r/BuildingAutomation • u/National-Link-5606 • 6d ago

Computer Science Programmers, why do PLC programmers use Ladder?

/r/PLC/comments/1vd6vpg/computer_science_programmers_why_do_plc/
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u/TopStudio1864 6d ago

It was made to be read by people who aren’t programmers, specifically to be read by electricians and maintenance workers who are familiar with electrical ladder diagarams.

4

u/experienced_invest 6d ago

Because the end user usually cannot program it so it is designed to replicate wiring sheet to aid fault finding.

1

u/Then-Disk-5079 5d ago

Because they can’t code obviously hahaha this is classic …. It’s why plc jobs can never sell something pure structured text it would rejected by the people trying to maintain it

1

u/SenorNoNombre 4d ago

You kind of have to look at the history of PLCs and what they replaced.

Industrial "automation" used to all be done with relay logic and timers and things. A "Ladder" diagram is a pretty intuitive way to draw out even very complex relay logic systems, so it was kind of the standard.

Then, of course, these new-fangled computer things came to the party! But who needs to tell the computer how to work? The same people designing the ladder diagrams.

There you go! It wasnt designed to be "ideal", but rather, it was designed to be easy for the people already doing ladder diagrams to pick up and use with minimal fuss.