QModMaster vs ModScan32: Which Modbus Master to Use
ModScan32 is a veteran commercial Modbus master from WinTECH Software; QModMaster is the free, open source alternative. Both talk to Modbus slaves — they differ in price, platform, and workflow.
Feature Comparison
| Feature | QModMaster | ModScan32 |
|---|---|---|
| License & Price | LGPLv3 — free, including commercial use | Commercial (WinTECH) — check the vendor’s site for current pricing |
| Platforms | Windows 7/10/11, Linux | Windows |
| Protocols | Modbus RTU + TCP | Serial, TAPI modem, and Modbus/TCP network; RTU and ASCII modes (per vendor) |
| Bus Monitor | Built-in raw-hex bus monitor | Debug mode shows the actual serial data streams (per vendor) |
| Portable | Yes — portable .zip, no installer | Desktop Windows application (see vendor docs) |
| Writing Registers | Function codes 05, 06, 15, 16 | Double-click any address/value to write (per vendor) |
| Support | Community only — no official tech support | Commercial vendor |
Where QModMaster Wins
- Free (LGPLv3) with no license paperwork — install it on every bench PC you own.
- Modbus TCP plus Linux support, so the same tool covers serial and Ethernet devices on any OS.
- Raw-hex bus monitor for seeing exactly what goes over the wire when something misbehaves.
Where ModScan32 Holds Its Ground
- Legacy serial workflows: TAPI modem (dial-up) connections for remote sites — something QModMaster simply doesn’t do.
- Debug mode that displays the actual serial data streams, per the vendor’s documentation.
- Simple write workflow: double-click an address/value pair to change it, with decimal, hex, binary, and floating-point display formats.
Frequently Asked Questions
Does ModScan32 support Modbus TCP?
Per the vendor’s documentation, ModScan32 supports direct serial connections, TAPI modem connections, and network connections using the Modbus/TCP protocol, with both RTU and ASCII transmission modes.
Is ModScan32 still maintained?
Check the vendor’s site for the current version and support status before planning around it.
Which is better for a beginner?
QModMaster: free, portable, and this site walks you through your first session in ten minutes. ModScan32 makes more sense once you specifically need its serial/modem workflow.
Can I run ModScan32 on Linux?
ModScan32 is a Windows application. If your bench runs Linux, QModMaster is the practical choice.