Here’s what can be confidently determined about the Honeywell 05423300 REV E Measurex PCBA, Processor/LAN based on available industrial part records and legacy Measurex documentation:

🔍 Product Summary — Honeywell 05423300 REV E

Part Name: PCBA, Processor/LAN

Manufacturer: Honeywell (Measurex division)

Application: Industrial process control system PCB assembly (Measurex platform) (Oncare Digital Assets)

The 05423300 PCBA is a printed circuit assembly used inside Honeywell Measurex distributed control systems (DCS) or process control racks. It’s categorized as a processor board with LAN capabilities, likely responsible for coordinating control logic and network communication within the Measurex rack. (Oncare Digital Assets)

🧠 What This Board Is

🧩 Functionality

Processor Module: Acts as one of the main control/processing boards in a Measurex system.

LAN Interface: Indicates network communication—likely used to interface with other chassis modules or host systems (e.g., remote diagnostics, operator stations, or distributed node communications).

Legacy PLC/DCS Component: Measurex systems were early distributed control systems for industrial automation (especially paper manufacturing). Honeywell acquired Measurex in 1997. (维基百科)

📌 Known Characteristics of Similar Measurex Processor Boards

Measurex processor boards typically have the following traits (similar to what you’d expect for 05423300):

CPU / Control Logic: Often based on legacy industrial microprocessors tailored to control loops and I/O processing.

Communication Interfaces: Might include proprietary LAN backplane signaling or standard interfaces adapted for rack communication.

Multilayer PCB: Designed for rugged use inside industrial PLC/DCS cabinets.

No Official Modern Datasheet Publicly Available: Honeywell does not publish current datasheets for discontinued Measurex boards, so exact CPU type, memory, clock, or electrical specs aren’t readily available in public catalogs. (Oncare Digital Assets)

📦 Typical Use Cases

Control Rack Processor: Works with I/O modules, sensor interfaces, analog/digital converters, and other control boards to execute process logic.

Network Communication: The “LAN” designation typically means it supports communication over a local industrial network or bus system inside the rack.

Maintenance & Replacement: Often sourced as a replacement PCB in legacy Measurex systems where original OEM support has ended.

📌 Notes on Honeywell/Measurex Part Listings

In Honeywell’s parts catalogs, the 05423300 appears with the description: PCBA, PROCESSOR/LAN which distinguishes it from other Measurex CPU modules (e.g., standard processors, control processors, etc.). (Oncare Digital Assets)

While the search listings don’t provide specific electrical or firmware details, they confirm the following context:

Part No.Description

05423300PCBA, Processor/LAN (your part)

05414200PCBA, Control Processor

05413900PCBA, Control Processor, BSC/LAN (similar networking role)

05329200Standard 86/88 Processor PCB

05366300Formation Processor PCB

📌 What’s Not Readily Available

Due to the age of Measurex systems and discontinued status:

Official Honeywell datasheets for 05423300 REV E are not publicly hosted by Honeywell.

Firmware details, CPU hardware type, instruction sets, pinouts, and power requirements require access to internal service manuals or legacy documentation.

OEM service manuals (often proprietary) would include installation, power spec, pinouts, and communication protocols.

⚙️ Tips If You’re Working With This Board

Check system documentation/manuals from your system’s rack enclosure—Honeywell Measurex manuals often include board-level detail.

Handle as industrial control hardware — these boards can be sensitive to electrostatic discharge.

Power & interfacing: These modules typically rely on the rack backplane for power; they don’t run standalone without their system chassis.

LAN interface: If connecting externally, ensure you know whether the LAN is proprietary or standard Ethernet.

If you have access to the system backplane documentation or can share a photo of the board’s connectors/labels, I can help interpret the pinouts and power requirements!