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

2.2 Design Considerations

Typical thermal energy meters use a pair of PT100, PT500, or PT1000 sensors, which are connected to a precision delta-sigma ADC, such as TI's ADS1220 family, or to an MCU or an analog front end (AFE) device, utilizing the ADC slope conversion approach based on a precision comparator and a digital timer. In the EU countries, the EN1434(2) specification series define the requirements for these meters.

The High Precision Temperature Measurement for Heat and Cold Meters Reference Design (TIDA-01526) implements a differential temperature measurement (DTM) subsystem using a 24-bit, low-power, delta-sigma ADC such as the ADS122U04 or ADS122C04 devices (but also applies to the ADS1220 device with an SPI interface). The TIDA-01526 is a low-cost, high-precision DTM subsystem, which can be combined with TI's ultra-sonic or rotation detection flow measurement subsystems, based on the MSP430FR6047 or MSP430FR6989, or TI's CC13xx and CC26xx wireless MCUs.

The TIDA-010002 reference design shows an alternative DTM system solution to TIDA-01526 by having the complete signal chain of a delta-sigma device together with the external RTD sensor integrated into a single active precision temperature semiconductor component, the TMP117 device.

The newly-introduced digital RTD approach in the TIDA-010002 represents an alternative to the traditional thin-film RTD sensors and brings multiple advantages, such as unique calibration parameters being programmed inside each DRTD and available to the host MCU for read out at any time.

Because of the improved linearity compared to the Platinum RTD sensors, a reduced effort for the calibration and pairing process can be expected.