Reading multiple PWM using a single counter

[Tanis]

Hi everyone.

Not really sure if this goes in digital i/o or counter/timer but here it is.

I'm trying to design a system where i send out an signal from a transducer, and have other transducer measure the delta t between the 1st transducer emitting the signal and it being recived by the other transducers.

So far my best (and cheapest) guess is to use something like this

http://www.senscomp.com/minis.htm

The transducer above using a trigger and return a digital high when an "echo" (or signal i would guess) is detected.

I want to use a large number of this transducers. So i was wondering if i could use https://www.ni.com/en-us/shop/model/usb-6501.html (ni-6501) or if have to use something like https://www.ni.com/en-us/shop/model/usb-6366.html (ni-6366). 

I mean, if the 6501 doesn't work i might as well go for a purely analog DAQ that allows me full control of the signal processing but as a cost saving measure i'm looking into the digital i/o plus counter solution.

Any help is appreciated.

Thanks so much for reading.

I'm trying to measure pulse/echo times using

[John_P1]

Hi Tanis,

So you'll have a single output pulse, and then some number of response pulses.  You'd like to measure the time between the output pulse and each of the response pulses.  Is this correct?  How many response pulses do you plan on needing?

A digital method would be more elegant and more reliable for the cost, given that you can utilize a high resolution timebase to make your measurement rather than actually having to sample the analog signal continuously.  The 6501 is software-timed only and will probably not meet your requirements, but you might look into something like the PCIe-6320 (8 clocked DI channels) or PCIe-6323 (32 clocked DI channels).  If I understand your application correctly, you should be able to use change detection to sample the digital port on each pulse.  You can use a counter to timestamp the change detection event based off of the internal 100 MHz timebase.  The counter could be armed off of the 1st transducer (the stimulus).

Best Regards,