scxi-1600 counter/timer

[jonhelpmejon]

Is there a way to use the pfio or pfi7 connectors on the scxi 1600 to record a ttl pulse 5v signal for speed and display on the labview software?

[Daniel_L]

Hi Jon,

Thank you for contacting National Instruments!  It sounds like you've either already purchased a SCXI 1600 or are considering it, and want to know if you can measure pulse widths with the PFI lines. 

The short answer is no, because the SCXI 1600 does not have any counters in the device.  Measuring pulse width is generally done with counters/timers, or at least with an analog input (and calculating the period programmatically in software).  That being said, I'd recommend using this device in conjuction with a counter timer board, or using another board altogether.  (Any multifunction DAQ card with counters should be able to read pulse widths).

Regards,

Daniel L.

Applications Engineer

National Instruments

[Justin_M]

Hi Jon,

Using the SCXI-1600 for anything other than controlling a SCXI chassis is not officially supported by National Instruments.  However, because its design is very similar to some of the DAQ devices we sell, there actually are counters on the 1600 that you can access.  These terminals are hidden in LabVIEW, but you can  view them by right clicking on a channel control or constant and selecting I/O Name Filtering...  Then, click the Internal Channels checkbox.

Once this is done, you will be able to select the two counters on the 1600.  I have attached an example that will count the edges of a TTL pulse train using the  PFI0 BNC input terminal.  Other types of counter tasks, such as frequency or pulse width measurements, will also work.  Note that my device name in the example is '1600', which should be changed to match the device name you have chosen in Measurement & Automation Explorer.

Thanks,

Justin M.
National Instruments

[jonhelpmejon]

Thanks Very Much,

I will give it a try.

[christophe14]

Hi Justin,

I'm very interesting to acces SCXI 1600 counters, your VI will be usefull for my application. I have just a little problem to open it.

My version of LABVIEW is 8.0 and your VI was created with 8.2

Can you convert your VI in Labview 8.0

Thank you very much.

Regards

Christophe.

[Sandra_T]

Hello Christophe14,

Here is the example in LabVIEW 8.0.

Regards,
  Sandra T.

Applications Engineer | National Instruments

[jonhelpmejon]

Thanks Sandra

[christophe14]

Thx Sandra and jonhelpmejon.

The VI works perfectly.

Christophe14

[diesel1]

The counter works fine but I am having trouble using it to measure a frequency.  Does anyone have an example showing how to measure frequency with the SCXI 1600?

Thanks
Darrick

[Chris_D]

Darrick,

There are several DAQmx examples for measuring frequency with a counter in the LabVIEW Example Finder. Open the Example Finder and look under Hardware Input and Output » DAQmx » Counter Measurements » Digital Frequency. There are examples for single counter low frequency measurements and 2 counter measurements for more accurate measurements.