is it possible in Labview? Suggest me...

[Ray.R]

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@shjukheter wrote:

Some one told me that , we can amplify it in labview to certain level without doing any amplification outside.

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That "someone" does not know about signal conditioning.  If you "amplify" it within LabVIEW, you're scaling up everything, including noise.

You may end up looking at a signal which is not what you are looing for.

Lynn provided you with a good explanation & suggestion.

[shjukheter]

The accelerometer which I have it now is not giving the good results. I am attached the pictures that I have taken when accelerometer is near to pump and without pump. The accelerometer itself contains amplification part but since it is giving low output ranges. I have contacted the accelerometer service person that he was saying ma be I need a 2g unit for higher outputs. I am using NI USB 6008 to connect with Labview. And here I found some accelerometer guide but I am unable pick one http://sensorwiki.org/doku.php/sensors/accelerometer . The images that I have taken with my existing accelerometer and its document can be found down here. I don't know how to go ahead of this situation.

[Yamaeda]

I had a similar problem, i needed a OP chip in between the accelerometer and sampling device to be able to sample the signal. It happened the sampler worked by charging a capacitor which basically sucked any and all signals from the acc. Just a tip. 🙂

/Y

[johnsold]

From looking at the data sheet I would agree that the 2g accelerometer is probably an appropriate choice.  What is the range of the accelerometer you are using now?  Were the signal images you posted taken with the pump stroke long enough to cause the undesirable noise or is this normal operation of the pump?  

The USB-6008 can go to +/-1 V in differential mode which should work nicely with the 2g accelerometer.  However, the bandwith of the more sensitive accelerometer is much lower that than of the less sensitive ones.  In fact your oscilloscope measurements appear to show much higher frequenices than the rated bandwidth of the sensors.  The sensor bandwidth seems to be 1-2 kHz according to the curves in the data sheet.  Are you sure that your oscilloscope traces are not the result of picking up power transients from the motor driver or switching transients from a power supply?

Where do you mount the accelerometer on the pump? From the image of the pump you posted earlier, the direction of the stroke of the pump is not obvious.  In general I would expect that the most sensitive pickup point would be in line with the stroke and near theplace where the impact which causes the noise takes place.

Lynn

[shjukheter]

Hi,

          Thank for you helping always and needed. I don't have any mount now to connect sensor near to pump but first I am in checking trails. I had connected accelerometer in line to pump on other side that have flat surface and the side which you saw that had inlet and outlet on other side. I have pressure sensor with me also but I want try with accelerometer until get signal into labview. Then all other will be easy later by doing this work. I struck here with accelerometer. Now, the accelerometer range is given as +/- 2 to +/-500g but I am really confused with g terms. If some one know good vibration sensor, I may want to purchase that. I have attached the current accelerometer datasheet in previous post. What I will do. I want some success.

[johnsold]

What is the complete part number of the accelerometer you have?  Something like 4610-500-xxx.  The second group of numbers (500) is the range in g.  The range of 2 to 500 g is the range of different models of the same basic style of accelerometer.  Any one device has only one value within that range.  The 2 g device would have a number like 4610-002-xxx.

The term "g" is used in acceleration measurement to refer to the acceleration of gravity at the surface of the earth or about 9.8 m/(s^2). So a 500 g accelerometer can measure up to 500 times the acceleration of gravity or 4900 m/(s^2).

Lynn

[shjukheter]

4610-020-060 is the model that i have now. Can i get any links for my operation.

[johnsold]

That is the 20 g model.  The data sheet says that its sensitivity is 100 mV/g.  Since you are seeing 20-50 mV, your signal is only about 0.5g.  If you switch to the 2 g model with a sensitivity of 1000 mV/g, you will get about 0.5 V.  With the USB-6009 at +/-1 V you should get a usable signal.

Lynn

[shjukheter]

Hi, Here i have choosen some accelerometers for my application but could not finalize any thing due to unkown factor about how to take the data into Labview. Could someone experianced, please help me. Here are the links for accelerometers.

http://www.madlabo.com/mad/gid/jishin/pdf/ADXL103_203_0.pdf and Video here...http://www.youtube.com/watch?v=-KyGC8TIoCE

2)

http://www.analog.com/static/imported-files/data_sheets/ADXL202E.pdf

http://www.meas-spec.com/product/t_product.aspx?id=8620

It seems those are very sensitive and can i use any of them.

[shjukheter]

On this forum i find one more Accelerometer which sounds great. http://www.sparkfun.com/datasheets/Accelerometers/SerAccel-v5.pdf

It is just plug USB cable and use it type no external power-supply needed and more can possible change different g levels. No use DAQmx here if i use this accelerometer. The only doubt i have, can use that as external sensor.