11-25-2009 07:11 AM
Solved! Go to Solution.
11-26-2009 02:01 AM
Hello Aqw!
With USB-6008 you have the option to use digital trigger on PFI 0 line. When an AI task is defined, you can configure PFI 0 as a digital trigger input. When the digital trigger is enabled, the AI task waits for a rising or falling edge on PFI 0 before starting the acquisition. To use ai/Start Trigger with a digital source, specify PFI 0 as the source and select rising or falling edge.
You can use for example an external button as the source of your digital trigger.
Does it answer your question?
Read more in USB 6008/6009 user manual:
http://www.ni.com/pdf/manuals/371303l.pdf
Regards,
Matyas
11-26-2009 02:19 AM
...
Useful starting point:
LabVIEW or CVI >> Help >> Find Examples... and search for "triggering"
Continuous analog acquisition with digital start is what your looking for, aren't you?
Best,
Matyas
12-01-2009 09:44 AM
12-02-2009 02:46 AM
Hi,
Please, film me up which method you think of!
Check this KB for some details:
http://digital.ni.com/public.nsf/allkb/7094D0AE57C62A4D86256D7B006AF6B2?OpenDocument
So, if you want to trigger your measurement: use the 1. method and try to connect a simple button with TTL logic to PFI0. OR if it's not okay for you and you need the 2. option...
Theoretically, there's no problem with connecting a fast analog signal to digital trigger source, because voltage is either way analog.
Please, try it! 🙂 Connect your analog signal to both an AI channel and PFI0 to trigger your measurement with the signal itself!
BUT, beware that the analog signal must be between 0-5 V and should be really fast-rising and/or fast-falling like a square wave signal for full success! We need to protect your equipment...
I hope it helps! 🙂
Matyas
12-02-2009 03:26 AM
12-02-2009 06:35 AM
Hi aqw 🙂
As is said in USB 6008 Use r Guide ans Specification, on page 19 in section Digital Trigger:
"When an AI task is defined, you can configure PFI 0 as a digital trigger input. When the digital trigger is enabled, the AI task waits for a rising or falling edge on PFI 0 before starting the acquisition. To use ai/Start Trigger with a digital source, specify PFI 0 as the source and select rising or falling edge."
By other words, yes, you need to use trigger on PFI0.
If you are looking for the way how to implement this solution into LabVIEW, I recommend to have a look at examples (Hardware input and output -> DAQmx -> Analog Measurements -> Voltage -> Acq & Graph Voltage-Int CLK - Dig Start). There should be complete examples for what you are looking for.
Best ergards,
Stefo