Allen-Bradley 1785-KE PLC-5 Communication Interface Module – Obsolete PLC-5 Spare Part

Technical Dossier

Product Details And Specifications

Allen-Bradley 1785-KE PLC-5 Communication Interface Module – Obsolete PLC-5 Spare Part

The 1785-KE is a Data Highway Plus (DH+) communication interface module designed for use in Allen-Bradley PLC-5 processor systems. It provides the critical DH+ network link that allows PLC-5 processors to communicate with programming terminals, SCADA systems, HMI panels, and peer controllers. Without this module, the entire communication backbone of a PLC-5 rack becomes non-functional.

RFQ support for obsolete parts: Send the model number, required quantity and destination so DriveKNMS can confirm sourcing options before quotation.

Solving the Discontinued Hardware Crisis

The Allen-Bradley PLC-5 platform was introduced in the 1980s and became one of the most widely deployed programmable logic controller families in North American and global heavy industry — including automotive assembly, oil refining, chemical processing, pulp and paper, and water treatment. Rockwell Automation officially discontinued the PLC-5 product line, but tens of thousands of installed systems remain in active operation globally.

Q: How are RFQ terms confirmed?
A: Quantity, required condition, documentation needs, destination and sourcing route are confirmed during RFQ review before quotation.

Condition & Reliability Assurance

Obsolete parts carry inherent risk if sourced without discipline. DriveKNMS applies a 5-step QA protocol to every 1785-KE unit before it leaves our facility:

Step 1 – Visual and Physical Inspection: Full board-level inspection for physical damage, corrosion on edge connectors and backplane pins, cracked solder joints, and damaged port connectors. Units with any structural compromise are rejected.

Step 2 – Electrolytic Capacitor Assessment: PLC-5 era modules contain electrolytic capacitors with a finite service life. Each unit is assessed for capacitor bulging, leakage, or ESR (Equivalent Series Resistance) degradation. Where necessary, capacitors are replaced with equivalent-spec modern components.

Step 3 – Firmware Version Verification: The 1785-KE firmware version directly affects compatibility with specific PLC-5 processor revisions. We document and disclose the firmware revision of each unit so your engineering team can confirm compatibility before installation.

Step 4 – Pin and Connector Integrity Check: Backplane connector pins are inspected under magnification for oxidation, bending, and contact resistance. DH+ port connectors are tested for continuity and mechanical integrity.

Key Features for System Maintenance

Drop-in Replacement: The 1785-KE installs directly into the existing PLC-5 rack slot with no hardware modification. No rewiring, no rack reconfiguration.

No Reprogramming Required: Replacing a 1785-KE does not require modification of the PLC-5 application program. The processor retains its logic; only the communication interface is restored. This eliminates the need for control system engineers to be on-site for software work during the replacement.

Q: Can you support multi-unit or repeat RFQ requests?
A: Yes. Send the model list, target quantity and destination so DRIVEKNMS can review sourcing options and quote the requirement as a project RFQ.

Q: How do I confirm the correct firmware revision for my system?
A: Provide your PLC-5 processor model number and current firmware revision when placing your inquiry. Our technical team will cross-reference compatibility and confirm the appropriate 1785-KE firmware revision for your application.