DAQ stimulation to acquisition

[Cycy]

Hi,

I want to run two DAQ assistants concurrently for acquisition and stimulation. However, I want the aqcisition one to stop when the stimulationg one stops. Any ideas on hoe to do that?

Thank you

Cycy

[BeCeGa]

Hi Cycy for doing that in DAQ you can use the triggers, in Daqmx, you can configure triggers to star and stop acquisitions

http://digital.ni.com/public.nsf/websearch/878BD3188B1CD64686256F8C0060CCAB?OpenDocument 

https://www.ni.com/en/support/documentation/supplemental/21/ni-daqmx-data-acquisition-triggering-tec...

https://forums.ni.com/t5/Example-Code/Start-Trigger-and-Stop-After-n-Pulses-for-Continuous-Analog/ta...

I hope this can help

[JamesC]

Hi Cycy,

Sorry for the slow response, I have generated a very simple example for you that will generate a sine wave, output it on Dev2/ao0 (my Dev 1 has no AO) and then read the data in on Dev2/ai0.

All this is happening within a while loop, and so the while loop stop button first stops the simulation, and then the acquisition and then finally stops thje loop.

It should be easier to implement than the triggers.

Regards
JamesC
NIUK and Ireland

[Cycy]

Hi James,

That helps a lot but how do I get the stopped output from the DAQ stimulator?

Thanks

Cycy

[JamesC]

Hi Cycy,

If you open the example you will see where the Stopped output comes from the DAQ Assistant, and then goes into the Stop (f) of the DAQ Assistant 2.

This link is highlighted in red.



Regards
JamesC
NIUK and Ireland

Message Edited by JamesC on 09-27-2006 12:56 PM

[Cycy]

Hi James,

For some reason, that stop output doesn't exist on my DAQ assistant. I copied and pasted the one you gave me. That seemed fine until I configured it. Then it just showed "invalid output" instead of "stopped". Is the way I'm configuring that VI preventing it to have that output?

Thanks

Cycy

[JamesC]

Hi Cycy,

I am using DAQmx 8.3, if you are using an earlier version of DAQmx you might not have this functionality.

Please go to this Link to download the latest version.

Regards
JamesC
NIUK and Ireland

[Cycy]

Hi James,

I was away from my lab for a while so I didn't have the chance to test it till today. I have downloaded DAQmx 8.3 and installed it but it still doesn't work... I have to copy the assistant from your program and wire it in mine. Then, when I configure it, it says :"this program contains errors. You may continue but it will not run while errors are still there". Then, when I close it, the "stopped" output has disapeared and I have bad wires. Any Ideas on how to get that "stopped" output to show itself without copying?

Thanks

Cycy

[AdamB]

Hi Cyny,

Inside your DAQ assistant, what task timing have you set up?

If you set up for "n number of samples" or "1 sample (SW timed)" then you do not have the option to stop the aquisition.  That is one option that you only have avalaible when you select "continuous samples" and "1 sample (HW timed)"

Do you see the stop output if you use the continuous samples option?

AdamB