When Should You Replace or Upgrade a PLC System?

Programmable Logic Controllers (PLCs) are the pillars of industrial automation and marine automation. Right from the control of production lines in industries to the monitoring of crucial operations in ships and platforms in offshore areas, PLCs are made to run for an extended period of time. The truth is that there is no such PLC system that will run without an end.

This blog discusses the key indicators and business scenarios that mean it’s the time to look for a replacement for your PLC system.

What Is a PLC System and Why It Matters?

A PLC system is also involved in the management of machines, processes, and equipment in a real-time environment. The system also receives signals from sensors, performs logic operations, and issues commands to motors, valves, and relays.

For industrial automation and sea automation, PLC reliability affects:

• Production efficiency

• Equipment safety

• Operational Uptime

• Maintenance cost

As PLCs operate uninterruptedly in difficult environments, at some stage, these systems will encounter either degradation, obsolescence, or diminished performance capacity

Main Indicators to Determine If Your PLC Needs to be Replaced

1. Frequent Breakdowns and Downtime

If your PLC system has always got faults, then it is likely that your system has aged. Frequent CPU errors, I/O module error, communication error, and other faults are likely indications that your system may have aged.

"The downtime that can result from a faulty PLC can often end up costing much more than an upgrade would have done in the first place."

2. Obsolete/Discontinued Hardware of PLC

INOLDER PLCs, most manufacturers no longer provide support for their older models. This is fraught with problems:

• Spare parts are difficult to source

• Unavailability of firmware updates

• Tech support or service continuing or available

In these kinds of situations, even a small problem can bring down your entire system for an extended period of two weeks. It is highly recommended to upgrade to an updated PLC platform for easier maintenance.

3. Spare Parts Availability Issues

"If your team is depending on a lot of used or refurbished PLC modules in order to keep things going in the first place, then perhaps now is a good time to rethink a strategy or two," because "refurbished PLC parts make a great stop-gap solution."

This is particularly important in marine automation, where backup crews are not readily available in an emergency situation.

4. System Can’t Meet Current Production Demands

With the growth of operations, traditional PLC systems could face issues such as:

• Higher I/O requirements

• Fast processing requirements

• Advanced communication protocols

If your PLC does not have the capability to support system expansion, data logging, or real-time monitoring functions, then it is likely to need a PLC upgrade to support today’s automation requirements.

5. Integration Problems with New Equipment

Contemporary automation solutions call for interfacing with:

• HMIs and SCADA Systems

• Sensors and smart devices

• Remote monitoring systems

Older PLCs may not be compatible with new technologies. If it becomes difficult or impossible to integrate new machines into your system, upgrading to a modern PLC control system can significantly improve flexibility and scalability.

6. Safety and Compliance Matters

Safety is Old PLCs may lack safety and regulatory compliances with modern safety standards. This could put your business at risk:

• Safety risks

• Compliance

• Insurance or certification issues

Upgrading means there will be improved diagnostics and “fail-safe” functions and a higher degree of system protection, which becomes crucial when working in a marine setting.

7. Increasing Maintenance Costs

When maintenance costs exceed the value of keeping the existing system alive, upgrading becomes a smarter investment. Continuous repairs, emergency sourcing of obsolete parts, and extended downtime all increase total operating costs over time.   

A newer PLC system typically reduces:

• Repair rate

• Energy consumption

• Troubleshooting time

Replacement or Upgrade: What’s the Difference?

An upgrade might entail the replacement of some system components like CPUs, I/O modules, or communication cards while concurrently maintaining the remaining system infrastructure.

It is appropriate in the following situations:

• All core hardware is still working

• Software migration is manageable

• Replacement parts remain partly accessible

Replacing a PLC System

Full replacement is indicated when:

• The PLC platform has become totally outdated

• Hardware breakdowns are common

• Expansion or modernization is impossible

By installing a completely new system, one can guarantee a stable and ready-for-the-future solution.

Industrial vs Marine PLC Conversion Options

In industrial automation, the upgrades in PLCs are focus on productivity, scalability, and integration with current production systems.

In marine automation, other considerations are:

• Resistance to vibration and humidity

• encryption of marine safety standards

• High reliability at remote locations

Upgrading at the right time avoids failures that could occur at sea or on offshore platforms.

Can Used or Refurbished PLCs Be a Smart Alternative?

In most instances, a second-hand PLC system is a cost-saving option, especially when:

• The current system must remain as is

• Cannot do the immediate replacement

• Budget constraints exist

Refurbished PLCs can help extend the life of a system while a plan is being developed for a structured upgrade.