NI9411 frequency measurement with analogue output

[r.youden]

I have an NI-9411 connected into a 9178 cDAQ module. I want to constantly measure the frequency of a digital signal then output this signal as an anlogue output using another of my NI modules. I am pretty new to the NI environment, does anyone know of a simple method using the DAQassistant?

Thanks for your help.

Richard

[r.youden]

I have alos noticed that when I go through the DAQassistant there are only 4 frequency channels to choose from whilst there are 6 differential frenquency channels in hardware, am I missing something obvious here?

Thanks again.

Richard

[Adam.B]

Hi Richard,

Do you want to output a voltage that varies with frequency or just an analog signal with the same frequency as the digital?

The easiest way for you to do this is to use two DAQ Assistant VIs and wire the output from your digital module into the output of your analog module.

If you wanted to output a varying voltage with frequency you would perform some simple scaling on your measured frequency and wire it straight to the output.

If you wanted a varying frequency analog signal, you could use the Simulate Signal express VI and wire the measured frequency into the frequency input.

The reason you only see four channels for frequency measurement is that this particular function utilises the hardware counters on your device to count the time period between pulses to work out the frequency, your cDAQ 9178 has four of these hardware counters.

For direct voltage level measuring you will see six differential channels available.

Hope this is helpful to you.

[r.youden]

Hi Adam.

Thanks for your reply. I have progressed a bit from when I posted this thread. I have been working with one of your colleagues, Alastair, an updeated thread can be found here:

http://forums.ni.com/t5/LabVIEW/Continually-update-input-value/td-p/2632423

If you could assist with my latest question i'd be very grateful.

Thanks.

Richard