Arduino Uno with Loadcell

Projects General Guidance
1

hi ,

am interfacing arduino uno with load cell by using AD620. (Analog Monitor to Serial Output).

Loadcell technical information is attached here. Excitation voltage is given 10 - 15VDC.

When am interfaced with AD620 the output is varying around 140mV when load cell is in idle condition (placed on table) . Please refer the analog output of AD620 module with arduino analog input. is it noise signal or did i missed something ?

So i like to do try with HX711 . but the problem is HX711 excitation voltage is 5v i think.
so does the load cell responds well with HX711 ? if not how to implememnt.

if you need more details please let me know.

_nikhil

Loadc cell technical sheet
Loadc cell technical sheet1080×1166 176 KB

adc620_m2.TXT (87.3 KB)

2

Hi,
Can you post a schematic of your project please.
Preferably not a Fritzy, an image of a hand drawn circuit will be fine.
Please include power supply(s), component names and pin labels.

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

3

wiring diagram
wiring diagram914×566 7.32 KB

Hi Tom,

Here am posting the tested circuit for your reference.

_nikhil

4

HX711 should be fine. With your cell's 3 mV/V sensitivity and the HX711's 128 gain, at full load, you'll be using a fair bit of the HX711's bandwidth.

5

Hi,
Thanks for the diagram.
The noise is probably coming from the DC-DC converter, HX711 would be a better solution.
I would put a 0.1uF capacitor as bypass across the E- and E+ connections at the loadcell.

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

6

hi DaveEvans,

Thank you for your support. I will check and update you the result.

_nikhil

7

Hi Tom,

OK. I will add a filter cap in it.

i also checked the same circuit by replacing AD620 with AD8608 as differential amp. this time i added 0.1uf cap across A0 and GND.

THis time ADC counts are getting stable most time not varying like ad620 test. but still some sudden spikes of 100mV have been reported.

Here am posting the test readings please check it.

Can you suggest a solution to overcome to avoid sudden spikes rather than a filter cap in E+ and E- .

In software am just monitoring , mapping to 0 to 5000mV and sending it out to serial port with delay of 500ms. is there any thing else to do with software?

_nikhil
AD8608 with Arduino.TXT (79.3 KB)

8

Instrumentation amps are usually used with Wheatstone bridges.

9

Hi,
Can you please post some images of your project so we can see your component layout?

Tom... :smiley: :+1: :coffee: :australia:

10

Hi all,

I have checked the loadcell with 128 gain Recently with HX711 and its working fine.

i Used GitHub HX711 library by bogde. GitHub - bogde/HX711: An Arduino library to interface the Avia Semiconductor HX711 24-Bit Analog-to-Digital Converter (ADC) for Weight Scales..

Thank you all for your support.

11

hi TomGeorge,

Currently am not using any PCB for my circuit rather than arduino. Amplifier it self mounted on General Purpose Board for testing. and using jumper wires to connect.

May be that also cause lot of noise.

thanks.