100+ Instrumentation Technician Interview Questions and Answers

Precautions are necessary to ensure safe and efficient plant operation.

• Regular maintenance of equipment and machinery

• Proper training and certification of personnel

• Strict adherence to safety protocols and procedures

• Regular inspections and audits to identify potential hazards

• Effective communication and coordination among team members

• Use of personal protective equipment (PPE) as required

• Emergency response planning and drills

• Proper handling and storage of hazardous materials

• Envir...read more

Knowledge of various transmitters, pressure switches, gauges, level switches, DCS and PLC working is required for instrumentation technician role.

• Must have knowledge of calibrations, troubleshooting and maintenance work for PT, LT, FT and DPT transmitters

• Should be familiar with calibrations and troubleshooting of pressure switches, pressure gauges and level switches

• Well-versed with DCS and PLC working

• Ability to read and interpret technical drawings and schematics

• Familiarity w...read more

The PLCs used in our plant are Siemens S7-300 and Allen Bradley ControlLogix. The DCS is Honeywell Experion.

• Siemens S7-300 and Allen Bradley ControlLogix are the PLCs used in our plant

• Honeywell Experion is the DCS used in our plant

There are three types of vibration in the field: axial, radial, and tangential.

• Axial vibration occurs parallel to the axis of rotation.

• Radial vibration occurs perpendicular to the axis of rotation.

• Tangential vibration occurs at a right angle to both axial and radial vibration.

• Vibration analysis is used to detect and diagnose problems in rotating machinery.

• Excessive vibration can lead to premature failure of bearings, gears, and other components.

The primary element for temperature measurement is a thermometer.

• A thermometer is a device used to measure temperature.

• It consists of a temperature sensor, such as a bulb filled with mercury or a thermocouple, and a scale to display the temperature.

• Thermometers can be used in various industries and applications, including healthcare, weather forecasting, and industrial processes.

• Examples of thermometers include mercury-in-glass thermometers, digital thermometers, and infrared...read more

There are several types of pressure gauges including Bourdon tube, diaphragm, capsule, and bellows gauges.

• Bourdon tube gauges are the most common and measure pressure through the movement of a curved tube.

• Diaphragm gauges use a flexible membrane to measure pressure.

• Capsule gauges use two diaphragms welded together to measure pressure.

• Bellows gauges use a series of convolutions to measure pressure.

• Other types of pressure gauges include digital gauges and differential pressure ...read more

Transmitter, RTD, thermocouple, control valve, and actuators are all important components in instrumentation technology.

• Transmitter is a device that converts a physical parameter into an electrical signal.

• RTD (Resistance Temperature Detector) is a type of temperature sensor that measures temperature by detecting changes in electrical resistance.

• Thermocouple is another type of temperature sensor that measures temperature by detecting changes in voltage.

• Control valve is a devic...read more

RTD stands for Resistance Temperature Detector and thermocouple is a temperature sensor made of two different metals.

• RTD measures temperature by detecting changes in electrical resistance of a metal wire as temperature changes.

• Thermocouple measures temperature by detecting changes in voltage as temperature changes.

• RTD is more accurate and stable than thermocouple.

• Thermocouple is cheaper and can measure a wider range of temperatures than RTD.

• RTD is commonly used in industries ...read more

An anti-surge valve is a control valve used in a compressor system to prevent surge and maintain stable operation.

• An anti-surge valve is typically installed in the discharge line of a compressor.

• It is designed to protect the compressor from surge, which is a phenomenon of unstable flow and pressure that can cause damage to the compressor.

• The valve opens or closes based on the compressor's operating conditions to maintain a safe flow rate and prevent surge.

• It works in conjunct...read more

The qualification for an Instrumentation Technician typically includes a degree or diploma in instrumentation technology or a related field.

• A degree or diploma in instrumentation technology or a related field is usually required.

• Knowledge of electrical and electronic systems is important.

• Experience with calibration and troubleshooting of instruments is often necessary.

• Familiarity with industry standards and regulations is beneficial.

• Strong analytical and problem-solving skill...read more

A control valve is a device used to regulate the flow of fluid or gas in a system. There are several types of control valves.

• Control valves are used in various industries such as oil and gas, chemical, and power generation.

• The most common types of control valves are globe valves, ball valves, butterfly valves, and diaphragm valves.

• Control valves can be operated manually or automatically through an actuator.

• They can control the flow rate, pressure, temperature, and level of a ...read more

Straight lengths are important in installing vortex orifice devices to ensure accurate flow measurement.

