Introduction to Programmable Logic Controllers

Course Description

ETS2542C is a combined lecture and laboratory course that provides students with the fundamental operational concepts common to Programmable Logic Controllers (PLCs). Students explore PLC principles, hardware architecture, programming techniques, and the fundamentals needed for simple industrial process control. Laboratory exercises reinforce theoretical content through hands-on programming, wiring, and troubleshooting activities using industry-standard equipment and software.

This course is part of Florida's Engineering Technologies > Specialty Engineering Technology taxonomy (SCNS prefix: ETS) and is a foundational requirement for advanced courses in automation, robotics, fluid power, and mechatronics.

Learning Outcomes

Required Outcomes

Upon successful completion of this course, students will be able to:

• Identify and describe the major hardware components of a PLC system, including the CPU, power supply, input/output modules, and programming terminal.
• Explain the PLC scan cycle and how a controller reads inputs, executes logic, and updates outputs in real time.
• Develop and enter ladder logic programs using basic instructions including examine-if-closed (XIC), examine-if-open (XIO), and output energize (OTE) coils.
• Program and apply timer and counter instructions to control sequences and timed operations.
• Connect and wire discrete input and output devices — including pushbuttons, limit switches, pilot lights, and relay coils — to a PLC I/O chassis.
• Use programming software (e.g., RSLogix 500 / Studio 5000 or equivalent) to create, upload, download, monitor, and edit PLC programs.
• Interpret and troubleshoot ladder logic programs to diagnose faults in a PLC-controlled system.
• Apply Boolean logic and number systems (binary, hexadecimal, BCD) relevant to PLC data addressing and bit manipulation.

Optional Outcomes

Depending on institutional focus, students may also be able to:

• Perform basic data manipulation instructions including move, compare, and math operations.
• Configure and program a sequencer instruction for repetitive machine cycles.
• Interface a PLC with analog input/output modules and interpret 4–20 mA signal loops.
• Demonstrate basic PLC communications using a data highway or Ethernet network connection.
• Integrate PLC control with electro-mechanical devices such as solenoid valves, proximity sensors, and photo sensors.
• Interpret process control system documentation including wiring diagrams and I/O lists.

Major Topics

Required Topics

1. Introduction to Industrial Automation and PLCs
   • History and evolution of PLCs vs. relay-based control
   • Applications of PLCs in manufacturing, process control, and automation
   • Overview of PLC manufacturers and families (Allen-Bradley MicroLogix, CompactLogix, ControlLogix)
2. PLC Hardware Architecture
   • CPU / processor unit
   • Power supply specifications
   • Discrete and analog input/output modules
   • Chassis / rack configuration
   • Programming terminals and communication ports
3. Number Systems and Boolean Logic
   • Binary, octal, hexadecimal, and BCD number systems
   • Conversion between number systems
   • Boolean algebra: AND, OR, NOT, NAND, NOR, XOR gates
   • Application of logic gates to ladder rung design
4. PLC Scan Cycle and Memory Organization
   • The input scan, program execution, and output scan
   • I/O addressing conventions (file-based and tag-based)
   • Data file types: bit, integer, float, string
5. Ladder Logic Programming — Basic Instructions
   • Normally open (XIC) and normally closed (XIO) contact instructions
   • Output energize (OTE), output latch (OTL), and output unlatch (OTU)
   • Series and parallel rung structures
   • Start/stop motor control circuits
6. Timer and Counter Instructions
   • Timer On-Delay (TON), Timer Off-Delay (TOF), Retentive Timer (RTO)
   • Count-Up (CTU) and Count-Down (CTD) counter instructions
   • Accumulated value, preset value, and done bit
7. Programming Software and Project Workflow
   • Introduction to RSLogix 500 / Studio 5000 or equivalent environment
   • Creating and configuring a new project
   • Uploading and downloading programs to/from the controller
   • Online monitoring and forcing I/O for testing
8. I/O Wiring and Field Device Interfacing
   • Sinking vs. sourcing I/O wiring
   • Discrete field devices: pushbuttons, selector switches, limit switches, proximity sensors, photoelectric sensors
   • Output devices: pilot lights, solenoid valves, motor starters
   • Safe wiring practices and panel layout
9. PLC Troubleshooting and Diagnostics
   • Interpreting indicator LEDs on CPU and I/O modules
   • Using the programming terminal for live fault diagnostics
   • Systematic troubleshooting methodology for PLC-controlled systems

