SDAA486 September   2026 CC1312R

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Smart Meter EU Regulations
    2. 1.2 Rotary Metrology Designs
  5. 2Smart Flow Meters and Sub-Metering Devices
    1. 2.1 Heat Cost Allocator (Sub-Metering)
      1. 2.1.1 HCA Key Functions
        1. 2.1.1.1 IrDA Communication Port
        2. 2.1.1.2 Temperature Measurement (Two-Sensor Method)
        3. 2.1.1.3 Segment LCD Support
    2. 2.2 Retrofit Add-On Module for Mechanical Water Meters
      1. 2.2.1 Retrofit Add-On Module Key Functions
      2. 2.2.2 Rotary Flow Metrology Implementation
        1. 2.2.2.1 Optical and Magnetic Rotary Sensing
        2. 2.2.2.2 Inductive Rotary Sensing
      3. 2.2.3 IrDA Wake-Up Detection
    3. 2.3 Smart Rotary Water Meter
      1. 2.3.1 Water Meter Key Functions
      2. 2.3.2 Segment LCD with CapTouch Activation
      3. 2.3.3 Tamper Detection With TMAG5231
      4. 2.3.4 OMS Compliant wM-Bus Communication Sub-system
    4. 2.4 Thermal Meters (Heat / Cold)
      1. 2.4.1 Thermal Meter Key Functions
      2. 2.4.2 Analog Signal Chain for DTM
      3. 2.4.3 Remarkable, Fully Digital Design for DTM
        1. 2.4.3.1 I2C and SMBus-Compatible Digital Sensor for Thermal Meters
        2. 2.4.3.2 1-Wire Compatible Digital Sensor for Thermal Meters
    5. 2.5 Bluetooth Low Energy (BLE) in Flow Meters
    6. 2.6 Influence of CRA on Smart Flow Meters and Heat Cost Allocators
      1. 2.6.1 Achieving CRA Conformance Through Careful System Design
        1. 2.6.1.1 Tamper Detection as a Physical Security Argument
        2. 2.6.1.2 Secure Key Storage
        3. 2.6.1.3 Secure Boot
        4. 2.6.1.4 Authenticated wM-Bus Communication
        5. 2.6.1.5 Secure Firmware Update via Over-the-Air Download (OAD)
        6. 2.6.1.6 Security Event Logging
  6. 3Summary
  7. 4References

2.4.3.2 1-Wire Compatible Digital Sensor for Thermal Meters

Building upon the high accuracy TMP117 device, the TMP1826 digital integrated ±0.2°C temperature sensor, compatible with 1-Wire® protocol has been developed. The use of 1-Wire® protocol enables the implementation of two-wire digital temperature sensors as an alternative to the common two-wire RTD100/500/1000 sensors. While the exterior look and feel of analog RTD elements and TMP1826 1-Wire™ temperature sensors are identical, it is important to note that these are not pin-to-pin compatible. The legacy analog result elements require a programmable current source excitation to measure the voltage drop across the PT element inside using a precision ADC, such as ADS1220. The digital sensor needs a simple digital 1-wire protocol to a MCU core, with one data line and one ground line.

With TMP1826 and the pin-to-pin TMP1827 with integrated SHA-256 authenticator, TI enables significant system cost reductions by radically simplifying the manufacturing flow for thermal meters calibration.

Table 2-3 Comparison Between Standard RTDs and 1-Wire Digital Temperature Sensors
RTD TMP1826/7 1-Wire
Total Wires 2 2
Recommended Max. Length 10m 300m
Analog signal chain Yes No (Inside TMP1826/7)
Programmable Current Source needed Yes None
Precision reference resistor Yes None
Layout complexity High, matched traces and Kelvin connection None (Digital interface)
Calibration points 3 1
Vendor information (per sensor) Not possible 2kbit EEPROM
NIST traceability Not possible Yes (Factory programmed)