wind speed program

[choonkok]

Hello. I have NI 6356 and a wind sensor from https://moderndevice.com/product/wind-sensor/ and i want to use labview to get the wind speed display.

The problem i encounter is when i supply the voltage to the sensor and the result i got is negative. May i have some advice on the wiring and program?

I wire the wind sensor GND to AO GND, V+ to AO 0, and Out to AI 1+

as for the VI, I used 2 DAQ assistance. 1 used the Generate singal > Analog Output > Voltage > AO 0 to supply voltage.

the other is Acquire signal > analog input > voltage > AI 1 to display on the graph.

As i needed to calibrate the sensor, so i supply 0.5V to the sensor to zero the wind speed. But the display will always show negative value.

May i have some advice on it? sorry that i'm quite new to labview and daq system.

[mikeporter]

Have you tried swapping the analog input signal leads?

Mike...

[choonkok]

Hello Mike.

Swapping the analog input signal leads as in change to another AI port? Or do I need to wire the AI - as well? Because currently I only wire to AI +.

[mikeporter]

Your description says you are powering the sensor with an AO port, and reading the data with an AI. You need to have both sides of the AI wired one side to the signal one side to analog ground.

Are you acquiring data single-ended or differentially? I sorry, I should have asked that first. How long is the wire between the sensor and the DAQ device reading it? If it is more than a foot or so you should be reading differentially.

Mike...

[choonkok]

Yup. It's differentially. So that mean I got to add another wire from the sensor GND to AI GND too? That's mean my sensor GND will have 2 wire, 1 to the AO GND and the other to the AI GND?

[mikeporter]

No, in differential the only thing that matters is the + side of the two channels that form the differential input. The DAQmx documentation shows how to properly wire differential inputs.

Can you show exactly how you have the thing wired?

Mike...

[choonkok]

Here is the photo of how I wired. The actual wire will be longer than this. 

[RavensFan]

With it being wired between AI+ and AGnd.   You need to have your channel setup for single ended referenced,  NOT differential.

Whether you should be using an AO channel to power the device is another question.  It dependes on the voltage/current requirements of the device, and whether the AO channel is able to output that .

[JÞB]

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@choonkok wrote:

Here is the photo of how I wired. The actual wire will be longer than this. 

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Looking closely at the jpgs.  You are wired to AI Gnd, AI1- and AO0.  You need to move the black wire up 1 terminal.  Of course, this explains why the output is always negative.

[RavensFan]

It looked to me that yellow goes into terminal 4.  AI1+ and black into terminal 6.  AI Gnd.  But that is hard to see becaused the black wire blends in with the black terminal strip.  So AI1 + to AI Gnd, should be set for single ended, not differential.