Triggering (on/off) data acquisition for an analog input

[ZMK16]

Hello,

I want to acquire a signal from a machine controller and save the data in a tdms file. To develop this application I created a simulated task. Everything is going well so far, except triggering the data acquisition. I want the application to start saving the data when the signal passes a specific value and to stop it when the signal is lower then the value, so it is an ongoing data acquisition that only saves the data when it is higher then the defined limit.

I already tried to use the DAQmx Trigger Vi but I always get the following error when I use it.

Requested value is not a supported value for this property. The property value may be invalid because it conflicts with another property.

Property: Start.TrigType
Requested Value: Analog Edge
Possible Values: Digital Edge, None

I also read a lot of different posts about this topic, but I'm still not able to get this going.

I am pretty new to LabVIEW so please excuse if I ask some queries.

Attached is a picture and the Vi itself.

[PalanivelThiruvenkadam]

Just i am curious to know, what is the purpose of the sequence structure in the attached code.

Answering to you question, You can have a comparision factor before Writing into file  and the make comparision output as a deciding facotr for a case whether to log or not.

[PalanivelThiruvenkadam]

Modified code without sequence structure and added case for Log OFF and ON, You just need to Compare with the Limits you specify insted=ad of constant True to a case structure

[ZMK16]

Hey Palanivel,

Thank you very much for the answer. I wasn't sure if the case structure is needed, but it seems like its not 😛

I am using LabVIEW 2014, so unfortunately I can't open your file. Is there a possibility for you to save the VI in a LV14 accessible version?

[PalanivelThiruvenkadam · Accepted solution]

Modified code has beed saved in LV2014