Component Snapshot At-a-Glance
- Model: 51305072-300
- Alt. P/N: 51305072-200 (CLCN-A A-path counterpart)
- Product Series: Honeywell TDC3000 / TPS LCN Local Control Network
- Hardware Type: Single-width rack slot CLCN-B LCN redundant paddle board
- Key Feature: Dedicated BNC LCN-B coax transceiver for dual-node redundant LCN network failover
- Primary Field Use: Establish secondary redundant LCN-B communication path for dual-node UCN/LCN chassis to avoid full network loss on single coax cable fault.
Hard-Numbers: Technical Specifications
- Protocol Support: Honeywell proprietary LCN Local Control Network synchronous bus
- Port Count: 1 x BNC coax LCN-B port; gold edge connector to chassis backplane
- Baud/Data Rate: Fixed LCN proprietary bus speed, synchronous node polling
- Operating Temperature: 0°C to +50°C operational cabinet; -40°C to +85°C storage
- Isolation Rating: 1500VDC galvanic isolation between LCN coax bus and chassis backplane logic
- Power Draw: Chassis backplane 24VDC, nominal 320mA, max 0.8W total module power
- Coax Interface: 75Ω LCN coax impedance matched BNC tee connector
- Vibration Tolerance: 0.5g continuous 10–60Hz cabinet vibration rating
- Shock Rating: 30g peak 11ms transient shock for offshore platform skids
- Certifications: CE EMC, UL recognized, ATEX Zone 2 cabinet compatible
- Form Factor: Standard TPS single slot paddle board, 114 × 12.7 × 118mm
- Weight: 0.16kg single board assembly
The Real-World Problem It Solves
Single-path LCN chassis only fitted with CLCN-A 51305072-200 boards lose all DCS node communication if the A coax cable cuts or shorts. Without matched CLCN-B hardware, operators get full blind spot on all UCN controllers, transmitters and history points during coax failure. Generic third-party LCN interface boards lack factory 75Ω impedance matching, creating signal reflection that triggers cyclic LCN timeouts and constant node drop alarms on large refinery LCN rings.Where you’ll typically find it:
- Refinery TPS dual-node NIM/HPM controller chassis running redundant LCN A/B network
- Fossil power plant boiler/turbine control cabinets with dual redundant LCN history modules
- Offshore FPSO legacy TDC3000 distributed control racks requiring fault-tolerant LCN communicationThis dedicated CLCN-B paddle board pairs with CLCN-A to deliver bumpless LCN failover, isolating single coax faults without cutting DCS node visibility.
Hardware Architecture & Under-the-Hood Logic
This passive transceiver paddle board contains isolated LCN signal conditioning circuitry; it does not run control logic, only regenerates LCN-B bus signals for dual-node chassis redundancy.
- Gold edge connector pulls regulated 24VDC chassis power and LCN backplane handshake signals to the board’s isolated transceiver circuit.
- Precision 75Ω impedance matching network matches LCN coax cable electrical properties to eliminate signal reflection on long cabinet-to-cabinet coax runs.
- Surge suppression components clamp lightning and welding transients on the BNC coax port to prevent PCB trace burnout.
- Bidirectional signal buffer transmits/receives synchronous LCN bus telegrams on the secondary B path separate from CLCN-A primary traffic.
- Front panel LED lights solid green for active LCN-B link; flashes red for coax open/short or impedance mismatch faults.
- Backplane handshake logic reports LCN-B link status to the chassis main node controller for system event journal logging and operator alarm generation.
Field Service Pitfalls: What Rookies Get Wrong
Installing Only CLCN-A 51305072-200 Without Matching CLCN-B 51305072-300
New technicians skip populating the B slot to cut spare part costs. Single LCN path operation creates a single point of failure; any coax damage drops all DCS node communication with zero failover.Field Rule: Every dual-node LCN chassis must install one CLCN-A (51305072-200) AND one CLCN-B (51305072-300) paddle board for full LCN redundancy.
Mismatched 50Ω CCTV Coax In Place Of 75Ω LCN Rated Coax
Crews reuse spare 50Ω coax cable for LCN-B runs to save material stock. Impedance mismatch causes severe signal reflection, triggering constant LCN node drop alarms and intermittent loss of HPM controller data.Quick Fix: Exclusively deploy Honeywell specified 75Ω LCN coax cable for all LCN A/B trunk runs; label coax reels by impedance rating to avoid mix-ups.
Missing LCN Bus Termination Resistor On End Nodes
Most apprentices remove or forget to install the 75Ω termination resistor on the last chassis BNC tee port. Unterminated bus signals reflect down the coax trunk, corrupting LCN polling frames and spawning continuous communication fault logs.Field Rule: Fit 75Ω termination resistor to the far end BNC tee of every LCN A/B coax trunk; remove termination resistors on all intermediate chassis nodes.
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.
