Bridge Modbus RTU and Modbus TCP on a single WBox. The gateway works as a serial-to-Ethernet Modbus gateway: a Modbus TCP master reaches the RS-485 serial slaves as if they were TCP devices, on one IP address.

Modbus RTU⇄WBoxgateway⇄Modbus TCPOne WBox gateway · native conversion · no PC

The two networks

Modbus RTU

Modbus RTU carries Modbus over an RS-485 serial line — the field level of meters, drives, sensors and PLCs.

Modbus TCP

Modbus TCP carries Modbus over Ethernet/IP (port 502) — used by SCADA systems, PLCs and IT platforms.

Further reading: Modbus RTU vs Modbus TCP: what is the difference? →

Typical use case

A SCADA system or PLC speaks Modbus TCP, but the meters, drives and sensors on site are Modbus RTU on RS-485. The WBox bridges them: the RTU slaves appear to the TCP master as TCP devices on a single IP — no serial port on the SCADA server and no serial cabling run back to the control room.

How the WBox bridges Modbus RTU and Modbus TCP

Enable the Modbus driver in both RTU and TCP roles. The WBox polls the RTU slaves on RS-485 (baud rate, parity, slave IDs) and exposes them as a Modbus TCP server (unit IDs mapped), or acts as a TCP client to an upstream master. Configurable polling and register caching protect the serial bus from a fast TCP master. The same gateway can also bridge to other protocols.

Frequently asked questions

Is the WBox a Modbus RTU/TCP gateway?

Yes. It bridges Modbus RTU (RS-485 serial) and Modbus TCP/IP on one device: a TCP master reaches the serial slaves as if they were TCP devices, on a single IP address.

Can several RTU slaves share one TCP connection?

Yes. The WBox polls all the RTU slaves on the RS-485 bus and presents them over Modbus TCP, mapped by unit ID — no serial port on the SCADA server and no per-device cabling back to the control room.

Can the WBox be the Modbus master or the slave side?

Either role: the WBox can be a Modbus TCP server exposing the RTU slaves, or a Modbus TCP client/master polling devices and republishing them — set per project.

Does a fast TCP poller overload the serial bus?

No. Configurable polling and register caching decouple the fast TCP side from the slower RS-485 bus, so the serial devices are polled at a safe rate.

What you need

One WBox gateway with the Modbus driver licence handles both the RTU and the TCP side:

Modbus Modbus Driver licence 100.00 CHF

Route Modbus RTU Modbus TCP on your project

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