Optional Topics

• Data Manipulation Instructions: MOV, COP, arithmetic (ADD, SUB, MUL, DIV), comparison (EQU, NEQ, LES, GRT)
• Sequencer Instructions: SQO, SQI, SQL for automated step-by-step machine control
• Analog I/O and Process Control: 4–20 mA current loops, scaling analog values, PID control overview
• PLC Communications: DH+ Data Highway, EtherNet/IP, RSLinx configuration
• Human-Machine Interface (HMI) Basics: Introduction to operator interface panels and tag-based HMI screen design
• Introduction to IEC 61131-3 Languages: Overview of Structured Text (ST), Function Block Diagram (FBD), and Sequential Function Chart (SFC)
• Motor Control Integration: Two-wire and three-wire start/stop circuits, integration with variable frequency drives (VFDs)

Resources & Tools

Software

• RSLogix 500 / RSLogix Micro Starter Lite (free) — Rockwell Automation; used for MicroLogix series PLCs
• Studio 5000 Logix Designer — Rockwell Automation; used for CompactLogix and ControlLogix families (30-day free trial available)
• Connected Components Workbench (CCW) — Free Rockwell Automation software with built-in simulator for Micro800 series PLCs
• RSLinx Classic — Rockwell Automation communication configuration utility

Hardware (Typical Lab Equipment)

• Allen-Bradley MicroLogix 1100 or 1400 trainer stations
• Allen-Bradley CompactLogix or ControlLogix demo panels (where available)
• Discrete I/O demonstration boards with pushbuttons, switches, and pilot lights
• Sensor demonstration stations (proximity, photoelectric, limit switches)

Recommended Textbooks / References

• Programmable Logic Controllers by Frank D. Petruzella (McGraw-Hill)
• Programmable Logic Controllers: Programming Methods and Applications by John R. Hackworth & Frederick D. Hackworth Jr.
• Rockwell Automation QuickStart Guides and Getting Results Guides (available free at literature.rockwellautomation.com)

Career Pathways

Successful completion of ETS2542C prepares students for entry-level and technician-level positions in industrial automation and supports progression into advanced engineering technology programs. Relevant career pathways include:

• PLC / Automation Technician — Programs, maintains, and troubleshoots PLC systems in manufacturing facilities
• Controls Technician / Controls Engineer — Designs and implements automated control systems for industrial processes
• Maintenance Electrician / Industrial Electrician — Services machinery with integrated PLC control systems
• Manufacturing / Production Technician — Supports high-tech production, distribution, and engineering R&D environments
• Mechatronics Technician — Integrates electrical, mechanical, and PLC control systems in automated machinery
• Robotics Technician — Many robotic workcell controllers interface directly with PLCs; ETS2542C is a prerequisite for robotics coursework at several Florida colleges

This course also fulfills a prerequisite requirement for advanced ETS courses including PLC II (applications and advanced programming), fluid power control, and industrial robotics.

Special Information

Laboratory Component

The "C" suffix in ETS2542C designates a combined lecture and laboratory course. Hands-on lab work is integral to the course grade and cannot be substituted. A lab fee is typically assessed at registration to cover consumables and equipment maintenance.

Industry Certification Alignment

• OSHA 10-Hour General Industry — Safety content in wiring and panel work aligns with OSHA 10 standards; many programs encourage or require completion.
• Rockwell Automation Training (RAT) — Course content aligns with Rockwell Automation's entry-level PLC programming competencies; students may pursue Rockwell ControlLogix/CompactLogix credentials after completing the course sequence.
• NIMS Mechatronics Credentials — PLC programming is a tested domain within the National Institute for Metalworking Skills (NIMS) Mechatronics Level 1 certification, which some Florida programs integrate into the ETS sequence.

Program Context

ETS2542C is a core course in the Engineering Technology Support Specialist College Credit Certificate and the Engineering Technology Associate in Science (A.S.) degree at multiple Florida colleges. Students completing only the PLC-focused certificate sequence (approximately 12 credit hours) may qualify for a PLC / Automation Specialist college credit certificate, depending on the institution.