Data acqusition not triggering on what i think is the Rising edge of my digital output

[NickHakala]

Hello all, 

I'm having some issues with the triggering of my thermocouple data acquisition. 

I am using an NI 9472 module to generate the output signals to a solenoid valve that controls a pneumatic cylinder. I'd like to begin logging data as soon as the cylinder beings moving. 

I am reading in voltages on an NI 9205 input module, and i am triggering the data acquisition using the PFIO channel on the device. 

I have configured my vi to allow for a digital trigger to start data logging on the rising edge of the digital signal. I have installed a wire connecting channel two of my NI 9472 (which actuates the pnumatic forward) to the PFIO channel of my NI 9205. However whenever i actuate my pnumatic i only start logging after i stop sending signal to the solenoid. 

Shouldn't sending my signal start logging data? 

some advice would be greatly appreciated.  

[TylerC1123]

Hi NickHakala,

I took a quick look at the code you attached to your post and it seems that you could be experiencing a race condition with the DAQ Tasks.

Here is a link to one of our tutorial pages relating to synchronization, if you look at Figure 2 you can see where they connect the error wire from the slave task to the master to ensure the slave is started first and looking for the signal from the master. Additionally, you may want to include the DAQmx Start Task VIs to this end, using a similar architecture to Figure 2 in the linked tutorial.

Give this a try and see if that helps out.

[NickHakala]

Hi Colville 

Thanks for responding to my issues. I have looked my triggering issue further. And i believe i've solved the synchronization issue a different way. 

Utilizing an event structure i can trigger my data acquisition on the insertion stroke of my pneumatic (when i energize my solenoid). However another issue has arisen, now after the event (data acquisition triggers) i can no longer control my other digital outputs on my other channels. This issue is probably an easy fix. However i am a relatively new user. 

If you have any comments that could make this possible it would be greatly appreciated. 

Cheers,

Nick