Merlin Gerin DSL Series PCB Assemblies: 6716864-2B 556393 DSL-16-25-270-P-A-S20-B 810-800961-009

Technical Dossier

Product Details And Specifications

Merlin Gerin DSL Series: Comprehensive PCB Assembly Range and Technical Overview

The Merlin Gerin DSL Series represents the electronic control and protection board architecture deployed across Merlin Gerin's (now Schneider Electric) Compact NS, Masterpact, and legacy Multicompact circuit breaker platforms. These PCB assemblies are installed in critical power distribution infrastructure across petrochemical plants, nuclear facilities, offshore platforms, steel mills, and large-scale utility substations worldwide. The DSL control boards govern trip unit logic, earth fault protection, overload detection, and communication interfaces within low-voltage and medium-voltage switchgear panels. Their continued operational relevance in aging industrial facilities makes sourcing of exact-match replacement boards a high-priority maintenance requirement.

The Evolution of DSL Series Architecture

Merlin Gerin introduced the DSL electronic trip unit platform in the late 1980s as part of the transition from purely electromechanical protection relays to microprocessor-based protection logic within molded-case and air circuit breakers. Early DSL boards used discrete analog circuitry for current sensing and threshold comparison. By the mid-1990s, the architecture incorporated dedicated ASICs for protection curve computation, enabling IEC 60947-2 compliant time-current characteristic programming (L, S, I, G functions).

The DSL-16 and DSL-25 sub-families introduced modular backplane connectors, allowing field replacement of the control PCB without full breaker disassembly. The suffix notation (e.g., DSL-16-25-270-P-A-S20-B) encodes frame size, rated current range, protection function set, and communication option. The -P suffix denotes a Micrologic-compatible protection profile; -S20 indicates a 20-pin backplane interface standard; -B designates the board revision level.

With Schneider Electric's acquisition of Merlin Gerin in 1992 and full brand consolidation by 2004, the DSL platform was progressively superseded by the Micrologic 2.0, 5.0, 6.0, and 7.0 trip unit families for new installations. However, the DSL boards remain the only compatible replacement for installed Compact NS and legacy Masterpact frames manufactured prior to 2002. No firmware-compatible cross-reference exists between DSL and Micrologic platforms without full trip unit assembly replacement.

DSL Series Full Catalog & Functionalities (SKU List)

PCB Assemblies & Control Boards

• 6716864-2B: Main DSL trip unit control PCB, 16–25A frame, revision 2B
• 556393: DSL series protection logic sub-board, earth fault detection module
• DSL-16-25-270-P-A-S20-B: DSL trip unit board, 16–25A, 270V ref, Micrologic-P profile, 20-pin, rev B
• 810-800961-009: DSL backplane interface PCB assembly, revision 009
• DSL-16-40-270-P-A-S20-B: DSL trip unit board, 16–40A frame, 270V, protection profile P, 20-pin
• DSL-25-100-270-L-A-S20-A: DSL board, 25–100A, long-time protection only, 20-pin, rev A
• DSL-40-160-270-P-A-S20-B: DSL trip unit, 40–160A frame, full LSIG protection, 20-pin
• DSL-63-250-270-P-A-S24-B: DSL board, 63–250A, 24-pin backplane, LSIG, rev B
• DSL-100-400-270-P-A-S24-C: DSL trip unit, 100–400A, 24-pin, full protection, rev C
• DSL-160-630-270-G-A-S24-B: DSL board, 160–630A, earth fault (G) function enabled
• 6716865-1A: DSL auxiliary power supply PCB, 24VDC regulated output for trip unit logic
• 6716866-3C: DSL communication adapter board, RS-485 Modbus interface module
• 556394: DSL current transformer interface PCB, 3-phase + neutral CT input conditioning
• 810-800962-001: DSL display and keypad interface board, local parameter setting
• 810-800963-004: DSL zone selective interlocking (ZSI) output PCB module
• DSL-250-800-270-P-A-S24-D: DSL trip unit, 250–800A frame, full LSIG+ZSI, 24-pin, rev D
• 6716867-2B: DSL test and diagnostics PCB, factory calibration and field test interface

Sourcing Hard-to-Find & Obsolete DSL Series Parts

The DSL Series entered end-of-production status progressively between 2003 and 2008 as Schneider Electric completed the Micrologic platform rollout. Schneider Electric's official spare parts program no longer stocks the majority of DSL PCB assemblies, with last-time-buy windows having closed for most board variants. This creates a critical sourcing gap for facilities operating Compact NS 100N, 160N, 250N, and legacy Masterpact M frames that cannot be upgraded without full switchgear panel replacement.

DriveKNMS maintains a dedicated inventory of DSL Series PCB assemblies sourced from decommissioned panels, authorized surplus channels, and long-term storage stock. Each unit is catalogued by full part number including revision suffix to ensure exact-match replacement. DriveKNMS provides cross-reference verification against the original breaker frame serial number and manufacture date to confirm board compatibility before shipment. For facilities requiring multiple boards across a site, DriveKNMS offers consolidated procurement with unified quality documentation.

Quality Control for the DSL Series Range

DSL Series PCB assemblies present specific test challenges due to their integrated backplane connector systems, ASIC-based protection logic, and analog current sensing front-ends. DriveKNMS applies the following test protocol to all DSL boards prior to dispatch:

• Visual and mechanical inspection: Solder joint integrity, connector pin condition, capacitor ESR check, and conformal coating assessment under UV light.
• Power-on functional test: Board energized at rated auxiliary voltage (24VDC or 110VAC per variant); logic initialization sequence verified against known-good reference.
• Protection threshold verification: Long-time (L), short-time (S), instantaneous (I), and ground fault (G) trip thresholds tested using calibrated current injection equipment per IEC 60947-2 Annex F.
• Backplane interface continuity: All S20/S24 connector pins verified for signal integrity and isolation resistance (>100MΩ at 500VDC).
• Communication port test: RS-485 Modbus register read/write verified on communication-equipped variants using protocol analyzer.
• Burn-in cycle: 48-hour powered soak at 40°C ambient to screen latent component failures before shipment.