Westermo 3640-1450 L308F2-SM-LC20 Retrofit Fiber Switch

Westermo 3640-1450 L308F2-SM-LC20 Retrofit Fiber Switch: Legacy System Compatibility & Smooth Upgrade

The Westermo 3640-1450 L308F2-SM-LC20 is a managed industrial Ethernet switch engineered for single-mode fiber connectivity in demanding automation environments. As legacy L308F series units reach end-of-life, this model serves as the primary retrofit-compatible replacement, enabling engineers and system integrators to modernize aging control networks without redesigning the entire communication architecture. Whether you are upgrading a SCADA backbone, replacing a failed fiber node in a substation ring, or extending the service life of an existing Westermo-based network, the L308F2-SM-LC20 delivers the port density, fiber reach, and protocol compatibility required for a controlled, low-risk migration.

Sourced directly from authorized channels and fully tested prior to shipment, each unit supplied by NINERMAS is backed by a 12-month warranty. Stock is maintained to support urgent replacement orders, minimizing unplanned downtime on critical production lines and utility networks.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Replacing the L308F2-SM-LC20 within a live automation network requires careful pre-migration planning to avoid disrupting upstream controllers and downstream field devices. Before scheduling the cutover window, engineers should audit the existing control cabinet layout to confirm that the replacement unit’s DIN rail footprint and fiber bend radius clearance are acceptable. In most L308F-series installations, the cabinet wiring harness connects directly to the RJ45 copper ports, so terminal block labeling and cable dressing should be documented photographically before removal of the legacy switch.

On the power side, the existing 24 V DC or 48 V DC supply rail feeding the original L308F must be verified against the L308F2-SM-LC20’s input range. If the cabinet uses a Westermo PWR-220-24 or similar DIN rail power supply, the dual redundant input capability of the replacement unit can be leveraged immediately by adding a secondary feed from an available breaker, improving overall system availability without additional hardware cost.

For sites running Westermo’s FRNT (Fast Recovery of Network Topology) ring protocol, the replacement switch must be pre-configured with the correct FRNT role — either master or slave — before insertion into the ring. Failure to set this correctly will cause a temporary loop condition during commissioning. The configuration can be prepared offline using the Web GUI connected to a laptop on a bench network, then verified against the existing ring’s node list before the live swap.

In multi-switch installations where the L308F2-SM-LC20 sits alongside other Westermo devices such as the Lynx 206-F2G, Viper 212-T1, or DDW-225 serial device servers, the SNMP management configuration — including community strings, trap destinations, and port descriptions — should be exported from the legacy unit if still accessible, or reconstructed from the site’s network documentation. SCADA systems polling device status via Modbus TCP or IEC 60870-5-104 over the Ethernet backbone will continue operating normally during the swap provided the replacement unit’s IP address and VLAN membership are configured identically to the outgoing device before the cutover.

Where the legacy network includes Westermo Redfox 5000 series managed switches or Wolverine DSL extenders at remote outstations, the fiber uplink from the L308F2-SM-LC20 must be tested for optical power budget compliance. The SM-LC20 designation confirms a 20 km single-mode reach at 1310 nm, which is sufficient for most substation-to-control-room fiber runs. Use an optical power meter to verify received power at both ends before finalizing the installation, and retain the test results as part of the site commissioning record.

For applications where the legacy switch also provided serial-to-Ethernet conversion via an attached Westermo Falcon 4622 or similar serial server, confirm that the serial device server’s IP routing and COM port mapping remain intact after the Ethernet switch replacement. The L308F2-SM-LC20 does not affect serial port configuration on attached devices, but VLAN segmentation changes during the retrofit could inadvertently isolate serial traffic if not accounted for in the VLAN migration plan.

Downtime Control During System Migration

Minimizing production downtime during an L308F series switch replacement depends on three factors: pre-staging the replacement unit, executing a rapid physical swap, and validating network restoration before releasing the system back to operations.

Pre-staging involves configuring the L308F2-SM-LC20 on a bench with the target IP address, VLAN assignments, FRNT role, SNMP parameters, and port descriptions loaded and saved to non-volatile memory. This step eliminates all configuration work from the live cutover window, reducing the actual switch-out to a physical disconnect-reconnect sequence that typically takes under 15 minutes for an experienced technician.

During the physical swap, the recommended sequence is: (1) notify the control room operator and place the affected loop or segment in manual control if the process permits; (2) disconnect fiber uplinks first to isolate the ring segment; (3) remove DC power from the legacy unit; (4) release the DIN rail clip and extract the unit; (5) insert the pre-staged L308F2-SM-LC20 and secure to the rail; (6) reconnect DC power and verify LED status; (7) reconnect fiber uplinks and confirm FRNT ring convergence on the network management system; (8) verify SCADA data flow and field device communication before returning the loop to automatic control.

Original PLC program logic residing in upstream Siemens S7, Allen-Bradley ControlLogix, or Schneider Modicon controllers is entirely unaffected by the Ethernet switch replacement, provided the IP addressing scheme is preserved. HMI screens connected via the same Ethernet backbone will experience a brief communication interruption during the fiber reconnection step, typically lasting less than 30 seconds with FRNT enabled, which is within the timeout tolerance of most SCADA and DCS communication drivers.

Post-swap validation should include a ping sweep of all field devices reachable through the replaced switch, a review of SNMP trap logs for any unexpected port state changes, and a confirmation that historian data is flowing without gaps. Retain the pre-shipment functional test report supplied with the unit as part of the site maintenance record.

Retrofit Support FAQ

Q1: Is the Westermo 3640-1450 L308F2-SM-LC20 a direct drop-in replacement for the original L308F-SM-LC20?
Yes. The L308F2-SM-LC20 shares the same DIN rail form factor, LC fiber connector type, RJ45 copper port layout, and DC power input range as the original L308F-SM-LC20. The primary differences are enhanced management features (SNMPv3, CLI) and improved redundancy protocol support (RSTP in addition to FRNT). No mechanical or wiring modifications are required for a standard replacement.

Q2: What pre-shipment testing is performed on each unit?
Every unit supplied by NINERMAS undergoes a functional power-on test confirming port link establishment on all copper and fiber interfaces, management GUI accessibility, and basic VLAN operation. A test report is included with each shipment. Units are shipped in original or equivalent protective packaging to prevent transit damage.

Q3: How do I handle the FRNT ring configuration during the cutover?
The replacement unit should be pre-configured with the correct FRNT role (master or slave) matching the outgoing device before insertion into the live ring. The FRNT role is set via the Web GUI under the Redundancy menu. If the original unit’s role is unknown, check the network documentation or temporarily connect a laptop to an adjacent switch’s management port to query the ring topology before proceeding.

Q4: What is the warranty coverage and what does it include?
NINERMAS provides a 12-month warranty on the Westermo 3640-1450 L308F2-SM-LC20 covering hardware defects under normal operating conditions. The warranty period begins from the date of shipment. In the event of a confirmed hardware fault, NINERMAS will arrange a replacement unit. Warranty claims should be initiated by contacting sale@ninermas.com with the order reference and a description of the fault.