4 X 4 wires load cells into Wheatstone bridge configurations

Thread Starter

abc14

Joined Oct 15, 2017
105
Hi Guys,


I am trying to connect 4 load cells where each of which has 4 wires, into Wheatstone bridge configuration.







Some body on this forum pointed that they could be connected like upload_2018-9-21_14-40-42.png


Am trying to connect them to Hx711 module, by Joining all the similar colours wires together.
 

joeyd999

Joined Jun 6, 2011
4,287
I've never understood the proclivity to wire load cells in parallel, especially in regard to the complexity and time/labor involved to trim each load cell such that the combination produces an acceptable result.

My preference is to sample each load cell independently -- either using separate hi-quality ΣΔ ADCs, or one ΣΔ with multiplexed bipolar inputs -- and process the calibration of each load cell independently. The algorithm to do this is utter simplicity, simply requiring a few different weight inputs (or weight locations) and solving a trivial matrix.

This is much faster and cheaper, and each cell adjustment does not affect the other cells.
 

Thread Starter

abc14

Joined Oct 15, 2017
105
I've never understood the proclivity to wire load cells in parallel, especially in regard to the complexity and time/labor involved to trim each load cell such that the combination produces an acceptable result.

My preference is to sample each load cell independently -- either using separate hi-quality ΣΔ ADCs, or one ΣΔ with multiplexed bipolar inputs -- and process the calibration of each load cell independently. The algorithm to do this is utter simplicity, simply requiring a few different weight inputs (or weight locations) and solving a trivial matrix.

This is much faster and cheaper, and each cell adjustment does not affect the other cells.
Process them independently ? You basically Wiring up each load cell to a separate HX711 ? That way are we not limiting the capacity ? Each cell is rated up 100KG, so total weight will always between 0-100KG ? where as in Parallel we could get upto 4 x 100KG = 400KG
 

ericgibbs

Joined Jan 29, 2010
9,116
hi joey,
Here on AAC we used that method a little while ago, the TS used 6 off, bridges and 6 off, HX711, connected to a Arduino,.
If this TS wants to go that way, its an option.
E
 

joeyd999

Joined Jun 6, 2011
4,287
You basically Wiring up each load cell to a separate HX711 ?
Sorry, I missed the "HX711" part of your post. I don't know this module, and I was speaking in general terms (in the spirit of which I assumed your post was speaking).

But, yes, if multiple HX711 parts can be used, and it makes sense to do so, my opinion is this would produce superior results.
 

Thread Starter

abc14

Joined Oct 15, 2017
105
I am still confuse about the the connections for parrllel.



we have four wires

LC1 LC2

Red Red HX711
Black Black Red
White white Blac
Green Green White
Green

LC3 LC4

Red Red
Black Black
White White
Green Green



Now, my Understanding is Black from LC1 connects to Black of LC3, and Same black wires for LC2, LC4 and White and Green of LC1 and LC2 are connected.


ONLY RED wires from each load cell goes to HX711 ?
 

ericgibbs

Joined Jan 29, 2010
9,116
hi abc,
Look thru the link in post#12.
It appears that you have a 'full bridge' ie: 4 wires on each cell.
Post a link to where you bought them, so that we can check.
E
 

ericgibbs

Joined Jan 29, 2010
9,116
hi abc,
If you want to parallel the 4 modules, connect all the wires of the same colour together as per your post #15 diagram.
E

BTW:
What is the bridge impedance.?
Red to Black
and
White to Green

EDIT:

Added the Data for the cell from eBay.
 

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Thread Starter

abc14

Joined Oct 15, 2017
105
hi abc,
If you want to parallel the 4 modules, connect all the wires of the same colour together as per your post #15 diagram.
E

I did that and my serial read values went up really high number, Normally with a single load I get aroun 209833 as raw readings without any weight. When I joined all the wires of same color together, and Subsequently joined them to the RED, BLACK, White and Green of HX711.


I got really high number somthing, but When putting some pressure number wasn't changing, so I thought I might be doing something wrong
 

Thread Starter

abc14

Joined Oct 15, 2017
105
I used similar image for reference. So to connect all 4 at the same time All i have to is Join wires with similar color and subsequently connect them matching Connections on HX711
 
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