Which DAQ to use to generate 8 PWM signals?

[Marek]

My application requires 8 PWM signals (up to 20KHz) to be used to control my hardware.

Which DAQ should I buy from NI that would be able to generate 8 PWM signals?

How do I generate a PWM signal using the DAQ?

[Kevin_Price]

Offhand, I'd think the PCI-6602 might be just the ticket.  It's got 8 counters and you can control your PWM freqs and duty cycles independently and update them on-the-fly without stopping.

You can check the shipping examples for "generating digital pulses" or search the site for stuff like this or this.

-Kevin P.

[Marek]

I'm not using LabView.  I'm either going to do it directly though Matlab/Simulink if it supports timers/counters and if not, then I'll write my own C++ code.  Is there any reference code that shows how to control the timers through C++ available?

[Steve_B]

Hi Marek,

Are you going to generate continuous pulses or were you planning on generating a finite pulse train? The finite pulse train requires 2 counters for each pulse train but a continuous pulse train can be done with 1 counter per pulse train. I would recommend that you look at the ANSI C examples as a guide for programming the device in C++. I have also included a link to a KnowledgeBase that discusses the location of the examples. I would also recommend that you reference the NI-DAQmx C Reference Help that can be found by going to Start>>Programs>>National Instruments>>NI-DAQ>>NI-DAQmx C Reference Help. This is a very useful guide for programming your DAQ device in a C language.

Location of ANSI C NI-DAQmx Shipping Examples and DAQmx Library File for Windows
https://www.ni.com/en/support/documentation/supplemental/18/location-of-ansi-c-ni-daqmx-shipping-exa...

[Marek]

I would like to generate a continous pulse train that I can vary the frequency of while it is running.

[Kevin_Price]

Can't help with any C programming syntax, but can verify that the 6602 board and the free DAQmx driver definitely *do* provide you the ability to generate 8 independent continuous TTL PWM signals, and you can vary the freq / duty cycle on the fly without stopping.

-Kevin P.