Unlock hundreds more features
Save your Quiz to the Dashboard
View and Export Results
Use AI to Create Quizzes and Analyse Results

OR
Sign inSign in with Facebook
Sign inSign in with Google
Quizzes > Programming & Software

PLC Quiz: HMI Fundamentals and Ladder Logic

Quick, free PLC practice test with instant results - 15 questions.

Editorial: Review CompletedCreated By: Daramola ToluwalopeUpdated Aug 24, 2025
Difficulty: Moderate
Questions: 20
Learning OutcomesStudy Material
Colorful paper art depicting a quiz on PLC and HMI fundamentals

Use this PLC and HMI fundamentals quiz to check your understanding of ladder logic, I/O, and basic control tasks in 15 multiple-choice questions. You'll see instant feedback with brief explanations to spot gaps before a lab or job task. If you want more practice, try our programming quiz or explore an electrical engineering quiz to round out your automation knowledge.

What is the primary function of a PLC in industrial automation?
Render graphics for operator interfaces
Store large historical databases
Execute control logic to automate machinery
Provide enterprise resource planning services
undefined
Which programming language is most commonly associated with relay-style control in PLCs?
Ladder Diagram (LD)
Sequential Function Chart (SFC)
Structured Text (ST)
Instruction List (IL)
undefined
What does HMI stand for in automation systems?
Human Machine Interface
Hardware Monitoring Instrument
Human Mechanism Interlock
High Memory Integration
undefined
Which PLC memory type retains values after a power cycle?
Retentive memory
Scratchpad memory
Cache memory
Volatile memory
undefined
Which HMI feature allows operators to save and recall sets of machine parameters for different products?
Audit trail
Alarm banner
Trends
Recipes
undefined
What is the primary purpose of an interlock in PLC logic?
Prevent unsafe or undesired operations when conditions are not met
Encrypt network communications
Increase scan speed under heavy load
Calibrate analog inputs automatically
undefined
Which statement best describes an HMI tag?
A data reference that links an HMI object to a PLC variable
A label used only for operator instructions
A unique hardware identifier for the HMI panel
A fixed memory address inside the HMI firmware
undefined
In a typical PLC scan cycle, what is the correct order of operations?
Write outputs, read inputs, execute logic
Read inputs, execute logic, write outputs
Execute logic, read inputs, write outputs
Execute logic, write outputs, read inputs
undefined
Which sensor output type sources current to the PLC input when active?
RTD
Analog 4-20 mA
NPN
PNP
undefined
What is the main advantage of a 4-20 mA analog signal over 0-10 V in industrial environments?
Less susceptible to electrical noise and can detect wire breaks
Requires fewer wires than voltage signals
Does not require power for the transmitter
Higher resolution than any voltage input
undefined
Which network protocol is commonly used for real-time control between PLCs and remote I/O over Ethernet?
EtherNet/IP
HTTP
FTP
SMTP
undefined
In a typical ISA-18.2/ISA-101-based alarm philosophy, an HMI alarm that requires operator acknowledgment and action but does not trip or stop the machine is typically classified as what priority?
Medium
Low
Critical
Emergency Stop
undefined
What does a TON instruction do in ladder logic?
Generates a one-scan pulse on a rising edge
Delays setting its done bit until the input has been true for a preset time
Counts rising edges until a preset is reached
Holds its accumulated value through power loss without configuration
undefined
Which device converts rotational motion into pulses used for position or speed feedback to a PLC?
Load cell
Incremental encoder
Proximity switch
RTD sensor
undefined
In HMI design, which practice best improves situational awareness according to ISA-101 principles?
Use of high-performance graphics with limited color for emphasis
Packing as much data as possible on one screen
Maximizing 3D effects and animations
Using bright colors for all objects
undefined
What is the principal function of a watchdog timer in a PLC system?
Provide real-time clock scheduling
Synchronize PLCs over a network
Detect program execution faults and trigger a safe state
Measure process cycle time for optimization
undefined
For a 12-bit analog input with a 0-10 V range, what is the raw count corresponding to 5 V (assume 0-4095 counts)?
Approximately 2048 counts
Approximately 1024 counts
Approximately 2560 counts
Approximately 4095 counts
undefined
Which PLC task type executes at a fixed, defined interval regardless of program length?
Periodic task
Continuous task
Background task
Event task without trigger
undefined
Which method best reduces analog signal noise entering a PLC?
Force input values to constants
Use DC outputs instead of AC
Increase PLC scan rate
Use shielded cable with proper single-point grounding
undefined
What is the purpose of a heartbeat tag between PLC and HMI?
Verify communication is active by toggling at a known rate
Store historical data on the HMI
Synchronize scan cycles exactly
Encrypt all messages
undefined
0

