| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that conventionally many S/W(software) processing are interposed before stoppage even in the case of an original fault and it takes time to attain a stop state. SOLUTION: A safety controller is provided with first and second MPUs 11 and 21 parallelly carrying out an arithmetic processing on the basis of the same input data, a bus collation circuit 20 collating the arithmetic results of the first and second MPUs, outputting a clear signal 41 in the case that they match and not outputting the clear in the case that they do not match, and first and second clock circuits 14 and 24 measuring the present time, resetting the present time when the clear signal is inputted and outputting a stop signal 40 stopping the arithmetic processing to the first and second MPUs when the clear signal is not inputted for a fixed period or longer. Thus, whether to continue or stop is quickly determined on the basis of the period of non-matching.
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