SENSING DEVICE

摘要

Intended is to provide a sensing device using a quartz sensor, which has an adsorbing layer formed on its surface for adsorbing a sensing object and which has its natural vibrations changed in number by the adsorption of the sensing object, so that the trouble of the quartz sensor may be detected so earlier as to keep the erroneous measurement result unrecognizable for the worker. The sensing device is equipped with a level detecting circuit for detecting the signal level of the oscillation output of an oscillation circuit. After a stable time period elapsed from the power ON, a computer fetches the detected level value and compares the signal level with a threshold value. When the signal level is lower than the threshold value, the computer judges and indicates a fault in a display unit, for example, thereby to inform the worker of the occurrence of the fault.