[TheCapn]

All my comment is adding a software anecdote to the story. It really is just regular Chesterton's Fence, a term I've never heard until now but dealt with for the last several years.

You're not wrong, but in the context of a PLC controlling a motor or gate it is far more segregated than the code you're probably thinking of. Having a timer override on a single gate's position limit sensor would have no effect on a separate sensor/gate/motor.

If the gate's function block had specific code built into it that affected all gates then what you're talking about would be more applicable.

[bombcar]

I think they’re thinking of things like that software control for the health machine that could get in a state where it would give a lethal dose to a patient.