Multi Channel DAQ Issue | NI USB 6212

[Jarir]

Dear Community Members, 

Hope you are doing well. I am trying to take data from two sensors and acquire data simultaneously. Through my code, both of the sensors are giving data separately. But whenever I am trying to get data simultaneously, then I am getting some errors. For example, the sensor data seems entangled. If I press on one sensors, in the code I find that there is changes in voltage on both of the sensors. But it should not happen. Could anyone please help me on this problem?

I have attached the circuit diagram and code in the attached files. Additionally I want to mention that I am using 24V external power supply.

Thank you

[santo_13 · Accepted solution]

The behaviour you're observing is called Ghosting and is quite common in DAQ with multiplexed ADC.

Please read more here - https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P84RSAS&l=en-US

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YHy6CAG&l=en-US

https://www.ni.com/en-us/support/documentation/supplemental/06/is-your-data-inaccurate-because-of-in...