Why not use USB 6008?

Hi,
I have an application that requires me to sample 6 AI channels at 1 kHz.
Processing every 20 ms.
I also need to output a PWM on 3 channels.
Normally I'd use PCI-DAQ cards.
e.g. a PCI-6023E and a PCI 6601 (timer/counter).
This costs about 700€.
Why shouldn't I use a NI USB 6008 (145€)
and two NI 6501 (99€).
Is there a big difference in programming and performance?
Are those devices all USB-2?
Because If I sample at 10Khz, I do not suppose that all that
data can go over a USB1-bus.
Thx !

Hi!
My observation is that a 6008 will work for you if you only need to acquire 6 channels at 1 kHz and you can handle 11 bits of resolution (to use six channels you must be in single ended mode, which losses one bit of resolution on this board). The other possible disadvantage of the 6008 is that you will have to learn to use DAQmx Base, if you haven't done so yet. However, if you are familiar with DAQmx, this should not be too difficult.
As for digital output, using two 6501's may not work for you. They will be software timed digital outputs, where it seems that you were looking for hardware timed outputs before (6601).
Both of these devices are USB 2.0 Full-Speed, which can handle this amount of data.
Good Luck with your project!
Justin

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Message Edited by Conseils on 05-08-2007 08:52 PM
Attachments:
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rpm sensor design.vi ‏70 KB

Hello Dadsf,
Welcome to the NI Discussion Forums! From your post, you would like to be able to count the number of pulses from your sensor that occur during a period of time and convert this to RPM. Let me know if I have interpreted this incorrectly. Your USB-6008 manual indicates that the device has a built in counter that can be used to count falling edge signals. If your sensor outputs digital signal this would be a good way to go. You can take the number of pulses that occur over a certain period of time (perhaps between two loop iterations) to find the number of pulses per second. The longer the period of time you acquire pulses for, the more accurate your average RPM will be. This will be at an expense of how often the user is updated with a new RPM value. Check out the links in my signature for some great information on how to get started with DAQmx and what all of the different terms in the DAQ Assistant mean.
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Xletview: why not use sun's javaTV source code directly ?

xletview : one emulator for viewing MHP Xlets on a PC;
I see many difference from sun's code about the part of javaTV.
Why the author Martin Sveden need to rewrite them and not use sun's javaTV source code directly ?
Thank you for your any answer.
Sorry for my horrible english.

