SLAAER4 March   2025 AFE781H1 , AFE782H1 , AFE881H1 , AFE882H1 , DAC8740H , DAC8741H , DAC8742H

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 The 4-20mA Loop
    2. 1.2 The HART Protocol
      1. 1.2.1 Adding HART to the 4-20mA Loop
      2. 1.2.2 HART FSK
  5. 2AFE882H1 EVM-Based HART Transmitter
    1. 2.1 AFE882H1 HART Modem
    2. 2.2 AFE882H1 Evaluation Module
    3. 2.3 HART Transmitter Construction
      1. 2.3.1 Detailed Schematic
        1. 2.3.1.1 Input Protection
        2. 2.3.1.2 Start Up With Low-Dropout Regulator
        3. 2.3.1.3 Voltage-to-Current Stage
        4. 2.3.1.4 Voltage-to-Current Calculation
        5. 2.3.1.5 HART Signal Transmission
        6. 2.3.1.6 HART Input Protection
        7. 2.3.1.7 HART Transmitter Board
        8. 2.3.1.8 Current Consumption
      2. 2.3.2 HART Protocol Stack
  6. 3HART Testing and Registration
    1. 3.1  HART History and the FieldComm Group
    2. 3.2  HART Testing Overview
      1. 3.2.1 HART Protocol Specifications
      2. 3.2.2 HART Protocol Test Specifications
      3. 3.2.3 Field Transmitter Device Testing
    3. 3.3  HART Test Equipment
    4. 3.4  HART Physical Layer Testing
      1. 3.4.1 FSK Sinusoid Test
      2. 3.4.2 Carrier Start and Stop Time Tests
      3. 3.4.3 Carrier Start and Stop Transient Tests
      4. 3.4.4 Output Noise During Silence
      5. 3.4.5 Analog Rate of Change Test
      6. 3.4.6 Receive Impedance Test
      7. 3.4.7 Noise Sensitivity Test
      8. 3.4.8 Carrier Detect Test
    5. 3.5  Data Link Layer Tests
      1. 3.5.1 Data Link Layer Test Specifications
      2. 3.5.2 Data Link Layer Test Logs
    6. 3.6  Universal Command Tests
    7. 3.7  Common-Practice Command Tests
    8. 3.8  Device Specific Command Tests
    9. 3.9  HART Protocol Test Submission
    10. 3.10 HART Registration
  7. 4Summary
  8. 5Acknowledgments
  9. 6References

3.7 Common-Practice Command Tests

The last of the HART tests verify that common-practice commands of the application layer (CAL) are implemented in the transmitter. The CAL test specification is described by HCF_TEST_4. These tests check for highly-recommended commands that are implemented in many HART devices. Here is a basic list of common-practice commands that can be implemented in HART devices and tested as part of the CAL tests:

  • Read selection of up to four dynamic variables
  • Write damping time constant
  • Write device range values
  • Calibrate (set zero, set span)
  • Set fixed output current
  • Perform self-test
  • Perform host reset
  • Trim primary variable zero
  • Write primary variable unit
  • Trim DAC zero and gain
  • Write transfer function (square root/linear)
  • Write sensor serial number
  • Read or write dynamic variable assignments

Table 3-11 shows the set of common-practice command tests run by the HART tester. While the transmitter designed in this application note uses a HART stack that shows functionality of the device, this design is not a full-functioned device used as a real transmitter in an application. Many commands have been implemented, but not all are supported from this list of tests. This complete set of CAL tests take about 4 hours to complete.

Table 3-11 CAL Command Test Results
TEST NUMBERDESCRIPTIONRESULT
CAL000Checks for common practice commandsPass
CAL001Write protect testNot implemented
CAL033Read device variablesPass
CAL034Write primary variable damping valuePass
CAL035Write primary variable range valuesPass
Primary variable units code unaffected by command 35Pass
CAL036Set primary variable upper range valueNot applicable
CAL037Set primary variable lower range valueNot applicable
CAL040Enter/exit fixed current modePass
CAL041Perform self testPass
CAL042Perform device resetPass
CAL043Set primary variable zeroNot applicable
CAL044Write primary variable unitsPass
CAL045Trim loop current zeroPass
CAL046Trim loop current gainPass
CAL047Write primary variable transfer functionNot applicable
CAL049Write primary variable transducer serial numberNot applicable
CAL050Read dynamic variable assignmentsNot applicable
CAL051Write dynamic variable assignmentsNot applicable
CAL052Set device variable zeroNot applicable
CAL053Write device variable unitsNot applicable
CAL054Read device variable informationPass
CAL055Write device variable damping valueNot applicable
CAL056Write device variable transducer serial numberNot applicable
CAL060Read analog channel and percent of rangeNot applicable
CAL062Read analog channelsNot applicable
CAL063Read analog channel informationNot applicable
CAL064Write analog channel additional damping valueNot applicable
CAL065Write analog channel range valuesNot applicable
CAL066Enter/exit fixed analog channel modeNot applicable
CAL067Trim analog channel zeroNot applicable
CAL068Trim analog channel gainNot applicable
CAL069Write analog channel transfer functionNot applicable
CAL070Read analog channel endpoint valuesNot applicable
CAL071Lock deviceNot applicable
CAL072SquawkPass
CAL073Find deviceNot applicable
CAL074Verify I/O system commandsNot applicable
CAL078Command aggregationNot applicable
CAL079Write device variableNot applicable
CAL080Verify device variable trim commandsNot applicable
CAL091TrendingNot applicable
CAL101Subsystem burst modeNot applicable
CAL103Support for multiple burst messagesPass
CAL104Smart data publishingPass
CAL107Write burst device variablesPass
CAL108Write burst mode command numberPass
CAL109Burst mode controlPass
CAL115Event notificationNot applicable
CAL512Country codeNot applicable
CAL518Location descriptionNot applicable
CAL520Process unit tagNot applicable
CAL523Read condensed status mapping arrayNot applicable
CAL524Manipulating condensed status mapNot applicable
CAL526Status simulationNot applicable

As with the DLL and UAL tests, running the CAL tests from hartmenu generates a set of logs for the registration submission.