Honeywell 51304542-100 LCN A Cable Interface Converter

Description

Product Introduction & Engineering Value

The Honeywell 51304542-100 provides the physical LCN A-side interface in legacy Honeywell control-system hardware. Its job is to connect the node-side LCN circuitry to the corresponding Local Control Network cable path, making it an important part of the communication architecture rather than a conventional process I/O channel.

For maintenance teams working on older TDC 3000 installations, the part-number suffix matters. 51304542-100 is the A-side KLCN_CA board, while 51304544-100 is the corresponding KLCN_CB B-side board. The two should not be treated as interchangeable just because they perform related interface functions.

Technical Specifications

The Enhanced PLC Gateway documentation is particularly useful here: it lists 51304542-100 as KLCN_CA and 51304544-100 as KLCN_CB, while the EC-compliant configuration uses different CLCN A/B part numbers.

Important specification note

Several third-party listings publish electrical values, communication rates, connector counts, or environmental specifications for this part, but those figures are inconsistent with one another. For example, one supplier describes it as a 24 VDC board, while another publishes unrelated RS-485/Ethernet specifications. Those values should not be treated as Honeywell-certified specifications without the applicable Honeywell manual.

For procurement and replacement work, the 51304542-100 / KLCN_CA identification and system configuration are much more reliable selection criteria than generic specifications copied from reseller databases.

51304542-100

51304542-100

Field Application & the “Trench” Experience

Picture a legacy TDC 3000 node supporting an Enhanced PLC Gateway. During maintenance, the node’s LCN communication path begins showing intermittent communication faults. The technician initially suspects the LCN cable, but the cable checks out. After isolating the node hardware, attention moves to the rear interface assembly. The installed board is marked 51304542-100, confirming the KLCN_CA A-side interface.

The replacement process is not simply “remove one PCB and install another.” The technician needs to confirm the K2LCN/front-board relationship, LCN A/B assignment, connector orientation, grounding, and node configuration before returning the gateway to service. Honeywell’s EPLCG service documentation explicitly identifies this board as part of the Dual Node Module board complement.

Specific application scenarios

• Enhanced PLC Gateway communication node — LCN interface hardware used in an EPLCG assembly.
• Legacy TDC 3000 LCN node maintenance — replacement of an A-side cable interface board during communication troubleshooting.
• Dual-path LCN architecture — A-side interface maintenance where a corresponding B-side KLCN board is also installed.
• Legacy control-system lifecycle support — maintaining installed hardware when original spare inventory has become difficult to source.

QA & Testing SOP

For a replacement 51304542-100, a useful receiving inspection should follow this sequence:

1. Part-number verification
Confirm the board label reads 51304542-100 and that the board designation corresponds to KLCN_CA.

2. Hardware inspection
Check the PCB, connectors, edge contacts, mounting hardware, labels, and any visible components for corrosion, physical damage, contamination, or signs of unauthorized repair.

3. Configuration verification
Compare the replacement against the removed board and the applicable EPLCG/TDC 3000 documentation. Pay particular attention to whether the installation requires the A-side KLCN_CA or B-side KLCN_CB.

4. Functional test
Where a qualified Honeywell test environment is available, verify LCN communication through the intended node configuration before placing the equipment back into process service.

5. Documentation
For New Surplus inventory, retain photographs of the original label, packaging, date/lot markings where available, and test report. For refurbished stock, obtain a description of the actual test performed.

The Veteran’s Tech Trap Guide

⚠️ Trap #1 — A-side and B-side are not interchangeable.

This is the most obvious mistake. 51304542-100 = KLCN_CA / LCN A, while 51304544-100 = KLCN_CB / LCN B. Verify the complete node configuration before ordering a replacement.

⚠️ Trap #2 — Do not confuse the non-EC and EC hardware families.

The EPLCG documentation identifies 51304542-100 for KLCN_CA, whereas the EC-compliant configuration uses 51305072-200 for CLCN A. A physically similar board with a different part number should not be substituted solely on appearance.

⚠️ Trap #3 — Don’t diagnose the board before checking the LCN path.

Intermittent LCN faults can originate from cabling, connectors, grounding, adjacent node hardware, or the interface board itself. Swapping the KLCN_CA immediately can turn a communication problem into a second problem.

PRO TIP: Before removing the original board, photograph the part number, board designation, cable routing, connector positions, and node slot location. For legacy Honeywell hardware, that record can save substantial troubleshooting time during recommissioning.

Dynamic FAQ

What is Honeywell 51304542-100?

It is the KLCN_CA LCN A Cable Interface Converter Board used in Honeywell legacy control-system hardware, including the Enhanced PLC Gateway architecture.

Is 51304542-100 an I/O module?

It is better classified as an LCN interface/converter board, not a conventional analog or digital process I/O module. Some reseller databases incorrectly or loosely describe it as an “I/O control board,” but Honeywell’s EPLCG documentation identifies its specific function as KLCN_CA / LCN A Cable Interface Converter Board.

What is the difference between 51304542-100 and 51304544-100?

51304542-100 is KLCN_CA for the LCN A path. 51304544-100 is KLCN_CB for the LCN B path. The distinction is important in dual-path LCN installations.

What system uses the 51304542-100?

Honeywell documentation lists it as part of the Enhanced Programmable Logic Controller Gateway (EPLCG) installed in a standard TDC 3000 Dual Node Module. In the documented 2-slot configuration, the K2LCN front board is paired with the KLCN_CA rear board.

Is 51304542-100 New Surplus?

The condition depends on the individual unit being offered. Some suppliers advertise this part as brand new or factory-original, but the part number itself does not establish New Surplus authenticity. Check the board label, packaging, manufacturing markings, physical condition, and supplier test documentation before purchasing.

What warranty is available?

Warranty is seller-specific. Some suppliers currently advertise 12-month warranties for 51304542-100, but this is a commercial supplier term rather than a Honeywell technical specification. Confirm the exact warranty, DOA coverage, test procedure, and return conditions before placing an order.