Counter voltage threshold?

[KarstenWilson]

I have a signal that is only outputing a range of voltage from 0.5V to 2.8V.  This does not seem to be triggering the counter.  A different encoder with 0-5V is working great.  Any way to change the voltage threshold?  I'm using NI-DAQmx from visual basic on an NI USB -6251.

Thanks,

Karsten Wilson

Hewlett Packard

karsten.wilson@hp.com

[BedbugsManly]

I also want to do this activity....

Pictures of Bed Bugs

[Beutlich]

There is a hardware solution and a software solution. The hardware solution involves using a zener diode to shift the thresholds based on the breakdown voltages. This is described briefly in the article <link no longer exists>. The software solution would be to use an Analog Input task, and do a software compare and generate the counter events based on implementing some processing on the analog signal. A good example of this would be the Analog Input Threshold community example.

[Henrik_Volkers]

For periode signals in the MHz range I just had tried this with success.

On a SCB68 screwboard  it was a free air construction 🙂 . I needed a 50Ohm termination, and the R/Cin_PFI are for Simulation only, and I a had lower amplitude.

Short modification.... not beautifull, but sim say it might work 😉

This is a 100kHz sim , blue your signal , green the collector voltage, however I didn't look at the soucre impedance!! Currently this is a low impedance source!