Louis Philippe Girouard

Hi lablc, To set the boundaries of your front panel, go to File -> VI Properties -> Window Size and adjust the Width and Height parameters. Then, go to your front panel window (when it's not running) and shrink it as much as you can. It should not let you shrink it past the settings you entered. From my experience, auto-scaling front panels in LabVIEW rarely produces good results. I always set the boundaries of my front panel first (in your case you would need to find the parameters that cause the panel to fit the screen for your resolution) and then I start developing the UI accordingly. LP.

What is the update rate of every Tag in your OPC Server? They should all be at 1000ms, if it's lower, there is a chance you are logging a lot more data than you need since your Shared Variables deviation is set to 0. If that doesn't do it, I would suggest increasing the deviation to minimize logging small changes in data that might not be of any use anyway. The SVE is not the most efficient application when it's asked to perform a lot of operations quickly. If you minimize how often each channel updates, you will reduce the load on the SVE and therefore allow it to handle more channels. Good luck, LP.

I totally understand your frustration, we are not a major NI integrator so imagine how much they tell us . We are the kings of work arounds. 5-10,000 hours!!! I would be very interested to hear about your findings, it would make a great post... Personally, I have never witnessed this phenomenon but I must say I never ask much of the Shared Variables I deploy on real-time systems. I will print this quote and post it on my office wall to remind me to always be gentle with RTS SVs.

Hi Steen, I totally agree with you about the limitations of Shared Variables and about the disappointing support from NI regarding SVs. However, I haven't given up on them quite yet. Actually, the majority of our systems are still designed with SVs as the main tool for intra-process (and extra-process) signalling, and I must say they work really well. I design data acquisition and control systems for thermal vacuum chambers that are used to perform space simulation. Tests can be up to one month long (24/7) but everything happens relatively slowly. The acquisition rate of our CompactRIOs is 1Hz and losing a reading once in a while is not an issue. Also, the outputs can take a couple seconds to react without causing problems. Finally, data loggers that record hundreds of temperature readings are queried only once every 10 seconds. In this environment, Shared Variables with the DSC module and a Citadel database can be an excellent solution, especially because they benefit from the power of the Distributed System Manager. When we consider other designs, like VIRegister, the DSM is the factor that tips the scale in favour of using Shared Variables. Having said that, I don't see anything wrong with VIRegister and I will consider it next time I design a high throughput application (yes, we do have some of those as well ). Regards, LP.