XleView is a fine effort, but it has its limitations. I tried using it for the GunBunny demo available in the JavaME SDK 3.0 Eary Access available in
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package org.havi.ui;
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implements HComponentOrdering, ImageObserver, MenuContainer, Serializable {
whereas the real standard is
public class HScene extends Container
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I hate to critize such a fine effort, but it is best to keep an imlementation separate from the public API.
I agree that having a lightweight, simple and Java feature-complete Xlet viewer running would be very helpful, especially if BD-J gains much popularity. I have found trying to work with the vendor players described at
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to be frustrating. I tried all four mentioned and I have gotten none of them to work for me yet. These are huge downloads and the "Intro Version" of Arcsoft pointed to at the SDK 3.0 Early Access page
http://www.arcsoft.com/products/totalmediatheatre/
just gives a "File not found" HTML page. This forum post mentions that perhaps it was recently taken down?
http://www.arcsoft.com/forum/forum_posts.asp?TID=1084
I have already emailed Michael Downs of Arcsoft since he is mentioned here:
http://wiki.java.net/bin/view/Mobileandembedded/BDJPCPlayers
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Download the JavaME 3.0 SDK EA and then download the correct version of PowerDVD that the SDK page points to:
http://www.brothersoft.com/powerdvd-download-50794.html
Download the RI binary and source of Java TV API 1.1
http://java.sun.com/javame/technology/javatv/index.jsp
Since I am too lazy to use anything but the latest 1.6 JRE as a runtime, I have to fix
com.sun.tv.media.util.MediaThread
to comment out its stop() method. This is becase stop() was deprecated and made final in J2SE 1.5
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.html#stop()
http://java.sun.com/j2se/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html
Next, I had to mae a change to Sun's JavaTV implementation to keep the GunBunny demo happy by providing a ServiceContext. The RunXlet program calls SIEmulator, but that environment does not provide a ServiceContex, so I added one back in:
com.sun.tv.receiver.SIEmulator
private static ServiceContext svcctx = null;
Add before every call to new AppSignalEvent() and add the svcctx as the second-to-last argument:
if(svcctx == null){ try { svcctx = new com.sun.tv.ServiceContextImpl(); }catch (Exception e){ e.printStackTrace(); } }
I then had to hack a few PowerDVD classes, which is evil of me. First, I had to build an empty class by the name of
sun.util.BDJPlugin
becuase some PowerDVD class extends it but it is not in its BDJ.jar and then I had to reverse-compile (evil!) and modify one of their internal classes to avoid a dependency on their native methods. What I ended up with was a hacked version of com.cl.bdj.helper.CUtil to avoid the native methods which access the registry where they query for registry settings but also provide a default value (which I return).
com.cl.bdj.helper.CUtil
private static String pGetRegistryString(long i ,String string ,String string3) {
return string3;
private static int pGetRegistryInt(long i ,String string ,int j) {
return j;
The last thing I had to do was to change com.hdccookbook.gunbunny.BaseXlet, to use the JavaTV container rather than the org.havi one:
import javax.tv.graphics.TVContainer;
import java.awt.Container;
change
// protected HScene scene;
protected Container scene;
public final void run() {
// waitForPresenting();
// scene = HSceneFactory.getInstance().getDefaultHScene();
scene = TVContainer.getRootContainer(xletContext);
In order to having working keys, I had to add the KeyListener interface to BaseXet and
run(){
addKeyListener(this);
and then add a near duplicate of the org.dvb.event.UserEvent* stuff that is already there:
public void keyPressed(KeyEvent e){
switch(e.getKeyCode()){
case KeyEvent.VK_0:
case KeyEvent.VK_1:
case KeyEvent.VK_2:
case KeyEvent.VK_3:
case KeyEvent.VK_4:
case KeyEvent.VK_5:
case KeyEvent.VK_6:
case KeyEvent.VK_7:
case KeyEvent.VK_8:
case KeyEvent.VK_9:
numberKeyPressed(e.getKeyCode() - KeyEvent.VK_0);
break;
case KeyEvent.VK_ENTER:
enterKeyPressed();
break;
case KeyEvent.VK_LEFT:
arrowLeftKeyPressed();
break;
case KeyEvent.VK_RIGHT:
arrowRightPressed();
break;
case KeyEvent.VK_UP:
arrowUpPressed();
break;
case KeyEvent.VK_DOWN:
arrowDownPressed();
break;
public void keyReleased(KeyEvent e){
// System.out.println("Released: e="+e+" code="+e.getKeyCode());
public void keyTyped(KeyEvent e) {
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It then comes up and functions, but the rendering is not very good. Again, this is complete hack. Running the Java TV 1.1 RI in a JRE 1.6 is not supported. If you try to run any of the other examples, you will discover that the XML parsing is broken in JRE 1.6 with this message:
Parsing failed: com.sun.org.apache.xerces.internal.impl.io.MalformedByteSequence
Exception: Invalid byte 1 of 1-byte UTF-8 sequence., file: lib\JavaTVSampleFile01.xml
and you have to go and change the lines in
lib\JavaTV.properties
from
ServiceFileHandler=com.sun.tv.receiver.ReceiverFile
# ServiceFileHandler=SampleData_01
to
# ServiceFileHandler=com.sun.tv.receiver.ReceiverFile
ServiceFileHandler=SampleData_01
and build samples\db\SampleData_01.java and put it in your classpath along with all these other hacks.
Nonetheless, if you want to develop a somewhat generic Xlet that uses some BD-J features, that is how you might do it. But the moment you exercise anything else in the vendor's BDJ.jar that simply doe snot work outside of their environment or invokes one of their native methods, you are again stuck.
It would be nice if Sun would at least bother to update the JavaTV RI with the fixes I hae mentioned. Their "jmflite" implementation does not render perfecly but at least it would give the programmer something to work with without having to deal with an older JRE, etc.
Andrew
Edited by: AndrewMorrow on Oct 20, 2008 2:48 AM

Why not use USB 6008?

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