| 摘要 |
PURPOSE:To enable avoiding noize effect without using metallic cable pipe by using a photo transmission for the transmission path, transmitting the judged results of a level judgment part to a criticality judgment part after converting to photo data and providing a power source part at the site. CONSTITUTION:The detection signals of radiation detected at each radiation detector 10 are judged for trip in each comparator 24. If the signal level of the radiation detection signal is exceeding a standard value, a trip signal is output. At a criticality judgment circuit 12, after converting the trip signal received with an O/E converter 15 to an electric signal, criticality judgment is done with the 2/3 logic. Then, in the case trip signals are output from more than two radiation detectors in the group for a detecting object, a criticality alarm is output. In this case, the effect of noise is avoided without using any special means for noise such as metallic cable pipes.
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