| 摘要 |
PURPOSE:To exactly know an oxygen concn. by subjecting an output voltage to a temp. correction according to ambient temp., determining the first value in the stage of starting detection as the oxygen concn. in the atm., calculating the ratio between said value and the 2nd and subsequent values and generating an output signal when the calculated ratio attains the prescribed conditions with respect to the preset standard value. CONSTITUTION:The oxygen concn. in the air is detected by an oxygen sensor body and is stored in the 1st storage circuit 7. The ambient temp. is detected by a temp. sensor 8 and is inputted to the 2nd storage circuit 10. The correction factors (a) corresponding to respective temps. are preliminarily stored in the 2nd storage circuit 10. A central arithmetic processing circuit 11 multiplies the correction factor (a) from the 2nd storage circuit 10 and the output V from the 1st storage circuit 7 and stores the multiplies value into the 3rd storage circuit 12. The processing circuit calculates the ratio k=V2'/V0' between the value V2' written in the 2nd time and the value V0' written in the 1st time, compares the (k) and the ratio V1/V0=K between the oxygen concn. 20.6% V0 in the atm. and dangerous oxygen concn. 18.0% V1 preliminarily stored therein and emits an alarm if k<K. |
