Petrofac Supervisor -Senior Instrument Technician Interview Questions and Answers

Instruments used in control and instrumentation include sensors, transmitters, controllers, and actuators.

• Sensors: devices that detect changes in physical properties and convert them into electrical signals (e.g. temperature sensors, pressure sensors)

• Transmitters: devices that send signals from sensors to controllers (e.g. signal transmitters)

• Controllers: devices that receive signals from sensors and transmitters to re...read more

PID loop is a control system feedback mechanism used in industrial processes to maintain desired setpoints.

• PID stands for Proportional, Integral, Derivative

• Proportional term responds to the current error

• Integral term corrects past errors

• Derivative term predicts future errors

• PID controller continuously calculates an error value as the difference between a desired setpoint and a measured process variable

• Example: PID loop...read more

Electromagnetic flowmeter measures flow rate by using Faraday's law of electromagnetic induction.

• Electromagnetic flowmeter is based on the principle of Faraday's law of electromagnetic induction.

• It consists of a flow tube, electrodes, and a magnetic field.

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

• The electrodes detect the voltage and the magnetic field ens...read more

Interacting systems have feedback loops and can influence each other's behavior, while non-interacting systems operate independently.

• Interacting systems have mutual dependencies and can affect each other's inputs, outputs, or behavior.

• Non-interacting systems operate independently and do not have any influence on each other.

• Interacting systems often involve feedback loops where the output of one system affects the input...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 l...read more

A PLC panel wiring diagram is a visual representation of the electrical connections and components in a programmable logic controller panel.

• A PLC panel wiring diagram shows the layout and connections of various components such as power supplies, input/output modules, relays, and sensors.

• It helps technicians understand how the electrical signals flow within the panel and how different devices are interconnected.

• The diag...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.

• Exam...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 det...read more

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...read more