Component Snapshot At-a-Glance

• Model:
• Alt. P/N: 12P3368X012, 12P3368X022, Revision E factory build variant
• Product Series: Emerson DeltaV S-Series LocalBus I/O Infrastructure Parts
• Hardware Type: Single-width dual left-port LocalBus carrier extender module
• Key Feature: Dual left-side D-shell connectors, passes full 12VDC/8A LocalBus power + serial bus signal in single extender unit
• Primary Field Use: Stretch DeltaV LocalBus routing across split cabinet layouts, add remote I/O carriers without relocating main controller rack

Hard-Numbers: Technical Specifications

• Protocol Support: DeltaV proprietary LocalBus 312.5kbps rack communication only, no external fieldbus compatibility
• Port Count: Dual left-side D-Sub LocalBus extension ports; right edge backplane finger mates directly to S-series I/O carrier slot
• Baud/Data Rate: Fixed LocalBus 312.5kbps synchronous serial transfer
• Operating Temperature: -40°C ~ +70°C full rated ambient; stable continuous run 0℃~+60℃ preferred rack temp
• Isolation Rating: 1500V channel-to-chassis surge isolation between LocalBus and cabinet earth ground
• Power Draw: Pass-through 12VDC LocalBus rated 8A max feed-through; internal quiescent draw ≤12mA idle
• Max Extension Length: Cumulative LocalBus cable limit 6.5m total across all chained extenders per DeltaV design spec
• Vibration Rating: 1mm peak-peak 5–16Hz; 0.5g constant 16–150Hz compressor/plant floor vibration tolerance
• Enclosure Rating: IP20 cabinet-only indoor mounting, ISA G3 industrial contaminant compliant
• Certification: Class I Div2 hazardous location approved for refinery/chemical rack installation

The Real-World Problem It Solves

Fixed factory-length DeltaV backplane carriers lock I/O slots into a single contiguous rack section; splitting equipment across two cabinet bays cuts off LocalBus power and communication without extension hardware. Rerouting entire controller backplane to shift carriers wastes dozens of man-hours during site retrofit and shutdown windows.

Where you’ll typically find it:

• Petrochemical distillation rack: Split I/O between primary DCS cabinet and adjacent auxiliary junction cabinet for field valve DI/DO grouping
• Coal boiler feedwater control panel: Extend LocalBus to separate MCC-mounted I/O carrier near pump starter cabinets
• Offshore wellhead control skid: Bridge compact stacked cabinet compartments with limited internal backplane routing space

This dual-port left extender splits LocalBus routing cleanly and eliminates full carrier rework for split-cabinet DCS layouts.

Hardware Architecture & Under-the-Hood Logic

This extender snaps into standard 1-wide empty slot on left end of DeltaV S-series I/O carrier, no onboard CPU; passive PCB bus trace design routes backplane power and serial signal straight to dual left D-sub ports with inline surge filtering components.

1. Right-edge gold finger pins tap full 12VDC LocalBus power and LocalBus serial signal directly from host carrier backplane traces
2. Internal PCB split bus distributes identical power/signal to two independent left-side D-shell extension connectors
3. SMD transient voltage suppressors clamp incoming surge spikes before bus signals exit to field extension cabling
4. External extension cables carry full LocalBus feed to downstream remote I/O carriers chained via matching modules
5. All downstream I/O points register back to main DeltaV controller over continuous extended LocalBus path

Field Service Pitfalls: What Rookies Get Wrong

Hot-Plugging Extender Under Energized LocalBusNew techs pull or insert while rack powered live; momentary backplane short collapses full LocalBus on entire carrier, triggering mass I/O fault and process interlock dropouts, seen repeatedly during refinery turnaround work.

• Field Rule: Cut carrier rack 12VDC feed before installing/removing any LocalBus extender module.

Exceeding Total 6.5M Cumulative Bus Cable LimitStacking multiple chained extenders with long field cabling pushes total LocalBus run over factory 6.5m cap; bus attenuation causes intermittent point dropouts and random MOD FAULT alarms across remote I/O cards.

• Quick Fix: Split oversized bus runs onto secondary independent LocalBus domain with separate DeltaV controller carrier when length exceeds 5m.

Mismatched Non-OEM Extension Cable Wiring PinoutUsing custom hand-wired D-sub cables instead of Emerson factory LocalBus cord reverses bus clock/data pins, downstream remote carriers fail enumeration entirely with steady red module fault lights.

• Field Rule: Only factory DeltaV specified LocalBus extension cables permitted for all outbound wiring.

Commercial Availability & Pricing Note

Please note: The listed price is for reference only and is not binding. Final pricing and terms are subject to negotiation based on current market conditions and availability.