HART Protocol Objective Questions and Answers

HART Protocol in full form is Highway Addressable Remote Transducer Protocol which is a widely-used communication protocol in industrial automation systems.

As a technology designed to enhance communication between field devices and control systems, HART has become an integral part of modern industrial processes.

HART Protocol Objective Questions

In this article, we present a series of HART Protocol objective questions and answers that cover different aspects of this technology, including its benefits, limitations, and common commands. Whether you are a beginner or an expert in industrial automation, these questions and answers will provide you with valuable insights into HART Protocol and its applications in modern industries.

What is the purpose of the HART protocol?

A) To transmit digital data over analog communication lines
B) To control analog devices with digital signals
C) To communicate between different HART devices
D) To transmit audio signals over communication lines

Explanation: The HART protocol is used to transmit digital data over analog communication lines, allowing communication between smart field devices and control systems.

What is the maximum length of the HART communication cable?

A) 500 meters
B) 1 kilometer
C) 2 kilometers
D) 5 kilometers

Explanation: The maximum length of the HART communication cable is 2 kilometers. Beyond this length, signal attenuation and noise may affect communication quality.

Which of the following is a benefit of using the HART protocol?

A) Improved accuracy of measurement
B) Faster communication speed
C) Reduced power consumption
D) Higher data transfer rate

Explanation: HART protocol allows for improved accuracy of measurement, as it provides access to additional information and diagnostics beyond the primary process variable.

What is the function of the HART modem?

A) To convert analog signals to digital signals
B) To convert digital signals to analog signals
C) To provide power to the HART device
D) To provide a physical connection between the HART device and the communication line

Explanation: The HART modem is used to provide a physical connection between the HART device and the communication line, allowing for the transmission of digital data.

What is the maximum number of HART devices that can be connected to a single communication line?

A) 5
B) 10
C) 15
D) 20

Explanation: The maximum number of HART devices that can be connected to a single communication line is 15. Beyond this number, the communication quality may be affected.

What is the function of HART burst mode?

A) To increase the communication speed
B) To provide a secondary communication path
C) To allow for continuous real-time updates
D) To reduce the power consumption of the device

Explanation: HART burst mode is used to increase the communication speed, allowing for faster transmission of data between HART devices and control systems.

Which of the following is a type of device that is commonly used as a HART master?

A) Sensor
B) Controller
C) Actuator
D) Transmitter

Explanation: A controller, such as a programmable logic controller (PLC), is commonly used as a HART master in industrial control systems.

Which of the following is a type of HART command used to write to device memory?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Extended is used to write to device memory, allowing for configuration settings and other parameters to be set remotely.

Which of the following is a type of device that is commonly used as a HART slave?

A) Controller
B) Sensor
C) Actuator
D) Transmitter

Explanation: A transmitter, such as a pressure transmitter, is commonly used as a HART slave in industrial control systems.

What is the purpose of the HART command 48?

A) To read the device status
B) To set the device configuration
C) To read the device tag
D) To set the device range

Explanation: HART command 48 is used to read the device status, including diagnostic information and device parameters.

What is the purpose of HART command 13?

A) To set the device configuration
B) To read the device tag
C) To read the device range
D) To set the device output

Explanation: HART command 13 is used to set the device configuration, including the process variable range and alarm settings.

What is the HART command used to set the device output?

A) Command 13
B) Command 21
C) Command 44
D) Command 48

Explanation: HART command 21 is used to set the device output, including the current output or control valve position.

Which of the following instrument is not a HART device type?

A) Pressure transmitter
B) Control valve
C) Flow meter
D) PLC

Explanation: HART devices include pressure transmitters, flow meters, level sensors, temperature sensors, and control valves, among others.

What is the purpose of the HART command 0?

A) To reset the device configuration to factory settings
B) To initiate a diagnostic test
C) To read the device configuration
D) To set the device range

Explanation: HART command 0 is used to reset the device configuration to factory settings, allowing for a fresh start in case of errors or malfunctions.

Which of the following is a limitation of the HART protocol?

A) Limited data transfer rate
B) Limited number of devices that can be connected
C) Limited distance between devices
D) Limited compatibility with other protocols

Explanation: One of the limitations of the HART protocol is its limited data transfer rate, which can be a bottleneck in data-intensive applications.

What is the function of the HART handshake protocol?

A) To establish a connection between HART devices
B) To synchronize data transmission between HART devices
C) To authenticate HART devices before communication
D) To detect errors and retransmit lost data packets

Explanation: The HART handshake protocol is used to synchronize data transmission between HART devices, ensuring that data is transmitted at the correct time and pace.

