MB3280 MOXA MGate Modbus TCP to RTU/ASCII Gateway

The MB3280 MOXA (MGate MB3280) is an industrial 2-port Modbus gateway designed to integrate multiple Modbus RTU or ASCII serial networks directly into modern Modbus TCP Ethernet systems. Featuring two software-selectable DB9 serial ports supporting RS-232, RS-422, and 2-wire/4-wire RS-485 interfaces, the MB3280 MOXA provides double the device density of single-port gateways, bridging field instrumentation, power meters, PLCs, and marine telemetry hardware with supervisory SCADA networks.

Capable of supporting up to 16 simultaneous Modbus TCP master connections, the MB3280 MOXA can route requests across both serial channels to manage up to 62 serial slave devices (31 per port). Outfitted with Moxa’s Automatic Data Direction Control (ADDC®) and intuitive web/utility management interfaces, it delivers high-performance protocol conversion, reduced cabinet wiring, and simplified deployment across industrial control systems.

Key Features of the MB3280 MOXA

• Dual Serial Channel Architecture: Features two independent software-configurable DB9 male ports for controlling separate RS-232, RS-422, or RS-485 serial loops.

• Bi-Directional Protocol Conversion: Seamlessly converts between Modbus TCP over Ethernet and Modbus RTU/ASCII protocols over serial.

• Expanded Slave Capacity: Manages up to 62 Modbus RTU/ASCII serial slave devices across both ports (up to 31 per port) while serving 16 concurrent TCP masters.

• Automatic Data Direction Control (ADDC®): Eliminates RS-485 timing and driver control issues on 2-wire and 4-wire multidrop bus networks.

• Flexible Power Input: Features a terminal block power input operating from 12 to 48 VDC for reliable deployment in industrial control panels.

• Streamlined Setup & Monitoring: Configurable via Moxa’s MGate Manager utility, Telnet, or a standard web browser interface.

Primary Applications

• Multi-Loop Industrial Monitoring: Aggregating RS-485 power meters, flow transmitters, and variable frequency drives (VFDs) onto central Ethernet SCADA platforms

• Substation & Marine Automation: Connecting legacy RS-485 serial RTUs and generator monitoring equipment to vessel or plant control backbones

• Factory Floor PLC Integration: Linking multiple independent serial PLC subnetworks to supervisory Ethernet control software

Technical Specifications

Package Contents

• 1 × MB3280 MOXA MGate Gateway Unit

• 3-pin Terminal Block Power Connector

• Quick Installation Guide & Document Access Sheet