Free PLC Simulator Online
The LearnSCADA PLC Simulator is a live Modbus simulator online: a small water plant, with a tank, an inlet valve, a pump, a drain and alarms, running on the internet right now. Point your own HMI, SCADA package or Modbus client at it and read real, changing values over Modbus TCP. It's for students, technicians and engineers who want to practice Modbus and SCADA without buying a PLC or wiring up a test bench. The demo is free and needs no account: connect now.
Connect to the free demo, no account
The shared demo plant is open to everyone. Watch it live below, and read the same values from your own software with the connection details underneath. Because everyone shares it, the demo is read-only: Modbus writes to it are refused.
Connect your own client to this plant
Modbus TCP, host sim.learnscada.com, port 502, any unit ID. Read-only, open to everyone, no sign-in.
How it works, step by step: User guide (PDF)
Learn what you're connecting to
- Understanding Modbus: the protocol behind every register on this plant: function codes, addressing and Modbus TCP.
- PLC Ladder Logic Fundamentals: the ladder logic a PLC runs to control a plant like this one.
Your own simulator dashboard
The demo is for reading. Your own simulator is for doing: a private plant only you use, with its own dashboard, its own Modbus port, and writes allowed, so you can start the pump, open the valves and watch your HMI follow. Load your own register maps (your own scenarios) from a spreadsheet.
Join free as a Free Reader to try it for 2 hours. Email only, no card. Your trial simulator keeps your scenarios between sessions, and the 2 hours of run time is spread over as many sessions as you like, once per account. Free Readers also get member prices on every PDF and sample chapters of every book.
Or own it: founding-member lifetime access, $97 one-time
Lifetime access for as long as the simulator service runs. Includes Pro Library membership for life. A founding-member offer for a limited time. Later the simulator moves to an annual subscription; founding members keep their lifetime access. Your own permanent Modbus port, runs of up to 12 hours per start, and your own register maps. Sign in to buy. Terms
Need it offline, or many devices at once?
This online simulator is one shared plant on the internet. LearnSCADA Sim, the free offline Modbus device simulator, runs on your own Windows PC or Docker host, on a network that touches nothing outside, and simulates up to 20 devices at once from their register maps.
1 of 5 simulators running right now.