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NI 9174 power input wiring

Hello All,

 

I am using NI 9174 chassis and NI PS15 power supply which provide 24Vdc. connection are pin V wired to +24Vdc, pin C wired to -24Vdc. 

But Seems like this connects pin C to ground too. Is there internal connection in the chassis that makes pin C connects to ground (enclosure)? 

Now I have all my COM are connect to Gound which I don't have in my drawing.

 

Can any one explain this?

 

Thank you very much

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Message 1 of 12
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Ya-hoo, 

 

Have you checked the output of the power supply with a DMM? It might be worth making sure the voltage is what you think it is. I would also recommend looking through the manual for the NI 9174. 

 

-aprillest

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Message 2 of 12
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Yes, output of the power supply is 24Vdc.

 

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Message 3 of 12
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There is no -24V connection so what you are saying doors not make much sense.
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Message 4 of 12
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I mean negative of 24Vdc power supply.

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Message 5 of 12
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According to the user manual for the NI cDAQ-9174, (link) it appears that the safe voltage input range is 9-30V. A range of -24V to 24V would be a 48V range, which is outside the limits for this device. Can you use a lower power range (i.e. -15V to 15V) for your application? 

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Message 6 of 12
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Hi All,

 

I am sorry for the confusion. Here is the clarification of my wiring.

I am using NI PS15 as power supply and connection is as in the picture.

 

Thanks,

NI 9174 V-C connection.PNG

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Message 7 of 12
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The connections look correct. What exactly is wrong? Doesn't the 9174 power up?
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Message 8 of 12
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9174 is powered up and system seems working fine.

One thing I'd like to know is why the COM is connected to system GROUND once V and C of 9174 are connected.

Thanks,

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Message 9 of 12
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The C of the 9174 stands for common and that is ground.
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Message 10 of 12
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