v1.1.2 — Latest Release

Download Modbus Simulator Free

Professional Modbus RTU + TCP + ASCII simulator for Windows engineers. Master & Slave modes. No hardware required. 30-day free trial.

✅ Windows 10/11 (64-bit) ✅ No installation required ✅ 30-day free trial ✅ No registration

What's Included in v1.1.2

Released April 2026 — All features in the free trial

Serial port simulation for RTU devices. Configure baud rate, parity, stop bits. Test over virtual COM ports.

Full TCP/IP master and slave simulation. Port 502 or custom. Connect from any Modbus TCP client.

Both modes in one application. No separate purchase. Switch between master and slave instantly.

Live coil, discrete input, input register, and holding register monitoring. Multiple display formats.

New in v1.1.1 — detailed request/response logging, error simulation, slave-mode log view.

New in v1.1.1 — scrollable request history in slave mode so you can see what master is sending.

Download the ZIP file — click the green button above. No account needed.

Extract the ZIP — right-click → Extract All. No installation wizard.

Run ModbusSimulator.exe — double-click. Windows may show SmartScreen warning — click "More info → Run anyway" (safe, unsigned freeware).

Enter trial key — 30-day free trial starts automatically. Buy license for unlimited use ($99 one-time).

Is Modbus Simulator really free?

Yes — 30 days free, no registration, no credit card. After the trial, a $99 one-time license unlocks unlimited use. No subscriptions.

Does it work on Windows 10 and Windows 11?

Yes, fully compatible with Windows 10 and Windows 11 (64-bit). Requires .NET 6 runtime (included in the download).

Can I use virtual COM ports for Modbus RTU?

Yes. We recommend com0com (free) to create virtual COM port pairs for RTU testing without physical hardware.

What is the difference between Modbus RTU and Modbus TCP simulator?

RTU uses serial communication (COM ports, RS-485). TCP uses Ethernet/IP on port 502. Our simulator supports both. See comparison guide →

How is ModbusSimulator different from Modbus Poll?

Modbus Poll is master-only ($149+/year). ModbusSimulator includes both master and slave modes for $99 one-time. See full comparison →