Trigger on first attempt

[sg18]

 I'd like some help / advice on my LabView program (attached) please. In the VI, the MyVoltageTask_1 is configured as a voltage signal corresponding to a pressure change inside an enclosed cylinder. The signal is transmitted to the BNC 2110 DAQ board / PCI 6133 DAQ card via a differential pressure transducer. 

Ideally, the program should trigger as soon as I let air into the cylinder and start acquiring data, and stop as soon as its done. However, LabView does not trigger when I let the air into the  cylinder on the first attempt, but if I exhaust the air and let it in again a second time, the program triggers and I can see a graph of the pressure trace. Please let me know if there is something I should / could change in the program to have the program trigger on the first attempt. Thanks!

[alcava.cr · Accepted solution]

Have you try changing the slope from falling to rising? I would start taking a look at the shipping examples first. Open the NI Example Finder and go to Hardware Input and Output»DAQmx»Analog Measurements»Voltage. Take a look at the example called "Cont Acq&Graph Voltage-Int Clk-Analog Start.vi" I contains the basic structure of what you are trying to achieve.

[sg18]

Hi,

Thanks for your response and suggestion. Yes, I did go through the shipping examples, and after making a few adjustments, the program works fine now.