300+ Automation Engineer Interview Questions and Answers

I have used various types of sensors with PLC.

• Proximity sensors

• Temperature sensors

• Pressure sensors

• Level sensors

• Flow sensors

• Position sensors

• Photoelectric sensors

• Ultrasonic sensors

• Humidity sensors

• Gas sensors

Use Java Selenium code to validate new and old prices of mobile phones on Amazon.

• Use WebDriver to open Amazon website

• Locate the elements for new and old prices using XPath or CSS selectors

• Get the text of both elements and compare them to validate

Different protocols used in automation engineering

• Modbus

• Profibus

• DeviceNet

• Ethernet/IP

• CANopen

• AS-Interface

• Foundation Fieldbus

• HART

• BACnet

• LonWorks

Xceptor is used for data extraction and Automation Anywhere is used for automating repetitive tasks.

• Xceptor is used in financial services for data extraction and processing.

• Automation Anywhere is used for automating repetitive tasks like data entry, invoice processing, etc.

• Xceptor can be used for reconciling trades and managing risk in financial services.

• Automation Anywhere can be used for automating HR processes like onboarding and offboarding employees.

• Xceptor can be used f...read more

Lists, tuples, and dictionaries are data structures in Python used to store collections of items.

• Lists are mutable and ordered collections of items, accessed by index. Example: my_list = [1, 2, 3]

• Tuples are immutable and ordered collections of items, accessed by index. Example: my_tuple = (1, 2, 3)

• Dictionaries are unordered collections of key-value pairs, accessed by key. Example: my_dict = {'key': 'value'}

PLC programs can be written in various languages such as ladder logic, structured text, function block diagram, and sequential function chart.

• Ladder logic is the most commonly used language in PLC programming.

• Structured text is similar to programming languages like C and Pascal.

• Function block diagram uses graphical blocks to represent functions.

• Sequential function chart is used for complex processes with multiple steps.

• The choice of language depends on the application and the...read more

Validating APIs using Rest Assured involves writing scripts to send requests and verify responses.

• Use Rest Assured library to send HTTP requests and validate responses

• Write test scripts using given(), when(), then() methods to set up request, send request, and validate response

• Verify status code, response body, headers, etc. in the script

• Use assertions to check expected values against actual values

To locate the Xpath for the 'Today's Deal' menu item on Amazon, inspect the element using browser developer tools.

• Open the Amazon website and right-click on the 'Today's Deal' menu item.

• Select 'Inspect' to open the browser developer tools.

• Look for the HTML code corresponding to the 'Today's Deal' menu item.

• Right-click on the HTML code and choose 'Copy' > 'Copy XPath'.

• The copied XPath can be used to locate the 'Today's Deal' menu item in automation scripts.

Communication between SCADA/HMI & PLC is crucial for automation. It enables real-time monitoring and control of industrial processes.

• SCADA/HMI sends commands to PLC for process control

• PLC sends data to SCADA/HMI for real-time monitoring

• Communication protocols like Modbus, Profibus, and Ethernet/IP are used

• Redundancy and fault-tolerant systems are implemented for reliability

The difference between public static void main (String[] args) and public static void main () is the presence of command line arguments.

• public static void main (String[] args) is used when command line arguments are required

• public static void main () is used when command line arguments are not required

• String[] args is an array of strings that contains any command line arguments passed to the program

• The absence of String[] args in public static void main () means that the prog...read more

To automate hybrid and native mobile applications, use tools like Appium and Selenium for testing and UI automation.

• Use Appium for automating native and hybrid mobile apps

• Use Selenium for automating web views in hybrid apps

• Identify elements using unique identifiers like resource-id, class name, etc.

• Use XPath or CSS selectors to locate elements

• Write test scripts in programming languages like Java, Python, etc.

• Use emulators or real devices for testing

• Perform functional, perform...read more

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

• SCADA is used in industries such as power plants, water treatment facilities, and manufacturing plants.

• PLC logic development can be done using ladder logic, function block diagrams, and structured text.

• Reporting knowledge involves generating reports on system performance and data analysis.

• MSSQL knowledge is important for storing and retrieving dat...read more

JavaScript is a dynamically typed language, while TypeScript is a statically typed superset of JavaScript.

• JavaScript is dynamically typed, allowing for flexibility but potentially leading to runtime errors.

• TypeScript is statically typed, catching errors at compile time and providing better code quality.

• TypeScript supports optional static typing, interfaces, and other features not available in JavaScript.

• JavaScript code can be directly run in the browser, while TypeScript code...read more

Steps to perform parallel testing using Playwright

• Install Playwright and set up your project

• Create multiple instances of browsers for parallel testing

• Run tests in parallel using different browser instances

• Use tools like Jest or Mocha for managing parallel test execution

Playwright provides three types of fixtures: page, context, and browser.

• Page fixtures are specific to a single page instance

• Context fixtures are shared across all pages in a browser context

• Browser fixtures are shared across all browser contexts

Option a is valid, option b is valid, option c is invalid.

• Option a is valid because ChromeDriver is a subclass of WebDriver, so it can be assigned to a WebDriver reference.

