UD Example Code (U3, U6, UE9) | LabJack
« Close

Datasheets and User Guides

App Notes

Software & Driver


UD Example Code (U3, U6, UE9)


LabJack makes wrappers and libraries available for many languages for the UD library.

The UD library is the Windows library/driver for the UD series of devices, the LabJack U3, U6 and UE9. For other LabJack devices, go to the Software page.

UD Example Code Table

Example Code/Wrappers: UD Library

U3 U6 UE9

U3, U6, UE9

Examples In... Windows Mac Linux

UD Quick Reference Snippet (Referencable)

Quick References

The attached quick reference .rtf files are useful when programming with the UD library. Each quick reference guide is tailored to a specific device, so it is easy to find relevant constants and copy them into your code.



i will be grateful if you help me with using the " Frequency Output (Mode 7)" timer (u3)  in vb.net with code please

For VB.NET you should use our .NET download which can be found here:


In the examples folder there for each of the LabJackUD devices (U3, U6, UE9) you should be able to find a VB.NET TimerCounter example that should provide a starting place.


I am using a Labjack U3 (Driver Version 3.25, Firmware 1.52, Harware 1.21) to sample date from a self constructed data glove. Though it is possible to sample data using single requests it does not seem possible to get the streaming mode to work. In fact the "U3 Simple Stream" example always crashes with an "unhandled exception" when calling "eGet(lngHandle, LJ_ioSTART_STREAM, 0, &dblValue, 0);" (VC6 example). Does anyone know a sollution to that problem, experienced the same or has an explanation? I would be very grateful for any help I can get on that matter.

Is this our unmodified U3_SimpleStream example?  If not does that example run for you?

Does LJControLPanel work?  What about our LJStreamUD program?

Thank you very much for your answer. I tried your unmodified U3_SimpleStream and U3_StreamCallback example many (!) times then I started modifying it to see if I can get some change in program behavior but without much of a result. Sometimes when starting the LJControlPanel before running the example it works though. LJStreamUD works as well. By the way I am using MS Visual Studio 2010.


--------------------Configuration: LabJava - JDK version 1.7.0_01 <Default> - <Default>--------------------

Exception in thread "main" java.lang.UnsatisfiedLinkError: com.labjack.labjackud.LJUDJavaJNI.OpenLabJack(IILjava/lang/String;I[I)I

at com.labjack.labjackud.LJUDJavaJNI.OpenLabJack(Native Method)

at com.labjack.labjackud.LJUD.OpenLabJack(LJUD.java:21)

at LabJava.main(LabJava.java:19)


Process completed.

**I used JCreator and try to interface with UD but when i run the code, it keeps pop up this results..can u help? UnsatisfiedLinkError?


Did you load LJUDJava.dll in your Java code?  Usually that error arises when the dll is not loaded or cannot be found.  The examples show how to do this with the System.loadLibrary call.  Also, take a look at this forum topic as it helps with issues like this: http://forums.labjack.com/index.php?showtopic=4899.

If this does not help to resolve your problem, a better place to continue this issue would be in the Java section of our forum or by support email.

How about Freebasic ?


I looked around but don't see that us or anyone else has ever used Freebasic to talk to our Windows UD driver.  The first thing to do is go through Freebasic support to see how to call functions from a Windows DLL.  If it looks possible, then try calling some of the functions from the UD driver documented in Section 4 of the U3/U6/UE9 user's guide.

Any reference on R? Thanks

We do not provide an R interface or examples to our LabJack devices. However, you might be able to access our driver's functions in R. Refer to the "Writing R Extensions -> System and foreign language interfaces" part of the R manual for help on this (our driver is a C interface):


Refer to our C/C++ examples for code help, and the header files for documentation. On Windows, for additional documentation look at section 4 of the UE9, U3, or U6 User's Guide.