Version compatibility in shared variable communication

[stephencox]

I have a cRIO running a new piece of hardware that arrives today.  I have done all the development in LV 2012/13, but we still have some older machines running LV 8.6.1.  These machines will be upgraded soon-ish, but the code is byzantine and so it will probably require some downtime to do the switch.  In the meantime, I found conflicting information online (e.g., here and here) about whether I can communicate between these systems using shared variables.  I do not want to do a lot of this, but it would greatly ease the transition if I could write a few booleans and doubles from the old computers to either the cRIO or to the new computer as a stopgap.

In LV 8.6.1, I can see the cRIO and the names of the shared variable libraries on the Distributed System Manager.  However, MAX says the system is unsupported if I try to connect that way.  The Distributed System Manager also seems unreliable--just poking around this morning, it has frozen a few times, and right now for some reason it doesn't show any of the variables, just the target's IP address (although it's not grey).  In LV itself, I can't figure out any way to make the shared variables appear, but I have never tried to use them in a pre-2012 version of Labview, so maybe I just don't understand how to do that.

Is there any way I can make this work, or do I have to do something stupid like communicate with text files and while loops between these systems until I get them all upgraded to the same version of Labview?

[Jordan-G]

Hi stephencox,

This KB is correct in that shared variables built in different versions of LabVIEW are able to communicate with each other. What version of the NI Distributed System Manager do you have installed on your system and are using to access the shared variables on the cRIOs that are running LabVIEW 8.6.1?

Regards,

Jordan G. 

[stephencox]

Sorry, I was not clear--the cRIO and the computer I use to write code for it are running LV 2013.  I have an old computer running 8.6.1 that needs to be able to talk to the cRIO occasionally through the shared variables.

I think I figured out at least part of my problem--I finally noticed a dropout on the shared variables on the LV 2013 computer as well.  So I lowered the clock speed and network publishing rate on the cRIO and the variables stopped dropping out constantly in the DSM in version 8.6.1.  I think maybe this was the problem, and the faster computer running LV 2013 was just better able to recover from occasional missed signal or something like that.  Anyway, I will try to implement the shared variables in the 8.6.1 code the next time I am able to take down the system.  Thanks for the clarification.