| 摘要 |
<p>PURPOSE:To speedily and precisely detect abnormality of an underground transmission system by making an abnormality discrimination circuit judge it as system abnormality in the case where an underground data is not outputted during an output period of a mud water state signal detected by a mud water pump driving state detector to detect change of a state of a mud water flow. CONSTITUTION:A driving state of a mud water pump 3, for example, a working state of a contact point of a driving switch and a contactor, etc., is detected by a mud water pump driving state detector 11. After its detected output is inputted to an abnormality discrimination circuit 12 and the mud water pump 3 is driven, initial setting time is set. In the meantime, a detection data from a transmitter 4 is inputted a demodulator 8 through a receiving antenna 6 and a receiving amplifier 7. Abnormality discrimination is carried out from both of the two signals by setting a transmission interval each time when the demodulated data is finished in demodulating. Unless the demodulated data is formed while the mud water pump is drive, an abnormality signal is outputted it is discriminated as abnormality of an underground transmission system by a data processing part 9, and it is displayed on a display device 10.</p> |
