The request
“Create a centrifugal pump HOA ladder with hand and auto selection, auto start-stop seal-in, overload protection, and a pump contactor output.”
Then tryAdd a low-level stop interlock.Add a pump run indicator lamp.
What is in this drawing
Read the decisions behind it.
01
Use separate internal coils for Hand and Auto commands so both modes safely drive one physical output without duplicate physical coils.
02
Place the pump overload contact in series with both mode commands so an overload drops the output and clears the Auto seal-in.
03
Add a parallel seal-in branch around the Auto Start pushbutton so the pump remains running after a momentary start.
Reusable for any single-motor HOA starter where hand operation bypasses PLC auto sequencing and auto mode requires start/stop or permissive logic.
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