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DAQ comunication problem

Hi,

 

I have made a application using LabVIEW that must read data from a DAQ (NI cDAQ-9184 and current module NI 9203) using tasks from NI MAX. I run the app at Windows starup, but sometimes when the app starts the comunication betwen DAQ and NI MAX is incomplete (The chassis is always turn on) and my app reads zeros when actually the module always receives a signal (4-20mA) from sensors. Then i must to open NI MAX and refresh the chassis or run some task and stop it to run my app again to obtain correct data. I need that app works without user interaction.

 

I hope you can help me... Regards.

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You likely have a weird race condition.  In essense, you are starting the application before any of the NI services start up to help you application.  You need some type of delay before you application starts.


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Ok, i will try. I think you right and my application probably runs before the device monitor...

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Hello andcp360,

 

We could try with a VI to search for the module 9203, and once the module was detected, run your application and then close itself.

 

I share with you a VI that could be useful, just change the values ​​of the VI, set them as default values and build your application.

Let me know if this works for you, best regards.
David P.
National Instruments
Applications Engineer
www.ni.com/soporte
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Thanks!

 

Finally, i only made a little delay in my app and then read the signals every 5 seconds...

 

 

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