example

[kanchankk]

 i want to take the output of two sensors  tgs823 and tgs825 with the same daq usb-6210 using labview but i am not getting any code for this can you please help me for this i already determined the voltage and current curve for tgs 823  code for the same is also attached

[Cavarval]

Hello,

I did a google search for the sensors and they seem to be resistive, but I am unsure whether the resistance you measure needs to be externally provided or if it is part of the sensor.

http://www.figarosensor.com/products/823pdf.pdf

https://www.soselectronic.com/a_info/resource/c/figaro/tgs825.pdf

Do you have this information? It is maybe a good idea to ping FIGARO USA about this.

http://www.figarosensor.com/contact/

Either case, we can see your screenshot, but we can't really see how the DAQ Assistant is configured. Can you provide a screenshot after double-clicking the DAQ Assistant, or even better, the VI?

Regards,

[kanchankk]

 output is taken at ai8 and ground is connected to 28 pin

and  sensor circuit is made by using load resistance of 1 k

[Cavarval]

I don't see anything wrong right away. Is it that you get wrong measurements or no measurements at all? I do see data in the graph from your original post's screenshot. Can you provide more details?

Regards,

[kanchankk]

Actually we are getting right  characteristics for voltage and current curve but not for resistance as it is increasing when sensor is sensed to ethanol which is unexpected ..

we also want to take the voltage and current reading for another sensor at the same time   , but we want to have individual curves for each sensor independent to one another ,so  can i provide vc and ground through same device  for two different sensor circuit connected to the input pins of same daq

[kanchankk]

can you please help me by providing any example code for taking the output of two sensors tgs823 and 825  using DAQassistant  as i am not getting how to use two tasks 

[crossrulz]

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@kanchankk wrote:

as i am not getting how to use two tasks 

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You don't.  Just add the channels to your current task.  You can split off the signals in your code.

[Cavarval]

As for why you are getting wrong resistance data, I am not sure (not really familiar with the sensor). Notice that in the sensors datasheet several resistances are mentioned, so probably you need to have into account both the external resistor and the internal resistance from the sensor. I would imagine the manufacturer would be able to provide feedback about it. Have you tried to reach them?

As for the independent graph per sensor, crossrulz is correct. I cannot have two analog input tasks in the same USB-6210, but if you add all the channels to the same DAQ Assistant, you can use a Split Signals function to separate all the measurements and Merge Signals functions to regroup the signals from each sensor.

The snippet uses all Voltage input channels, but you can use the same idea in your own VI.

Regards,