• Option b is valid because ChromeDriver is a subclass of WebDriver, so it can be instantiated using a WebDriver reference.

• Option c is invalid because WebDriver is an interface and cannot be instantiated directly. It can only be used as a reference type.

Program to remove vowels from string array input by user

• Iterate through each string in the array

• For each string, iterate through each character and remove vowels

• Use a function to check if a character is a vowel (e.g. 'aeiouAEIOU')

CI is the practice of regularly integrating code changes into a shared repository, while CD is the automated process of deploying code changes to production.

• CI focuses on integrating code changes frequently to detect and fix integration errors early on.

• CD automates the deployment process to quickly and reliably release code changes to production.

• CI is a part of the software development process, while CD is a part of the software delivery process.

• Examples: Jenkins is a popular...read more

Explaining type script and java script arrow function loops with if else condition.

• TypeScript and JavaScript both support arrow functions for concise syntax.

• Arrow functions can be used in loops to simplify code.

• If-else conditions can be used with arrow functions to add logic.

• Example: const numbers = [1, 2, 3]; numbers.forEach(num => {if(num % 2 === 0) {console.log(num + ' is even');} else {console.log(num + ' is odd');}});

The primary purpose of using Selenium in automation testing is to automate web application testing.

• Automate repetitive manual testing tasks

• Increase test coverage and efficiency

• Support multiple browsers and platforms

• Integrate with continuous integration tools like Jenkins

• Execute parallel testing to save time

• Verify functionality and performance of web applications

throw is used to throw an exception in Java, while throws is used to declare an exception that a method might throw.

• throw is used to explicitly throw an exception within a method.

• throws is used in the method signature to declare that the method might throw a specific type of exception.

• Example: throw new Exception("An error occurred!");

• Example: public void method() throws IOException {}

I will support the team by taking on additional responsibilities and tasks to ensure the project or task is completed successfully.

• Take on additional responsibilities to fill in for the lack of manpower

• Collaborate with team members to distribute workload effectively

• Provide guidance and assistance to team members as needed

• Prioritize tasks and deadlines to ensure project completion

• Communicate effectively with team members and stakeholders

Handling a situation where a critical test case fails during automation testing

• Identify the root cause of the failure by analyzing logs and error messages

• Update the test case script to fix the issue

• Re-run the test case to ensure it passes successfully

• Document the issue and resolution for future reference

str1 will be stored in the string pool while str2 will be stored in the heap memory.

• str1 will be stored in the string pool, which is a part of the heap memory.

• str2 will create a new String object in the heap memory, separate from the string pool.

getwindowhandle returns the handle of the current window, getwindowhandles() returns handles of all open windows

• getwindowhandle returns a single window handle, while getwindowhandles() returns a set of window handles

• getwindowhandle is used to switch between windows in Selenium WebDriver

• Output type of getwindowhandle is String, while output type of getwindowhandles() is Set

The code takes a name as input, prints each letter, and checks if any vowels repeat in the name.

• Create a function that takes a string input for the name

• Iterate through each letter in the name and print them individually

• Check for vowel repetition by keeping track of vowels encountered

Unicast and multicast are communication methods used in produce consume tag.

• Unicast is a one-to-one communication method where a message is sent to a single recipient.

• Multicast is a one-to-many communication method where a message is sent to multiple recipients.

• Produce consume tag is a mechanism used in automation systems to communicate between producers and consumers.

• Unicast is used when the producer needs to send a message to a specific consumer.

• Multicast is used when the p...read more

Questions related to PLC, motors, and maintenance in automation engineering.

• PLC is a programmable logic controller used for automation, while PC is a personal computer used for general purposes.

• Types of motors include AC, DC, servo, stepper, etc.

• PLC I/O refers to the input/output modules used to connect sensors and actuators to the PLC.

• PLC instructions include ladder logic, function block diagrams, structured text, etc.

• Relays and contactors are used for switching high voltage...read more

The most used locators in automation testing are ID, class name, name, xpath, and CSS selector.

• ID: Unique identifier for an element

• Class name: Name of the class attribute of an element

• Name: Name attribute of an element

• XPath: Path of the element in the XML document

• CSS selector: Selector based on CSS attributes

Use Python in Robot Framework to generate random mobile numbers for 10 users.

• Use the Faker library in Python to generate random mobile numbers

• Create a loop to generate mobile numbers for 10 users

• Implement the logic in a Robot Framework test case

IEC61850 is a communication protocol for power systems, while MODBUS is a general-purpose protocol for industrial automation.

• IEC61850 is designed specifically for communication between devices in power systems, while MODBUS can be used in a variety of industrial applications.

• IEC61850 uses a hierarchical data model, while MODBUS uses a flat data model.

• IEC61850 supports peer-to-peer communication, while MODBUS uses a master-slave architecture.

• IEC61850 has built-in support for t...read more

To find dynamic Xpath, inspect the element and identify its unique attributes.

• Inspect the element using browser developer tools

• Identify unique attributes like class, id, name, etc.

