Strange behavior with LabVIEW 2014

[Steffan.W]

Hi there.

I was playing around with LabVIEW 2014 and the Mindstorms Toolkit. I notice very strange behavior of the motors. For example this simple program works fine form LabVIEW 2010 but running the very same vi from LabVIEW 2014 the motor behaves completely different. The motor start spinning fwd and rev a few times before it runs slowly (not smooth) until it reaches 1 revolution.

I am using firmware 1.31 on a NXT1.0 brick. Did I miss something, is it something with a driver that needs to be updated?

Also when I run vi’s that uses Bluetooth communication the brick often hangs (clicking sound). Never had that in 2010.

[garrett8357]

Hi Steffan,

The reason you are seeing the jerking is because you are moving the motor at full power for an instant before you begin the call to move motor distance. To power the motor at 10 % for a full rotation, you only need the call to Move Motor Distance, like shown below.

I am not sure what you mean about bluetooth. The brick starts clicking during the execution of the program? Is it possible to reproduce consistently?

[Steffan.W]

Thanks Garrett, makes perfect sense and, indeed, does work much better but still I have some doubts (wonder how it can work in LV2010). It still behaves different than in 2010. Movement is less smooth and it runs faster, almost double speed. I even notice a difference when I run both small vi’s. The upper rotates much faster than the lower. I do not see that in LV2010.

Bluetooth: this vi comes with the LabVIEW examples: \Direct only\ComputerControlNXTCar.vi.

 

I run it from the PC and it communicates via bluetooth with example \Bluetooth\BluetoothDriveReceive.vi which is running on the brick. Works perfectly in LV2010 but I cannot get it to work in 2014. When I run this application the event structure does not respond to keyboard characters. So it seems to hang. When I remove the event structure it runs but then my brick hangs and starts to click.

Last few days I noticed some more issues about motion and Bluetooth that puzzled me but I cannot recall them all.

Any thoughts maybe?

[Steffan.W]

Am I wrong when I state that the Mindstorm Toolkit is pracically useless in combination with LabVIEW 2014? I did some more testing and I cannot believe how bad it is. One issue after another. No anyone else experienced this?

[garrett8357]

Hi Steffan,

To address your issues in your previous post, the event structure has not changed behavior between LV 2010 and LV 2014. Make sure the front panel of your VI is in focus when you do keypresses and the event will trigger. You're correct that when the event structure is removed, the vi running on the brick crashed the brick due to a compiler bug. The issue was identified and fixed and the fix will first become available for the LabVIEW 2012 SP1 MINDSTORMS Module f5 patch for the MINDSTORMS Competition Toolkit 2014-2015. This will be available through ni.com and the Update Service sometime next week.

We are always working to improve the product. Please do not hesitate to post any issue you are having here, and I will try to provide a workaround or help you acheive desired behavior.