What is the HART command used to read the device tag?

A) Command 0
B) Command 13
C) Command 48
D) Command 73

Explanation: HART command 73 is used to read the device tag, which includes information about the device manufacturer, model, and serial number.

Which of the following is an advantage of using the HART protocol over other communication protocols?

A) Higher data transfer rate
B) Longer communication distance
C) Better noise immunity
D) Higher power consumption

Explanation: HART protocol has better noise immunity compared to other communication protocols, which allows for more reliable communication in noisy industrial environments.

What is the HART command used to read the device range?

A) Command 13
B) Command 21
C) Command 44
D) Command 48

Explanation: HART command 44 is used to read the device range, including the process variable range and calibration settings.

Which of the following is a type of HART command used for vendor-specific functions?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Specific is used for vendor-specific functions, allowing manufacturers to add custom commands for device-specific features.

What is the HART command used to read the device configuration?

A) Command 0
B) Command 13
C) Command 40
D) Command 73

Explanation: HART command 40 is used to read the device configuration, including the process variable range, calibration settings, and other device parameters.

Which of the following is a limitation of using HART protocol in a control system?

A) Limited number of devices that can be connected
B) Limited distance between devices
C) Limited compatibility with legacy devices
D) Limited support for complex control algorithms

Explanation: HART protocol has limited support for complex control algorithms, which may limit its use in advanced control systems.

Which of the following types of devices can use the HART protocol?

A) Analog devices only
B) Digital devices only
C) Both analog and digital devices
D) Only devices manufactured by specific vendors

Explanation: HART protocol can be used with both analog and digital devices, allowing for a wide range of industrial applications.

Which of the following is a type of HART command used to configure the device?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Common Practice is used for device configuration, allowing for standard commands to configure most HART devices.

Which of the following types of communication is used by the HART protocol?

A) Analog
B) Digital
C) Frequency modulation
D) Amplitude modulation

Explanation: HART protocol uses digital communication, allowing for higher data transfer rates and better noise immunity compared to analog communication.

Which of the following is an advantage of using the HART protocol in a control system?

A) Easy integration with legacy devices
B) High data transfer rate
C) Long communication distance
D) Low power consumption

Explanation: HART protocol has good backward compatibility and can be easily integrated with legacy devices, which is important in industrial environments with older equipment.

What is the purpose of the HART command 21?

A) To read the device range
B) To read the device configuration
C) To set the device range
D) To set the device configuration

Explanation: HART command 21 is used to set the device range, including the process variable range and calibration settings.

Which of the following types of communication is used by the HART protocol for digital data transmission?

A) Pulse Width Modulation
B) Frequency Shift Keying
C) Amplitude Shift Keying
D) Phase Shift Keying

Explanation: HART protocol uses Frequency Shift Keying (FSK) for digital data transmission, which allows for reliable communication in noisy industrial environments.

Which of the following is a type of HART command used for commonly used functions?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Universal is used for commonly used functions, allowing for standard commands to be used across different HART devices.

What is the maximum distance between two HART devices in a communication loop?

A) 500 meters
B) 1 kilometer
C) 2 kilometers
D) 5 kilometers

Explanation: The maximum distance between two HART devices in a communication loop is typically limited to 500 meters, which is determined by the available power and communication bandwidth.

Which of the following is a type of HART command used to perform advanced functions?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Extended is used to perform advanced functions, allowing for customized commands to be added for specific device features.

Which of the following types of devices is most commonly used with the HART protocol?

A) Sensors
B) Controllers
C) Actuators
D) Transmitters

Explanation: HART protocol is most commonly used with transmitters, which are used to measure process variables such as temperature, pressure, and flow rate.

Which of the following is a limitation of using HART protocol in a control system?

A) Limited support for advanced device features
B) Limited compatibility with legacy devices
C) Limited communication distance
D) Limited number of devices that can be connected

Explanation: The number of devices that can be connected on a single HART loop is limited to 15, which may be a limitation in larger industrial applications.

Which of the following is a type of device that can be connected to a HART communication loop?

A) Ethernet switch
B) Fiber optic transmitter
C) Pressure sensor

Explanation: Devices such as pressure sensors, flow meters, and temperature sensors can be connected to a HART communication loop to transmit analog and digital data.

Which of the following is a type of HART command used for device-specific functions?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Specific is used for device-specific functions, allowing for customized commands to be added for unique device features.

What is the maximum data transfer rate supported by the HART protocol?

