DIN-Rail 1-Port RS485 to Ethernet Device Server | Modbus/MQTT gateway

The 1CH-RS485-ETH is an industrial RS485 to Ethernet converter specifically designed for demanding industrial environments. This versatile serial device server integrates multiple functions including serial port server, Modbus gateway, MQTT gateway, and RS485 to JSON conversion.

This industrial Ethernet serial server features RS485 and Ethernet ports, with screw terminal power input accepting 9-24V wide voltage. The rail-mount case design offers compact dimensions and easy installation, making it ideal for data acquisition, IoT gateway applications, safety & security IoT systems, and intelligent instrument monitoring.

As a serial to Ethernet converter, the device enables seamless connectivity between serial devices and Ethernet networks. The Modbus serial to Ethernet converter capability allows for efficient protocol conversion, while the Ethernet to serial gateway functionality ensures reliable data transmission across different network architectures.

The industrial serial device server provides a cost-effective solution for modernizing legacy equipment and enabling IoT connectivity in industrial automation, building management, and energy monitoring applications.

When used as a Modbus gateway, it supports Modbus TCP to Modbus RTU, so that the host computer can use the Modbus TCP protocol to collect data from RS485 Modbus RTU devices. On the contrary, if the RS485 end is used as a master station, it can also be used. It supports more advanced Modbus gateway functions, including configurable Modus gateways, storage-type Modbus gateways, etc., which fully meet various configurations and usages of Modbus gateways. The multi-host function it supports allows multiple computer master stations to access an RS485 slave device at the same time.

Advanced Modbus Gateway Capabilities

This device is more than just transparent transmission. It is a transparent bridge between Modbus TCP (host) and Modbus RTU (slave) and allows reverse master slave routing. It has improved multi-host support to avoid possible data collision in complex network where multiple SCADA servers can poll a single RS485 slave. Edge-computing also includes configurable routing and storage-type polling to reduce network latency.

Supports uploading collected data in JSON format, automatic data collection, and supports Modbus RTU, 645 instrument version 97, 645 instrument version 07, and various non-standard RS485 protocols. Users can use Vircom to configure the uploaded data format and JSON keywords. When uploading, it can support MQTT protocol, HTTP POST protocol, HTTP GET protocol, transparent transmission protocol, and various non-standard network protocols.

Q1: Our legacy SCADA software only recognizes local COM ports and doesn’t support TCP/IP. Can we still use this gateway?

A: Absolutely. The device supports a “Real Com Driver” mode. By installing our Vircom utility on your SCADA PC, it creates a virtual local serial port (e.g., COM3) and seamlessly maps all Ethernet traffic to it. This is the fastest way to bring legacy equipment onto an IP network without rewriting a single line of code.

Q2: Since it supports “Multi-host” polling, won’t the half-duplex RS485 bus crash if multiple SCADA servers send Modbus TCP requests simultaneously?

A: It won’t crash because the gateway handles the traffic queuing. When multiple TCP masters send queries at once, the gateway buffers the requests in its memory and dispatches them sequentially down the RS485 bus. Field Tip: We highly recommend increasing the Response Timeout setting in your SCADA software by 50–100ms to accommodate this physical layer queuing delay.

Q3: The specs mention specific cloud platforms. Can I connect this to AWS IoT or my own private Mosquitto MQTT broker?

A: Yes. The pre-configured platforms are just for quick setup. For private clouds or overseas deployments, you can manually input your custom MQTT broker IP or domain via the Vircom configuration tool. Since the gateway supports highly customizable JSON formatting, you can freely define your own Topics and Payloads to match your exact network architecture.

Q4: How should I wire the RS485 bus if my field meters are heavily distributed across the facility?

A: The physical layer supports up to 32 slave nodes but you have to wire them in a strict daisy-chain topology. Never use a star topology. Always install a 120-ohm termination resistor at the far end of the bus to prevent signal reflection. If your devices are separated by trenches or exceed copper wiring limits, we suggest replacing the physical cable with our [Point-to-Point Wireless RS485 Converters]

Documents

[User Manual] Valtoris-1CH-RS485-ETH User Manual

Utilities

[Setup Software] VirCom7.22

🔌 Wiring & Troubleshooting Guides

• [RS232 to Ethernet Cable Pinout: Two Common Wiring Diagrams] — Before wiring your field meters to the gateway’s terminal block, consult this guide for standard RS485 A/B pinouts and 120-ohm termination resistor placement to eliminate signal reflection.
• [Fixing Timeout Errors: How to Set Up a Modbus RTU to TCP Gateway] — Resolve “communication timeout” errors when multiple SCADA systems attempt to poll the same gateway simultaneously, and learn the correct routing settings to ensure stable Modbus TCP-to-RTU translation.