• Use these attributes to create a dynamic Xpath

• Use functions like contains(), starts-with(), etc. to make the Xpath more dynamic

Yes, I am comfortable with testing as well as development.

• I have experience in both testing and development roles.

• I believe that having a background in development can actually enhance my testing skills.

• I am open to learning and adapting to new challenges in the testing field.

The ML1400 has 20 digital I/O ports and 2 analog I/O ports.

• The ML1400 has a total of 22 ports.

• There are 20 digital I/O ports that can be used for input or output of digital signals.

• There are 2 analog I/O ports that can be used for input or output of analog signals.

• These ports can be used to connect sensors, actuators, and other devices to the ML1400.

Valves are devices used to control the flow of fluids or gases. There are several types of valves used in different applications.

• Gate valves

• Globe valves

• Ball valves

• Butterfly valves

• Check valves

• Diaphragm valves

• Needle valves

• Pinch valves

• Pressure relief valves

• Solenoid valves

str1==str2 compares the memory addresses of the two strings, while str1.equals(str2) compares the actual contents of the strings.

• str1==str2 checks if the two string variables point to the same memory location.

• str1.equals(str2) compares the actual characters in the strings for equality.

• Example: String str1 = "hello"; String str2 = "hello"; str1==str2 will return false, but str1.equals(str2) will return true.

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: V = I * R (Voltage = Current * Resistance)

• Resistors are used to limit or control the flow of electric current in a circuit.

• Capacitors store and release electrical energy in a circuit.

• Four seasons: Spring, Summer, Fall, Winter

• 5 years of working experience in automation engineering

• Skills include PLC programming, HMI design, and troubl...read more

Using 2L and 5L water bottles, you can measure 3L of water.

• Fill the 5L bottle completely.

• Pour the water from the 5L bottle into the 2L bottle until it is full.

• Now, the 5L bottle has 3L of water remaining.

• Empty the 2L bottle.

• Pour the 3L of water from the 5L bottle into the empty 2L bottle.

• Fill the 5L bottle again.

• Pour water from the 5L bottle into the 2L bottle until it is full.

• Now, the 5L bottle has 4L of water remaining.

• Transfer 1L of water from the 5L bottle to the 2L bottl...read more

Central debouncing mechanisms in DEM are used to eliminate false triggering of signals.

• DEM stands for Digital Engine Management.

• Central debouncing mechanisms are used to filter out noise and eliminate false triggering of signals.

• These mechanisms include hardware and software filters.

• Hardware filters include capacitors and resistors.

• Software filters include algorithms that analyze the signal and remove noise.

• Examples of signals that require debouncing include throttle position...read more

You can check the OS on which the Selenium program is running by using the 'System.getProperty()' method in Java.

• Use 'System.getProperty('os.name')' to get the name of the operating system

• Use 'System.getProperty('os.version')' to get the version of the operating system

• Use 'System.getProperty('os.arch')' to get the architecture of the operating system

I am proficient in ladder logic and structured text programming languages for PLCs.

• Ladder logic is a graphical programming language commonly used in PLCs.

• Structured text is a high-level programming language used for complex logic and calculations.

• I am also familiar with function block diagrams and sequential function charts.

• I have experience with PLC programming software such as Siemens TIA Portal and Allen-Bradley Studio 5000.

• I am constantly learning and staying up-to-date w...read more

You can divide the test cases into two batches and run them separately.

• Divide the 100 test cases into two batches of 50 each

• Run the first batch of 50 test cases

• Once the first batch is completed, run the second batch of 50 test cases

Selenium WebDriver is newer and more advanced than Selenium RC.

• Selenium WebDriver is faster and more reliable than Selenium RC.

• Selenium WebDriver supports multiple programming languages, while Selenium RC only supports Java.

• Selenium WebDriver does not require a separate server to run tests, unlike Selenium RC.

• Selenium WebDriver has a simpler and more user-friendly API compared to Selenium RC.

Query for second largest and nth salary

• Use ORDER BY and LIMIT to get second largest salary

• Use OFFSET and LIMIT to get nth salary

• Example: SELECT salary FROM employees ORDER BY salary DESC LIMIT 1,1

• Example: SELECT salary FROM employees ORDER BY salary DESC LIMIT n-1,1

A test automation framework is a set of guidelines, coding standards, concepts, processes, practices, tools, and utilities that help to create automated tests.

• Provides structure and organization for automated tests

• Promotes reusability of code and components

• Enhances test maintenance and scalability

• Supports multiple test types such as functional, regression, and performance testing

• Integrates with continuous integration tools for automated test execution

• Examples: Selenium WebDri...read more

The combined characters in the given testing example 'Testing Testing Testing' is 'te'.

• Iterate through the text and check for consecutive characters 'te'.

• Combine the characters 'te' whenever they are found together.

• Return the combined text 'te' as the result.

I manage the process of inputting files by creating a structured system, using version control, and automating repetitive tasks.

• Create a structured system for organizing files based on project, date, or type

• Use version control to track changes and collaborate with team members

• Automate repetitive tasks such as file renaming or moving using scripts or tools like Jenkins