To be honest, AMS/IAS is not difficult for end-user handling and troubleshooting.
Still, as a junior ETO, I used to hesitate and overthink everything during the early days of my career.

On board, this feeling was made worse by comments like:

“Don’t touch it.”
“That system is sensitive.”

When responsibility came, confidence dropped.
Even simple tasks felt risky, and overthinking took over.

I faced this situation myself.
Later, many Junior ETOs asked me similar questions.
So, based on my experience on tankers, I want to explain AMS and IAS in a simple and practical way, especially for those who are just starting their careers.

AMS – Alarm Monitoring System

In older ships, each machinery system worked as a standalone system.
To collect alarms from different systems in one place, ships used AMS.

Main Purpose of AMS

• Monitor alarms
• Record alarm history (logging)

AMS is mainly an alarm system, not a control system.

How AMS Works (Basic)

• Sensors and transducers monitor process conditions
• When a value reaches an alarm set point, an alarm is triggered

Common AMS Inputs

• NO / NC alarm contacts → Digital Input (DI)
• Analog signals (pressure, level, etc.) → Analog Input (AI)
• Temperature sensors → RTD input modules

About AMS Outputs (Important Clarification)

In classic AMS:

• Outputs are usually limited to:
  • Alarm lamps
  • Horns
  • Common alarm relays

AMS normally does NOT control machinery.

Some modern or hybrid systems may have DO or AO modules,
but process control is usually handled by PLCs or IAS, not AMS.

AMS Architecture (Simple View)

• I/O modules are grouped together
• Data is sent via:
  • Communication modules
  • Data concentrators
  • PLCs
• Information is displayed on the AMS workstation (PC)

IAS – Integrated Automation System

As ships became more complex, the number of systems increased:

• SCR
• EGCS
• BWTS

Each system had its own alarms and controls.
This increased operator workload.

To solve this, ship automation adopted the Distributed Control System (DCS) concept from industry.
This led to Integrated Automation System (IAS).

What IAS Does

IAS is not just an alarm system.

It handles:

• Alarm monitoring
• Process control
• Interlocks
• Protections
• Automation logic

All in one integrated system.

IAS Architecture (Very Important)

• Controllers / Process stations (PLC or automation controllers)
  • Connected directly to I/O modules
  • Execute:
    • Control logic
    • Alarm logic
    • Interlocks and protections
• Workstation PCs (HMI)
  • Used for monitoring and operation only
  • Do NOT execute control logic

✅ Important rule:
Even if the workstation PC is shut down,
process control continues because logic runs in the controller.

Large IAS systems may also use:

• Servers for:
  • Data storage
  • Trends
  • Events

AMS vs IAS (Clear Difference)

AMS	IAS
Alarm monitoring only	Alarm + control + automation
Mostly monitoring	Full automation system
Limited outputs	Full control capability

IAS includes alarms, but it is not just a bigger AMS.

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Differences Between Makers

System behavior depends on:

• Maker
• User access level

From my experience:

• Kongsberg → Gate function logic
• Honeywell → Function block logic

Different look, same basic principles.

What an ETO Must Understand First

You do not need to be a programmer.
But you must understand system architecture.

As an ETO, always know:

1. Which system connects to which system
2. What each I/O module is used for
3. Where controllers, workstations, and servers are located

If you understand architecture,
system manuals become easier,
and onboard troubleshooting becomes possible.

Programming & Networking – Do You Need Them?

Programming (Basic Understanding)

• You do not need to write programs
• But understanding logic helps when:
  • Maker sends modification instructions
  • Function blocks need adjustment

Networking (Basic Understanding)

Very helpful for troubleshooting:

• Communication loss
• Offline stations
• Data not updating

Common onboard concepts:

• Industrial Ethernet
• Redundant networks

What You Should NOT Touch Alone

For safety and class compliance:

• Protection logic
• Safety interlocks
• Alarm set points without approval
• PLC firmware and system backups

Always follow maker and company procedures.

Simple Alarm Troubleshooting Flow

When an alarm appears:

1. Is the process condition real?
2. Check sensor and I/O status
3. Check communication status
4. Review alarm history or trends
5. Do not rest alarms blindly

One Final Important Reminder

Even if:

• Maker is the same
• System name is the same

System architecture can be different on every ship.

• Even sister ships can differ
• Never assume wiring or configuration

AMS / IAS is not something to fear.
With basic understanding of architecture and logic,
an ETO can handle most onboard situations confidently.

This post is written especially for Junior ETOs
who do not know where to start.

Safe sailing 🚢