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

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

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

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.

Yes, I am familiar with preventive maintenance jobs.

• Preventive maintenance involves regularly scheduled inspections, cleaning, and repairs to prevent equipment breakdowns.

• I have experience performing preventive maintenance on various types of instrumentation equipment, such as calibrators, transmitters, and controllers.

• Examples of preventive maintenance tasks I have performed include checking for leaks, replacing worn parts, and testing equipment performance.

• I understand the ...read more

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

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

Thermocouple range refers to the temperature range within which a thermocouple can accurately measure temperature.

• Thermocouple range varies depending on the type of thermocouple used.

• Common thermocouple types include J, K, T, E, and N.

• For example, a type K thermocouple has a range of -200 to 1350 degrees Celsius.

• It is important to select the appropriate thermocouple type for the temperature range being measured.

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

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

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

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.

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

RTD and thermocouples are essential for temperature measurement; calibration ensures accuracy and troubleshooting resolves issues.

• RTD (Resistance Temperature Detector) uses resistance change to measure temperature; calibration involves comparing against a standard.

• Thermocouples generate a voltage based on temperature difference; calibration requires a reference junction and known temperature points.

• Common troubleshooting for RTDs includes checking for broken wires or poor con...read more

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

Transmitters output signals, while I to P relays convert current to pressure for control systems.

• Transmitters typically output a standardized signal, such as 4-20 mA or 0-10 V.

• An example of a transmitter is a pressure transmitter that sends a 4-20 mA signal proportional to the measured pressure.

• I to P relays convert an input current signal (e.g., 4-20 mA) into a proportional pneumatic output pressure.

• For instance, a 4 mA input might correspond to 0 psi, while a 20 mA input co...read more

Transmitters convert physical parameters into signals; I to P relays convert current to pressure for control systems.

• Transmitters measure variables like temperature, pressure, or flow and send signals to control systems.

• I to P relays convert a current input (4-20 mA) into a proportional pneumatic output (3-15 psi).

• Example: A temperature transmitter sends a 4-20 mA signal to a control system based on temperature readings.

• I to P relays are used in pneumatic control systems to r...read more

Thermocouples measure temperature using the voltage generated by two different metals, while RTDs use the change in resistance of a metal wire.

• Thermocouples use two different metals to generate a voltage proportional to temperature, while RTDs use a metal wire with a known resistance-temperature relationship.

• Thermocouples are typically less accurate but have a wider temperature range compared to RTDs.

• RTDs are more stable and accurate over a narrow temperature range, making th...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 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