The scenario
An Allen-Bradley MicroLogix 1400 controls a motor starter through a three-position Hand/Off/Auto selector. Hand mode drives the motor directly, Auto mode follows a start/stop circuit with seal-in, and Off mode removes power.
What is in this drawing
Read the decisions behind it.
01
Use a parallel OR block so either Hand selector or Auto run relay energizes the motor starter.
02
Seal in the Auto run relay with a start pushbutton branch to maintain auto operation until Stop is pressed.
03
Place the overload contact in series before the motor starter output so any overload drops the motor in both modes.
Reusable for any HOA motor starter panel where Hand is hard-wired command and Auto is PLC-supervised, provided input/output addresses are remapped to the target PLC.
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