40+ Automation Engineer Interview Questions and Answers for Freshers

There are various types of PLCs with different communication protocols.

• PLC types include Programmable Logic Controller, Compact Programmable Logic Controller, Modular Programmable Logic Controller, and more.

• Communication protocols include Modbus, Profibus, DeviceNet, Ethernet/IP, and more.

• The type of PLC and communication protocol used depends on the specific automation application.

• PLCs can communicate with other devices such as sensors, actuators, and HMIs using different pr...read more

2D refers to two-dimensional objects or images, while 3D refers to three-dimensional objects or images.

• 2D objects have length and width, while 3D objects have length, width, and depth

• 2D images are flat, while 3D images have depth and can be viewed from different angles

• 2D objects can be represented on a piece of paper or screen, while 3D objects require special software or equipment to view

• Examples of 2D objects include drawings, photographs, and paintings, while examples of 3...read more

NO and NC contacts are types of electrical switches. A motor is a device that converts electrical energy into mechanical energy. Servo and AC drives are motor controllers.

• NO (Normally Open) and NC (Normally Closed) contacts are types of electrical switches used in control circuits.

• A switch is an electrical component that can be used to make or break an electrical circuit.

• A motor is a device that converts electrical energy into mechanical energy to perform work.

• A servo drive i...read more

The code will output 10 because the variable i is accessed through a reference of class A.

• When a subclass object is assigned to a superclass reference, the superclass reference can only access the superclass members.

• In this case, even though the object is of class B, the variable i is accessed from class A.

• Output: 10

VFD selection depends on motor voltage, current, and power rating.

• Check motor nameplate data for voltage, current, and power rating

• Select VFD with compatible voltage and current rating

• Ensure VFD power rating is equal to or greater than motor power rating

• Consider additional features such as overload protection and communication protocols

• Consult manufacturer's specifications and guidelines

Sensors are devices that detect and respond to physical stimuli, converting them into electrical signals.

• Sensors can detect various physical properties such as temperature, pressure, light, sound, and motion.

• They work by converting the physical stimulus into an electrical signal that can be measured and analyzed.

• Different types of sensors use different mechanisms to detect physical stimuli, such as thermocouples for temperature, piezoelectric crystals for pressure, and photod...read more

Automation is the use of technology to perform tasks without human intervention.

• Automation involves the use of software, hardware, and other technologies to perform tasks.

• It can be used to increase efficiency, reduce errors, and save time and money.

• Examples include automated manufacturing processes, robotic assembly lines, and automated testing.

• Automation can also be used in industries such as finance, healthcare, and transportation.

• It requires careful planning, design, and i...read more

Analog outputs in 4-20 mA range are commonly used in industrial automation for their reliability, noise immunity, and ease of implementation.

• 4-20 mA signals are less susceptible to noise interference compared to voltage signals.

• The 4-20 mA range allows for easy detection of faults in the system, as a 0 mA signal indicates a broken wire or device failure.

• These signals can travel long distances without significant signal loss, making them ideal for industrial environments.

• Many ...read more

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction.

• Transformers are used to increase or decrease the voltage of an alternating current (AC) power supply.

• They are used in power distribution systems to step up the voltage for long-distance transmission and step it down for local distribution.

• Transformers are also used in electronic devices to isolate circuits, match impedances, and provide galvani...read more

Yes, I have knowledge of servo drives.

• I have experience in programming and troubleshooting servo drives.

• I am familiar with different types of servo drives such as AC and DC servo drives.

• I have worked with servo motors and have knowledge of their operation and control.

• I have experience in integrating servo drives with PLCs and other automation systems.

• I am familiar with industry standards and safety regulations related to servo drives.

Power factor is the ratio of real power to apparent power in an AC circuit.

• Power factor = Real power / Apparent power

• It is measured in a scale of 0 to 1 or 0 to 100%

• A power factor of 1 means all the power is being used efficiently

• A power factor of less than 1 means some power is being wasted

• Capacitors can be used to improve power factor

I use Selenium WebDriver to write automation test scripts.

• Selenium WebDriver is a popular tool for automating web applications

• It supports multiple programming languages like Java, Python, C#

• Allows interaction with web elements like buttons, text fields, etc.

