Using digital output to trigger counter acquisition

[B^2]

I am currently using a cDAQ 9174, with a digital out 9401 module. I am using the digital output to trigger a solenoid and want this to be the start point for my data acquisition. The output usually pulses quite rapidly and I want to use this output to trigger data acquisition from 2 9361 counter modules.

Is there an easy way to use the output from the 9401 module to trigger acquisition as I cant sample it as an input once its programmed to be an output.

Currently I am using a fourth module a 9421 digital input as a bit of a bodge job to hardware trigger the acquisition, but this seems like overkill and im sure there must be an easier way.

[Bob_Schor]

I haven't read the specs on your device, but many DAQmx devices have a "Trigger" option that allows a Trigger, typically a PFn line (e.g. PF1), to serve as a "Start" signal.  What I've tried is to connect a wire from the DO you are using to (check your manual for location) an appropriate PF input, and to include the DAQmx Trigger function.

Bob Schor

[B^2]

Unfortunately, I have a 9421 which doesn't support triggering, so my alternative is to use software triggering.

I send a digital signal to the output module for a certain time and I want the counter to record that data for the duration of the digital signal. Any ideas on how to do this?

[ikaiser]

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@B^2 wrote:

I am currently using a cDAQ 9174, with a digital out 9401 module. [...] I want to use this output to trigger data acquisition from 2 9361 counter modules.

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Do you know that you can "wire" triggers internally? Have a look at the example "Task » Hardware Input and Output » DAQmx » Synchronization » Analog Input - Synchronization.vi" in LabVIEW's example finder. It links one module to an other one and then starts the tasks together. No need for external wires between the modules. (Note: I don't have a cDAQ here to test but I am quite sure it works with your hardware)

[ikaiser]

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@B^2 wrote:

I send a digital signal to the output module for a certain time and I want the counter to record that data for the duration of the digital signal. Any ideas on how to do this?

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This sounds like a job for a "Pause Trigger". See here: NI-DAQmx Data Acquisition Triggering Techniques Using LabVIEW, especially the sections F, G and H, Digital / Analog Pause Triggers

[GYALI]

hi 

I am implementing i2c protocol in ni-usb 6363 daq card to communicate with i2c board. I have some question regarding that:-

  1. can I start counter output and stop counter output without using any physical channel or         PFI channel.

  2.  how to implement some delay between counter and DO.(actually my requirement is that          once the counter is stable i.e high or low at that point of time DO should change from 0          to 1 or 1 to 0).

if u need my program than reply me I will give.

regards 

arvind

[ikaiser]

Hello arvind,

I recommend starting a new thread for your question. Posting it at the end of a several month old, somewhat unrelated thread it will most likely be unnoticed.