Master connections
Connect to devices to read and write coils and registers. Organize polling in tabs, split and dock poll views, or detach them into separate windows.
TCP · UDP · RTU · ASCII
OCTOBRAIN SOFTWARE · MODBUS WORKBENCH
Modbus work,
in one place.
Connect to devices, read and write registers, and simulate servers. Octo Modbus is a Windows desktop tool for development and field diagnostics.
Free download · Pro licenses available · The shared installer starts with Free. Unlock Pro features with a license key. Download Free or choose a Pro license below.
// WATCH OCTO MODBUS
See Octo Modbus in action
Explore Master connections, the Simulator, display formats, charts, and split Poll views through actual application screens.
// BUILT FOR MODBUS WORK
Tools from connection to validation
Connect over supported protocols, inspect server behavior, and analyze register values in one desktop workflow.
Server and Windows service
Respond to external master requests with the server feature, or run a server using the standalone Windows service host.
TCP · UDP · RTU · ASCII
Built-in simulator
Run a server and inspect or edit simulated data tables. Open multiple data panels to compare values.
TCP · UDP · RTU · ASCII
Data types and byte order
Interpret values with advanced integer and floating-point types and configurable byte order.
SIGNED · UNSIGNED · FLOAT · ENDIAN
Charts and logging
Inspect changing values in charts and record or export communication data for diagnostics.
CHART · LOG · CSV
Repeatable workflows
Organize recurring checks with register maps, workspaces, and the automation API.
MAPS · WORKSPACE · AUTOMATION API
// FREE & PRO
Choose the edition for your workflow
The shared installer includes Free by default. Activate a Pro license key to unlock Pro features. Free includes one concurrent connection and up to three Poll windows for basic Modbus communication.
| Feature | Free | Pro |
|---|---|---|
| Concurrent connections | 1 | Multiple |
| Poll windows | Up to 3 | Unlimited |
| Basic Modbus read/write | Included | Included |
| Raw frame viewer | Included | Included |
| Advanced data types and Endian | — | Included |
| Server simulator | — | Included |
| Charts, data logging, CSV export | — | Included |
| Register maps, workspaces, automation API | — | Included |
Pro license pricing
Prices are in USD, excluding tax. Purchase is perpetual, and 1.x updates are free. Each key is for one PC. To transfer, deactivate the key on the old PC before activating it on the new PC.
After the first online activation, offline use is supported. Payment is processed by Lemon Squeezy. The license key is sent separately and automatically by Octo Modbus to the purchase email address. Enter the key in the app under Help → License.
Installer and user guides
Windows x64 installer EXEKorean user guide PDFKorean user guide WordEnglish user guide PDFEnglish user guide WordWindows Server Service · Standard ZIP
Separate Server Service package: administrator rights are required to register and manage the service. Installation does not start it automatically by default. The Standard service requires a signed license file issued for that device. Contact support to request a device license.
The installer is signed with Microsoft Artifact Signing. Windows displays the publisher as 옥토브레인 (OctoBrain). SmartScreen messages may vary with the PC security policy and file reputation.
License, updates, transfers, and support
The purchased version is licensed for perpetual use. Updates within the 1.x version series are free. Availability and terms for future major-version updates will be announced separately.
To move a license to another PC, deactivate it on the old PC before activating it on the new PC. For license support, contact support@octo-brain.com.
// FAQ
Frequently asked questions
How are Free and Pro provided?
The shared installer is available as a free download. Basic features are included in Free; activate a Pro license key to unlock Pro features.
Which connection modes are supported?
Master and Server features support Modbus TCP, UDP, RTU, and ASCII.
How do licenses and updates work?
The purchased version is licensed for perpetual use, and updates within the 1.x version series are free. Availability and terms for future major-version updates will be announced separately. Internet access is required for initial activation; offline use is supported afterward. Each license key is for one PC.
Can I move a license to another PC?
Yes. Deactivate the license on the old PC before activating it on the new PC.
Where can I get product support?
Contact support@octo-brain.com.
What if I need multiple PCs?
Packs for 3, 5, and 10 PCs are planned, with a separate license for each PC. See the table above for pack pricing.
Octo Modbus 1.0.0
Start with Free in the shared installer and unlock the features you need with a Pro key. Refund Policy · Privacy Policy