How can I make an analogue falling edge trigger

[Pelle_Pelle]

I'm using a Labjack DAQ board which doesn't support the DAQ-NI VIs. I Need to make a trigger which will stop the acquisition when it detects a significant voltage drop from the peak current. Any advice would be grateful.

Thank you.

[e-Cash-Money]

Hello Pelle,

I've never used a Labjack DAQ board before so I'm not sure how you would setup an acquisition that stops on an analog edge.  However, I know that it is very easy to setup a continuous acquisition that stops on an analog edge using our DAQ board and NI-DAQmx driver.  One thing that you might want to check is to make sure that the Labjack board actually supports analog "stop" triggering.  I know that LabVIEW and the NI-DAQmx driver installs examples of how to use analog triggering, perhaps the Labjack driver installs examples as well?

[Pelle_Pelle]

Hi,

I haven't found any example of stop on analog trigger, but I was wondering if i could use a while loop with a function that could detect a variation of voltage such as -dv/dt >= value which would do about the same as the falling edge trigger for my application. If such a function exist, any help using it would be greatly appreciated. The analog input is 0-10 volt.

Thank you,

Pelle

[George M.]

Hi Pelle,

You will need to contact Labjack for information on setting up an analog trigger for this device.  If you are interfacing this board with LabVIEW, then you will have to use Labjack's driver to do so, and they will be able to tell you how to program it.  I am pretty sure that Labjack has a forum for questions on their hardware as well. 

However, if you would like to have the seemless integration of NI's hardware with LabVIEW, then I will be glad to help you find the device that is right for you.  I hope this helps, and please let me know if you have any further questions.

Have a Great Day!

George M.