PUSR USR-DR134 RS485 to Ethernet Serial Device Server Instruction Manual

1. Introduction

The PUSR USR-DR134 is a compact, industrial-grade serial device server designed for transparent data transmission between RS485 serial ports and Ethernet networks. It functions as a Modbus Gateway, converting Modbus RTU to Modbus TCP, and supports various protocols including MQTT, TCP, UDP, and HTTP for flexible integration into industrial automation and IoT systems. Its ultra-small DIN-rail design allows for easy installation in space-constrained environments.

2. Key Features

• Ultra-small size serial server device with one serial port.
• Realizes transparent transmission between RS485 and Ethernet ports.
• Supports advanced features such as timeout restart, DHCP, DNS, heartbeat packet, and registration packet.
• Modbus Gateway functionality: Connects to PLC, SCADA systems, or private servers for local or remote monitoring.
• Industrial-grade design with hardware watchdog for reliable, non-downtime operation in harsh environments.
• Easy integration and installation with DIN-rail and locating hole mounting.

Image: The PUSR USR-DR134 serial device server, shown next to a lipstick to illustrate its compact "lipstick" size. This highlights its suitability for space-constrained installations.

Image: An overview diagram showcasing the USR-DR134's core features, including its ultra-small form factor, RS485/RS232 to Ethernet conversion capability, and transparent data transmission.

3. Setup and Installation

3.1 Physical Installation

The USR-DR134 is designed for easy installation using DIN-rail mounting or locating hole mounting.

1. Securely attach the device to a standard DIN-rail by snapping it into place.
2. Alternatively, use the locating holes to mount the device to a surface with appropriate screws.
3. Ensure proper ventilation around the device for optimal performance.

Image: The USR-DR134 device mounted on a DIN-rail, demonstrating its compact size and simple installation method.

3.2 Wiring Connections

Connect the RS485 serial device to the serial port terminals on the USR-DR134.

Connect an Ethernet cable from the device's Ethernet port to your network switch or router.

Provide power to the device using the designated power input terminals. Refer to the device labeling for correct voltage and polarity.

Image: A detailed view of the USR-DR134's ports and LED indicators, including POW (Power), WORK, COM (Serial Communication), and LINK (Ethernet Link).

3.3 Initial Configuration

The device can be configured via its web interface or dedicated configuration software.

1. Connect your computer to the same local network as the USR-DR134.
2. Use the provided configuration tool or access the device's default IP address in a web browser.
3. Configure network parameters (IP address, subnet mask, gateway) and serial port settings (baud rate, data bits, parity, stop bits).
4. Set up the desired operating mode (e.g., TCP Client, TCP Server, UDP, Modbus Gateway).

4. Operating Instructions

4.1 Transparent Transmission

The USR-DR134 facilitates bidirectional transparent data transmission. Data sent to the serial port is forwarded to the Ethernet network, and data received from the Ethernet network is sent to the serial port.

Image: A diagram illustrating the bidirectional transparent transmission function, showing how serial devices communicate with an Internet/LAN network through the USR-DR134.

4.2 Modbus Gateway Functionality

The device supports Modbus RTU to Modbus TCP conversion, enabling Modbus RTU devices to communicate with Modbus TCP masters over an Ethernet network.

• Configure the device as a Modbus RTU master or slave, and a Modbus TCP master or slave as required by your application.
• It supports Modbus autonomous polling and JSON autonomous reporting for efficient data acquisition.

Image: Illustration of Modbus RTU to Modbus TCP conversion, showing how the USR-DR134 bridges communication between Modbus devices and a monitoring system, including Modbus polling and RTU/JSON reporting.

4.3 MQTT/TCP/UDP/HTTP Protocols

The USR-DR134 supports various network protocols for versatile data communication:

• MQTT: Ideal for IoT applications, enabling lightweight messaging to MQTT brokers.
• TCP/UDP: Standard network protocols for reliable (TCP) or fast (UDP) data transfer.
• HTTP: Allows for web-based communication and data reporting.

Image: The USR-DR134 configured as an MQTT Gateway, demonstrating its ability to connect to cloud platforms like PUSR Cloud, AWS, and Thingsboard for topic distribution and custom modes.

5. Maintenance

• Keep the device clean and free from dust and debris to ensure proper ventilation.
• Periodically check all cable connections to ensure they are secure.
• Refer to the manufacturer's website for any available firmware updates to enhance performance and security.
• In industrial environments, ensure the operating temperature and humidity remain within the specified ranges.

6. Troubleshooting

6.1 Power LED (POW) is Off

Solution: Check the power supply connection and ensure it provides the correct voltage (e.g., 5-36V DC) and polarity. Verify the power source is active.

6.2 Link LED is Off or Flashing Incorrectly

Solution: Verify the Ethernet cable is securely connected to both the device and the network switch/router. Check the network cable for damage. Ensure the network port on the switch is active.

6.3 COM LED is Off or Flashing Incorrectly

Solution: Check the RS485 serial connection to the external device. Verify the serial port settings (baud rate, data bits, parity, stop bits) on the USR-DR134 match those of the connected serial device.

6.4 No Data Transmission

• Confirm all physical connections (power, Ethernet, serial) are correct and secure.
• Verify the device's IP address and network settings are correctly configured and accessible from your network.
• Check the operating mode settings (e.g., TCP Client, TCP Server) and ensure they match your application's requirements.
• For Modbus applications, ensure Modbus RTU/TCP settings are correct, including slave IDs and register addresses.
• If using advanced features like heartbeat or registration packets, ensure they are configured properly.

6.5 Device Unresponsive

Solution: If the device becomes unresponsive, try power cycling it. The built-in hardware watchdog should automatically restart the device in case of a system malfunction, ensuring continuous operation.

7. Specifications

8. Warranty and Support

Warranty: The PUSR USR-DR134 comes with a 2-year warranty. Please retain your proof of purchase for warranty claims.

Support: For technical assistance, troubleshooting, or further inquiries, please visit the official PUSR website or contact their customer support.

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9. Product Overview Video