digital and analog USB 6008

digital and analog USB 6008

Post by Miaa » Wed, 28 May 2008 07:10:04

step 1:
I am uisng USB 6008 and LV8.0, i have 8 analog channels and 4 digital channels. Step1,  is to use 4 digital channels ( P1.0, P 1.1, P1.2, P1.3 )  to allow me to read one by one the 8 Analog channels ( AI0,AI1.....AI7) . So the 4 digital channels will go through some logic. I am connecting +5V to the P1.0 ( pin number 25 )  and ground to GND ( pin number 32 )  of USB 6008. After that i run the following VI to show me the reading, i am getting +15V whereas i should be getting +5V.
I am trying to expand on the bottom code (see block diagram). And am curious how should i connect my 4 digital channels on the left hand side FOR loop.
Kindly, correct me if i am using the wrong pins of USB6008 DAQ board.

analog logic.lvproj:

digital and analog USB 6008

Post by Dennis Knu » Wed, 28 May 2008 08:10:05

All that you attached was the proj file and that is not the same as attaching the VI. You need to attach the VI you've written.
I also don't understand what you have described. There is no reason to use digital channels to select one of the analog inputs and there is no way to use digital channels as outputs to select an analog input unless you are doing this in software and this seems a pretty round-about way of doing something. Since you say you are connecting +5V to a digital line, that would mean that you have the digital configured as an input and if you are reading a digital input, you cannot read +15 V from it.


digital and analog USB 6008

Post by Miaa » Wed, 28 May 2008 11:40:06

kindly, see the attached drawing for schematics.
Also, which pin numbers of the USB 6008 the three wires be connected if one has to see all the possible  pattern of three bits 000, 001, 010 etc etc on the LabVIEW LED indicators? Is there any sample VI which one can use ??

Block A.doc:

digital and analog USB 6008

Post by Dennis Knu » Wed, 28 May 2008 12:10:04

I thought you had a question about the LabVIEW code that you wrote? You attached a project but no VI. Since you did not attach the VI as I asked, can I assume you no longer have a question about it?
I'm not sure why you posted the schematic. You have not provided any explanation of what blocks A and B are and what you are trying to do with the inputs to them. It looks like you are powering some buffers with the digital outputs. Is that true? The digital outputs of the 6008 are pretty low current. Check the current requirements for your buffers to see what they require and then check the data sheet of the 6008 to see if it can provide enough current.
You have two digital ports that you can use. I would assume that you already have the user guide with the pinsouts. To make it simple, use the first three inputs of either port 0 or port 1. That would mean pins 17,19,10 for port 0 or pins 26,27,28 for port 1. There are a couple of simple examples you can look at. Start with Read Dig Chan.Message Edited by Dennis Knutson on 05-26-2008 08:51 PM

digital and analog USB 6008

Post by Miaa » Wed, 28 May 2008 23:40:06

attached is the error when +3v DC signal is sent to pin number 26 of usb6008 ( P1.1) .  I think i should be getting logic 1 after the Labview program. But instead i am getting the attached snap shot of error. I am using the attached manual as reference.



read digital

digital and analog USB 6008

Post by Dennis Knu » Thu, 29 May 2008 00:10:06

I don't get that error when I run the VI and with the exact same port/line selected. It's a different DAQ board but I don't see how that would make a difference.

digital and analog USB 6008

Post by Nathan_ » Thu, 29 May 2008 05:40:12

Hi Miaa,

Your code looks good. The -50405 error is usually caused when
communication is lost to the USB-6008. To debug what is going wrong, try
disconnecting all external connections. Then reset the device in Measurement
and Automation Explorer (MAX) by right-clicking on it and selecting reset
device. Then make sure the device passes a self test in MAX. If all this works
then slowly hook up your external circuitry one channel at a time.  One possible cause of this error is when the
USB-6008?s 5 volt line is shorted to GND. This will cause the device to shutoff
in order to protect itself. Please let me know if you have any questions.


Message Edited by Nathan_R on 05-27-2008 03:33 PM