Labview Benefits

[davidthefat]

My mentor talked to me about perhaps using Labview this year to do some realtime system analysis. My mentor is a big fan of testing systems and graphing data to show visually. The main competition bot will not be using Labview, but my mentor is entertaining the idea of buying the second cRio for just testing the systems. Now, I would like to know how the real time system analysis consists of. Are there any data that can not be accessed without it? I have been going by just printing out the data, but there often is formatting errors that throw it off, are there any of those inaccuracies in the real time system analysis software?

I've also heard that there are a lot more overhead for Labview than let's say Java.

[Mark McLeod]

Your initial use of LabVIEW should be done with zero overhead to your robot.
Just use it to graph in real-time the data sent back by your regular C/Java code.
That just has LabVIEW running on your PC and doesn't require a second cRIO. You should develop that capability using your existing 2011 robot.

Just make yourself a custom LV Dashboard that plots what you want to watch.
Everything's there and already running for you to start. Just add your data passing and processing at either end.

[Greg McKaskle]

Personally, I think what your mentor is going for is more of a process than a tool issue. Generally, it means that you measure and inspect what is really happening in the system. You use the measured data to identify potential issues that the code may not be prepared for. You use it to improve areas where it already works, but isn't optimal. And you test code or mechanism changes to show what impact they caused.

In other words, rather than trust only your eyes or anecdotal results, you try to develop data that convinces you and other members of your team and leads you to build a better robot, achieve a better performance, and better understanding of what you have built.

Incidentally, LV includes data input and data viewing into each function that you build. Each parameter in and out of each function is potentially viewable during execution. This will sometimes allow you to do just-in-time data viewing. I know, it never happens, but what if ...
* The robot is misbehaving
* Gee. I've never seen that before and have no idea what is causing it.
* I wish I had a printf of some stuff to know what might make it do that.
Provided the robot will continue with its misbehavior, LV allows you to drill down, function by function, looking at inputs and outputs until you find the issue.

Additionally, LV includes probes for wires. These are like watchpoints in C, but allow you to view the data while the system continues to run. And while printfs are awesome, graphs and charts are often even better, especially when trying to convey trends or large amounts of data that changes rapidly. You can do the graph on a LV panel, or you can log the data from C++ and view the file in an engineering tool.

I'd encourage you to look at LV and go through a few monitoring exercises with the mentor to help understand the engineering process that it promotes. Then learn how to apply that process in whatever tools you are using at the time. You don't always have to use it, but it is a good approach to be able to reference.

As always, if you have questions, just ask

Greg McKaskle