Replace Simply Modbus with a single tool that covers Modbus TCP, RTU, ASCII and UDP — plus a full slave simulator for testing your SCADA, HMI, and master applications.
No credit card · No registration · Windows 10/11 (64-bit)
Simply Modbus is a lightweight Modbus master utility that has served engineers well for years. But as projects get more complex, its limitations become friction points:
Simply Modbus sells "Simply Modbus TCP" and "Simply Modbus RTU" as two separate products at $119 and $99 respectively. Most real-world industrial projects use both — you need TCP for Ethernet-connected PLCs and RTU for serial field devices. ModbusSimulator includes all four Modbus variants (TCP, RTU, ASCII, UDP) in a single $59 license.
Simply Modbus is master-only. If you need to test your SCADA screens, HMI tags, or custom master software against a simulated device — you can't do it with Simply Modbus. ModbusSimulator includes a full slave/server simulator that responds to any FC01–FC16 request, supports up to 8 Unit IDs simultaneously, and can inject exception responses and delays to test edge cases.
Simply Modbus was built for 32-bit Windows. On modern Windows 11 64-bit systems with high-DPI displays, it may appear blurry or small. ModbusSimulator is a native 64-bit application designed for current hardware.
Simply Modbus has no structured data logging or CSV export. ModbusSimulator logs every request and response with timestamps and lets you export to CSV for commissioning reports or analysis.
| Feature | ModbusSimulator ($59) | Simply Modbus TCP ($119) | Simply Modbus RTU ($59) |
|---|---|---|---|
| Modbus TCP master | ✅ | ✅ | ❌ |
| Modbus RTU master | ✅ | ❌ | ✅ |
| Modbus ASCII | ✅ | ❌ | ⚠ Partial |
| Modbus UDP | ✅ | ❌ | ❌ |
| Slave/server simulator | ✅ (8 slaves) | ❌ | ❌ |
| Exception response testing | ✅ | ❌ | ❌ |
| Response delay simulation | ✅ | ❌ | ❌ |
| 32-bit float / DWORD | ✅ Built-in | ⚠ Manual | ⚠ Manual |
| CSV export / data logging | ✅ | ❌ | ❌ |
| Windows 11 64-bit | ✅ Native | ⚠ 32-bit | ⚠ 32-bit |
| Free trial | ✅ 30 days full | ⚠ Limited | ⚠ Limited |
| Total cost (TCP + RTU) | $59 | $218 combined | |
For $59 — the price of Simply Modbus RTU alone — you get TCP + RTU + ASCII + UDP, a full slave simulator, data logging, and a native 64-bit interface. Engineers who work with both TCP and RTU devices save over $100 compared to buying both Simply Modbus editions.
The transition takes under 5 minutes:
If you have a register list, import it from CSV to avoid manual entry. ModbusSimulator accepts standard CSV register maps with columns for address, name, type, and scaling.
Explore related tools and comparison pages:
ModbusSimulator offers a full-featured 30-day free trial — no credit card, no account. You get TCP + RTU + ASCII + UDP + slave simulator access from day one. After the trial, $59 one-time for a permanent license covering all modes.
Yes. ModbusSimulator supports FC01 (Read Coils), FC02 (Read Discrete Inputs), FC03 (Read Holding Registers), FC04 (Read Input Registers), FC05 (Write Single Coil), FC06 (Write Single Register), FC15 (Write Multiple Coils), and FC16 (Write Multiple Registers) — the full standard Modbus function code set.
Yes — this is ModbusSimulator's key advantage over Simply Modbus. The slave simulator can emulate up to 8 simultaneous devices with different Unit IDs, configurable register values, exception response injection, and configurable response delays. Use it to test SCADA, HMI, and master applications before the real hardware arrives.
Simply Modbus was originally built as separate desktop utilities for different protocols. This approach means engineers who need both TCP and RTU must purchase two licenses totaling $218. ModbusSimulator was designed from the start as a unified tool covering all Modbus variants in a single license.
Yes. ModbusSimulator works with virtual COM ports created by com0com (free), VSPE, or other virtual serial port software. This lets you run complete RTU master/slave testing on a single PC without any physical serial hardware.
TCP + RTU + ASCII + UDP + Slave Simulator · One tool · One license · $59 after trial
No credit card · No registration · Windows 10/11 64-bit