Reference Design Library > Sensor Solutions > Temperature Sensing > TMPSNSRD-RTD2: RTD w/ 22bit ADC, USB Interface

TMPSNSRD-RTD2: RTD w/ 22bit ADC, USB Interface

Summary

The RTD Reference Design demonstrates how to implement a Resistive Temperature Detector (RTD) and accurately measure temperature. This solution uses the MCP3551 22-Bit Analog-to-Digital Converter (ADC) to measure voltage across the RTD. The ADC and the RTD are referenced using an on-board reference voltage, and the ADC inputs are directly connected to the RTD terminals. This provides a ratio metric temperature measurement. The solution uses a current limiting resistor to bias the RTD. It provides a reliable and accurate RTD instrumentation without the need for extensive circuit compensation and calibration routines.

This solution uses an on-board (local) surface mount RTD and an external RTD. The local and external RTDs are selected using JP2.

In addition, this reference design includes a silicon temperature sensor, MCP9804. This sensor is used for comparison only, it is not needed for the RTD instrumentation circuit. The MCP3551 and MCP9804 outputs are read using a USB PIC® MCU. This controller is also connected to a PC using USB interface. The Thermal Management software is used to plot the RTD temperature data in strip chart format.

The RTD Reference Design has the following features:
  • Surface mount PT100 RTD
  • External RTD connector (not included)
  • Thermal Management GUI
  • 22-Bit ADC MCP3551
  • ±1°C Maximum accuracy temperature sensor MCP9804
  • PIC18F2550 microcontroller
  • USB interface to PC

Specifications

Manufacturer Microchip Technology
Category Sensor Solutions
Sub-Category Temperature Sensing
Eval Board Part Number TMPSNSRD-RTD2-ND
Eval Board Supplier Microchip Technology
Eval Board Normally In Stock
Purpose RTD (Resistive Temperature Detector)
Sensing Method RTD, External
RTD, On Board
Silicon
Accuracy ±0.25 ~ ±1°C (IC)
Sensing Range -40°C ~ 125°C (Local)
Features GUI / Design Software
I²C Interface
SPI Interface
USB Interface
Design Author Microchip Technology
Main I.C. Base Part MCP3551
MCP9804
Component Count + Extras 25 + 4
Date Created By Author 2010-08
Date Added To Library 2011-08

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Support Documents & Media

Thermal Management Utility v1.3.2 TMPSNSRD-RTD2 - User Guide MCP3551 - Datasheet MCP9804 -Datasheet

Media

TMPSNSRD_RTD2_Schematic_Full.PNG TMPSNSRD_RTD2_Board_Full.jpg TMPSNSRD_RTD2_Simplified_Full.PNG