Labview Video Tutorial? Dashboard

[Abrakadabra]

Resurrecting an oldie but goodie...

Danny - Is there a new place to get your Dashboard Tutorial Flash videos that you mentioned in the post up above? The LASA Robotics site seems to have switched to Joomla, and the Forum no longer seems to be there. My team is really hot to use the Labview Dashboard this year, and as I remember, those videos were very useful to my understanding of the whole process when I first checked it out.

Thanks!

[Danny Diaz]

Ewww, you don't want to use that.

What you want to use is the Simulation Toolkit, it has a much better and easier to use dashboard mechanism built into it. If you use the default VI as your template for your dashboard program, everything you need is right there. Can you give me the weekend to install my presentation-generation software into my new laptop and create a quick video to show you how to do it? I promise it will be WELL worth the wait...

-Danny

[Abrakadabra]

Sure - bring it on!

(it's too late for the Golden Globes, but maybe there could be an Oscar waiting in the wings? )

In the meantime, I'l grab the Simulation toolkit...

[Danny Diaz]

I'd recommend grabbing it again, I needed to update some of the error handling code - Team 418's test platform with a 2004 RC/OI is starting to get flaky, and some bytes are getting corrupt every so often. I needed to update the toolkit to better handle getting corrupt data so that you either get good data or nothing at all.

But, anyway, I promised a new tutorial and I'm here to make good on it. I didn't add any voice to this tutorial, but I think it's going to be very easy to follow and understand. What I did was showed you how to use the components from the FRC Robot Modeling toolkit to create a really basic Dashboard, but it's very easy to expand to add much, much more capabilities, especially if you're sending back data via the user bytes. I went through the actual build phase pretty quick, and made a few "uh oh"s that I did correct, but you'll see. I did the whole thing in under 5 minutes, and should be easily reproducible by anyone on your LV programming team. Remember it's assumed that you've installed the FRC Modeling Toolkit.

As always, if you have any questions, feel free to ask.

To download the tutorial, download the ZIP file and open the HTML page to view the FLASH video.

http://downloads.lasarobotics.org/FIRST_Tutorials/

-Danny

[Kingofl337]

Here is a sample on how to write user bytes in easyC.

[Abrakadabra]

Hi Danny -

Thanks for the tutorial. It went a little fast in places so we had to watch it a few times, but we finally got a finished product that looks almost exactly like yours. However, when we run, we get a few seconds of data transmission and then an error:

Error -1073807252 occurred at VISA read
in PacketReader.vi -> DashboardProvider.vi
Possible Reasons
An overrun error occurred during the transfer.
A character was not read from the hardware
before the next character.

At this point the DashboardProvider is halted, but the Dashboard itself is still going.

We are using the USB<->Serial converter cable sold by IFI for the VEX system. Could that be the issue? Has anyone else had any luck with this adapter?

(It's getting real hard to find a decent but inexpensive laptop with a real serial port!)

Thanks for any guidance you can provide!

[Danny Diaz]

Okay, I'm going to shoot from the hip here since I cannot test it right now - the only thing I can think is happening is that I forgot to put a wait in the while loop. The program runs fine on my dual core laptop, but I haven't checked to see if one cores is pegged out. See, when you create a while loop you're supposed to put some kind of wait or blocking call in it so that the while loop doesn't just spin and eat all the processor (that way the thread running the loop yields for other threads in the system to be able to run). Open the Dashboard Provider VI and you'll see what I mean, the while loops there have a "wait for millisecond multiple" and usually it has 10 wired into it (that means the processing within the loop will be suspended until the next 10 ms multiple). I had thought the "Dashboard Read" VI would take some time to read the datasocket variable (actually I thought it was a blocking call), but I could be incorrect - if this is the case then the thread reading the datasocket variable in your while loop is using a significant amount of the processor and it is starving the serial port read; that's why the overrun is probably happening (you can verify this by watching your CPU utilization while you're running the VI). On a dual core target if you're lucky and the serial read happens to be running on one processor and the datasocket read hogs the second processor, everything will run fine. However, if you're on a single core target then you're in for some serious trouble, which is probably what's happening to you (or you're unlucky and both threads got scheduled on the same processor).

I won't be able to get my hands on the testing platform again until Saturday, so if this is the case I'll update the video then with this new code. Until then, please accept this new VI (attached) and let me know if this solves your problem.

-Danny