What's the type of load cell output and how to interface it with 89c51?

[neelam]

hi friends
can anybody please tell me that what is the kind of output that a load cell gives and how can i interface it with microcontroller 89c51.
the weigh scale is from 0gms - 25 gms with resolution of 0.01 .which load cell to use for this?

waiting for reply
please help
neelam

 

[MAKeller]

Re: load cell output?

Neelam,

The standard output of most load cells is 2mV/V.
Most use a wheat stone bridge and have a max
output of +/- 20mV @ 10V excitation.

The folowing companies sell load cells.

www.columbiaresearchlabs.com
www.lebow.com
www.interfacetech.com

There are many more, checkout Sensor Magazine website for more listings.

Have a great day.

MAKeller

 

[neelam]

load cell output?

Thanks a lot for replying MAKeller. can you please tell me what do you please explain me in detail, about,---> "2mV/V" and "output of +/- 20mV @ 10V excitation".

Thanks once again.

 

[techie]

load cell output?

If you apply 10V at the excitation pins, and put full weight on the load cell, it will give 2mv X 10V = 20mv output at the output pins..

That is quite small to be measured directly by the ADC inputs unless the ADC has a built in amplifier. So conventionally, you will need a low noise amplifier and an ADC to be able to read by 89C51.

 

[7rots51]

Re: load cell output?

AD7730 from ADI have all the needs for signal conditioning AND digitizing the load cell data.

 

[engnr4a]

load cell output?

plz help i want to knwo why load cell have to o/p signal (+ve&-ve) and which one used to be read with muc

 

[techie]

load cell output?

Load Cell is a wheatstone bridge. It has differential outputs. You have to use suitable differential amplifier or ADC to read it.

 

[arbj]

load cell output?

you could use the CS5520 /CS5516 interfaces from Cirrus logic for the load cell.

 

[the mask]

load cell output?

hi for same topics i have load cell and its work good but i cant measure output voltage change