About trigger config

[aero]

Dear Sir/Madam:

I found that when I want to configure the trigger and gate conditions for analog output operations using "AO Trigger and Gate Config", I can using the input signal as a trigger signal, but I can only set the trigger or gate condition as "trigger on rising edge" . Suppose the input signal is a sine wave, I want to use this sine wave as a trigger signal to generate one square wave cycle every time the trigger condition is met. It seems impossible using this method. Because I cannot set the trigger condition as "trigger on a rising slope", and I also cannot set the "trigger level". Is there any other method I can use to fulfile this task? Just something like configuring the trigger conditions for starting the scan
and channel clocks and the scan counter using "AI Trigger Config", I can specify very complicated trigger conditions. Thank you very much and have a nice day.

[Geneva L.]

Aero,

This question actually belongs in the Measurement Devices >> Multifunction IO category of the Developer Exchange. In the future, you will find it beneficial to post in that section, where you'll see similar type questions and get the opportunity to interact with other users interested in this type of application.

It sounds like you want to retrigger your analog output continuously. Also, note that you can choose rising or falling edge for the AO trigger. You can find out more about the parameters by looking at the LabVIEW Help on that function. For more information on this concept, you can usually do a search at the http://www.ni.com/support pages to find technical documents and examples. There are two examples that are currently being reviewed to get onto the web, but they are not there yet. One is a rather easy way to do this retriggering. However, a faster method is in the more complex example, which utilizes counters. You can try the easy way first, and if it is not meeting your speed requirements for your application, then you can take the other approach.

Let me describe the complex example. This was written to use a digital trigger signal wired to the gate of counter 0 of your E Series board. Counter 0 will generate a pulse, which is connected to counter 1. Counter 1 produces a pulse train based on that pulse, and this pulse train is being used as the update clock for the analog output operations. Thus, your waveform is output at each edge of the update clock. You are triggering your update clock, and thus triggering your waveform. Now, you said that you want your trigger to be an analog signal level. The PCI-6052E analog trigger circuitry generates a digital signal when it detects that the analog trigger conditions have been met. This signal is called ATCOUT. You can internally route that signal to the gate of counter 0, so that you can use the written example. This involves calling some additional functions. For starters, you can get the idea of how to get ATCOUT by looking at the Continuous Generation - E Series A-Trig example in the LabVIEW >> Examples >> Daq >> Anlogout directory. To route ATCOUT, you would have to call the functions that appear in the RoutingATCOUT.vi below. Note, I have not tried making these changes to the advanced example yet, but I'm offering you the idea first. It might take changing the way the counters are generating the pulse train in that particular example, but the concept can be done.