The GW-225i is a Modbus TCP-RTU/ASCII gateway that allows a Modbus/TCP host to communicate with Modbus RTU/ASCII serial devices over an Ethernet network, eliminating the cable length limitation of traditional serial communication devices. The module can be used to create a pair connection application (as well as a serial-bridge or serial tunnel application) and can then route data over TCP/IP between two Modbus RTU/ASCII serial devices, which is useful when connecting mainframe computers, servers, or other serial devices that use Modbus RTU/ASCII protocols and do not have Ethernet capabilities.

The read cache function is used to store previous requests and responses in the GW-225i module's memory buffer. When other HMI/SCADA master controllers send the same requests to the same RTU slave device, the cached response is returned immediately. This function greatly reduces the load on serial port communication, ensures faster TCP responses, and improves the stability of the entire system.

The GW-225i module features a powerful 32-bit MCU that enables efficient network traffic management and also has an integrated web server that provides an intuitive web management interface allowing users to modify the module's configuration, including DHCP/static IP, gateway/mask, and serial port settings.

The module contains a dual watchdog, which includes a CPU watchdog (for hardware functions) and a host watchdog (for software functions). The CPU watchdog automatically resets the CPU if the integrated firmware operates abnormally, while the host watchdog automatically resets the CPU if there is no communication between the module and the host (PC or PLC) for a predefined period of time (system timeout). The dual watchdog is an important feature that ensures continuous operation of the module, even in harsh environments. In addition, the GW-225i also adds 3000 VDC isolation and a +/-4 kV ESD protection component that diverts potentially harmful charge from sensitive circuitry to protect the module and equipment from sudden and momentary electrical currents.

With 2 Ethernet ports, the GW-225i allows daisy-chaining, which ensures flexibility in device placement, simplifies installation, and reduces infrastructure costs. The GW-225i module offers true compliance with the IEEE 802.3af standard (classification, Class 1) and Power over Ethernet (PoE) functionality using a standard Category 5 Ethernet cable to receive power from a PoE switch such as the NS-205PSE. If there is no PoE switch on site, the module also accepts power from a DC terminal block.

Technical Features

CPU Module

• CPU: 32-bit ARM

COM Ports

• Ports: 2 x RS-485/422
• Baud Rate: 115200 bps Max.
• Bias Resistor: Yes, 1 KΩ
• Parity: None, odd, even, mark, space
• Data Bits: 5, 6, 7, 8
• Stop Bits: 1, 2
• Node Address: 254 (max.)
• ESD Protection: +/- 4KV
• Power Isolation: 1000 VDC
• Signal Isolation: 3000 VDC

Ethernet

• Ports: 10/100 Base-TX, 8-pin RJ-45 x 2, (Auto-negotiation, Auto-MDI/MDIX, LED indicator) PoE (IEEE 802.3af, Class 1)

Power Supply

• Consumption: 0.07 A at 24 VDC
• Power over PoE: IEEE 802.3af, Class 1
• Power over Terminal Block: +12 ~ 48 VDC

Mechanical Specifications

• Enclosure: Plastic
• Dimensions (L x W x H): 97mm x 33mm x 126mm
• Installation: DIN rail mounting

Environmental Conditions

• Operating Temperature: -25 ~ +75 °C
• Storage Temperature: -30 ~ +80 °C
• Humidity: 10 ~ 90% RH, non-condensing