Kongsberg Norcontrol RDi-32, RAi-16, RDo-16, MEI, ESU & Remote I/O Modules

Kongsberg / Norcontrol marine automation systems use a modular Distributed Processing Unit (DPU) and Remote I/O architecture to collect field signals, process alarms, drive outputs and communicate with shipboard automation networks.

The units shown in the SM MARINE SERVICE™ stock image belong to this legacy Kongsberg/Norcontrol remote-I/O family, with RDo-16 markings visible on multiple modules.

These older modules remain highly important because many vessels still operate K-Chief, DataChief C20, AutoChief and related Norcontrol/Kongsberg automation systems.

Kongsberg's current K-Chief 600 documentation confirms the same architectural concept: distributed standard I/O modules communicate across CAN and network infrastructure, allowing alarm monitoring, machinery control, ballast, cargo, HVAC, power-management and propulsion applications to be integrated into the vessel automation system.

What Are Kongsberg Remote I/O / DPU Modules?

A remote I/O module interfaces between field equipment and the central marine automation system.

Instead of running every sensor and relay cable directly to one central processor, Kongsberg's architecture places distributed modules around the ship.

These modules may receive:

• Digital ON/OFF signals
• Analogue sensor signals
• Temperature values
• Pressure measurements
• Tank levels
• Engine alarm contacts
• Pump and valve feedback
• Generator information

or provide commands to:

• Relays
• Solenoid valves
• Pumps
• Motors
• Alarms
• Control circuits

The data is then transmitted to the K-Chief, DataChief or AutoChief control environment.

Kongsberg RDi-32 – Remote Digital Input Module

One of the most common legacy modules is the:

RDi-32
Part No.: 8100154

The RDi-32 is a 32-channel Remote Digital Input Module.

A current market listing identifies RDi-32 Part No. 8100154 as a multi-purpose distributed processing unit used for digital input signals, with an 18–32VDC supply on a documented revision.

Typical RDi-32 signals include:

Pump RUN / STOP
Motor TRIP
Valve OPEN / CLOSED
High-level switch
Low-level switch
Pressure-switch alarm
Common machinery alarm
Generator trip
Purifier alarm
Safety contact

For many older K-Chief/DataChief systems, the RDi-32 is one of the most frequently requested spare modules.

Kongsberg RDi-32A – Part No. 8100172

Another related variant is:

RDi-32A
Part No.: 8100172

The DataChief C20 instruction material identifies RDi-32A separately from standard RDi-32.

Current replacement listings describe the 8100172 variant as a 32-channel digital-input module used particularly for active input signals, with multiple documented revisions including D1, D3 and E2.

Therefore:

RDi-32 and RDi-32A should not automatically be treated as interchangeable.

The exact part number and revision should always be checked.

Kongsberg RAi-16 – Remote Analogue Input Module

RAi-16
Part No.: 8100148

is a 16-channel Remote Analogue Input Module.

Commercial and marine automation references consistently identify 8100148 as the RAi-16 16-channel analogue input module.

A documented RAi-16 unit includes:

Part No.: 8100148
Revision: E1
CAN Open
HA451671A
Made in Norway.

Typical RAi-16 input applications include:

Pressure transmitters
Temperature transmitters
Tank-level transmitters
Flow transmitters
Current signals
Voltage signals
Resistance-based measurements depending on configuration

For search purposes, buyers often type both:

RAI-16

and

RAi-16

so both forms should be included in SEO content.

Kongsberg RDo-16 – Remote Digital Output Module

The modules visible in the provided stock photograph are marked:

RDo-16

The legacy Kongsberg part number widely associated with RDo-16 is:

8100155.

RDo-16 is a 16-channel Remote Digital Output Module used to control external devices through digital/relay outputs.

Typical marine applications can include:

Pump start/stop commands
Valve control
Solenoid control
Alarm outputs
Indicator lamps
Machinery interlocks
Generator auxiliary commands

An AutoChief engineering reference specifically describes adding RDO-16 units for various relay outputs such as alarms and indications.

This makes RDo-16 important not only in alarm-monitoring systems but also in propulsion and machinery control applications.

Modern RDo-16xe Successor Family

Kongsberg's modern related module is:

RDo-16xe
Part No.: 329699

The official Kongsberg datasheet describes RDo-16xe as a flexible 16-channel digital output module with redundant CAN communication, 18–32VDC supply, relay outputs and built-in status/error monitoring.

This is a related later-generation family member, not proof that an RDo-16 8100155 can be directly replaced by an RDo-16xe 329699.

Migration or replacement compatibility must be checked through system engineering.

