Relay Logic / Ladder Schematics

Anyone here ever worked on equipment documented by "Ladder Schematics"?

Relays in Ladder Logic Tutorials

PC Ladder Logic Example






Edited by ad4mg: copyrighted article and graphics removed and replaced by links to same.

Ladder logic is fun. Relay logic can be quite interesting.
Many times an alarm light is triggered by a drop out of a relay. In a ladder logic situation the NC contact would be energized until the pressure switch broke contact which in turn drops the relay

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Originally Posted by kb2crk

Ladder logic is fun. Relay logic can be quite interesting.
Many times an alarm light is triggered by a drop out of a relay. In a ladder logic situation the NC contact would be energized until the pressure switch broke contact which in turn drops the relay

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Ladder Logic took up a lot of paper, long and spread out so you could see every component.

Relay "Logic" was a combination relay charging times and discharging time which were controlled by making a relay "Fast to charge-slow to discharge", Slow to charge (resistor in series with power bus) , etc all of which were controlled by resistors and knowledge of charging and discharging times.

Where they were placed on the ladder schematic was the timing that was supposed to happen (Logic High) to controlled other events in the process at the correct time.

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