1. what you need to know before starting
The [👉 Valtoris 1CH-RS485-ETH Modbus Gateway] is a versatile RS485 data acquisition device and IoT gateway designed for demanding industrial environments. It combines the functions of a serial port server, Modbus gateway, MQTT gateway, and RS485 to JSON converter in one unit.
If you’re working with MCGS and need to bring data from Modbus RTU devices into your SCADA system, this guide walks through the setup step by step. We’ll cover hardware configuration, software settings, testing, and a few real‑world tips that don’t always make it into the manuals.
Figure 1: 1CH-RS485-ETH Overview
Modbus TCP to Modbus RTU Protocol Conversion
The conversion between Modbus TCP and RTU is straightforward. For example, a Modbus RTU write register command like 01 06 00 01 00 01 19 CA sent from an RTU device is received by the Valtoris gateway via RS485 and converted to Modbus TCP format: 00 00 00 00 00 06 01 06 00 01 00 01. This TCP command is then transmitted to the Modbus TCP device over Ethernet.
This conversion allows Modbus RTU data to travel over Ethernet while preserving addresses, function codes, and registers—so both sides see the same data.
2. Device setup: not as complicated as it looks
2.1 First, set the IP address
The first step is to configure the IP address of the Valtoris 1CH-RS485-ETH so it’s on the same subnet as your SCADA system. Use the device’s web interface—just plug it into the same switch, open a browser, and enter the default IP (check the quick start guide).
For example, if your SCADA PC is at 192.168.1.222, set the gateway to something like 192.168.1.188 (with subnet mask 255.255.255.0 and default gateway 192.168.1.1 if needed). The default Modbus TCP port is 502, and you’ll rarely need to change it.
Figure 2: Device Configuration Settings
2.2 Advanced Configuration Options
For more advanced configurations, the Valtoris Modbus gateway offers several modes through its industrial-grade design:
Storage-based Modbus Gateway: This mode allows the device to cache commands from the SCADA system, improving data retrieval speeds
Non-storage Modbus Gateway: The device does not support caching but supports multi-master communication and bus conflict detection
Client as Modbus Slave: This is used when collecting data from Modbus TCP slaves and integrating with Modbus RTU master devices
Simple Modbus TCP to RTU Conversion: This mode simplifies the conversion but does not support advanced features like multi-host or storage functionality
| Mode | Description | Best Use Case |
|---|---|---|
| Storage-based Modbus Gateway | Caches SCADA commands for faster data retrieval | High-speed polling, systems needing reduced latency |
| Non-storage Modbus Gateway | No caching; supports multi-master and bus conflict detection | Complex networks with multiple masters accessing the same bus |
| Client as Modbus Slave | Modbus TCP devices act as slaves to a Modbus RTU master | Integrating TCP devices into legacy RTU networks |
| Simple TCP to RTU Conversion | Basic conversion without advanced features | Simple point-to-point applications |
Figure 3: Advanced Options for Modbus Gateway
If you’re unsure which mode to pick, start with Non-storage—it’s the most forgiving in mixed environments. You can change it later in the web interface under “Modbus Mode.”
3. Setting up MCGS
3.1 Setting Up Devices in MCGS
MCGS, a SCADA software platform developed by KunLun Tongtai, allows users to rapidly build and configure supervisory control and data acquisition systems. The Valtoris industrial serial server integrates seamlessly with this platform.
To configure the device, create a Generic TCP/IP Parent Device and select Modbus TCP as the child device. This serial communication server ensures reliable data transmission between your RS485 devices and the SCADA system.
Figure 4: Device Window in MCGS
Figure 5: TCP/IP Parent Device Setup
3.2 Device Property Settings
After adding the device, configure the Modbus RTU address for the slave device (typically set to 1). This serial device server ensures proper communication between the Modbus master (MCGS) and the Modbus slave (RS485 device) through its robust industrial design.
Figure 6: Device Property Settings
4. Testing the connection
4.1 Use a simulator first
Before you connect to the hardware you should try it out with a Modbus slave simulation software, like the one from Witte. This Modbus slave simulation software will help you. You need to set it to the COM port this is important if you are using a USB-to-RS485 adapter.. You can use a TCP port. Make sure the baud rate and parity match the settings on your device. Then you can hit connect. When you do this you should see the Modbus registers updating. There should be no errors, with the Modbus connection.
Figure 7: Connection Setup in Modbus Slave
Figure 8: Modbus Slave Definition
4.2 Check values in MCGS
In MCGS runtime, look at the channels you created (holding registers, etc.). If a channel reads 0, that’s usually good—Modbus often returns 0 when there’s no error. If you see error codes, double‑check the IP, port, and slave address. Try reading a few registers with function code 03—they should match the simulator’s values.
Figure 9: MCGS Device Properties Setup
Figure 10: Test Results in MCGS
5. Things that might come up
Packet sticking
Modbus RTU relies on timing to separate frames. When converted to TCP, multiple frames can get bundled into one packet—this is called “sticking.” When devices do not work properly you should try making the gateways frame interval timeout a little. For example you can change it from 10 milliseconds to 20 milliseconds. People who work with these devices say that this fix works for 90 percent of the problems, with devices not working smoothly.
Security note
Modbus TCP has no built‑in security. A quick Shodan search reveals thousands of exposed Modbus devices. If your gateway is on a shared network, consider putting it on a dedicated VLAN or enabling IP whitelisting (Valtoris supports this) to restrict access.
5. Final thoughts
Setting up a Modbus gateway isn’t complicated once you know the steps: assign an IP, pick a mode, configure MCGS, and test. What separates a reliable setup from a troublesome one is attention to details like frame timeouts and network security.
We’ve used Valtoris gateways in several projects and they’ve been solid. But more important than the brand is matching the hardware to your actual needs—number of devices, polling frequency, and network layout. If you’re unsure, start simple and test.
Hope this guide saves you some time—and maybe a few headaches.
Ready to implement this setup? If you are upgrading your facility’s legacy network, secure your [👉 Valtoris 1CH-RS485-ETH directly from our online shop ] for fast shipping and guaranteed MCGS compatibility.
Looking for broader integration strategies? Explore our comprehensive industrial automation case studies and enterprise solutions on the [👉 Valtoris Corporate Website ].
