SLAAER4
March 2025
AFE781H1
,
AFE782H1
,
AFE881H1
,
AFE882H1
,
DAC8740H
,
DAC8741H
,
DAC8742H
1
Abstract
Trademarks
1
Introduction
1.1
The 4-20mA Loop
1.2
The HART Protocol
1.2.1
Adding HART to the 4-20mA Loop
1.2.2
HART FSK
2
AFE882H1 EVM-Based HART Transmitter
2.1
AFE882H1 HART Modem
2.2
AFE882H1 Evaluation Module
2.3
HART Transmitter Construction
2.3.1
Detailed Schematic
2.3.1.1
Input Protection
2.3.1.2
Start Up With Low-Dropout Regulator
2.3.1.3
Voltage-to-Current Stage
2.3.1.4
Voltage-to-Current Calculation
2.3.1.5
HART Signal Transmission
2.3.1.6
HART Input Protection
2.3.1.7
HART Transmitter Board
2.3.1.8
Current Consumption
2.3.2
HART Protocol Stack
3
HART Testing and Registration
3.1
HART History and the FieldComm Group
3.2
HART Testing Overview
3.2.1
HART Protocol Specifications
3.2.2
HART Protocol Test Specifications
3.2.3
Field Transmitter Device Testing
3.3
HART Test Equipment
3.4
HART Physical Layer Testing
3.4.1
FSK Sinusoid Test
3.4.2
Carrier Start and Stop Time Tests
3.4.3
Carrier Start and Stop Transient Tests
3.4.4
Output Noise During Silence
3.4.5
Analog Rate of Change Test
3.4.6
Receive Impedance Test
3.4.7
Noise Sensitivity Test
3.4.8
Carrier Detect Test
3.5
Data Link Layer Tests
3.5.1
Data Link Layer Test Specifications
3.5.2
Data Link Layer Test Logs
3.6
Universal Command Tests
3.7
Common-Practice Command Tests
3.8
Device Specific Command Tests
3.9
HART Protocol Test Submission
3.10
HART Registration
4
Summary
5
Acknowledgments
6
References
6
References
Texas Instruments,
AFEx81H1 16-Bit and 14-Bit, Low-Power DACs With Internal HART® Modem, Voltage Reference, and Diagnostic ADC for 4-mA to 20-mA Loop-Powered Applications
, data sheet.
Texas Instruments,
AFEx82H1 16-Bit and 14-Bit, Low-Power DACs With Internal HART® Modem, Voltage Reference, and Diagnostic ADC for 4-mA to 20-mA Loop-Powered Applications
, data sheet.
Texas Instruments,
MSP430FR596x, MSP430FR594x Mixed-Signal Microcontrollers
, data sheet.
Texas Instruments,
MSP430FR5969 LaunchPad™ Development Kit (MSP‑EXP430FR5969)
, user's guide.
Texas Instruments,
AFE881H1EVM User's Guide
.
Texas Instruments,
AFE882H1EVM User's Guide
.
Texas Instruments,
A Basic Guide to the HART Protocol
, application note.
Texas Instruments,
Design and Test of a HART-Enabled Field Transmitter for 4-20mA Loops
, application note.