Learning Outcomes

  1. Analyse basic PLC architecture and modules
  2. Identify key HMI design principles
  3. Evaluate communication protocols between PLCs and HMIs
  4. Demonstrate troubleshooting of PLC ladder logic issues
  5. Apply programming instructions for PLC control processes
  6. Master operator interface navigation and monitoring

Cheat Sheet

  1. Understand the Core Components of PLC Architecture - Dive into the heart of PLC systems by exploring the CPU, power supply, memory, I/O interfaces, and communication modules. Think of these parts as the brain, energy source, and senses that keep your industrial processes running smoothly. Get the big picture and build a solid foundation! Programmable Logic Controller
  2. Master the Basics of Ladder Logic Programming - Ladder logic is like a fun puzzle where electrical relay diagrams become your code! Learn how to read and create these rungs, so you can wire up logic that makes machines come to life. Spark your creativity and watch your programs execute flawlessly. Programmable Logic Controller
  3. Grasp the Fundamentals of HMI Design Principles - A sleek Human-Machine Interface (HMI) is your window into the PLC world, so clarity and consistency are key. Design screens that guide operators with ease and prevent confusion during high-pressure situations. After all, a good HMI is like a friendly teammate cheering you on! Programmable Logic Controller
  4. Learn About Communication Protocols Between PLCs and HMIs - Protocols such as Modbus and EtherNet/IP are the secret handshake that lets PLCs and HMIs chat without a hitch. Understand how data packets travel back and forth so you can troubleshoot any traffic jam in your network. Smooth communication means a happy, responsive system! Programmable Logic Controller
  5. Develop Skills in Troubleshooting PLC Ladder Logic Issues - Nothing beats the thrill of hunting down a pesky bug in your ladder logic and squashing it for good. Practice decoding error messages and testing logic step by step to become the Sherlock Holmes of PLCs. Before you know it, you'll solve issues in record time! Programmable Logic Controller
  6. Apply Programming Instructions for PLC Control Processes - Timers, counters, and comparison functions are your toolbox for crafting precise control sequences. Experiment with each instruction to see how they affect process timing, counts, and decision-making. Mix and match these tools to build rock-solid automation! Programmable Logic Controller
  7. Master Operator Interface Navigation and Monitoring - Become a fast navigator by exploring common HMI layouts, alarms, and trend displays. A quick glance should tell you exactly what's happening on the factory floor, so design interfaces that highlight key data. Stay on top of operations like a pro air-traffic controller! Programmable Logic Controller
  8. Understand the Importance of Redundancy in PLC Systems - Redundant CPUs and I/O modules are like having a superhero sidekick ready to jump in if the main hero falls. Implementing redundancy reduces downtime and keeps critical processes up and running. Plan for the unexpected and sleep easier knowing you've got a backup! Programmable Logic Controller
  9. Explore the Evolution and History of PLCs - Travel back to the 1960s when PLCs were born to replace bulky relay cabinets and revolutionize manufacturing. Learn about major breakthroughs and how PLCs evolved into the powerful controllers we use today. History isn't just dates - it's the story of innovation in action! Programmable Logic Controller
  10. Stay Updated on Modern PLC Programming Languages - Beyond ladder logic, languages like Structured Text and Function Block Diagram open new doors for complex control strategies. Try them out to expand your programming toolkit and tackle sophisticated automation challenges. The more languages you speak, the more worlds you can automate! Programmable Logic Controller
Make a Quiz (FREE) Copy & Edit This Quiz Create a Quiz with AI

Manufacturing Quizzes

Powered by: Quiz Maker