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

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.

Lead resistance is the resistance encountered in the electrical leads connecting a sensor or instrument to a measuring device.

• Lead resistance can affect the accuracy of measurements by introducing additional resistance in the circuit.

• It is important to account for lead resistance when designing and calibrating instrumentation systems.

• Lead resistance can be minimized by using high-quality, low-resistance leads.

• Examples of instruments where lead resistance is a concern include ...read more

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

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

Pressure, temperature, flow, and level are key parameters in instrumentation engineering.

• Pressure is the force exerted by a fluid on its container, measured in units like psi or bar.

• Temperature is the degree of hotness or coldness of a substance, measured in units like Celsius or Fahrenheit.

• Flow is the rate at which a fluid passes through a system, measured in units like liters per minute.

• Level is the height of a substance in a container, measured in units like meters or feet...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

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

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 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

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.

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

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