The Godfather talking
You may crack software. How about me?
Sonsivri
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
March 29, 2024, 10:03:45 10:03


Login with username, password and session length


Pages: [1]
Print
Author Topic: vehicle scale system  (Read 3138 times)
0 Members and 1 Guest are viewing this topic.
falcon _bd
Active Member
***
Offline Offline

Posts: 139

Thank You
-Given: 66
-Receive: 117


falconbd.com


WWW
« on: August 24, 2008, 08:23:12 20:23 »

I am going to start a project about vehicle scale system with load cell. so i need some one's help who practically work with this.
please advice me 
Logged

Kwaigo
Newbie
*
Offline Offline

Posts: 25

Thank You
-Given: 5
-Receive: 6


« Reply #1 on: September 02, 2008, 08:38:54 20:38 »

Hello. You mean deformable aluminium beam with film resistor? What is your load cell?
Logged
falcon _bd
Active Member
***
Offline Offline

Posts: 139

Thank You
-Given: 66
-Receive: 117


falconbd.com


WWW
« Reply #2 on: September 03, 2008, 12:41:34 00:41 »

i am using the load cell from chinesesensor

http://www.chinesesensor.com/index.php/load-cell/bridge-style/13-bridge-style-load-cell/6-czl-110
Logged

Kwaigo
Newbie
*
Offline Offline

Posts: 25

Thank You
-Given: 5
-Receive: 6


« Reply #3 on: September 03, 2008, 10:16:59 10:16 »

This is a resistive bridge sensor. Like in ordinary electronic scale.
Use 24bit delta-sigma ADC (ADS1251 for example). Put AD reference voltage to one bridge diagonal, and other diagonal connect to differential AD input. 24bit resolution enough to exclude preamplifer, because LSB few times less than noise. Some ADC contain PGA at input. You can use it.
Software must obtain two calibration values: zero load and full scale(or part of it).
If scale must be precise in wide temperature range, You need also temperature sensor and temperature compensation value.
Logged
falcon _bd
Active Member
***
Offline Offline

Posts: 139

Thank You
-Given: 66
-Receive: 117


falconbd.com


WWW
« Reply #4 on: September 03, 2008, 12:27:24 12:27 »

But I want to use pic 16f887 . which has  10 bit ADC . is that resolution  is not enough ? can you please explain the full project in block diagram with pic MCU.
Logged

Kwaigo
Newbie
*
Offline Offline

Posts: 25

Thank You
-Given: 5
-Receive: 6


« Reply #5 on: September 03, 2008, 08:42:51 20:42 »

1) Internal 10 bit ADC have high noise, bad linearity, and bad interference immunity. It applicable only for temperature sensor, if you need one. However, if you agree with 2-3% tolerance you can use it. But that case precision DC amplifier required.
Sigma-delta ADC is integrator, and many ADC`s have built-in filter(like ADS1251), and reject 50-60 Hz interferences thousand times.
2) I can help you with block diagram only if you give me technical parameters of the scale: precision, temperature range, display type (digit count) wire length (from sensor to ADC)
« Last Edit: September 03, 2008, 08:48:47 20:48 by Kwaigo » Logged
Pages: [1]
Print
Jump to:  


DISCLAIMER
WE DONT HOST ANY ILLEGAL FILES ON THE SERVER
USE CONTACT US TO REPORT ILLEGAL FILES
ADMINISTRATORS CANNOT BE HELD RESPONSIBLE FOR USERS POSTS AND LINKS

... Copyright © 2003-2999 Sonsivri.to ...
Powered by SMF 1.1.18 | SMF © 2006-2009, Simple Machines LLC | HarzeM Dilber MC