TIDUEA0A March   2019  – September 2020

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 Device Recommendation
      2. 2.3.2 Digital Temperature Sensor - TMP117
      3. 2.3.3 Digital Temperature Sensor - TMP116
      4. 2.3.4 ESD Protection Devices
    4. 2.4 System Design Theory
      1. 2.4.1 PT100, PT500, PT1000 based Measurement in Heat Meters
      2. 2.4.2 TMP117 Configuration as Temperature Sensor
      3. 2.4.3 Digital RTD Solution Using TMP117
      4. 2.4.4 Ambient Temperature Considerations
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Interface Test Software for TMP116
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup for Performance Testing
      2. 3.2.2 EMI and EMC Test Requirements for DRTD
      3. 3.2.3 TMP117 EMI/EMC Test Results
      4. 3.2.4 TMP117 Based Temperature Probe Measurement Performance Test Results
      5. 3.2.5 TMP116 Based Temperature Probe Measurement Performance Test Results
      6. 3.2.6 I2C-bus Cable Length Considerations
      7. 3.2.7 Power Supply
      8. 3.2.8 ESD Test Results for TMP116
      9. 3.2.9 Summary
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7About the Author
  13. 8Revision History

2.4.1 PT100, PT500, PT1000 based Measurement in Heat Meters

In Figure 2-5 the ADS1220 Delta-Sigma device is used to measure the resistance of two 4-wire PT sensors in series and passes the data to the MSP430 host MCU for conversion from a resistance value to a temperature value, as implemented in the TIDA-01526. There the 4-wire interface is part of the Kelvin connection, where two outer leads on RTD1 and RTD2 carry the measurement current IIDAC1 and the two inner leads are connected to AIN0-1 and AIN2-3 analog inputs of the ADS1220 to measure the voltage across RTD1 and RTD2 and thus their respective resistance values.

GUID-B41273A8-289C-4A04-94D3-6B2C399CB605-low.gifFigure 2-5 DTM Subsystem With a 24-bit Delta-Sigma Device and a Pair of 4-Wire RTDs