• Straight lengths help to stabilize the flow profile before it reaches the device

• They prevent turbulence and eddies that can affect the accuracy of the measurement

• The length required depends on the type of device and the flow conditions

• For example, a vortex flow meter may require 10 diameters of straight pipe upstream and 5 diameters downstream

• Proper installation ensures rel...read more

Input devices of PLC are sensors, switches, and meters. Output devices are actuators, relays, and valves.

• Input devices are used to collect data from the environment and send it to the PLC for processing.

• Output devices are used to control the environment based on the processed data from the PLC.

• Examples of input devices include temperature sensors, pressure switches, and flow meters.

• Examples of output devices include motors, solenoid valves, and indicator lights.

P&ID is a diagram that shows the interconnection of process equipment and instrumentation. Automation and control system is a system that controls and monitors industrial processes. Open loop and closed loop systems are used for different purposes. PLC, SCADA, and DCs are used for automation and control.

• P&ID stands for Piping and Instrumentation Diagram

• Automation and control system is used to control and monitor industrial processes

• Open loop system is used for simple processe...read more

The square root output is used for flow in dp tx to linearize the relationship between flow and pressure.

• Square root output is used to compensate for the non-linear relationship between flow and pressure.

• It helps to convert the pressure measurement into a linear flow measurement.

• This is done because the pressure drop across an orifice or a flow element is proportional to the square of the flow rate.

• By taking the square root of the pressure measurement, the resulting output be...read more

To check zero dp type transmitters, follow these steps:

• Isolate the transmitter from the process

• Ensure the transmitter is at atmospheric pressure

• Verify that the output signal is reading zero

• Adjust the zero if necessary

• Reconnect the transmitter to the process and verify the output signal

Types of control valves, pressure parameters, types of gauges, SCADA and PLC full forms.

• Types of control valves include globe, butterfly, ball, and diaphragm valves.

• Pressure parameters include gauge pressure, absolute pressure, and differential pressure.

• Types of gauges include pressure gauges, temperature gauges, and flow meters.

• SCADA stands for Supervisory Control and Data Acquisition.

• PLC stands for Programmable Logic Controller.

A thermocouple is a temperature sensor made of two different metals that produce a voltage proportional to the temperature difference.

• Consists of two dissimilar metal wires joined at one end

• Produces a voltage when exposed to a temperature gradient

• Used to measure temperature in various industries such as HVAC, automotive, and manufacturing

• Common types include J, K, and T thermocouples

• Requires a reference junction to accurately measure temperature

Yes, I have experience working with gas turbines.

• I have worked with gas turbines in my previous job as an instrumentation technician.

• I am familiar with the maintenance and troubleshooting of gas turbines.

• I have experience in calibrating and testing gas turbine sensors and instruments.

• I have knowledge of the safety protocols and regulations related to gas turbines.

As an Instrument Technician, I have experience in calibrating and maintaining various instruments such as furnaces, operated by DCS or PLC.

• I have experience in calibrating and maintaining instruments such as pressure gauges, temperature sensors, flow meters, and level transmitters.

• I am familiar with DCS and PLC systems and can troubleshoot any issues that may arise.

• I have worked with furnaces and have experience in maintaining and repairing them.

• I am knowledgeable in safety p...read more

Instrumentation is the science and art of measuring and controlling variables in a process or system.

• Instrumentation involves the use of various instruments and devices to measure and monitor physical quantities such as temperature, pressure, flow rate, and level.

• It also includes the control and automation of processes using instruments like sensors, transmitters, controllers, and actuators.

• Instrumentation technicians are responsible for installing, calibrating, maintaining, ...read more

A booster relay is an electrical device used to amplify or boost a signal.

• It is commonly used in control circuits to increase the strength of a signal

• It can be used to control high voltage or high current devices

• Examples include motor starters, solenoid valves, and lighting circuits

Control valve gland packing is a sealing material used to prevent leakage around the valve stem. There are mainly two types of gland packing - compression packing and mechanical packing.

• Control valve gland packing is a sealing material placed around the valve stem to prevent leakage.

• Compression packing is made of materials like graphite, PTFE, or synthetic fibers and is compressed around the stem using a gland follower.

• Mechanical packing uses a series of rings that are compre...read more

The gap while fixing the vibration probes refers to the distance between the probe tip and the target surface.

• The gap should be carefully adjusted to ensure accurate readings.

