PXI-4461 software trigger

[Eagle01]

Can a PXI-4461 software trigger?  if so how do I use it.  My hardware is a PXI-1056 and PXI-6652. I'm using PXI-PCI8336 for communication between the PC and the PXI box

[DavidMN]

Hi Eagle01,

The PXI-4461 is capable of software triggering.  To accomplish this form of triggering, you will need to acquire data until it reaches a threshold you define.  Once that threshold (trigger) is reached, you can then move on to processing the data received after the trigger.

[Eagle01]

Hi,

I found the following c function:

niSync_ConnectSWTrigToTerminal
niSync_SendSoftwareTrigger
niSync_ConnectTrigTerminals

Where can I find an explaination of these function listing there parameters and an example how I can use them with my hardware.

[kikiduu]

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Eagle01 wrote:

Hi,

I found the following c function:

niSync_ConnectSWTrigToTerminal
niSync_SendSoftwareTrigger
niSync_ConnectTrigTerminals

Where can I find an explaination of these function listing there parameters and an example how I can use them with my hardware.

---

Sorry I was not able to get these fucntions, but if you can elaborate on what you want to do with software trigger, may be I can help. Are you looking to acquire some data based on a certain software event? Do you want to do continuous acquisition after you receive the trigger? Or do you want to acquire finite number of samples on each trigger?

[Eagle01]

I'm trying to figure out how to use software trigger to determine if they would be useful  to me.  What I'm doing is creating a generic wraper around the NI software so it can be easily controlled be my existing software. I found these functions in the PXI NI-Sync User Manual, but it just says the functions name it doesn't list the parameters and how to use it.

Message Edited by Eagle01 on 03-23-2009 10:31 AM

[kikiduu]

I have not used NI Sync till now, so can't comment on it..

The 'DAQmxSetTrigAttribute()' function can be used to set the 'DAQmx_AdvTrig_Type' attribute. But from what I can get from DAQmx C-reference help, this is to set 'the type of trigger to use to advance to the next entry in a switch scan list'. So this function, I guess, is not going to help you.

Now if you want to start a finite samples acquisition on a particular software event, you can follow these steps.

1. Configure your DAQmx channels

2. Set sample clock (sampling rate, number of samples to read)

3. Use 'DAQmxTaskControl()' and set the action as 'DAQmx_Val_Task_Commit'. This will progranm the hardware as much as is possible based on your configuration.

4. Wait on the software event.

5. Once the event occurs, start the task.

6. Read the samples.

7. Stop the task

8. If you want to continue to aquire data on further events, go to step 4. Else to 9.

9. Clear the task.

As you might have noticed this doesn't uses any DAQmx triggering functions. 

Message Edited by kikiduu on 03-24-2009 12:55 AM