What kind of processing am I doing or need to do?

[Lab Student]

I was using signal conditioning to acquire two signals but have since determined that it isn't necessary. I can now directly input both the "trigger" signal and accelerometer data directly into the Laptop. my question is, how do I go about writing a program in Labview that will look at and start on the trigger of the horn, acquire the data and sense a rise in the other signal and then another change in the same signal. What sort of acquisition, or processing is this and what has to be done.

[MikeG]

Lab Student,

Thank you for contacting National Instruments.

Though you don�t state it explicitly, I am assuming you are using an E-Series DAQcard. I will also assume you are using LabVIEW 6.1 or later. It seems like you want to do a finite or continuous analog input operation that starts on a trigger. As far as guidance in programming, it would be useful to look at an example program. From LabVIEW, first open the example finder and browse according to task.

If you are using Traditional NI DAQ, select Hardware Input and Output>>Traditional DAQ>>Analog input. If you want to acquire continuously (indefinitely), select Cont Acq&Graph (buffered) D-Trig.vi. Otherwise, choose another example from this list that includes reference to a trigger. If you ar
e using an analog trigger, as opposed to digital, there are examples in the list for that need as well.

If you are using DAQmx, select Hardware Input and Output>>DAQmx>>Analog Measurement>>Voltage. Select Cont Acq&Graph Voltage-Ext Clk-Dig Start.vi. When you run this example, set the clock source to onboard clock.

If you don�t have a preference between DAQmx and Traditional DAQ, and you have LabVIEW 7.0 or later, use DAQmx. It is the newer, more intuitive DAQ driver. Examine these examples and disect them using the context help (CTRL + H). This will put you on the right track.

Regards,
Mike Geruso
National Instruments Support