any way to make voltage my trigger source?

[hellolv]

in DAQ Assistant, I can choose voltage to be my trigger source, but with a DAQmx Trigger VI, voltage is not one of the trigger source options.

any way to make voltage my trigger source?




hellolv

[Dennis_Knutson]

Do you not see this?

Message Edited by Dennis Knutson on 10-02-2007 03:51 PM

[hellolv]

Yes, but what do I wire into the source?

Can you give me an example?

[Dennis_Knutson]

You wire the name of the trigger source. It would be the same as you chose in the DAQ Assistant i.e. APF10. You ahve the same examples I do presumably. Open the example finder and expand Hardware Input and Output>DAQmx>Analog Measurements>Voltage. There are a couple there that use an analog trigger. Acq&Graph Voltage-Ext Clock-Analog Ref is one and its at the top of the list in my example finder.

[hellolv]

Hi Dennis,

Sorry I did not make myself clear previously.    In DAQ Assistant, I could choose Voltage as the trigger source instead of a real channel.  Is that option still available in DAQmx Trigger?  Can I trigger the analog input with itself(rising edge)?

Thanks.

hellolv

[Dennis_Knutson]

Below is the options I see with the DAQ Assistant trigger. The trigger source there is the same thing you would specify for the trigger source with the DAQmx Trigger function. The DAQ Assistant is using the lower level DAQmx functions. Use the DAQ Assistant to create a task with a trigger. Then, from the block diagram, right click on it and select 'Open Front Panel'. This will convert the assistant to a regular subVI. Look at the DAQmx Trigger function and see how it is wired.

Message Edited by Dennis Knutson on 10-02-2007 08:19 PM

[jaced]

Hi Hellolv,

I think I see your confusion, in the DAQ Assistant you selected "voltage". what this is really referencing is the task that is created by the DAQ assistant. As you can see in the images below "voltage" has a physical channel associated with it. In this case Dev5/ai0 is the physical channel used by Voltage. I hope this clears up the confusion. I have also attached a screen shot of a LabVIEW shipping example, this example explains how to create a DAQmx program using a hardware trigger, to set-up the VI all that is needed is to set the trigger source to analog input channel you will be acquiring on. The example name is Acq&Graph Voltage-Int Clk-HW Trig Restarts.vi, you can find the examples by going to

Help»find examples»Hardware Input and Output»DAQmx»Analog Measurements»Voltage.

 You can also access the Context help by going to help»show context help, then hovering over any area of a vi that you would like more information on. in the context help window you can click detailed help and you will be directed to the help file for that particular vi.

-JaceD

Voltage Channels in DAQ Assistant

Trigger Configuration in DAQ Assistant

Acq&Graph Voltage-int Clk-HW trig restarts

Message Edited by jaced on 10-03-2007 02:14 PM