ModbusSimulator
✅ Engineers' Choice 2026

Best Modbus Poll Alternative — Free to Try, $99 One-Time

Tired of Modbus Poll's $149+/year subscription? ModbusSimulator includes Master and Slave modes, all protocols, and costs $99 once — no renewals, ever.

⬇ Download Free Trial — v1.1.2 See Full Comparison ↓

Windows 10/11 · 30-day free trial · No credit card · No registration

Modbus Poll vs ModbusSimulator — Price

Why pay annually when you can own it forever?

❌ Modbus Poll
$149
per year (renewal required)
3 years = $447+
Master only — no Slave mode
✅ ModbusSimulator
$99
one-time (lifetime license)
3 years = still $99
Master + Slave included

Full Feature Comparison

ModbusSimulator vs Modbus Poll (Witte Software)

Feature ModbusSimulator Modbus Poll
Price $99 one-time $149/year (subscription)
Free Trial 30 days — no registration Limited demo only
Master Mode ✅ Full support ✅ Full support
Slave Mode ✅ Included (same price) ❌ Not available
Modbus RTU (Serial/RS-485) ✅ COM ports, virtual COM ✅ Yes
Modbus TCP ✅ Port 502 or custom ✅ Yes
Modbus ASCII ✅ Included ✅ Yes
Modbus UDP ✅ Included ❌ Extra license needed
Real-time Register View ✅ Coil, DI, IR, HR ✅ Yes
Multiple Data Formats ✅ Int, float, hex, binary, BCD ✅ Yes
Slave Request Log ✅ Scrollable log in slave mode ❌ Master only, no slave logging
Fault Simulation ✅ Exception codes, timeouts ❌ Limited
Diagnostic Mode ✅ Request/response detail ✅ Yes
OS Support Windows 10/11 (64-bit) Windows (32/64-bit)
License model One-time, perpetual Annual subscription
Multi-device support Up to 8 simultaneous Varies by version

Why Engineers Switch from Modbus Poll

💰 No Annual Renewal

Modbus Poll charges $149 every year. ModbusSimulator is $99 once — you own it forever. After 2 years you're already saving money.

🔄 Master + Slave in One App

Modbus Poll is master-only. To test a full Modbus network, you need a slave simulator too. ModbusSimulator includes both — no second purchase.

📋 Slave Request Log

When acting as Slave, see every request your master device sends. Essential for debugging PLC communication — Modbus Poll can't do this.

🐛 Fault Simulation

Simulate exception responses, timeouts, and CRC errors to test how your application handles Modbus failures. Critical for robust system testing.

🆓 Real 30-Day Trial

Full-featured trial — no feature locks, no registration. Download, run, test. Buy only when you're convinced it works for your setup.

📡 All Protocols Included

RTU, TCP, ASCII, UDP — all in the base license. Modbus Poll charges extra for UDP. ModbusSimulator includes everything upfront.

Also looking for a pymodslave or ModRSsim2 alternative?

ModbusSimulator replaces all of these with a single, professional Windows application:

Try ModbusSimulator Free — 30 Days

Frequently Asked Questions

Is ModbusSimulator really a Modbus Poll alternative?

Yes. ModbusSimulator covers all core Modbus Poll features (RTU master, TCP master, register monitoring, multiple data formats) and adds features Modbus Poll doesn't have — Slave simulation, fault injection, and a slave request log. The main differences: ModbusSimulator is $99 one-time vs Modbus Poll's $149/year, and includes Slave mode at no extra cost.

Can I use ModbusSimulator with virtual COM ports for RTU testing?

Yes. Use com0com (free) to create a virtual COM port pair on Windows. ModbusSimulator connects to one port as Master and the other as Slave for complete RTU simulation without any physical hardware.

Does ModbusSimulator work with SCADA systems like Ignition, AVEVA, or WinCC?

Yes. ModbusSimulator exposes a standard Modbus TCP server on port 502 (or custom port) that any SCADA system can connect to as a client. Use it to simulate PLC/field device behavior during SCADA development and testing.

What happens when the 30-day trial ends?

After 30 days, the application will prompt for a license key. All your configurations and test setups are preserved. Purchase a $99 one-time license to continue using the software — no subscription required.

Is there a multi-seat or team license?

Yes. 3 licenses cost $79 each (save $60 vs buying individually). Contact [email protected] for volume pricing for 5+ licenses.

Does ModbusSimulator run on Linux or macOS?

Currently Windows 10/11 (64-bit) only. Linux and macOS versions are on the roadmap. For non-Windows testing, pymodbus (Python library) is a good alternative for scripting.

Ready to Switch from Modbus Poll?

30-day free trial · No credit card · Download in 30 seconds

⬇ Download Free — v1.1.2 (Windows) View Pricing →

Questions? Email [email protected]