Kongsberg RAo-8 – Remote Analogue Output Module

Another important related legacy module is:

RAo-8

The DataChief C20 documentation lists:

RAo-8 – Remote Analogue Output Module – 8100153.

RAo modules are used where the automation system must output an analogue control value rather than a simple ON/OFF command.

Applications may include:

Valve-position command
speed/reference command
control signal output
analogue indicator/reference signal

Current Kongsberg hardware families also include RAo-8xe, showing that analogue-output modules remain part of the distributed K-Chief architecture.

Kongsberg RIO-C1 / RIO-C2 / RIO-C3 / RIO-C4

The older DataChief and Kongsberg architecture also includes several combined Remote I/O modules.

Verified legacy references include:

RIO-C1 – 8100181
RIO-C2 – 8100182
RIO-C3-GP – 8100251
RIO-C3-GDCP – 8100225
RIO-C4 – 8100226.

These modules have more specialised combined control/protection roles than the simple RAi/RDi/RDo families.

In later Kongsberg architectures, related families include:

RIO-C2xe
RIO-C3GPxe
RIO-C4xe.

These are extremely useful related-model keywords because engineers often search by the entire Kongsberg I/O family rather than a single module.

Kongsberg dPSC – Dual Process Segment Controller

Another important legacy module is:

dPSC
Part No.: 8100183

This is documented as the:

Dual Process Segment Controller.

The dPSC supports distributed process-segment communication within the older Kongsberg/Norcontrol automation architecture.

When communication between a group of I/O modules and the main automation system fails, the dPSC or surrounding CAN/process network can become part of the troubleshooting process.

Kongsberg PSS – Process Segment StarCoupler

PSS
Part No.: 8100184

is the Process Segment StarCoupler.

It forms part of the distributed network architecture and is another highly relevant spare when maintaining older K-Chief / DataChief systems.

The current K-Chief 600 hardware family still includes a Process Segment Star Coupler in its approved distributed automation hardware list.

Kongsberg MEI – Main Engine Interface

MEI
Part No.: 8100276

stands for:

Main Engine Interface.

Kongsberg AutoChief architecture places the MEI in the engine-room section of the propulsion-control system as the interface between the main engine and the redundant CAN-based control network.

Market examples identify units such as:

MEI 8100276
Revision C2
Part 6200436
HA460593C.

MEI incorporates several digital and analogue input/output functions and sends data through the CAN network.

For SEO, important terms include:

Kongsberg Main Engine Interface
MEI 8100276
AutoChief MEI module
Main engine CAN interface

Kongsberg ESU – Engine Safety Unit

The Kongsberg ESU – Engine Safety Unit is not simply another general I/O module.

Its role is engine protection.

Official Kongsberg documentation describes ESU as an engine safety-monitoring and emergency shutdown unit monitoring:

engine sensors
RPM
manual emergency stop

and providing relay outputs, solenoid control, dual redundant 24VDC power, CAN-bus communication and self-checking.

Legacy market references include ESU 8100278, while historical AutoChief approval documentation also lists ESU part references within the platform.

Because revision/system generation matters, exact label matching is essential.

Kongsberg ESU-12 – Engine Safety Unit 12

A related later engine-protection unit is:

ESU-12

Kongsberg's official datasheet describes ESU-12 as an engine safety monitoring and emergency shutdown unit with:

21 digital inputs
four relay output channels
dual redundant 24VDC inputs
solenoid driver
alarm/event time stamping
CAN-bus status monitoring
self-checking.

Current AutoChief approval material separately lists ESU-12 as approved hardware.

This makes ESU, ESU-12 and Engine Safety Unit Kongsberg powerful related buyer keywords.

Kongsberg SCU – Segment Controller Unit

Another related Kongsberg automation controller is:

SCU – Segment Controller Unit
Part No.: 329785

The SCU is part of later K-Chief/AutoChief distributed automation architectures and communicates with remote I/O modules over redundant networks.

It should be included as a related model because vessels searching for remote I/O failures often also search:

SCU
Segment Controller
K-Chief controller
AutoChief controller

However, SCU is a controller, not a direct substitute for RDi/RAi/RDo I/O modules.

Kongsberg PSO-P – Power Switch Over Unit

Legacy spare lists also identify:

PSO-P
K-Chief Power Switch Over Unit

with documented part references such as 8100334 in older market inventory.

This unit belongs to the broader Kongsberg automation power and redundancy architecture.

Again, it is a related component—not an input/output module replacement.

