How Do I Acquire Voltage Data

[PSUstudent]

Hello I am looking at reading a voltage from an external source, and using that voltage to trigger an event if it is above some value or not. Is this possible to do with the serial port.
I know some of the other posts on serial port things involve a stream coming into the serial port, but we don't have a stream. If the serial port is not possible to use, then might you have a suggestion of what I could use. Our options are USB, serial, PS/2, ethernet port, and firewire port. We are using LabVIEW 8.0

Thanks

[Chris_VH]

You can use almost anything you could think of to get a voltage reading into LabVIEW, which serial would be fine. Once you get it into LabVIEW as a string most likely, you would have to manipulate it to become a number, compare that to your limiting voltage, use a case structure, and bam, you have another portion of your design project answered.

[Dennis_Knutson]

I don't see how any of these connections could be used to get a voltage unless you have some sort of instrument connected to the other end. None of the ports do an analog to digital conversion so you would need some sort of external hardware to do that. The least expensive device from NI for capturing an analog signal is the USB-6008.

Message Edited by Dennis Knutson on 03-30-2009 03:27 PM

[Chris_VH]

Good point,

I assumed that the serial would be hooked to a device, not just used as a probe for voltage.

If you're trying to just hook up the cabling to a voltage and read that, its not going to work for you, you need some sort of device that can be read via the numerous amounts of protocols in LabVIEW.