1?

Any suggestions about ways of communicating with those tags would greatly be appreciated. If you need additionnal information to answer, just let me know.

Thanks in advance

[Jeff M]

Hi Maxime,

There have been mixed reviews on this question. I believe that yes, in some cases there will be compatibility problems. However in theory, I think it should work if the versions of Logos are the same for both DSC 6 and DSC 7. I will need to set-up it up on some of our test machines to verify this is the case.

The ideal scenario would be for each computer to use the same version.

Regards,

Jeff M.

Applications Engineering
National Instruments

[Maxime]

Hi,

I saw that I forgot to mention that the old computer is running on Win98, which is why it won't be upgraded to LV7.1...

Here is some more information about our current situation, hoping that it can help: the older computer is connected to many devices. Some are used to take measurements, others are instruments to control. Each one of these inputs and outputs has an associated tag, and the tags are saved in a .spc file on the computer. The most recent computer has a few more devices connected and is used to manage and control every device, connected to both computers (the VI doing this task has been created under LV6.1). This computer also has a .sfc file containing a few tags, made with v6.1; some of them are referring to tags on the older computer (in order to control the remote devices or to read measurements) using the logos server.

Now I think that any useful detail should be there, but still, just ask if you need more information.

Thanks for taking the time to help me.

Maxime

[Maxime]

Just to correct a mistake in my last message, I don't know when I invented these file extensions, but I was talking about .scf files (not .sfc or .spc...).

[bdougr]

The newer labview computer can read the tags over the network with no problems. For the DSC 7.1 system it is just another resource to get data from. The only thing I have seen is sometimes the 7.1 system will not get fresh data and just requires the engine shut down and restarted. I think the happens when the 'other' system is rebooted or network fails. (actually network glitches will definetly do it)

[Maxime]

I just finished some tests, and I've confirmed that the 7.1 system can read data coming from the 6.1 one. Now, the problem is that the 6.1 needs data from the 7.1 too, since most control VI's are on the newer computer and many devices to be controlled are on the older one. In the tag configuration editor of the 6.1 system, under the connection tag, when I select the server (Logos), then browse for the item name, I try to access the WinXP computer. Unfortunately, there's a red "X" apperaing on the computer icon with written on the right. I tried to type the item name manually (\\computername\LabVIEW\tagname), but it didn't work.

Is there a way to tell the 7.1 system to communicate in a language understandable by the other one? The computers really need to be able to communicate with each other using the tags...

[bdougr]

this should be pretty easy to solve.
on the 6.1 system create some memory tags for the entries you want
on the 7.1 system write to these tags

[Maxime]

Thanks bdougr!!

I tried to put all my tags (those needing to communicate) on the Win98 system on "memory", using "input" and "output" on the WinXP computer to read or write the tags and it worked perfectly on my test VI's. I'm pretty sure that it will work for my main VI's too.

I will post again if something's wrong, but for now, I think that everything should be fine.

Thanks to both of you for your help!

Message Edited by Maxime on 05-26-2005 03:11 PM