TEMPERATURE AND STATIC PRESSURE COMPENSATING METHOD OF PRESSURE AND DIFFERENTIAL PRESSURE TRANSMITTER

摘要

PURPOSE:To compensate fluctuations of the zero point and the span with an inexpensive and simple constitution by compensating these fluctuations due to fluctuations of temperature and static pressure on a basis of the fluctuation of a dielectric constant of a sealed liquid. CONSTITUTION:Signals related to electrostatic capacities C1 and C2 obtained through an operating circuit 11 are led to a dielectric constant operating circuit 19, and a zero point fluctuation compensating signal proportional to the dielectric constant is calculated. This signal is added to the output signal of the operating circuit 11 at an addition point 20 to compensate the fluctuation of the zero point due to fluctuations of temperature and static pressure. The dielectric constant may be operated on a basis of the electrostatic capacity of a reference electrostatic capacity means 21 provided in a sealed liquid 5.