USB-2408 drivers with LabVIEW- How to get Started? Problems with FTP...

[Hannamon]

I'm brand new at this... I can't even get the drivers downloaded from the ftp site.  I've been using both regular MS-Edge and Gogle, and FP Clients such as WinSCP and FileZilla... I've tried accessing the files as an anonymous user, but no avail.  It's been years since I've used FP protocol, and I simply don't know how to begin.  Could really use some pointers, here...  have contacted the manufacturer directly, to no avail.

[Fausto]

Hello @Hannamon.

If you are using a Windows OS system with LabVIEW 2015-2022 (LabVIEW 2023 not supported as of this post) and a MCC USB-2408 module, then you need to install the MCC DAQ software.  https://www.mccdaq.com/Software-Downloads  Select InstaCal and ULx for NI LabVIEW during the installation.

 

After the installation has completed, connect the USB-2408 to the Windows system's USB port and launch InstaCal.  InstaCal should detect the USB-2408 and allow you to configure the channels.  Afterwards, close InstaCal and launch LabVIEW.  (You should not have both applications open at the same time.)  The MCC vi examples are saved to the 'C:\Program Files\National Instruments\LabVIEW 20xx\examples\ULx' folder.

Please review the following posts to get started with ULx for NI LabVIEW and a MCC device.

 

 

 

KnowledgeBase article:  https://kb.mccdaq.com/KnowledgebaseArticle50481.aspx

 

Regards,

Fausto

[Hannamon]

I found the LabVIEW drivers on the MC website... no idea why it was pointing me to the FTP site... and via the manual, found that I needed the InstaCal.exe to set up the USB-2408.  Through the examples and the LabVIEW Forums, was able to get the Single-Ended Voltage Measurement mode operating reliably.  However, the differential mode is another story.  I know that I have to configure tha USB-2408 via the InstaCal program, which I have done, but I cannot get the LabVIEW software to perform reliably.  Is there any way I can be pointed in the right direction?

[Fausto]

Hello @Hannamon.

On 4/28/2023 at 3:57 PM, Hannamon said:

I cannot get the LabVIEW software to perform reliably.

Please elaborate your concern.  It appears that you were able to configure the input channels to differential mode in InstaCal.

Are you signals wired correctly to the USB-2408?  Refer to pages 11-12 in the USB-2408 User's Guide.

https://www.mccdaq.com/pdfs/manuals/USB-2408.pdf

What are your signal type(s), i.e. voltage, temperature?

Please reply with a screen capture of the channel configuration from InstaCal.

Regards,

Fausto

[Hannamon]

(1) Uploaded as requested.

(2) Yes.  Minus the the 100k resistor, wired exactly as shown on pgs. 11-12.

(3) Signal type = Voltage

[Fausto]

Thank you for the screen capture.  Settings look fine.  Please elaborate your concern regarding reliability of the data in LabVIEW.

[Hannamon]

I'm looking for an example in LabVIEW to configure the code to measure differential output.  Is it enough to measure the various channels (once configuring the A/D via InstaCal.exe) i.e. For 0L/0H measure Channel 0 and Channel 8 and subtract the two to get the differential o/p, as for the "Configure.vi" there doesn't appear to be any differential configuration.

Again, if an example could be provided, this would help a lot.

Also, is it  REQUIRED to use the 100k resistor to AGND?

Edited May 1, 2023 by Hannamon

[Fausto]

Hello @Hannamon.

As mentioned in the user's guide, use the 100 kOhm resistor to the AGND terminal if your signal is not referenced to ground (floating).

 

Take a look at the MCC example 'C:\Program Files\National Instruments\LabVIEW 20xx\examples\ULx\Analog In\Measure Voltage.llb'  --> Select 'ULx Acq&Graph Voltage-Int Clk.vi'.  It is setup for a single channel.  You will need to lower the Sampling Rate.  Set the channel to differential input in InstaCal, before launching LabVIEW.

 

Take a look at the attached .vi example, for a multiple channel acquisition.

USB-2408TCandVolts_LV85.llb

Regards,

Fausto

Edited May 1, 2023 by Fausto
minor edit

[Hannamon]

Does this imply that EACH diff i/p must have this 100k resistor connected to AGND, or just CH0L/H?  Also, I'm assuming that (for SE measurements for example), if I need to do more than one, I would enter a "Dev0/Ai0:2" for example, and the crux would be in how I actually acquire the data.  So, two separate thought threads going on here.

Edited May 1, 2023 by Hannamon

[Fausto]

Whether or not you use the 100k resistor depends on the signal source connected to a particular input channel, in differential mode.

1 hour ago, Hannamon said:

if I need to do more than one, I would enter a "Dev0/Ai0:2" for example

Correct.

 

1 hour ago, Hannamon said:

So, two separate thought threads going on here.

Please elaborate if I haven't answered your question.

[Hannamon]

All the SE questions have been answered.  The final one I had was the 0:2 which you answered.  I tried it, and it seemed to work.

Now we are left with the original differential question.  Do I connect the 100k resistor to just the C0H/C0L (specifically the C0L) channel or all differential channels?  After recalibrating with Instcal.exe, do I address the channels by Dev0/Ai0 and Dev0/Ai8 and subtract H from L?  Is there a LV example of this?

[Hannamon]

I'm still waiting on some LV Differential examples... this issue has arisen again... Please supply an examle of acquiring a voltage through means of a differential channel.  I know I have to use InstaCal to configure to the USB-2408 first.

Edited May 10, 2023 by Hannamon