Newer K-Chief 600 / K-Chief Hardware Families

For stronger modern search coverage, current Kongsberg documentation lists related DPU families including:

RAi-16xe – 329714
RDo-16xe – 329699
RAi-10tc – 8100161
RDi-32xe – 333523
RDi-32Axe – 333824
RAo-8xe – 333505
RIO-C2xe – 333346
PSS – 8100184.

These numbers are important SEO references because ship engineers may search newer and older generations together while investigating upgrade or replacement options.

They should not be marketed as plug-and-play substitutes unless Kongsberg/system documentation confirms the migration path.

RDIOR400 / RDIOR420 & Later Remote I/O Families

Kongsberg also has later remote-I/O families that appear frequently in the replacement market:

RDIOR400
RDIOR420
RDIO420S
RMP420
RMP420S
RMP422i
RMP422Si
RMP200-8
RMP201-8
RSER200-4
RHUB200-5.

Official Kongsberg documentation describes RDIOR420 as a combined digital input/output and relay module with:

16 configurable solid-state DI/DO channels
16 relay channels
redundant I/O process-bus interfaces.

These are useful related search terms for Kongsberg automation repair and replacement pages.

K-Chief & DataChief Applications

Kongsberg states that the K-Chief platform supports applications including:

Alarm and Monitoring
Auxiliary Control
Ballast Automation
Cargo Automation
Fire Systems
HVAC
Power Management
Propulsion Control
Reefer Monitoring.

This explains why RDi/RAi/RDo modules may be found throughout many different sections of a ship.

Main Engine Monitoring

RAi and RDi modules may receive signals such as:

Jacket water temperature
Lube oil pressure
Bearing temperature
Fuel pressure
Engine running status
Trip signal
Slowdown status
Common alarm

MEI and ESU modules handle more specialised propulsion-control and safety functions.

Generator Monitoring

These modules can also be used around auxiliary engines and generators for:

Generator running feedback
Breaker status
Engine alarms
temperature and pressure sensing
trip feedback
control outputs

The RIO-C3/RIO-C4 families are particularly relevant to generator protection/control applications.

Pumps, Compressors & Valves

Digital input and output modules can monitor and command:

Pumps
compressors
fans
valves
solenoids

A digital input might read a pump RUN contact while an RDo output may command a start relay.

Purifier & Separator Monitoring

Typical inputs can include:

Purifier running
common alarm
temperature signal
pressure signal
sludge tank high level
discharge feedback

This is one reason these modules are widely distributed throughout engine-room automation cabinets.

Common Problems & Troubleshooting

Module Has No Power

Check the module's DC supply, fuse/protection arrangement, common return and power connectors.

Many Kongsberg distributed modules use marine 24VDC-class control power, but the exact allowed range must be checked for the model.

For example, the current RDo-16xe official specification uses 18–32VDC.

CAN Communication Failure

Many Kongsberg DPU modules communicate over redundant CAN networks.

Check:

CAN A / CAN B wiring
termination
connector seating
power supply
segment controller / star coupler
module configuration

before replacing the I/O unit.

One Digital Input Does Not Change State

Check:

field switch/contact
24V signal
field wiring
terminal block
channel LED
input conditioning stage

If the field signal reaches the module correctly but the channel remains inactive, the input circuit may be defective.

Analogue Value Is Incorrect

For an RAi module, check:

transmitter output
4–20mA loop
sensor power
common return
field calibration
channel wiring

before concluding the module has failed.

RDo Output Does Not Operate

Check:

command status
output LED
relay/solid-state channel
external load
output fuse/protection
interlock logic

A control-system interlock may intentionally prevent the output from energising.

Module Shows Watchdog / Status Fault

Some Kongsberg modules provide status indications for:

Power
Watchdog
Run
CAN
Error / Info

A watchdog or communication fault can be caused by the module itself, low DC supply, CAN network faults or host-controller problems.

Can These Kongsberg Modules Be Repaired?

Many legacy Kongsberg/Norcontrol modules are still actively repaired and refurbished in the marine aftermarket.

Common repair areas may include:

power-supply stage
input protection components
opto-isolation circuits
output relays
CAN communication circuits
damaged terminal connections
ageing capacitors
cracked solder joints

Commercial repair providers specifically advertise component-level repairs for modules such as RDi-32A and related Kongsberg automation products.

Repairability depends on the exact fault and module condition.

Important Revision Matching

This is extremely important.

The same model can appear in multiple revisions.

Examples include documented:

RDi-32A Rev D1
RDi-32A Rev D3
RDi-32A Rev E2.

RAi-16 units also appear with different revisions and ECO numbers.

