| 摘要 |
<p>Disclosed is a safety sensor provided with a plurality of input signal lines for inputting signals for setting. Specifically disclosed is a safety sensor wherein at least one input signal line (signal line Q3) is provided with a high-level detection circuit (201) and a low-level detection circuit (202). In an initialization process wherein setting of an operation mode is permitted, a CPU (203) registers in a memory (204) the on/off states of detection signals from the respective detection circuits (201, 202) on condition that the on/off states of detection signals are mutually opposite, and the CPU (203) identifies the connection state of the input signal line (Q3) on the basis of the on/off states and sets an operation mode corresponding to the connection state. After setting the operation mode is completed, the CPU (203) monitors the detection signals from the respective detection circuits (201, 202) and determines, when at least either of the detection signals comes into a state different from the states registered in the memory (204), occurrence of abnormality in the connection state of the input signal line (Q3).</p> |
