ModbusSimulator gives Windows engineers a Modbus TCP + RTU + ASCII + UDP tool with built-in slave simulation — everything Modbus Doctor lacks on Windows.
No credit card · No registration · Windows 10/11 (64-bit)
Modbus Doctor is a Modbus diagnostic utility primarily designed for macOS. It provides basic Modbus TCP and RTU master functionality for reading and writing registers. While it works well for quick diagnostics on a Mac, engineers on Windows workstations face immediate limitations:
Modbus Doctor's Windows version feels like an afterthought compared to its macOS implementation. The UI is not optimized for Windows conventions, and some features available on Mac are missing or reduced on Windows. ModbusSimulator is built exclusively for Windows — it uses the Windows API natively and feels at home on Windows 10 and 11.
Modbus Doctor can poll a real device (master mode) but it cannot emulate a Modbus slave. If you need to test a SCADA system, HMI, or custom master application against a simulated device, you need a different tool. ModbusSimulator's slave simulator can run 8 simultaneous slave instances with fully configurable register values and exception responses.
Modbus Doctor provides a basic log view but no structured data export. ModbusSimulator logs every request and response with timestamps and lets you export the full session to CSV — essential for commissioning reports and factory acceptance testing (FAT) documentation.
Modbus Doctor is optimized for quick device diagnostics. ModbusSimulator is designed for the full engineering workflow: develop, test, commission, and document. It covers the diagnostic use case and adds simulation, logging, and configuration export on top.
| Feature | ModbusSimulator | Modbus Doctor |
|---|---|---|
| Primary platform | Windows 10/11 (native) | macOS (primary), Windows (limited) |
| Modbus TCP master | ✅ Yes | ✅ Yes |
| Modbus RTU master (serial) | ✅ Yes | ✅ Yes |
| Modbus ASCII | ✅ Yes | ⚠ Limited |
| Modbus UDP | ✅ Yes | ❌ No |
| Slave/server simulator | ✅ Up to 8 slaves | ❌ No |
| Multiple Unit ID support | ✅ 1–247 | ⚠ Limited |
| Exception response simulation | ✅ Yes | ❌ No |
| Response delay simulation | ✅ Configurable ms | ❌ No |
| 32-bit float / DWORD | ✅ Built-in | ⚠ Manual calc |
| CSV export / data logging | ✅ Yes | ❌ No |
| Register map import (CSV) | ✅ Yes | ❌ No |
| Price | $59 one-time | ~$49 (Mac); pricing varies |
| Free trial | ✅ 30 days, full features | ⚠ Limited |
If you work on Windows and need a tool that goes beyond basic diagnostics — with slave simulation, CSV logging, and full protocol coverage — ModbusSimulator is the clear choice. The 30-day free trial lets you validate every feature before committing.
Building SCADA screens or configuring HMI tags without the physical device? ModbusSimulator's slave simulator lets you run up to 8 simulated devices simultaneously — each with configurable register values, update rates, and exception responses. Test every screen, every alarm, every trend before the hardware arrives on site.
FAT requires documented proof that a system communicates correctly with all devices. ModbusSimulator's session log (exportable to CSV) gives you a timestamped record of every request and response — the kind of documentation FAT processes demand. Modbus Doctor provides no comparable export.
ModbusSimulator's slave simulator can inject configurable response delays (simulate slow network) and return specific exception codes (01–11). This lets you verify your master application handles timeouts and errors correctly before connecting to real hardware — Modbus Doctor has no equivalent capability.
ModbusSimulator can run multiple slave instances on a single TCP port or serial bus, each with a different Unit ID. Simulate a network of 8 devices — energy meter on ID 1, VFD on ID 2, I/O module on ID 3 — all from one PC. Essential for testing multi-drop RS-485 networks without the full hardware rack.
Looking at other Modbus tools?
Modbus Doctor is a Modbus diagnostic tool built primarily for macOS. Windows engineers look for alternatives because its Windows version has limited functionality, no slave simulation, and no data export. ModbusSimulator is a native Windows 64-bit application with full protocol support and a built-in slave simulator.
Yes — ModbusSimulator. It runs on Windows 10/11 64-bit and provides Modbus TCP + RTU + ASCII + UDP in both master and slave modes. Download the 30-day free trial from /download with no registration required.
Yes. ModbusSimulator's slave simulator supports up to 8 simultaneous slave instances, all four register types, exception response injection, and configurable response delays. Modbus Doctor does not include any slave simulation capability.
Yes. ModbusSimulator logs every Modbus request and response (function code, address, value, timestamp) and exports the full session to CSV. You can use this for commissioning documentation, FAT reports, or Excel-based analysis.
ModbusSimulator is $59 one-time for a perpetual license covering all features and future updates. There is a 30-day full-featured free trial with no credit card required. Modbus Doctor pricing varies by edition; the Windows version offers fewer features than its Mac counterpart at a comparable or higher price.
TCP + RTU + ASCII + UDP + Slave Simulator · Windows 10/11 · 30-day free trial
No credit card · No registration · Windows 10/11 64-bit