Electromagnetic chuck controller: AC voltage 380V after the transformer step-down, after rectifier rectifier into 110V DC after the control device into the sucker at this time the sucker is filled with magnetism, demagnetization when the reverse voltage line, the controller to achieve demagnetization function. Access Control controller: Access controller works in two modes. One is patrol mode, the other is recognition mode. In the patrol mode, the controller continuously sends the query code to the reader and receives the reply order of the reader. This pattern will continue until the card reader senses the cards.