LearnElectricals · PLC course

PLC course

A PLC is the industrial computer that runs machines instead of relay circuits. In this course you will learn how it works, wire sensors and contactors to its cards, and write Ladder programs yourself on a real simulator with buttons, sensors and moving machines: a motor with seal-in, star-delta with a timer, a box counter, a tank with alarms, a traffic light and a garage door. The simulator tests every exercise for you.

10 lessons · Ladder simulator · final exam and certificateCompletion certificate
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Before you start: you will get more from this course if you understand contactor control circuits (seal-in, interlock, star-delta) from the Classic Control course →, and sensors and the 4–20mA signal from the Instrumentation course →. It is not required, but it makes things much easier.

How to study here

  1. Read the explanation: one idea per part, in simple words
  2. Write the program on the simulator: tap a cell and choose a contact or a coil
  3. Press RUN and press the buttons: watch the power flow through the rung and the machine move
  4. Test the program: the simulator checks it for you. Answer the questions to mark the lesson done
Important: this simulator is a generic trainer with IEC / Siemens style addresses (I0.0, Q0.0, M0.0, T0 and C0). The idea and the logic are the same in every PLC, but address formats and instruction names differ: Allen-Bradley writes I:0/0 and O:0/0, while Delta and Mitsubishi write X0 and Y0. Lesson 3 has a comparison table, and below you will find simulators in each brand's style.

Lessons in order; each lesson builds on the one before

Practice on real brands the same logic with each brand's addresses and look

Once you understand the idea here, try it on a simulator that looks like the software of the brand you will work with: %I0.0 addresses in Siemens, X0 in Delta, and tags like Start_PB in Allen-Bradley. Each one has 9 exercises from real plants, including position control with an encoder, and the last one is a challenge.

Course Completion Certificate

Ladder (LD) is one of the languages of the IEC 61131-3 standard. The simulator here is a generic trainer for learning and does not replace the vendor software (TIA Portal, Studio 5000, ISPSoft, GX Works…). Safety: test every new program first with the machine isolated or in a safe state, never force an output while people are near the machine, and remember that a relay output card can carry 230V. Your progress is saved on this device only.
© 2026 LearnElectricals. All rights reserved. This site is not affiliated with any of the companies mentioned (such as Siemens, Allen-Bradley, Delta, Schneider and others); names and trademarks belong to their owners and are used only to explain the devices.