Control Panels

HOA

Hand-Off-Auto

Definition

A selector switch giving an operator direct manual control of a device, disabling it entirely, or passing control to the controller.

Hand must work when the controller does not. Bringing the Auto position back to the PLC as an input stops the controller reporting a start failure for a pump running perfectly well in hand.

Hand-Off-Auto SelectorsWhat each position of an HOA selector does, how it is wired into the starter circuit, which protections must survive Hand, what the controller should see, and the mistakes that let a pump run with nobody watching.

HOA

Definition

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