Generating a 10-bit signal through USB-6363

[joeyjojo]

Greetings,

I am needing to characterize a 10-bit DAC at work using Labview and the NI USB-6363. I have very little experience using Labview and need some direction in completing this task. We are only interested in the INL and DNL. What I have in mind is outputing the 10 binary signal to the DAC. The DAC's output is going to a digital multimeter that will be linked back to Labview via IEEE-488 to USB connection.

I have all this setup, I'm just getting lost with how to go about doing this in Labview. Thanks!

[A_Donfigulation_Error_Has]

Hi joeyjojo,

The first thing to do to get started is to install the latest DAQmx drivers if you haven't done so already. They can be found here. Since you seem to be a new user, I highly recommend you going through some example code. You can find the example code after you install the DAQmx drivers by opening LabVIEW and navigating to Help -> Find Examples... . From here navigate to Hardware Input and Output -> DAQmx -> Digital Generation. This section includes all example code about digital generation, I recommend starting with Write Dig  Port.vi and Cont Write Dig Port-Int Clk.vi.

This DevZone here is also a great resource in getting started.

Regards,

Jason L.

[joeyjojo]

Thanks for the reply. I ran some of the examples and was able to verify that my device is working, but none of them were similar to what I need to do.

I'm needing to send the 10-bit signal in parallel (I didn't clarify that before). The goal is to sweep the DAC from 0000000000 to 1111111111. I have Port0.<0:9> hooked up to channels b9:b0 on the DAC (b0 is LSB). Is there anything built into LabView that will do this? I have LabView 2011 and it's the complete software package. The DAC output will then go to an Agilent 34401 Multimeter hooked back into LabView via GPIB.

I have used quite a few engineering applications before but have NO experience in LabView. It's kinda frustrating because I know exactly what I want/need to do. It's now a matter of getting the software to do it for me.

Thanks for the help!

[Lea_D · Accepted solution]

Hi joeyjojo,

The USB-6363 uses the daqmx library as Jason mentioned. A good overview of the daqmx driver can also be found here. It sounds like you're going to be doing digital generation. Definitely check out the examples that Jason sent you to.... especially the one called write digital channel. 

Use the DAQmx write VI to configure the device to  read a digital 2D U32 NChannel NSample. This will take in a 2-D array where each row corresponds to a new channel and each column is a new sample. You can also look in the daqmx help to get a better explanation of the Daqmx Write. To get to te daqmx help, just go to Help » LabVIEW Help. In the Heirachey, open up VI and Function Reference » Measurement I/O Vis and Functions »DAQmx - Data Acquisiton VIs and Functions » Additional information, and there will be a section in there on DAQmx Write.

The best idea would probably be to start coding and let us know if you're getting a certain error. Additionally, if you've never used LabVIEW, it might be looking into for our DAQ and LabVIEW training. Keep us posted how we can help!

[joeyjojo]

Thanks for the help! I got it working perfectly now. I ended up going with the Write Digital Port example which helped out a lot.

I have one last question. Is it possible to change the digital output voltage level to around 3V instead of 5V? The device I'm checking has an upper voltage limit of 3.6V.

[Lea_D]

Hey joeyjojo,

I'm glad to hear it's working perfectly. 

In regards to your question, I'm  not seeing anything about being able to change these logic levels. Would it be possible for you to put together a voltage divider for the circuit so that you could take the 5 Volt signal and get it down to about 3 Volts? We have a Basic Analog Circuits DeveloperZone article, and about a third down the page is a Voltage Divder Calculation section.

I know alot of our HSDIO devices have the capability to select logic families. I think most (if not all) have a 3.3 Volt logic family, but you should verify the logic families for the specific card. Changes for this though would be having a PCI or PXI card and not a USB interface as well has using the HSDIO driver.

[dhaneeshamd]

got a small problem Lee, I require the same 10 bit ramp up sequence but im using NI PXI 6363 with port0<0:7> and the last two bits port2<0:1>, how can i create a 10 bit ramp up sequence which is software controlled (timed) i.e. i need 1sec delay between each step.

[Dennis_Knutson]

You can do the same thing and start with the Write Dig Port example. You would add the second port. Change the while loop to a for loop and connect the iteration terminal to the data input of the DAQmx Write.

A 1 second delay is going to be a very long test.

Edit: In 2012, the example to start with is Digital - SW-Timed Output. You would change the DAQmx Write to Digital U32 1Chan 1Samp and add the additional lines.

[GYALI]

Hi lea 

I just want to know that in ni-usb 6363 card voltage divider circuit is already there inside the card or I need to make voltage divider circuit eternally. 

[iradovanovic]

Gyali,

Can you post this question on a new forum post to get more visibility? You are replying to one that is 5 years old.