Westermo L308F2-SM-LC20 3640-1450 Managed Fiber Switch – WeOS Series

Westermo L308F2-SM-LC20 (3640-1450): Single-Mode Fiber Managed Switch for Industrial Network Backbones

The Westermo L308F2-SM-LC20, order reference 3640-1450, is a DIN-rail-mounted managed Layer 2 Ethernet switch module with two 100BASE-FX single-mode LC fiber uplinks rated to 20 km and eight 10/100BASE-TX copper access ports. It operates on Westermo’s WeOS firmware platform, which provides a consistent CLI and SNMP management interface across the full Westermo product family. The module is certified to IEC 61850-3 and IEEE 1613, making it a direct fit for substation automation, railway trackside communication, and process control ring topologies where deterministic packet delivery and electromagnetic immunity are non-negotiable design constraints.

In a typical deployment, field devices — protection relays, RTUs, PLCs, or HMI panels — connect to the eight RJ45 access ports. The two SM LC20 fiber uplinks carry aggregated traffic to a core switch or SCADA server over existing single-mode cable plant, eliminating the need for intermediate repeaters across inter-building or inter-substation spans up to 20 km. Westermo’s proprietary Fast Recovery Network Technology (FRNT) provides ring redundancy with a failover time below 20 ms, independent of ring size — a deterministic characteristic that RSTP alone cannot guarantee in large topologies.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The L308F2-SM-LC20 is built around a dedicated Layer 2 ASIC switching fabric with a non-blocking 1.0 Gbps aggregate capacity. At 100 Mbps full-duplex on all ten ports simultaneously, the theoretical maximum throughput demand is 1.0 Gbps — the fabric is sized exactly at wire-rate with no oversubscription, which is a deliberate design choice for deterministic latency in process control environments where jitter accumulation across multiple hops degrades time-sensitive protocol performance.

EMC and Signal Isolation Architecture: The RJ45 copper ports incorporate 1500 V isolation transformers at the physical layer, providing galvanic separation between the switching fabric and field wiring. This is not a software feature — it is a passive hardware barrier that attenuates conducted interference from motor drives, contactors, and high-voltage switching transients that are endemic to substation and factory floor environments. The fiber uplink ports provide inherent galvanic isolation by design, eliminating ground loop currents across long inter-building cable runs.

FRNT Ring Arbitration Logic: Westermo’s Fast Recovery Network Technology operates at Layer 2 without relying on spanning tree topology recalculation timers. FRNT uses a dedicated control frame mechanism to detect link failure and signal the ring master to unblock the redundant port within a deterministic window of less than 20 ms, regardless of the number of nodes in the ring. This is architecturally distinct from RSTP, where convergence time scales with network diameter and can exceed 1–2 seconds in larger topologies. For protection relay GOOSE messaging, which has a maximum allowable transfer time of 4 ms under IEC 61850, the network infrastructure must recover faster than the application timeout — FRNT satisfies this constraint where RSTP does not.

Wide-Range DC Power Input: The 10–60 VDC input range is not achieved through a simple linear regulator but through a switching power supply stage internal to the module. This allows the L308F2-SM-LC20 to operate directly from 12 V, 24 V, or 48 V substation battery bus systems without external DC-DC converters, reducing BOM complexity and eliminating an additional failure point in the power distribution chain. Dual redundant power input terminals support parallel feed from two independent power sources with automatic switchover.

Thermal Design: The steel enclosure acts as a passive heat sink. With a maximum power dissipation of approximately 8 W, the thermal load per unit volume is low enough to sustain operation at +70 °C ambient without forced air cooling — a critical requirement for sealed outdoor cabinets and unheated trackside enclosures where fan-based cooling introduces maintenance intervals and failure modes.

System Integration Benefits

• Deterministic ring recovery under 20 ms: FRNT arbitration logic provides sub-20 ms failover independent of ring node count, meeting the network availability requirements of IEC 61850 GOOSE and SAMPLED VALUES applications without protocol-level workarounds.
• 20 km single-mode fiber reach: Eliminates optical repeaters and media converters for inter-substation or inter-building links up to 20 km, reducing active component count and associated failure probability in the optical path.
• Unified WeOS management plane: Consistent CLI syntax, SNMP MIB structure, and Web GUI across all WeOS devices reduces operator training overhead and enables centralized configuration management via WeConfig NMS or third-party SNMP platforms (PRTG, Nagios, Zabbix).
• 256-VLAN segmentation capacity: Supports separation of process control, safety instrumented system (SIS), engineering workstation, and management traffic on a single physical infrastructure, reducing inter-domain interference without requiring additional switch hardware.
• IEEE 802.1p QoS with 4 hardware queues: Priority queuing is implemented in hardware at the port level, ensuring that time-critical frames (GOOSE, PROFINET RT, EtherNet/IP) are not delayed by bulk data transfers or management traffic during congestion events.
• IEC 61850-3 and IEEE 1613 certification: Pre-qualified for the electromagnetic immunity, dielectric withstand, and environmental stress test requirements of power utility and railway standards, reducing the engineering effort required for system-level type testing.
• SNMP v3 with authentication and encryption: Supports SHA authentication and AES-128 encryption for management traffic, satisfying NERC CIP and IEC 62351 network security requirements without additional VPN overlay infrastructure.
• Passive convection cooling to +70 °C: No moving parts in the thermal management path eliminates fan failure as a maintenance event, extending mean time between maintenance (MTBM) intervals in sealed enclosures.
• Dual redundant DC power inputs: Parallel feed from two independent power sources with automatic switchover provides power path redundancy without external transfer switches or UPS bypass logic.
• RMON 1 and 2 statistics: Port-level traffic counters, error statistics, and history groups are accessible via SNMP, enabling proactive fault detection and bandwidth utilization trending without dedicated network probes.

Quality Assurance & Global Logistics

Every Westermo L308F2-SM-LC20 unit supplied by siemensplc.com is sourced through verified distribution channels with full supply chain traceability. Prior to dispatch, each module undergoes physical inspection covering enclosure integrity, label authenticity, serial number verification against Westermo’s product database, and firmware version confirmation. Original OEM packaging, including anti-static protection and factory seals, is preserved throughout the storage and handling process.

A Certificate of Conformance (CoC) is available upon request for project documentation and quality management system (QMS) records. Units are not sourced from grey-market or unverified secondary channels — counterfeit risk is mitigated at the intake stage through systematic verification procedures.

Logistics operations are based in Xiamen, China, with access to major international freight carriers including DHL Express, FedEx International Priority, UPS Worldwide Express, and consolidated sea freight for volume orders. Standard in-stock orders are processed and dispatched within 1–3 business days. Export documentation — commercial invoice, packing list, and certificate of origin — is prepared for all international shipments. Assistance with export licensing and customs classification (HS code 8517.62) is available upon request. Emergency procurement requests are handled on a priority basis — contact the sales team directly for expedited processing timelines.

Payment terms accepted: T/T (bank wire transfer), L/C (letter of credit for orders above threshold), PayPal, and major credit cards. Minimum order quantity is 1 piece. Volume pricing is available for project quantities — submit an RFQ with quantity and required delivery date for a formal quotation.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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