getting digital output from analog input

[tavis]

I apologize if this is a basic question, but I'm new to DAQ and couldn't find an answer. I have a valve which gives off a signal when it is open. When connected to an analog input, the signal is a sine wave between 0v and .5v. I would like to hook this up as a digital signal to let me know when the valve is open. I am using an SCB-68 board and configuring it in MAX. Is what I want to do possible? The valve signal comes from 2 wires.

[mepausle]

If we assume your board is capable of reading +/- 5V directly, and that the valve voltage is a time-varying DC signal, then you could plumb it directly into an analog input channel using MAX and it's wonderful wizards. The Labview VI itself would consist of simple logic (if V_valve > 5, then ....). You could use a case structure to determine what actions you would like to take in response to the input voltage. This is by far the 'brute force' method.

Something more elegant may be to breadboard something up that does this off the computer. I am not sure this is strictly possible, but there has to be a combination of IC's out there that would convert your varying signal into a TTL signal. You could then use a digital input on your DAQ board if you were truly adverse to the first method.

Regards,