• Common gap sizes range from 0.5mm to 2mm depending on the application.

• Using shims or spacers can help maintain a consistent gap.

• Regularly checking and adjusting the gap is important for proper functioning of the probes.

Control valve calibration involves adjusting the valve to ensure it operates correctly and accurately.

• Determine the valve's range and characteristics

• Connect the valve to a calibration device

• Adjust the valve's position to match the desired output

• Verify the valve's accuracy and repeatability

• Document the calibration process and results

PLC stands for Programmable Logic Controller and DCS stands for Distributed Control System.

• PLC is a digital computer used for automation of electromechanical processes.

• DCS is a control system used to control and monitor industrial processes.

• PLC is used in discrete manufacturing industries while DCS is used in continuous process industries.

• PLC is programmed using ladder logic while DCS is programmed using function blocks.

• Examples of PLC include Siemens S7-1200 and Allen-Bradle...read more

Magnetic flowmeters, also known as mag flowmeters, measure fluid flow by using Faraday's law of electromagnetic induction.

• Mag flowmeters work based on the principle of Faraday's law of electromagnetic induction.

• They consist of a pipe with a magnetic field and electrodes on the sides.

• When a conductive fluid flows through the pipe, it generates a voltage proportional to the flow rate.

• The electrodes measure this voltage and convert it into a flow rate reading.

• Mag flowmeters are ...read more

Pressure unit is a measurement of force per unit area exerted on a surface.

• Pressure unit measures the amount of force applied to a given area.

• It is commonly used in various fields such as physics, engineering, and meteorology.

• The SI unit for pressure is Pascal (Pa), which is equal to one Newton per square meter (N/m²).

• Other commonly used pressure units include pounds per square inch (psi), atmospheres (atm), and bar.

• For example, tire pressure is often measured in psi, while a...read more

Calibration procedures for various instruments including air flow, control valves, gate valves, dampers, and nozzle valves.

• Calibration involves comparing the readings of an instrument to a known standard.

• Air flow can be calibrated using a pitot tube or hot wire anemometer.

• Control valves can be calibrated by adjusting the position of the valve stem.

• Gate valves can be calibrated by measuring the torque required to turn the valve.

• Dampers can be calibrated by measuring the angle ...read more

The number of parts in an actuator varies depending on the type and model.

• Actuators can have as few as two parts or as many as several dozen.

• Common parts include a motor, gears, a control board, and a housing.

• Additional parts may include sensors, limit switches, and feedback mechanisms.

• The number of parts can also vary depending on the application and specific requirements.

There are several types of drawings used in instrumentation.

• Piping and Instrumentation Diagrams (P&IDs)

• Electrical Schematics

• Loop Diagrams

• Wiring Diagrams

• Process Flow Diagrams (PFDs)

• Isometric Drawings

The orifice tab is provided to accurately measure the flow rate of a fluid through a pipe.

• The orifice tab creates a pressure drop across the orifice plate, which is directly proportional to the flow rate.

• By measuring the pressure drop, the flow rate can be calculated using the Bernoulli's equation or the Orifice Equation.

• The orifice tab helps in controlling and regulating the flow of fluids in various industries such as oil and gas, chemical, and water treatment.

• It is commonl...read more

I handle work under pressure by staying organized, prioritizing tasks, and maintaining a positive attitude.

• Stay organized by creating to-do lists and setting realistic deadlines

• Prioritize tasks based on urgency and importance

• Maintain a positive attitude by taking breaks, practicing deep breathing, and seeking support from colleagues

• Practice effective time management techniques to ensure tasks are completed efficiently

Control valves are used to regulate the flow of fluids in a process system.

• Control valves can be classified into different types such as globe valves, butterfly valves, ball valves, and plug valves.

• The working principle of control valves involves the use of a valve body, actuator, and positioner.

• The valve body contains a flow passage that can be opened or closed to control the flow of fluid.

• The actuator is responsible for moving the valve stem to open or close the valve.

• The p...read more

RTD stands for Resistance Temperature Detector.

• RTD is a type of temperature sensor that measures temperature by correlating the resistance of the RTD element with temperature.

• It is commonly used in industrial applications where accuracy and stability are important.

• RTDs are made of pure metals or alloys with a known temperature-resistance relationship, such as platinum.

• They provide accurate and reliable temperature measurements over a wide temperature range.

• RTDs are commonly u...read more

I have experience working with AWS, Azure, and Google Cloud Platform.

