Calibrating the three-axis accelerometer (PP877)

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AndrewA
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Joined: Tue Oct 21, 2014 3:07 pm

Calibrating the three-axis accelerometer (PP877)

Post by AndrewA » Fri Apr 29, 2016 9:25 am

Hi all,

The offset and gain of the three-axis accelerometer does vary from unit to unit, so for accurate results it best calibrate each axis.
I have created some probe files and a spreadsheet file help calibrate the three-axis accelerometer with the PicoScope software.
I created three custom probes for each axis; X, Y, and Z.
These are setup with default scaling relationship of-

Code: Select all

g = 10 x volts - 10
The custom probe files can be import into PicoScope. See page 55-
https://www.picotech.com/download/manua ... -guide.pdf

If you want a more accurate results you need to calibrate each axis using offset and scale values.
I have attached a spreadsheet if you wish to do this.
You need a levelled table, and for each axis and hold the accelerometer down flat for +1g and -1g and enter the voltages for each. (Set the scope channels to the +-2v range)
You will them need to edit the each custom probe and change them to the scaled values, from the spreadsheet.
Attachments
3-axis accelerometer Setup.zip
3-axis accelerometer Setup
(34.1 KiB) Downloaded 280 times
Regards Andrew
Technical Specialist

yves.anguill
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Joined: Fri Apr 05, 2019 12:02 pm

Re: Calibrating the three-axis accelerometer (PP877)

Post by yves.anguill » Fri Apr 05, 2019 12:24 pm

subject : PP877 accelerometer kit sensibility
I've just bought a PP877 kit in order to shock-test industrial relays and make a few field measurement (not metrology). The kit is extremely easy to use and I'm quite pleased with it, but...

i'm a little puzzled by an apparent discrepancy in the PP877 datasheet :
maximum g range is -/+ 5 g (ie 10g peak-peak) and the max voltage range is 0-2V
I've made a soft-shock measurement till saturation (I suppose - to + 5g) and the scope measured - to + 1V (roughly...)
so sensibility should be about 200mV / g.
An "handshake" test at about 1g peak also found around 200mV/g (sinus +/-25cm 1 Hertz)
but the datasheet tells 99-122mV / g ... could anyone tell me where is the truth ?

thanks in advance

AndrewA
PICO STAFF
PICO STAFF
Posts: 218
Joined: Tue Oct 21, 2014 3:07 pm

Re: Calibrating the three-axis accelerometer (PP877)

Post by AndrewA » Fri Apr 05, 2019 2:02 pm

I have just tested a new PP877 accelerometer, and it works correctly as per the datasheet.
The full range is 0-2V per axis -5g to +5g respectively.
So for each axis, you get ~1.1V axis facing up to ~0.9V axis facing down.
Axis as marked on the sensor.
Do you have the scope DC coupled?
If you think the sensor is reading incorrectly you could return it us. I would need you to email support@picotech.com and issue a returns number.
Regards Andrew
Technical Specialist

yves.anguill
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Joined: Fri Apr 05, 2019 12:02 pm

Re: Calibrating the three-axis accelerometer (PP877)

Post by yves.anguill » Wed Apr 10, 2019 12:48 pm

thanks very much for your reply
I'll make te tests according to what you told and let you know the results.

best regards

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