My first Industrial product design experience.
This load cell measurement and controller module have 1 gram precision with a 100 kilo gram load cell. Design consists of PIC18F2520, medium range microcontroller from Microchip, as main processor.
We have read the analog data from load cell with 24 bit Sigma-Delta Analog to Digital Converter. User customizable FIR filtering used for signal processing which gives a better stability in reading. The controller has four buttons in the front panel for user input, we have provision to bring touch based solution in future versions.
For the six digit display Max7221, common cathode seven segment display controller chip used. This chip use SPI (serial peripheral interface) bus to communicate with microcontroller. I have designed the PCB board with PROTEUS design suit. This is very flexible to work with and making custom footprints for different components very easy.
The board is powered from a industrial standard 24 volts power source, which stepped down using buck converter circuit. This module can send measurement data to programmable logic controller(PLC) and SCADA (Supervisory Control And Data Acquisition) monitoring systems through standard MODBUS protocol.
According to user settings it can also send 24V HIGH/LOW switching signal through relays. Apart from that, industrial standard analog 0-10V signaling circuit also implemented, using MCP4321, 12 bit DAC (digital to analog controller) from Microchip.
As a low cost product I hope this will bring great success. We are currently working on mold design.