20+ Instrument Engineer Interview Questions and Answers for Freshers

Questions related to general working ranges, temperature sensors, and purpose of instruments for Instrumentation Engineer position.

• General current and voltage working ranges of instruments depend on the type of instrument and its application.

• Temperature sensors types include thermocouples, RTDs, thermistors, and infrared sensors.

• Thermocouples work on the principle of Seebeck effect, while RTDs work on the principle of change in resistance with temperature.

• Instruments may or m...read more

Calibration of instruments ensures accuracy and reliability of measurements.

• Ensures accuracy and reliability of measurements

• Helps in maintaining quality standards

• Prevents errors in readings

• Increases instrument lifespan

• Compliance with regulations and standards

• Examples: calibrating a thermometer for accurate temperature readings, calibrating a pressure gauge for precise pressure measurements

3Wire RTD is preferred over 2Wire RTD due to better accuracy and noise reduction.

• 3Wire RTD compensates for lead wire resistance, resulting in more accurate temperature measurements.

• 3Wire RTD provides better noise reduction compared to 2Wire RTD.

• 3Wire RTD allows for easier implementation of temperature compensation techniques.

• 2Wire RTD is more susceptible to lead wire resistance errors and noise interference.

Half duplex communication allows data to be transmitted in both directions, but not simultaneously.

• Data can be sent and received, but not at the same time

• Common examples include walkie-talkies and CB radios

• Requires a switch between sending and receiving modes

There are different types of calibration that can be done depending on the instrument being used.

• Zero calibration

• Span calibration

• Linearity calibration

• Sensitivity calibration

• Temperature calibration

• Humidity calibration

• Pressure calibration

AC drives use alternating current to control the speed of an electric motor, while DC drives use direct current for the same purpose.

• AC drives are more commonly used due to their ability to provide variable speed control and energy efficiency.

• DC drives are simpler in design and are often used in applications where precise speed control is required, such as in cranes or elevators.

• AC drives are typically more cost-effective and easier to maintain compared to DC drives.

• Examples ...read more

Instrumentation is the science and art of measurement and control of process variables within a production or manufacturing area.

• Instrumentation involves the use of sensors, transmitters, controllers, and final control elements to monitor and control processes.

• Examples of instrumentation include pressure gauges, temperature sensors, flow meters, and control valves.

• Instrumentation plays a crucial role in ensuring the efficiency, safety, and quality of industrial processes.

RTD stands for Resistance Temperature Detector. It is a temperature sensor that operates on the principle that the resistance of a metal increases with temperature.

• RTD is commonly used in industrial applications for temperature measurement.

• Platinum is a popular material for RTDs due to its high accuracy and stability.

• RTDs are known for their high accuracy and repeatability compared to other temperature sensors.

• RTDs are commonly used in industries such as oil and gas, chemical...read more

Various types of communication protocols include Modbus, Profibus, HART, Foundation Fieldbus, and Ethernet/IP.

• Modbus - commonly used in industrial automation

• Profibus - used in process automation

• HART - for smart field devices

• Foundation Fieldbus - for process control

• Ethernet/IP - for industrial Ethernet communication

Hydraulic pressure is the force exerted by a fluid in a closed system, while pneumatic pressure is the force exerted by a gas in a closed system.

• Hydraulic pressure is generated by the movement of a liquid, such as oil, in a confined space.

• Pneumatic pressure is created by the compression of a gas, such as air, in a closed system.

• Both types of pressure are used in various industrial applications, such as in hydraulic systems for heavy machinery or pneumatic systems for air tool...read more

Standard maintenance procedures for instruments involve regular inspections, calibrations, and repairs to ensure optimal performance.

• Regularly inspect instruments for any signs of wear or damage

• Calibrate instruments according to manufacturer's guidelines

• Perform routine maintenance tasks such as cleaning and lubricating

• Keep detailed records of maintenance activities for each instrument

• Train staff on proper instrument maintenance procedures

• Schedule preventive maintenance to avo...read more

Automation is the use of technology to control and monitor processes, reducing human intervention.

• Automation involves the use of control systems to operate equipment and machinery.

• It aims to increase efficiency, productivity, and safety by minimizing human error.

• Examples include automated manufacturing processes, smart home systems, and self-driving cars.

Network topology types refer to the layout of a computer network and how different devices are connected.

