SLAAEH0 November   2023 AFE781H1 , AFE782H1 , AFE881H1 , AFE882H1 , DAC161P997 , DAC161S997 , DAC7750 , DAC7760 , DAC8740H , DAC8741H , DAC8742H , DAC8750 , DAC8760 , DAC8771 , DAC8775

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to the HART Protocol
    1. 1.1 Different Forms of the HART Protocol
    2. 1.2 HART as an Enhancement to the 4-20 mA Loop
    3. 1.3 The HART FSK Signal
    4. 1.4 HART Configurations
    5. 1.5 HART Protocol Structure
      1. 1.5.1 HART Communication
      2. 1.5.2 HART Bytes
      3. 1.5.3 HART Data Frame Structure
        1. 1.5.3.1 HART Start Byte
        2. 1.5.3.2 HART Device Addressing
        3. 1.5.3.3 HART Commands
  5. 2HART Protocol and Test Specifications
    1. 2.1 The OSI Protocol Model
    2. 2.2 HART Protocol Specifications
    3. 2.3 HART Test Specifications
  6. 3TI HART Enabled Devices
    1. 3.1 TI DACs with HART Connections
    2. 3.2 TI HART Modems
  7. 4Conclusion
  8. 5References

3 TI HART Enabled Devices

Texas Instruments produces several devices designed to integrate a HART FSK signal. Some devices are digital-to-analog converters (DACs) with a voltage or current output that couple in a HART signal that can be modulated on the output. Other devices are modems that send and receive HART signals through either a UART interface or SPI.

Table 3-1 shows a list of TI devices that provide device connectivity to the HART protocol. The following sections describe these devices in more detail.

Table 3-1 Device Reference
Device Type TI Device DAC Resolution Features HART Connectivity
DAC for field transmitter device DAC161S997 16-bit Field transmitter device with precision DAC with internal reference, integrated op-amp, SPI, and matched resistors for setting current loop drive HART signal capacitively coupled out to DAC from C2 pin
DAC161P997 16-bit Field transmitter device with precision DAC with internal reference, integrated op-amp, single-wire interface, and matched resistors for setting current loop drive
Current output DAC DAC8750 16-bit Single-channel programmable current output DAC with internal reference for 4-20mA current loop applications HART signal capacitively coupled out to DAC through HART-IN pin
DAC7750 12-bit
Current and voltage output DAC DAC8760 16-bit Single-channel programmable current and voltage output DAC with internal reference for 4-20mA analog output applications HART signal capacitively coupled out to DAC through HART-IN pin
DAC7760 12-bit
DAC8771 16-bit Single-channel programmable current and voltage output DAC, with internal reference and buck-boost converter for analog output applications HART signal capacitively coupled into DAC through HART-IN_x pin
DAC8775 16-bit Four-channel programmable current and voltage output DAC, with internal reference and buck-boost converter for analog output applications
HART modem device DAC8740H HART modem with UART interface HART signal capacitively coupled into modem on MOD_IN or MOD_INF depending on input filtering, HART sinusoid out on MOD_OUT
DAC8741H HART modem with SPI
DAC8742H HART modem with SPI and UART interface
HART modem device with DAC AFE881H1 16-bit Field transmitter device with precision DAC with 0.15-V to 1.25-V output range, internal reference, and ADC HART signal capacitively coupled into modem on MOD_IN or MOD_INF depending on input filtering, HART sinusoid out on MOD_OUT
AFE781H1 14-bit
AFE882H1 16-bit Field transmitter device with precision DAC with 0-V to 2.5-V output range, internal reference, and ADC
AFE782H1 14-bit