Learn PLC Programming Without Hardware: PLCSIM, Emulators and Factory I/O
The hardware question
The first thing a fresher asks is whether to buy a PLC. The answer in 2026 is not yet. Every major vendor's tool has a simulator, most are free or in the trial, and one 3D simulator makes them look like a factory. Buy hardware when you have a program that needs it.
What each simulator gives you
Siemens S7-PLCSIM comes with the TIA Portal trial. Logic, timers, counters, HMI screens, PID with a simulation block. PLCSIM V20 adds scripted sequences and hardware events, covered in the commissioning course. PLCSIM Advanced, a separate product, simulates the whole S7-1500 with its network.
Rockwell RSLogix Emulate and the Micro800 simulator in Connected Components Workbench cover the Rockwell side; the RSLogix 500 and Micro800 courses run in them.
GX Simulator, CX-Simulator and the CODESYS built-in simulation cover Mitsubishi, Omron and the IEC 61131-3 world.
What a simulator cannot do
It cannot simulate a loose wire, a sensor with the wrong sinking/sourcing polarity, a contactor that chatters, or noise on an analog loop. Those are the faults that fill a maintenance engineer's week, and the panel building and instrumentation courses teach them with real photographs and wiring, not simulation.
Factory I/O: the machine you do not own
Factory I/O connects to PLCSIM and to real PLCs and gives you conveyors, sorting stations, a filling tank, an assembler, a pick-and-place robot, an elevator and a warehouse, each with sensors and actuators you map to PLC addresses. The Factory I/O course programs nine of them. A learner who has made the palletiser stack boxes has an interview story that most graduates with a real PLC on the shelf do not.
When to buy hardware
When you have a working program and want to see the download, the diagnostics LEDs, the memory card and a real PROFINET fault. An S7-1200 starter kit or a Micro820 is enough. Buy it for the commissioning course, not for the first one.
Frequently asked questions
Is PLCSIM free? It is part of the 21-day TIA Portal trial, which can be reinstalled.
Is Factory I/O free? A 30-day trial with every scene; the course fits inside it.
Can I get a job having only used simulators? Yes, if you can show the programs and understand the wiring topics; employers hire for what you can do, and simulation proves most of it.
