Application Scenarios
At a petrochemical complex, an I/A Series DCS control room sat 300 to 800 meters from three remote field cabinets, with cable trays routed through electrically noisy distribution areas. Copper links suffered recurrent CRC errors and intermittent packet loss. Deploying copper-port switches at each end would have required media converters to extend distance, adding failure points and management blind spots. The Foxboro X440-G2-24fx-GE4 RH102AN resolved this with a pure-fiber architecture: its 24 LC fiber ports connected I/A Series controllers and remote I/O in each cabinet over multimode fiber, while the four gigabit SFP uplink ports aggregated traffic to the control room core. Fiber immunity eliminated electrical noise from the control network, and a single switch handled all three cabinets, keeping the DCS topology flat and manageable.
Parameter
| Parameter | Value/Description |
|---|---|
| Product Model | X440-G2-24fx-GE4 RH102AN |
| Manufacturer | Foxboro (Emerson Automation Solutions) |
| Product Category | Managed industrial Ethernet switch, Layer 2/3 |
| Operating System | ExtremeXOS |
| Fixed Ports | 24 × 100BASE-FX, LC connectors |
| Uplink Ports | 4 × 1GBASE-X SFP (unpopulated) |
| Management Ports | 1 × 10/100/1000BASE-T out-of-band, 1 × RJ45 serial console |
| Switching Capacity | 12.8 Gbps |
| Forwarding Rate | 9.5 Mpps |
| Operating Temperature | 0°C to 60°C (extended-temperature model) |
| Power Input | 100–240 V AC, rear redundant power connector |
| Dimensions/Weight | 1U rack mount, approx. 3.93 kg |
Technical Principles and Innovative Values
- Purpose-Built High-Density 100BASE-FX Fiber Access: The core value of the X440-G2-24fx-GE4 RH102AN lies in packing 24 fiber ports into 1U. In DCS environments, control data between controllers and remote I/O does not require gigabit bandwidth, but link distance and noise immunity are paramount. 100BASE-FX over multimode fiber reaches up to 2 km on 62.5/125 µm cable, covering most intra-plant cabinet distances while avoiding the cost premium of gigabit fiber ports. This port configuration reflects an engineering philosophy of “sufficient and reliable” rather than peak performance.
- ExtremeXOS Deterministic Network Behavior: Running ExtremeXOS, the switch supports static routing, OSPF, BGP, and VRF for Layer 3 functionality. In redundant I/A Series DCS topologies, OSPF or static routes enable efficient path selection between control subnets, while ExtremeXOS process isolation reduces the risk of a single protocol stack failure cascading across the network. For scenarios requiring limited interworking between the DCS network and plant MES or historian systems, VRF support allows one physical switch to host multiple logically isolated routing domains.
- Extended Temperature Range and Redundant Power for Industrial Fit: The 24fx-GE4 is among the few X440-G2 variants rated for 0°C to 60°C operation . Control cabinet interior temperatures often exceed ambient during summer, and this margin sustains operation through HVAC faults or poor ventilation. The rear redundant power connector accepts an external RPS or second feed, consistent with the redundancy philosophy of I/A Series systems themselves.