• Can perform actions like click, type, select, etc. on web elements

Automation is the use of technology to perform tasks without human intervention.

• Increases efficiency and productivity

• Reduces errors and improves accuracy

• Saves time and money

• Allows for 24/7 operation

• Enables scalability and consistency

• Examples include robotic process automation, industrial automation, and test automation

PLCs are specialized computers used for industrial automation, while microcontrollers are small computers used in various electronic devices.

• PLCs are designed for controlling industrial processes, while microcontrollers are used in a wide range of electronic devices.

• PLCs are typically programmed using ladder logic or other specialized languages, while microcontrollers are programmed using C/C++ or other high-level languages.

• PLCs are more robust and reliable for industrial app...read more

VFD stands for Variable Frequency Drive.

• It is an electronic device that controls the speed of an AC motor by varying the frequency of the electrical supply to the motor.

• It is used to save energy and improve process control in industrial applications.

• VFDs are commonly used in HVAC systems, pumps, fans, and conveyors.

• They can also be used to control the speed of electric vehicles and wind turbines.

STP stands for Spanning Tree Protocol. It is a network protocol that ensures a loop-free topology in Ethernet networks.

• STP is used to prevent loops in Ethernet networks by blocking redundant paths.

• It works by electing a root bridge and calculating the shortest path to it for each network segment.

• STP uses Bridge Protocol Data Units (BPDUs) to exchange information between switches.

• If a link or switch fails, STP recalculates the topology to maintain network connectivity.

• STP has ...read more

Computer Numerical Control

• CNC stands for Computer Numerical Control

• It is a manufacturing process where pre-programmed computer software dictates the movement of factory tools and machinery

• CNC machines are used in various industries such as automotive, aerospace, and electronics

• Examples of CNC machines include CNC mills, lathes, and routers

Explanation of wait and exception handling in Selenium

• Wait in Selenium is used to pause the execution of the script for a certain amount of time

• There are two types of waits: Implicit and Explicit

• Exception handling in Selenium is used to handle unexpected errors during the execution of the script

• Common exceptions in Selenium include NoSuchElementException and TimeoutException

• Handling exceptions can be done using try-catch blocks or by using TestNG annotations

VFD is used to control the speed of AC motors and save energy.

• Variable frequency drive (VFD) is used to control the speed of AC motors.

• It saves energy by adjusting the motor speed to match the load requirements.

• VFDs also provide soft start and stop, reducing mechanical stress on the motor.

• They can improve process control and reduce maintenance costs.

• Examples of VFD applications include HVAC systems, pumps, and conveyors.

Program to remove special characters from a string

• Iterate through each character in the string

• Check if the character is a special character using regex or a predefined list

• If it is not a special character, add it to a new string

• Return the new string without special characters

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

• Ohm's law is a fundamental law of electrical engineering.

• It states that the current through a conductor is directly proportional to the voltage across it.

• The proportionality constant is the resistance of the conductor.

• The formula for Ohm's law is I = V/R, where I is the current, V is the voltage, and R is the resistance.

• Ohm's law is used to ca...read more

SCADA stands for Supervisory Control and Data Acquisition. It is a system used for monitoring and controlling industrial processes.

• SCADA systems are used in various industries such as oil and gas, water treatment, and manufacturing.

• They collect data from sensors and other devices and display it in a graphical interface for operators to monitor.

• SCADA systems can also be used to control processes remotely, such as turning on or off pumps or valves.

• They often include features su...read more

Pneumatic cylinder uses compressed air to create linear motion.

• Compressed air is supplied to one end of the cylinder, which pushes the piston and creates linear motion.

• The other end of the cylinder is vented to the atmosphere.

• The piston is connected to a load, which moves in response to the linear motion.

• Pneumatic cylinders are commonly used in automation and manufacturing industries.

• They are preferred over hydraulic cylinders due to their lower cost and simpler design.

PLC programming is the process of creating and editing programs for programmable logic controllers to automate industrial processes.

• PLC programming involves writing logic for controlling machinery and processes

• It uses ladder logic, function block diagrams, or structured text languages

• Programs are typically written using specialized software like Siemens TIA Portal or Allen-Bradley Studio 5000

• PLC programs can be used in various industries such as manufacturing, automotive, and...read more

I have learned multiple programming languages including Python, Java, and C++.

