I am using an accelerometer for vibration measurements capacity of +/- 10,000 g.
The accelerometer (single ended) is connected with a signal conditioning device to provide excitation/power supply on the accelerometer. The signal conditioning device is then connected with the NI PXIe-6361 module. I have attached the settings used for the power supply and acceleration certificate as well (red marks).
The voltage readings seems to work as they provide signals, but I would like to ask whether the conversion of voltage to acceleration units is correct in the attached vi. As I read from the manuals, the voltage is divided over the sensitivity of the sensor (V/ (mV/g)). On the other hand, each 1 volt corresponds to 1000 g and therefore, +/- 10 V = +/- 10,000g, as per the accelerometer specifications. Moreover, I would like to ask whether a simple test can be carried out to verify the readings (i.e. drop accelerometer or overturn it to read -1g?)
Is there any possibility to advise me what is going wrong with the acceleration setup please?
Just a small comment. The nominal zero-g voltage is not zero as it will be the initial offset obtained from the average of the first 1000 points to make it zero.
Have you tried using MAX while connected to your accelerometer? Did you notice that you can create a Custom Scale that will allow you to specify the equation changing Volts into Acceleration (in whatever unit you want, i.e. g's, meter/sec/sec, etc.)? You could save the Scale in MAX and then use it in your Create Channel function. You can also specify the Scale using a DAQmx function, Create Scale, that also lets you specify the offset. So you could start with a Scale that assumes a zero offset, take 1000 readings that are supposed to give you 0 (g's, for example), then "adjust" the Scale to take the offset into account.
As for calibrating your accelerometer, I would not "drop it". You didn't mention if it is a 1-axis accelerometer or a multi-axis one. I'm going to assume one axis, and that you are calibrating (or "zeroing") it with the axis horizontal, which should give you 0 g. Note that turning it upside down should still give you 0 g. However, turning it 90° so the axis points up or down should give you ±1g.
The accelerometer is 1-axis as shown in the attached image.
I guess that your recommendation would be to create a custom scale using DAQmx function using MAX scale. I have attempted to do it with the following values usign a table scale.
Volts (V) - Acceleration (g)
-10 - -10000
0 - 0
+10 - +10000
It does give an error, scale is wrong??? Even if you create a table, the <in place element structure> does not need to be placed to divide the voltage over the sensitivity of the accelerometer right?
I configured the accelerometers by creating a scaling table in MAX. They produce very high g values even with a small touch.