| 摘要 |
<p>Contacts (1a-1n) are connected in series through a wiring cable (2). A relay (3) for detecting a state where all contacts (1a-1n) are closed is connected through the wiring cable (2) with one end of a switch group (1) consisting of the contacts (1a-1n) connected in series. A power supply (4) for supplying a current to the relay (3) with all the contacts (1a-1n) closed is connected with the other end of the switch group (1) through the wiring cable (2). Furthermore, contacts of the relay (3) are connected with a control section (5).</p> |
