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Connect 3 wirer NPN to NI 9421

Hi all!

 

I have a NPN sinking sensor (3 wires) that I want to connect to my NI9421, however I am lost.

 

Basically I have connected the power source to my sensor, and connected the sensor ground to my power source ground. Then I connected the sensor output wire to the NI9421's digital input pin, and the COM pin of the NI9421 to my power source ground. I am not getting any signal.

 

What am I doing wrong here?

 

Many thanks!

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You will need to use a sourcing sensor for the 9421 inputs.

 

-AK2DM

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"It’s the questions that drive us.”
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Thank you for your answer.

 

I got confused because at page 13: http://www.ni.com/pdf/manuals/373504g.pdf it says "The NI 9421 has sinking inputs". Hence why I have got NPN sinking open collector sensors.

 

Is there a way to "convert" my sensors so that I can connect them to the NI9421?

 

Many thanks!

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Still struggling with this one. I cannot even get pulses from my sensor.

 

Its a NPN sensor, 3 wires:

 

1. + is connected to 24VDC +

2. - is connected to 24VDC ground

3. signal

 

I try to connect an oscilloscope between signal and 24VDC+ but I don't see any pulse.

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