A) 1200 bits per second
B) 2400 bits per second
C) 4800 bits per second
D) 9600 bits per second

Explanation: HART protocol supports a maximum data transfer rate of 9600 bits per second, which is suitable for transmitting both analog and digital data in industrial control systems.

Which of the following is a type of HART command used to read device status and diagnostic information?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Universal is used to read device status and diagnostic information, providing valuable insights into the health of the device and its performance.

Which of the following is a limitation of using HART protocol in a control system?

A) Limited support for advanced device features
B) Limited compatibility with legacy devices
C) Limited communication distance
D) Limited data transfer rate

Explanation: HART protocol has a relatively low data transfer rate compared to other communication protocols, which may limit its suitability for certain applications.

What is the purpose of the HART command 22?

A) To read the device configuration
B) To write to the device’s memory
C) To read the device status
D) To write to the device identification number

Explanation: HART command 22 is used to read the device status, providing information about the device’s current operating conditions and any diagnostic information.

Which of the following is a type of device that is commonly used as a HART repeater?

A) Sensor
B) Controller
C) Actuator
D) Transmitter

Explanation: A controller, such as a gateway or bridge, is commonly used as a HART repeater in industrial control systems, allowing for HART signals to be transmitted over longer distances.

What is the purpose of the HART command 28?

A) To read the device status
B) To write to the device configuration
C) To read the device memory
D) To write to the device status

Explanation: HART command 28 is used to write to the device status, allowing for changes to be made to the device’s operating parameters.

What is the purpose of the HART command 36?

A) To read the device identification number
B) To write to the device’s memory
C) To read the device status
D) To write to the device configuration

Explanation: HART command 36 is used to read the device identification number, providing information about the device manufacturer, model, and version.

Which of the following is a type of HART command used to read the device measurement values?

A) Universal
B) Extended
C) Common Practice
D) Specific

Explanation: HART command type Universal is used to read the device measurement values, allowing for retrieval of data such as temperature, pressure, or flow rate.

What is the purpose of the HART command 42?

A) To read the device diagnostics
B) To write to the device memory
C) To read the device measurement values
D) To write to the device status

Explanation: HART command 42 is used to read the device diagnostics, providing detailed information about the device’s performance and status.

What is the purpose of the HART command 32?

A) To write to the device configuration
B) To read the device status
C) To read the device measurement values
D) To write to the device memory

Explanation: HART command 32 is used to read the device status, providing information about the device’s operation and performance.

Which HART command can be used to configure the device address?

B) WRITE
D) CONFIGURE

Explanation: The ADDRESS command is used to configure the HART device address, which is a unique identifier used to differentiate the device from others on the HART network.

Which HART command is used to read the device status?

B) STATUS
C) DIAGNOSTICS
D) DEVICE

Explanation: The READ command is used to read the device status, which includes information such as device health, operating status, and process variables.

Which HART command is used to initiate a device calibration?

A) CALIBRATE
B) CONFIGURE
C) SETUP
D) VERIFY

Explanation: The CALIBRATE command is used to initiate a device calibration, which typically involves adjusting the device output signal to match a known input signal.

Which HART command is used to set up the device communication parameters?

A) COMM
B) PARAMETERS
C) CONFIGURE
D) SETUP

Explanation: The COMM command is used to set up the device communication parameters, which include information such as baud rate, parity, and address mode.

Which HART command is used to query the device’s model and serial number?

A) MODEL
B) SERIAL
C) DEVICE
D) IDENTIFY

Explanation: The DEVICE command is used to query the device’s model and serial number, which is important for identifying the device and tracking its use over time.

Which HART command is used to initiate a device self-test?

A) TEST
B) SELF
C) DIAGNOSTICS
D) VERIFY

Explanation: The DIAGNOSTICS command can also be used to initiate a device self-test, which tests the device’s internal components and verifies that it is operating correctly.

Which HART command is used to retrieve the device’s measurement range?

A) RANGE
B) MEASUREMENT
C) PARAMETERS
D) LIMITS

Explanation: The RANGE command is used to retrieve the device’s measurement range, which specifies the minimum and maximum values that the device can measure accurately.

Which HART command is used to initiate a device reset to factory defaults?

A) RESET
B) DEFAULT
C) INITIATE
D) CONFIGURE

Explanation: The RESET command is used to initiate a device reset to factory defaults, which will restore the device to its original configuration settings.

Which HART command is used to retrieve the device’s process variable?

A) PROCESS
B) VARIABLE
C) MEASUREMENT
D) PARAMETER

Explanation: The PROCESS command is used to retrieve the device’s process variable, which is the physical quantity being measured by the device (e.g. pressure, temperature, etc.).