Alarm device for returning and connecting loading and unloading swing arm in place

The invention relates to an alarm device for returning and connecting a loading and unloading swing arm in place. A self-loop of an electrostatic releaser is a first electrostatic loop; the electrostatic releaser and a tank truck form a second electrostatic loop through a grounding wire; the first electrostatic loop is switched to trigger a first annunciator to send a signal to a controller; the second electrostatic loop is switched on to trigger a second annunciator to send a signal to the controller; when a swing arm is connected with a feeding connector of the tank truck in place, a third annunciator is triggered to send a signal to the controller; the swing arm returns in place, and a fourth annunciator is triggered to send a signal to the controller; an alarm is arranged in a workingloop of an electromagnetic relay KA1 and is a normally closed loop; and when the controller receives signals sent by the first annunciator or the second annunciator and receives signals sent by the third annunciator or the fo