Can I use the USB-6002 DAQ to generate a pwm signals?

[velez001]

Can the USB-6002 be used to generate PWM signals?

If so, which is the maximum frequency and minimum pulse width?

What is the speed of the digital lines when used as output? Can I use teh digital lines to send digital pulses of about 2 microseconds?

Thanks,

Aaron

[JCH_26]

Hey Aaron

Pulling data fro mhe datasheet:

COUNTER

Number of counters 1

Resolution 32-bit 

Counter measurements Edge counting, rising or falling 

Counter direction Count up 

Counter source PFI 0 or PFI 1

Maximum input frequency 5 MHz

Minimum high pulse width 100 ns 

Minimum low pulse width 100 ns

TIMEBASE 

Timebase frequency 80 MHz 

Timebase accuracy ±100 ppm 

Timing resolution 12.5 ns

PFI Line outputs probably would be more suitable.

Regards

J

[velez001]

I asked NI for asistance. They told me to post my questions in the forum. Then I get a NI engeneer posting the datasheet...

This is far from a decent custumer support!

Can someone, plese, answer my question is a comprenhensive way?

All the best,

Aaron Velez

[JCH_26]

Hi Aaron

Aplogies you feel that way, typically techincal support calls/e-mails are a paid for service, the forums have a wide community (not just NI Egnineers) that can help solve issues//answer questions.

I was merely answering the question of minimum pulse widths and frequencies etc..

What specifically are you looking to get?

Have you tried coding with the 6002?

Regards

J

[velez001]

Then it is very unfortunate that the so call paid services told me to post my question in the Forum.

I understand that the main fault was when a NI support told me (by phone) to post my question in the Forum....

So, do not owrry, it is not your fault. I will contact custumer support again.

Thanks,

Aaron

[JCH_26]

Hi Aaron

If there is a valid SSP (Standard Service Program) associated with your NI account then yuo shouldn't have any issue using the phone support 🙂

Regards

J

[Dennis_Knutson]

As you can see from the specs, the digital I/O is software timed so your pwm signal would be subject to jitter and limited to a rate of about 1kHz or so. The counter is an event counter only and can't be used to generate a signal.

[shidalgo]

Hi! I have the same question. Did you get the answer at the end? Which the max frequency?

[ikaiser]

The USB-6002's counter can only detect (and count) events. They cannot be used to create PWM signals. You can test this yourself by adding a USB-6002 in NI MAX (either a real one or a simulated one), then clicking "Create Task". Navigate to Generate Signals » Counter Output » Pulse Output, and it will show you "No supported devices found" afterwards. Digital Output has only "Line Output".

Here the solution Dennis_Knutson described comes into play: You can use a LabVIEW program to output 1s and 0s in quick succession. However, I strongly disadvise like Dennis did, as the timing of this software-based approach will be quite bad, you will experience a lot of jitter. The execution rate of your output loop will spread a lot, additional to that comes the transfer time through your USB. In chapter 4 here you can get a general impression of jitter on a PC: Make it Faster: More Throughput or Less Latency?

[jesLVbcn]

I did a service request to NI using my SSP to ask if it's possible to generate a PWM signal with my USB-6000. I wanted a PWM signal to control a H-Bridge motor driver. The answer by the application engineer was NOT and the only way is to generate PWM signal by software in case you need a low frequency and low resolution signal.

With this answer I always use my RIO Eval Kit when I need to generate a PWM signal

I hope this helps you a little bit more