Model Definition

490: Modicon network accessory series code

NAA: Modbus Plus signal repeater category

27104: Standard model of Modbus Plus repeater

Technical Specifications

Hardware & Interface

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

Ports: Two independent Modbus Plus ports for segment interconnection

Connection: Screw terminal blocks for field wiring

Operating Voltage: 24 V DC

Power Consumption: Low power design

Weight: ~0.37 kg

Dimensions: Standard industrial enclosure

Environmental & Performance

Operating Temp: 0 °C to +60 °C

Storage Temp: -25 °C to +80 °C

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

Isolation: Complete galvanic isolation between two network segments

Anti-interference: Reinforced circuit design for harsh industrial environments

Core Functions

Signal Amplification: Restores and boosts weak signals for long-distance data transmission

Network Segmentation: Isolates electrical noise and prevents single-segment faults from spreading

Capacity Expansion: Increases the maximum number of nodes and overall coverage of MB+ network

Reliable Transmission: Ensures stable communication under complex on-site conditions

Application Scenarios

Long-distance Modbus Plus network layout in large factories

Multi-segment networking for large-scale Modicon PLC systems

Routine maintenance and retrofitting of legacy MB+ production lines

Industrial sites with strong electromagnetic interference

Usage & Maintenance

Mount the device on standard DIN rail inside control cabinets

Connect 24 V DC power supply and Modbus Plus cables to corresponding terminals

Inspect wiring and status indicators regularly during operation

Keep the unit well ventilated and free from dust

Migrate to modern Ethernet communication solutions during overall system upgrade