• Worked with AWS services such as EC2, S3, RDS, and Lambda

• Familiar with Azure services like Virtual Machines, Blob Storage, and Azure Functions

• Utilized Google Cloud Platform services including Compute Engine, Cloud Storage, and BigQuery

Flow meters are devices used to measure the flow rate of a fluid or gas.

• Flow meters are commonly used in industries such as oil and gas, water treatment, and manufacturing.

• They can measure flow rates in various units such as liters per minute, cubic meters per hour, or gallons per minute.

• Different types of flow meters include electromagnetic, ultrasonic, turbine, and differential pressure flow meters.

• Flow meters can be used to monitor and control the flow of fluids in pipelin...read more

Instrumentation equipment refers to devices used to measure, control, and monitor various parameters in industrial processes.

• Instruments like pressure gauges, flow meters, and temperature sensors are commonly used in instrumentation.

• Control valves and actuators are used to regulate the flow of fluids or gases.

• Programmable Logic Controllers (PLCs) are used for automation and control of processes.

• Analytical instruments like pH meters and gas chromatographs are used for chemical...read more

Yes, there are standards governing types of thermocouple.

• The International Electrotechnical Commission (IEC) and the American National Standards Institute (ANSI) have established standards for thermocouples.

• These standards define the types of thermocouples, their temperature ranges, and their accuracy.

• Examples of thermocouple types include Type J, Type K, Type T, and Type E.

• Each type has a different combination of metals used in the thermocouple wires, which affects its tempe...read more

A transmitter is a device used in instrumentation to convert a physical measurement into an electrical signal.

• Transmitters are commonly used in industries such as oil and gas, chemical, and power plants.

• They are used to measure variables such as pressure, temperature, flow rate, level, and pH.

• Transmitters typically consist of a sensing element, signal conditioning circuitry, and an output signal.

• The sensing element detects the physical measurement and converts it into an elec...read more

Proximity refers to the closeness or nearness of an object to another object or a sensor.

• Proximity is often measured using sensors such as infrared, ultrasonic, or capacitive sensors.

• Proximity sensors are commonly used in industrial automation, robotics, and automotive applications.

• Examples of proximity sensors include photoelectric sensors, inductive sensors, and magnetic sensors.

• Proximity sensors can detect the presence or absence of an object, as well as its distance and p...read more

Control valve positioner is a device used to control the position of a control valve based on the input signal.

• Control valve positioner ensures accurate control of the valve position.

• It receives a control signal from the controller and adjusts the valve position accordingly.

• The positioner compares the valve position with the desired position and sends a pneumatic signal to the actuator to adjust the valve accordingly.

• There are different types of control valve positioners such...read more

Archimedes principle states that the buoyant force on an object is equal to the weight of the fluid displaced by the object.

• Buoyant force is the upward force exerted on an object submerged in a fluid.

• The weight of the fluid displaced by the object is equal to the buoyant force.

• Archimedes principle is used to explain why objects float or sink in fluids.

• Example: A ship floats on water because the weight of the water it displaces is equal to the weight of the ship.

Calibration is the process of adjusting and verifying the accuracy of a measuring instrument or tool.

• Calibration ensures that the instrument or tool is providing accurate and reliable measurements.

• It involves comparing the readings of the instrument to a known standard or reference.

• Adjustments are made to the instrument to bring its readings in line with the standard.

• Calibration is important in industries such as manufacturing, engineering, and healthcare.

• Examples of instrume...read more

A control valve is a device used to regulate the flow of fluid or gas in a process system.

• Control valves are commonly used in industries such as oil and gas, chemical, and power plants.

• They can be operated manually or automatically through an electrical or pneumatic signal.

• Control valves consist of a valve body, actuator, and positioner.

• They can control variables such as flow rate, pressure, temperature, and level.

• Examples of control valves include globe valves, butterfly val...read more

As an instrumentation technician, I am skilled in troubleshooting, repairing, calibrating, and testing various types of process control instruments.

• I have experience in identifying and diagnosing problems with instruments and determining the appropriate solutions.

• I am proficient in repairing and replacing faulty components and ensuring that instruments are functioning properly.

• I am knowledgeable in calibrating instruments to ensure accurate readings and maintaining proper doc...read more

A pressure switch is used to monitor and control pressure levels in a system.

• Connect the pressure switch to the system using appropriate fittings

• Set the switch to the desired pressure range

• Calibrate the switch if necessary

• Monitor the switch for any changes in pressure and adjust as needed