| 摘要 |
PROBLEM TO BE SOLVED: To simplify wiring between a signal source unit such as a proximity sensor and a signal processing unit such as an input module of a PLC, and to simplify configurations of the units. SOLUTION: In the signal processing system, the proximity sensor 1 outputs a signal having a level changing in predetermined timing in response to predetermined processing to the input module 2 as a detection signal S1, inverts the level of the signal for a predetermined time, with a predetermined frequency under satisfaction of the condition that the level of the signal does not change over the predetermined time without performing the predetermined processing, and outputs the inverted signal to the input module 2 as a self-diagnostic signal S2. The input module 2 decides that the proximity sensor 1 performs the predetermined processing when the detection signal S1 is input, and decides that the proximity sensor 1, for example, fails when the self-diagnostic signal S2 is input. COPYRIGHT: (C)2011,JPO&INPIT
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