LabVIEW for LEGO MINDSTORMS and LabVIEW for Education

[Macattack]

How to you specify angle of rotation for the motors using the 2011 Motor On icon? I want to specify the angles the motors rotate and I want to sync them so two motors turn at the same rate and hopefully my vehicle moves straight.  I have been using Labview 8.5 and the Sync Distance motor icon but can't find it in the 2011 version. 

[Joe Steak]

Hey Macattack,

With the Motor On icon, the input on the top specifies which Ports you want to control.

In your situation for example, you could have a motor connected to Port A and Port B. Then on the Motor On function, right click on the top input and do create>> constant or control. You will then be able to choose Ports A and B and it will output to both of those motors at the same rate and make the vehicle move straight.

Hope this helps!

Joe S

Applications Engineer

National Instruments

[Macattack]

I want to specify the distance in angles.  How do you do that? 

I know how to select the ports for the motors.  The old Sync motor icon used a feedback control to alter the rotations so the motors physically went the same distance.  It does not appear that the Motor On does this type of feedback.

[ESearl]

Hi Macattack,

You need to dig a little deeper in the palette now to find the fixed distance/angle function.

NXTIO : Complete : Motors : DriveDistance.

-Ethan

[Macattack]

Ethan,

Thanks.  I had found that too but it still doesn't seem like they are synched with a feedback control like the old icon did.  I think I will just have to write a sync distance IV myself.

[ESearl · Accepted solution]

The fixed distance uses the standard PID control that is provided with the NXT firmware. It has been tinkered a little from the version that shipped in the old toolkit though.

If you would like to use the old version though, all the old toolkit subVIs are still shipped in the new NXT Toolkit.

You can find direct mode at NXT I/O : NXT Direct I/O  (This is only available on a VI that is targetted to the computer)

The remote mode palette is at  NXT I/O : NXT Native I/O ( This is only available on a VI that is targetted to NXT.)

Let me know if you have more questions.