| 摘要 |
The invention relates to an apparatus for detecting liquid electric conductivity which applies stable reference signals to a conductivity detection unit, treats output signals as low noise and consistently and accurately detects infinitesimal liquid conductivity. The present invention provides the apparatus for detecting liquid electric conductivity comprising: the conductivity detection unit which detects the conductivity of liquid and converts the conductivity to current while maintaining a constant temperature; a temperature control unit which controls the conductivity detection unit so that the conductivity detection unit maintains the constant temperature; a reference signal generation unit which generates reference signals and supplies the reference signals to the conductivity detection unit; a current-voltage conversion unit which converts the current outputted from the conductivity detection unit to voltage; a lock-in detection unit which performs synchronous demodulation and filtering on the voltage signals converted in the current-voltage conversion unit and amplifies them; an AD conversion unit which converts analog signals outputted from the lock-in detection unit into digital signals; and a signal process and control unit which receives measurement signals and measurement conditions from the AD conversion unit and temperature control unit, displays conductivity measurement conditions and measurement states, transfers conductivity signals and temperature signals to an external device, treats various data and generates control commands. [Reference numerals] (100) Conductivity detection unit;(110) Temperature control unit;(120) Reference signal generation unit;(130) Current-voltage conversion unit;(140) Lock-in detection unit;(150) AD conversion unit;(160) Signal process and control unit |
