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USB-6001 signal unstable when connecting other USB device

Hello all,

 

I'm using a USB-6001 to acquire 0-10V signal coming from transmitter and I got stable signal but when I connect laptop to the power supply  or if a connect another system on the laptop via USB (an that has external power supply) my signal starts to be unstable and the values change! But it becomes stable as soon as only the DAQ is connected on USB on my laptop.

 

My transmitter has 3 wires and is connected in differential mode

 

Vcc -> connected to external wall AC/DC adapter  + 

Gnd -> connected to external wall AC/DC adapter  -   and to AI0 4(-)

Vout -> connected To AI0 0 (+) of the DAQ

 

Unstable config.JPG

 

 

External AC adapter is 24VDC as no ground (2 plug adapters)

 

I suspect grounding issue as it disappears when I have another USB connected if I connect GND of the AC adapter to GND of the DAQ.

Differential 1.JPG

 

My question is :

Considering my transmitter wiring, should I use instead the RSE connection :

cedrik63_0-1641924246754.png

 

 

Or can I use Differential connection, or it makes no difference between both ?

 Differential 1.JPG

 

 

Thank you very much

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Since your signal is single-ended, best to use RSE configuration.

 

Connect AIGND of DAQ to GND of the sensor.

Santhosh
Soliton Technologies

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Thank you for your answer!

 

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