Therefore, when ordering a replacement, always compare:

Model
Part Number
Revision
ECO number
Hardware marking
CAN/LMT reference
connector layout

Do not rely on model name alone.

Legacy Part Number Reference Table

These legacy references are documented across DataChief material and marine spare inventories.

Spare Parts & Replacement Availability

SM MARINE SERVICE™ supports sourcing and supply of Kongsberg/Norcontrol marine automation modules including:

RDi-32
RDi-32A
RAi-16
RDo-16
RAo-8
RIO-C1 / C2 / C3 / C4
dPSC
PSS
MEI
ESU / ESU-12
PSO-P
SCU
RDIOR400 / RDIOR420
RMP / RDIO / RSER related units

Depending on availability, modules may be supplied as:

New / New Old Stock
Used Tested Working
Refurbished
Reconditioned

SM MARINE SERVICE™ already maintains a dedicated technical page for Kongsberg Norcontrol dPSC / RAi-16 / RDi-32 marine automation modules. The page covers legacy K-Chief/DataChief remote I/O applications and is a useful internal reference for buyers searching these modules.

For broader marine automation sourcing, visit SM MARINE SERVICE™.

Why Ships Still Need Legacy Kongsberg Modules

Kongsberg/Norcontrol automation systems were installed on a large number of commercial ships and offshore vessels.

A complete automation-system retrofit can involve:

new controllers
new I/O
rewiring
software engineering
alarm database conversion
commissioning
class approval
extended vessel downtime

When the existing automation system remains serviceable, replacing or repairing a failed legacy module can therefore be the most practical maintenance approach.

This is why modules such as RDi-32 8100154, RAi-16 8100148 and RDo-16 8100155 continue to appear in the international marine spare-parts market.

FAQ

What is Kongsberg RDi-32?

RDi-32 is a 32-channel Remote Digital Input Module, commonly referenced as part number 8100154.

What is RDi-32A?

RDi-32A is another 32-channel digital-input module, commonly referenced as 8100172, with several documented revisions.

What is Kongsberg RAi-16?

RAi-16 is a 16-channel Remote Analogue Input Module, commonly associated with part number 8100148.

What is Kongsberg RDo-16?

RDo-16 is a 16-channel Remote Digital Output Module, with legacy part number 8100155.

What is MEI 8100276?

MEI is the Main Engine Interface Module used to interface main-engine signals with Kongsberg propulsion/automation systems.

What is ESU?

ESU means Engine Safety Unit. It monitors engine-safety inputs, RPM and emergency-stop signals and can initiate protective outputs.

What is ESU-12?

ESU-12 is a later Engine Safety Unit with multiple digital inputs, relay outputs, redundant 24VDC power and CAN communication.

What is dPSC?

dPSC means Dual Process Segment Controller, part number 8100183 in legacy systems.

What is PSS?

PSS means Process Segment StarCoupler, commonly part number 8100184.

What is RDIOR420?

RDIOR420 is a later combined digital I/O and relay module with 16 configurable solid-state channels plus 16 relay channels.

Is RDS a Kongsberg module family?

I could not verify RDS as a standard Kongsberg/Norcontrol module designation in the official and credible technical sources reviewed. The verified families include RDi, RDo, RAi, RAo, RIO, RDIOR, MEI, ESU, dPSC, PSS and SCU.

Can RDi-32xe replace RDi-32 8100154 directly?

This should not be assumed. RDi-32xe belongs to a later hardware generation, so system architecture, configuration and upgrade path must be verified.

Can these modules be repaired?

Many legacy modules can be repaired depending on fault type, including power, input/output and communication-related failures. Module condition must be evaluated individually.

What should I send when requesting a replacement?

Provide the exact model, part number, revision, ECO number, clear photos, system name and fault description. Revision matching is especially important.

Where can I buy Kongsberg Norcontrol automation modules?

SM MARINE SERVICE™ can support worldwide sourcing of Kongsberg/Norcontrol legacy and current marine automation modules, subject to stock availability.

Short Product Description

Kongsberg Norcontrol RDi-32, RDi-32A, RAi-16 and RDo-16 are distributed marine automation I/O modules used in legacy K-Chief, DataChief and AutoChief systems. Important legacy references include RDi-32 8100154, RDi-32A 8100172, RAi-16 8100148 and RDo-16 8100155, with related modules including RAo-8, RIO-C1/C2/C3/C4, dPSC 8100183, PSS 8100184, MEI 8100276, ESU, ESU-12, SCU and later RDIOR/RMP families. SM MARINE SERVICE™ supplies, sources and supports repair/replacement of new, used, refurbished and reconditioned Kongsberg marine automation modules worldwide.

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