Swapping out a PLC is easy — replacing the software is the hard part.

If a PLC engineer had to choose between replacing a PLC or replacing its programming software,
many engineers would likely prefer to replace the PLC.
Because if the PLC breaks, you can just swap it out;
but if the software changes, the entire project workflow may have to change with it.
This is an often underestimated issue in today's domestic PLC substitution.

Why Is Hardware Increasingly Easier to Replace, While Software Remains So Difficult?

Anyone who has truly worked on automation projects knows that a mature project involves far more than just a PLC.
It includes the program architecture that engineers are familiar with, accumulated function blocks, variable naming conventions, communication methods, and a complete supporting suite including HMI, servo, motion control, vision, safety, and more.
More importantly:
engineers have become accustomed to this software.
How to organise programs, how to find variables, where to check alarms, how to monitor online, how to locate issues when they arise…
These things may seem trivial, but they affect project progress every single day.
So for engineers, replacing a PLC may just be changing hardware;
but replacing the software is essentially replacing a whole engineering methodology.

This is also why Siemens TIA Portal and Omron Sysmac Studio are truly formidable – not just because "the PLC has many features."
Rather, over the years, they have gradually built a complete engineering environment integrating PLC, HMI, motion control, drives, communications, simulation, and more.
Once engineers have been working within it for years, enterprises further accumulate a wealth of program templates, function blocks, and project experience.
At this point, a very interesting realisation emerges:

The true moat of a PLC may not be the hardware at all, but the software ecosystem behind it.

01Domestic PLCs Have Entered a Critical Phase: Competition Shifts from Features to Experience

Domestic PLCs have now entered a critical phase.
Basic programming capabilities, IEC 61131-3 languages, online monitoring, download and debugging, and communication configuration are increasingly no longer the decisive differentiators.
What truly begins to set players apart are some seemingly "minor" factors:
Is the program easy to organise?
Are variables easy to manage?
Is search fast enough?
Can errors be quickly located?
Is debugging smooth?
Can projects be reused?
Can past work be accumulated and retained?
These are where engineers actually spend their time every day.

So the next-stage competition for domestic PLCs is no longer about:
"Is my CPU a little faster than yours?"
Rather, it is about:
"Can my software help a Siemens or Omron engineer learn less, modify less, and fall into fewer pitfalls?"

02One Step Further: From Programming Tool to Engineering Platform

Taking it a step further, the competition will shift again.
A truly mature PLC ecosystem is ultimately not just a programming software.
It should be:
PLC + motion control + servo + robotics + vision + HMI + SCADA + industrial networking, and even further integration with MES and industrial data.
Whoever can truly unify all these is not selling just a PLC,
but a complete engineering system.

03AI Will Push the Competition to the Next Level

The emergence of AI will push this competition to yet another level.
In the future, PLC software will compete not just on "how fast can you write code," but on:
Can it generate control logic from natural language?
Can it call upon the enterprise's accumulated program templates?
Can it automatically check code?
Can it run simulations for verification?
Can it turn an engineer's decade of accumulated experience into engineering knowledge that the software can invoke?
At that point, the competition in PLC software will have fundamentally changed.
It will no longer be about who has more IDE features, but who has more engineering assets at their disposal.

So, domestic PLC substitution can be seen as having two halves.
The first half is hardware substitution.
In this phase, competition is about performance, reliability, cost, and supply chain.
The second half is software ecosystem substitution.
Competition is about engineer habits, program assets, toolchains, and the entire automation ecosystem.

A PLC can be replaced, but the engineering assets accumulated by an enterprise over more than a decade are not so easily moved.