• Common types include star, bus, ring, mesh, and hybrid topologies

• Star topology has a central hub with all devices connected to it

• Bus topology uses a single cable to connect all devices in a linear fashion

• Ring topology connects devices in a circular manner

• Mesh topology has each device connected to every other device

• Hybrid topology is a combination of two or more different t...read more

Supervisory Control and Data Acquisition

• SCADA stands for Supervisory Control and Data Acquisition

• It is a system used for monitoring and controlling industrial processes

• SCADA systems are commonly used in industries such as power plants, water treatment facilities, and manufacturing plants

A dp transmitter is a device used to measure the difference in pressure between two points in a system.

• Measures differential pressure in a system

• Consists of two pressure sensors connected to a diaphragm

• Used in industries like oil and gas, chemical, and pharmaceuticals

A flow transmitter is a device used to measure the flow rate of a fluid in a pipeline or system.

• Flow transmitters can be used in various industries such as oil and gas, water treatment, and pharmaceuticals.

• They typically work by measuring the velocity of the fluid and calculating the flow rate based on the cross-sectional area of the pipe.

• Common types of flow transmitters include electromagnetic, ultrasonic, and thermal mass flow meters.

• Flow transmitters are essential for mon...read more

A control valve is a device used to regulate the flow of a fluid in a process system by varying the size of the flow passage.

• Control valves are essential components in process control systems.

• They can be operated manually or automatically.

• Control valves can be used to control variables such as flow rate, pressure, temperature, and level.

• Examples of control valves include globe valves, butterfly valves, and ball valves.

Calibration is the process of comparing measurements of an instrument to a known standard to ensure accuracy.

• Calibration involves adjusting the instrument to match the standard.

• It is important for maintaining accuracy and reliability of instruments.

• Calibration is typically done regularly to ensure consistent performance.

• Examples include calibrating a thermometer to ensure accurate temperature readings.

• Calibration may also involve adjusting settings or parameters of an instrum...read more

Control on frequency of dialogue is important to ensure effective communication and avoid overwhelming the listener.

• Be mindful of the pace at which you speak

• Pause periodically to allow the listener to process information

• Avoid speaking too fast or too slow

• Adjust your tone and volume to maintain engagement

A thermocouple is a temperature sensor that consists of two different metals joined together at one end.

• Consists of two different metals joined together at one end

• Generates a voltage proportional to the temperature difference between the two ends

• Commonly used in industrial temperature measurement applications

A transmeter is a device used to measure and transmit data from sensors to a control system.

• Transmeters are commonly used in industrial processes to monitor variables such as temperature, pressure, flow, and level.

• They convert the physical quantity being measured into an electrical signal, which is then transmitted to a control system for monitoring and control.

• Examples of transmeters include pressure transmitters, temperature transmitters, flow transmitters, and level transm...read more

Resistance is the opposition to the flow of electric current in a circuit.

• Resistance is measured in ohms (Ω).

• It is caused by the collisions of electrons with atoms in a conductor.

• Higher resistance leads to lower current flow in a circuit.

• Examples of resistors include light bulbs, heating elements, and electronic components.

• Ohm's Law states that V = I * R, where V is voltage, I is current, and R is resistance.

Load cell specification includes capacity, accuracy, material, and output signal.

• Capacity: Specifies the maximum load the cell can measure, usually in pounds or kilograms.

• Accuracy: Indicates how precise the load cell can measure the load, often expressed as a percentage of full scale.

• Material: Determines the durability and compatibility of the load cell with the environment it will be used in.

• Output Signal: Describes the type of signal the load cell produces, such as analog v...read more

Flow meters are devices used to measure the flow rate of a fluid in a pipe or conduit.

• Differential pressure flow meters

• Ultrasonic flow meters

• Magnetic flow meters

• Vortex flow meters

• Coriolis flow meters

• Turbine flow meters

• Positive displacement flow meters

AB PLC is a programmable logic controller manufactured by Allen Bradley.

• AB PLCs are widely used in industrial automation for controlling machinery and processes.

• They come in various models such as CompactLogix, ControlLogix, MicroLogix, etc.

• AB PLCs use ladder logic programming for creating control logic.

• They have digital and analog input/output modules for interfacing with sensors and actuators.

• AB PLCs can communicate with other devices using protocols like Ethernet/IP, Modbu...read more