Model Definition

490: Modicon network accessory series code

NAA: Modbus Plus signal repeater type

27101: Standard model for signal amplification and network isolation

Technical Specifications

Hardware & Interface

Protocol: Modbus Plus (MB+), 1 Mbps baud rate

Ports: Two Modbus Plus ports for segment connection

Connector: Terminal block for field wiring

Input Voltage: 24 V DC

Power Consumption: Low power design

Dimensions: Standard industrial enclosure size

Weight: ~0.35 kg

Environmental & Performance

Operating Temp: 0 °C to +60 °C

Storage Temp: -25 °C to +80 °C

Relative Humidity: 5% to 95%, non-condensing

Isolation: Electrical isolation between two network segments

Max Extension: Effectively extends network transmission range

Core Functions

Signal Amplification: Boosts weak Modbus Plus signals for long-distance transmission

Network Isolation: Separates different network segments to suppress surge and interference

Network Expansion: Increases total number of accessible nodes on the whole network

Fault Isolation: Prevents local segment faults from affecting the entire network

Application Scenarios

Long-distance Modbus Plus network layout in factory workshops

Large-scale Modicon PLC systems requiring multiple network segments

On-site renovation and maintenance of legacy Modbus Plus automation lines

Industrial environments with strong electromagnetic interference

Usage & Maintenance

Mount the device on standard DIN rail inside control cabinet

Supply 24 V DC power and connect Modbus Plus cables to corresponding ports

Check cable connection status and running indicators regularly

Keep the device ventilated and free from dust accumulation

Replace with modern Ethernet communication solutions during system upgrade