Signal Express Reference trigger on B series (USB-6009)

[skrubol]

I'm currently evaluating Labview Signal Express 2.0 and am having some triggering issues.  Is it possible to set up a reference trigger on a USB-6009?  I get options with a DAQPad-6251, but nothing with the 6009.  Is it just not capable?  Anyone know what the most basic USB DAQ that supports reference triggers is?  Is there a way around it?  I need to capture digital signals (capturing in analog is fine) around an event (actually a few thousand samples before the event, and about 1000 after.)  I am able to do this easily with the 6251 (10k before, 2k after,) but am looking for a more economical way to do this for several units.
Thanks in advance for any help.

[Matt_A]

Hello skrubol,

You were correct when you guessed that the USB-6009 does not support reference triggering. If you view the USB-6008/6009 User Guide and Specifications here you will note that only digital start triggers are supported. This is because the USB-6009 does not utilize the DAQ-STC2 engine for digital timing and triggering. This engine is found in our M Series devices and allows for additional triggering modes. The most modestly priced USB device that contains the DAQ-STC2 engine (and therefore supports reference triggering) is the NI USB-6210. For more information about this device you can view the product page here; the NI USB-621x User Manual also contains more detailed information about the DAQ-STC2 engine on page 2-3 (page 21 of the PDF).

To address your question about a workaround, I would suggest that you consider post acquisition analysis. You could continuously acquire data and use software to monitor for a certain signal. Then, you could programmatically select X number of samples before and after this signal. This type of programming would probably require a greater degree of determinism than LabVIEW SignalExpress is able to provide, so you may need to do some work in LabVIEW if you choose to pursue this route. You could convert your LabVIEW SignalExpress project to LabVIEW code using Generate Code from the Tools menu; or you could write the code in LabVIEW to process your data and import that function to LabVIEW SignalExpress using the Run LabVIEW VI step in LabVIEW SignalExpress. I hope this information is helpful.

[Matt_F]

Hello Skrubol,

Another option is to set a start condition for your logging in LabVIEW SignalExpress. 

From the recording options tab, select the channel you want to record and then select the Start Conditions option.  From this dialog you can set LabVIEW SignalExpress to start logging when the signal goes above or below a certain level as well as save a certain amount of precondition data.

Regards,

Matt F

[skrubol]

Thank you Matt's.  The recording options will do just what I need, as we can modify the firmware of the device we're monitoring to change the state of a line only when there is a failure.