Just like rackmounts hold big instruments or computers, control panels small or big have to hold DIN Instruments, switches and annunciators to make it easy for the operator. The maintenance work also is simple from the backside. It can be kept near the machinery which it controls.
Some Control panels go into Control Rooms at a distance away or at a greater height from the shop floor. This way they can monitor and give instructions while managing a larger process like processing of chemicals and at the same time safeguarding the instrumentation and computers with controlled environments.
Some of the pdf circuits are not easy to read, some have errors, this is mainly due to the importing of schematics from an older ORCAD Dos Version. I have corrected some circuits, some are to be checked. Also some circuits were not corrected after they were drawn by New Learners, as i wanted them to document what they learnt and familiarize with computers, Some did a good job. This section has no electronic parts, so you can figure out the diagrams.
Some example circuits of panels here Electrical Control Panel Wiring
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