Kongsberg RMP420 306712 Remote IO Module

Technical Dossier

Product Details And Specifications

Kongsberg RMP420 Series: Comprehensive Module Range and Technical Overview

The Kongsberg RMP420 series is a Remote I/O module platform developed by Kongsberg Maritime and Kongsberg Digital for use in distributed control system (DCS) architectures deployed across global heavy industry. Installations span offshore oil & gas platforms, onshore refineries, petrochemical complexes, LNG terminals, and nuclear auxiliary systems. The RMP420 backplane-based architecture enables high-density I/O marshalling in environments where panel space, cable routing, and signal integrity are critical engineering constraints. Its modular design allows field engineers to replace individual I/O cards without interrupting the entire rack, a requirement in continuous-process industries where unplanned downtime carries significant financial and safety consequences.

The RMP420 platform interfaces with Kongsberg's K-Pos, K-Chief, and SDP (Satellite Differential Positioning) supervisory layers, as well as third-party SCADA systems via standard fieldbus protocols. Its deployment in safety-instrumented systems (SIS) and basic process control systems (BPCS) across more than two decades of industrial operation has established it as a long-lifecycle platform with an extensive installed base requiring ongoing spare parts support.

The Evolution of RMP420 Architecture

The RMP420 series emerged from Kongsberg's transition from proprietary hardwired control panels to distributed, rack-mounted I/O in the late 1990s. Early revisions used parallel backplane communication with limited hot-swap capability. Subsequent hardware revisions introduced serial backplane buses, improving noise immunity and enabling longer rack extensions in large marshalling cabinets.

Mid-generation RMP420 modules introduced HART pass-through capability on analog input cards, allowing field device diagnostics without additional multiplexers. Later revisions added redundant power supply inputs and improved EMC shielding to meet IEC 61000-4 immunity levels required for offshore and nuclear auxiliary applications.

As the platform matured, Kongsberg introduced the RMP500 and RMP600 series as forward-compatible successors. However, the RMP420 installed base remains active at thousands of sites globally, and direct hardware replacement with newer series requires engineering re-qualification — making original RMP420 spare parts the preferred maintenance solution for most operators.

RMP420 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced modules within the Kongsberg RMP420 platform. Modules are classified by functional category.

Remote I/O & Backplane Modules

• RMP420 306712: Remote IO module, rack-mount backplane interface unit for distributed I/O marshalling
• RMP420 306700: Base remote I/O processor module, primary rack controller for RMP420 chassis
• RMP420 306701: Redundant remote I/O processor, hot-standby CPU for fault-tolerant rack configurations
• RMP420 306702: Backplane bus extender module, extends I/O rack capacity across cabinet segments
• RMP420 306703: Rack power distribution module, internal 24 VDC bus management for RMP420 chassis

Analog Input (AI) Modules

• RMP420 306710: 8-channel analog input, 4–20 mA, 12-bit resolution, HART pass-through enabled
• RMP420 306711: 16-channel analog input, 4–20 mA, single-ended, high-density marshalling card
• RMP420 306714: 8-channel thermocouple input, multi-type (J/K/T/E/R/S/B), cold-junction compensated
• RMP420 306715: 8-channel RTD input, PT100/PT1000, 3-wire and 4-wire configurations supported

Analog Output (AO) Modules

• RMP420 306720: 8-channel analog output, 4–20 mA, 12-bit resolution, loop-powered field devices
• RMP420 306721: 4-channel analog output, 0–10 V / 4–20 mA selectable, isolated outputs

Digital Input (DI) Modules

• RMP420 306730: 32-channel digital input, 24 VDC, sink/source configurable, status LED per channel
• RMP420 306731: 16-channel digital input, 120 VAC, optically isolated, for high-voltage field signals
• RMP420 306732: 32-channel digital input, NAMUR sensor compatible, intrinsically safe barrier interface

Digital Output (DO) Modules

• RMP420 306740: 32-channel digital output, 24 VDC, 0.5 A per channel, short-circuit protected
• RMP420 306741: 16-channel relay output, SPDT contacts, 2 A / 250 VAC, for motor starter and valve control

Communication & CPU Modules

• RMP420 306750: Modbus RTU/TCP communication adapter, serial and Ethernet dual-port gateway
• RMP420 306751: PROFIBUS DP slave adapter, 12 Mbit/s, for integration with third-party DCS masters
• RMP420 306752: Ethernet IP adapter module, EtherNet/IP Class 1 and Class 3 connection support

Power Supply Modules

• RMP420 306760: 24 VDC rack power supply, 10 A output, wide-range AC input 85–264 VAC
• RMP420 306761: Redundant power supply module, N+1 configuration, automatic failover without interruption

Sourcing Hard-to-Find & Obsolete RMP420 Parts

Kongsberg has transitioned active development to the RMP500 and RMP600 platforms. The RMP420 series is classified as a mature/end-of-life product line, with factory new stock no longer available through standard distribution channels. DriveKNMS maintains a dedicated inventory of RMP420 modules sourced from decommissioned systems, controlled-environment warehouses, and verified surplus channels.

All RMP420 units offered by DriveKNMS are subject to full functional testing prior to dispatch. For operators managing long-term maintenance contracts on RMP420-equipped systems, DriveKNMS provides consignment stocking agreements, allowing critical spare modules to be held on-site or in a bonded warehouse against future demand. This eliminates lead-time risk for unplanned failures in continuous-process environments where replacement procurement windows are measured in hours, not weeks.

DriveKNMS also supports cross-reference engineering: if a specific RMP420 part number is unavailable, our technical team evaluates compatible substitute modules within the RMP420 family or identifies validated RMP500-series equivalents where a hardware upgrade path exists.

Quality Control for the RMP420 Range

RMP420 modules present specific test challenges due to their backplane-dependent architecture. Standalone bench testing of I/O cards without a functioning backplane and processor module produces incomplete results. DriveKNMS operates a dedicated RMP420 test rack that replicates the original Kongsberg chassis environment, enabling full functional verification of each module under realistic operating conditions.

Test procedures for RMP420 units include: backplane communication handshake verification, channel-by-channel signal injection and measurement for all AI/AO/DI/DO modules, HART communication integrity check on HART-enabled analog cards, relay contact resistance measurement on DO relay modules, power supply load regulation and ripple testing, and thermal soak at rated operating temperature for a minimum of 4 hours. Modules that pass all test stages are issued a DriveKNMS test certificate with individual channel data and are shipped with ESD-protective packaging.