• Python - used for automation scripts and data analysis

• Java - used for developing applications and web services

• C++ - used for system programming and performance-critical applications

PLC stands for Programmable Logic Controller. It is an industrial computer used to automate processes and control machinery.

• PLCs are highly reliable and can operate in harsh environments

• They can be easily programmed and reprogrammed to accommodate changes in the manufacturing process

• PLCs can communicate with other devices and systems, allowing for seamless integration

• They can improve efficiency and productivity while reducing costs

• Examples of PLC applications include assembly...read more

final, finally, and finalize are related keywords in Java with different meanings and usage.

• final is a keyword used to declare constants, variables, methods, and classes that cannot be changed or extended.

• finally is a block used in exception handling to ensure a piece of code is always executed, whether an exception is thrown or not.

• finalize is a method used in Java to perform cleanup operations on an object before it is garbage collected.

There are several PLC names available in the market for automation engineers.

• Siemens SIMATIC S7

• Allen-Bradley ControlLogix

• Schneider Electric Modicon

• Mitsubishi Electric MELSEC

• ABB AC500

• Omron CJ2M

• Beckhoff TwinCAT

• Rockwell Automation CompactLogix

Instrumentation refers to the use of instruments or devices to measure, control, or monitor a process or system.

• Instruments are used to gather data about a process or system

• Data is then used to control or monitor the process or system

• Examples include sensors, gauges, and meters

• Instrumentation is used in various industries such as manufacturing, energy, and transportation

Automation refers to the use of technology to perform tasks with minimal human intervention.

• Automation involves using software or hardware to perform repetitive tasks automatically

• It can increase efficiency, accuracy, and consistency in processes

• Examples include automated testing in software development, robotic process automation in business processes, and smart home devices

PLC is a programmable logic controller used for industrial automation. SCADA is a supervisory control and data acquisition system.

• PLC is a digital computer used to control industrial processes

• It receives inputs from sensors and controls outputs to actuators

• SCADA is a software system used to monitor and control industrial processes

• It collects data from PLCs and displays it to operators

• Examples of PLC applications include manufacturing, transportation, and energy

• Examples of SCA...read more

Program to compare two lists of strings

• Iterate through both lists and compare each element

• Use a loop to check if each element in list 1 is present in list 2

• Consider using built-in functions like 'equals' or 'contains' for comparison

Complex device drivers are necessary to enable communication between the operating system and hardware devices.

• Complex device drivers are needed for devices that require advanced functionality or features.

• They provide a way for the operating system to communicate with the hardware device.

• Complex device drivers often include additional software components to manage the device's capabilities.

• Examples include graphics card drivers, network card drivers, and sound card drivers.

Panel design refers to the process of designing and creating electrical control panels for industrial automation systems.

• Panel design involves selecting appropriate components such as circuit breakers, relays, and switches.

• The design must also consider factors such as wiring, labeling, and safety standards.

• CAD software is often used to create detailed panel layouts and schematics.

• Examples of industrial automation systems that require panel design include manufacturing lines, ...read more

Framework and TestNG are essential concepts in automation testing.

• Framework is a set of guidelines, coding standards, and best practices to develop test scripts.

• TestNG is a testing framework that supports various annotations, test sequencing, and parallel execution.

• TestNG provides features like grouping, parameterization, and reporting to enhance test automation.

• Framework and TestNG together provide a robust and scalable automation solution.

Oops concepts are fundamental to Java programming and include inheritance, polymorphism, encapsulation, and abstraction.

• Inheritance allows a class to inherit properties and methods from a parent class.

• Polymorphism allows objects to take on multiple forms and behave differently based on their context.

• Encapsulation hides the implementation details of a class and only exposes necessary information.

• Abstraction allows for the creation of abstract classes and interfaces that can be...read more

PLC scan time is the time taken by a PLC to complete one cycle of scanning.

• PLC scan time is the time taken by a PLC to read inputs, execute the program, and update outputs.

• It is important to keep the scan time as low as possible to ensure efficient operation of the system.

• Factors affecting scan time include the complexity of the program, the number of I/O points, and the speed of the processor.

• Scan time can be reduced by optimizing the program, using faster processors, and re...read more