semi period counter input usb-6210

[Niro]

Hi everybody,

I have tried since few days to acquire a PWM duty cycle on input counter on the usb-6210. It works almostly but the measures are not every time precise. It seens that the trigger is not correctly functioning. I put it off and the vi has still the same behavior.

Does anyone have experience with this kind of acquisition??

For information, I try to read a PWM of 1kHz and I use for counter input and trigger the input CTR0.

[Niro]

I can just precise that I have configured the Input Counter in semi-period from it I extract the duty cycle...

I really looking to find solution to have good repeatability of the measures.

Thanks..

Niro

[Naity]

Hi,

The trigger propery does not work on USB 6210 for semi period measurment. In your case (fixed frequency PWM) you could measure the pulse instead of 2 semi period and quite easily get the duty cycle (with Pulse.Frequency or Pulse.Time).

Best Regards from Munich 

[Niro]

Hello everyone,

First, thank's for yours responses.

Naity, you are right that I can not do it with the USB-6210. In fact, this is right for all family of USB. But the pulse frequency is also not working properly on this card. To solve the problem, I use now a PCI 6221. With it, it is possible to measure both semi-period and to extract the duty-cycle. I just not take into account the first sample which is about 0 [s]. But taking the second and the third, all is correct.

The trigger armstart is also working correctly.

For information, the usb family card is usefull in case of edge counter for example but not for my application.. 😕

Thank you all.