Thursday, February 2, 2012

LabVIEW Scalable Tabs to Control Separate Test Applications on the Same Interface

I was working on a new project this week and wanted to have a smart way to switch between the different tasks the application had to perform without having a side bar, or HMI style buttons. So here's what I came up with:

The buttons across the top are from a system tab control which is behind a single sub-panel container. When the user clicks on another tab, the application automatically switches between tasks by unloading and loading the tasks in the sub-panel.

Another feature I wanted was for the tabs to be justified across the user interface and for all the controls on the screen to be able to size with the window. The scaling of the controls is not very fluid, but when the user re-sizes the window, all the controls on the main screen scale. I will probably have to scale the sub-panel task controls as well, but that can be a function of the sub-panel task and the main application does not have to worry about what is going on in the sub-panel.
I can never remember how to set the position of the panel/pane, so I figured this was a good place to keep track of that as well. The block diagram above shows the reaction to scaling the window by the vi as well as the loading of the initial sub vi. I have seen various examples of sub-panels, but none with tabs like this.

A write-up with example code is here.

Wednesday, February 1, 2012

Ugh, not this again

Received an email yesterday from, a Steve Harris website about the Byron Electric generating plant going off line. Since this plant is a nuclear facility, I was mildly curious about what was happening.

So here's what happened, the plant went into automatic shutdown after an insulator in the switch yard failed and caused a short in the plant's power distribution system. As a result of the automatic shutdown, the plant's steam turbines are bypassed so that they don't make any power. This vents steam to the atmosphere. The steam that is released has some radioactive hydrogen isotopes in it because, well, hydrogen is hard to keep it from leaking through micro-cracks and such. Radioactive hydrogen isotopes have a very short life cycle, much less than the eight days from the stuff that Fukushima was and is spewing out. Normally, this steam is processed in a semi-closed system allowing the condensate to be reclaimed and reused to make more steam; however, this system is NOT tied directly to the reactor cooling systems, although the potential for cross-contamination exists, which is where the hydrogen isotope (tritium) comes from because the steam generation system and the reactor cooling system must interact with each other to produce steam through heat transfer.

As a child of the nuclear age, I know that most of the problems with nuclear power come from greedy operators and inept government regulations. If the operators of these plants would maintain them correctly and take them out of service or refurbish the plants properly, there is pretty low risk of any problems. However, those problems can be monumental if something goes wrong like Fukushima, or Chernobyl. There are still highly radioactive areas around Chernobyl after all these years, but plants and animal wildlife seems to manage just fine without our help in those "dangerous" areas.

What's the point?

HYPE, and lots of it, conjured up just to separate YOU from your sanity and your money. Steve Harris is a really smart guy and has some pretty cools ideas, but sending up the massive warnings about minimal problems has not been very good for the American population. Can you say Homeland (In)Security Administration?

Buyer beware is all I can say.