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Which I/O System is right for your simulator?

by | Feb 22, 2018 | Simulation & Training

As the majority of nuclear power plants simulators around the world are reaching 30+ years of age, input / output (I/O) system replacements are becoming more common. Hardware engineers are tired of complicated repairs, obsolete parts and maxed out racks. Trainers and operators are tired of weekly downtime where they cannot train on the simulator due to I/O problems.

In this industry there used to not be a choice of I/O systems. Ever since simulators were required back in 1991, nuclear power plants have routinely used proprietary systems. Their promise of “plug n’ play” functionality coupled with a quick turnaround for implementing technology and obsolescence upgrades have kept the industry largely captive to the hefty price tag. Until now that is.

Commercial, off-the-shelf I/O system providers with decades of proven experience in industrial, building and marine automation offer independent, modular solutions at a lower price point. But which solution is best for you? In this blog we’ll discuss the pros and cons of some of the most well-known I/O system providers.

Legacy vs New Modular I/O Systems: Pros and Cons

Before you compare suppliers, it is important to consider why you may want to choose a modular I/O system in the first place.

Here is a chart of the pros and cons of upgrading legacy proprietary systems versus replacement with a new modular I/O solution.




Typically faster to implement

Potentially less re-wiring



Higher potential for obsolescence




Lower cost, easily obtained in the market

Large installed base

Easy to maintain & troubleshoot

Easier to run wires

Small Footprint

Draws less electricity

Generates less heat


Time required to implement

When removing modules with power on, downstream modules are affected
(*most solutions)

A NOTE ABOUT TIME TO IMPLEMENTATION: The major barrier to choosing modular I/O solutions has always been the time required to implement versus their custom counterpart. However, along with advancements in the systems themselves, GSE has been able to bring the implementation time down to a couple of weeks for a typical simulator.

The picture below demonstrates the vast difference in accessibility between the legacy I/O systems currently at most plants and a replacement modular I/O solution. You guessed it! The one on the right is the replacement I/O; a modern, modular implementation where you can actually access everything without stepping over wires!

Modular IO Vendors: Pros and Cons

If you’ve read this far, you’re likely interested in learning more about the modular solution providers available today and how their solution stacks up against the competition.

As an experienced simulator I/O replacement partner, we have extensively researched and implemented some of the top names in modular I/O. The chart below compares a handful of the most prominent modular I/O solution providers;  Beckoff (EtherCAT IO), Wago (750), and Weidmuller (u-Remote).



Lowest overall cost

Easily obtained in the market

Large installed base

High Voltage Power distribution module available

Analog Input DC power and distribution modules available


When removing modules with power on, downstream modules are affected



Low cost

Easily obtained in the market

Large installed base

High Voltage Power distribution module available


When removing modules with power on, downstream modules are affected



Newest Design

Electronics modules can be replaced with power on–best hot swapable IO on the market

Electronic module is sold and replaced separately if needed. No wiring required to replace the electronics

Discrete wiring also has removable connectors

Programmable Analog Outputs (point by point)


Keying is not supported on these connectors

No alternative power distribution modules available


If you’re tired of the headaches caused by IO/ failures; simulator downtime and obsolete parts, one of the above modular systems might be the best solution.

We hope you’ve found our pros and cons lists helpful as you research your simulator I/O options.

GSE can help you determine which I/O solution is best for your plant’s simulator. We’ve implemented modular systems on over a dozen simulators. Contact us to schedule a consultation.

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