LabVIEW Toolkit for LEGO MINDSTORMS NXT bugs

[John Field]

Hi Manfred,

That is the source of the problem and good job on finding the soultion. The compiler that the toolkit uses, does a string compare and is looking for 'Default'. The reason that we don't support localized versions of LabVIEW better is that we didn't want to deviate the compiler very much from the one used in the (already shipping) LEGO MINDSTORMS NXT software.

So, I've made a note of this bug moving forward.

You may find other interesting issues trying to use the toolkit in German and so, it is probably a good idea to get an english version of LabVIEW, if possible. You can always apply for the Windows edition we are making available for NXT programming:

http://digital.ni.com/express.nsf/bycode/lvtoolkitlego

Thanks.

- john

[Borsch]

Hi John,

thanks for your support.

Using the english version should be a good solution for me, but I am trying to teach my son in programming LabVIEW. With his 15 years it is easyer to do it with a german version. Of course, he already has to learn (technical) english, but if you want to get more young people to be LabVIEW-Programmers in Germany (these are the NI customers of the future) you should give them the possibility to start with a german version.

As a workaround I will modify the NXT-VIs, so that they will have only a "Default" value (without "0").

Thanks

Manfred

[Daniel Zeyen]

Hello Everybody!

I'm using a German version of LabVIEW (8.20) too. And I have a problem in transferring NXT Toolkit code to the NXT brick. I've just written a little program for displaying a short text on the brick (see the picture). Then I started Tools\NXT Module\NXT Terminal but there's no program to choose for uploading it.

Any help is appreciated!

Regards
Daniel

[Gam@]

Hi!.

On time, I have no problem with Lego Toolkit.

Mass compiler checked, Ok.

All examples run. Ok

This is the toolkit that all Legowalker need for total control! Yeah.!

My plataform: Win Xp, Labview 8.0, AMD sempron 1.8 Ghz, 512 RAM

Thanks.

Gamaliel Torres

[tol]

Hello!

I got this problem. Vi file works fine in labview, i can connect with USB and BT, but when i build executable file, only USB connection is possible, when i try connect by BT, program doesn't wait for connection but immediately, returns error that connection isn't present.

Other problem is that, when i put several direct commands blocks(for example 2 motor control blocks, and some sensors) in one program, i make connection from 1 "create NXT object" block, to make program working, i got to connect these blocks to "destroy NXT object", so i got 1 "create" block at start and 5 "destroy" blocks at end outside the loop, when program is in loop it's works good, but when leaving loop, there is error "Error -1073807346 occurred at destroyNXT.vi:2   Possible reason(s):

VISA:  (Hex 0xBFFF000E) The given session or object reference is invalid."

Should i create NXT object for each direct command block i'm using in my program?

Best regards

Miki

[UlfM]

Hi, Miki!

For the moment I have no idea concerning your BT-problem, but let me try to propose a solution for your Direct Command question.

If you have a look on the sensor and motor VIs you'll find that they have an NXT Object Input and a corresponding output. If you want to send many commands to your NXT (also in a loop), the idea is that you connect the NXT object output of one VI to the input in the next command vi (like one does most of the time with the error cluster, too). In this way you also define the order in which the commands are executed. The NXT object output of the last command VI inside the loop (which is now the end of a "command chain") should be connected to the input on the single Destroy NXT Object outside of the loop. So you end up with many commands, but with one single "Create NXT object" before and "Destroy NXT Object" behind the loop.

The passing of the NXT object through the loop should be done using a shift register - in case one of the VIs inside the loop changes the NXT object. (As far as I know this is not the case, but I think it's better style, and the overhead should be neglectable.)

Hope I was able to make the idea of "chaining" the commands clear - otherwise I'll try my best in another iteration ;-)))

Regards

Ulf

[UlfM]

Sorry, once more me! I forgot to mention the examples coming with the toolkit. You can find them as follows:

menu "Help" -> "Find examples..."

In the "NI Example Finder" window in the upper left quarter mark "Browse according to:" -> "Directory Structure".

Within the example list you can find now an entry "NXTToolkit" with subfolder "Direct Commands". A very good example for chaining commands inside a loop is "Multiple Rotation Sensor Graph.vi".

Mybest

Ulf

Message Edited by UlfM on 12-17-2006 05:30 PM

[tol]

Hello Ulf!

Thank you for reply, i understand now how it works, i don't know why i didn't try chaining in first place, but my method of connecting  in parallel works too if your program ends anyway outside loop.

Question for BT issue is for executable file, if i want to show my program someone who hasn't Labview i got to build executable file, or installer, but in exe file "find NXT" block doesn't try to connect to NXT but it just checking if this connection is present or not. In vi file it works good.

Best regards,

Miki

[JamesB.]

Hi Miki -

Can you provide some more details about your problem with Bluetooth in a built executable?  Specifically, I'm interested in how many computers you are working with, the operating systems on those computers, and the error code that is returned.

[tol]

Hello James,

I use windows XP, Labview 8.0, i built and tried executable file at my computer.

I made simple program for remote control.

Which you can see here: "no error" and "error"

Program works good when it's running under Labview (for both connections types USB and BT). When i built and run exe file, program looks and work in same way like in Labview, except connecting, with USB it works fine, but when i choose BT connection and run program it's immediately return error msg, which i wrote in "error" case structure. When program is running as vi, and robot is off, it's returning error msg after 20 seconds, if robot is on it will connect it under 20 seconds.

Best regards,

Miki