Abstract: An electromagnetic flow meter for measuring the flow rate of a fluid by applying to the fluid a magnetic field generated with an exciting current and measuring the resulting signal voltage generated at a pair of electrodes; wherein the exciting current comprises two frequency components which are lower and higher than the usual commercial frequency and the signal voltage comprises two frequencies which are discriminated so that a higher frequency is extracted as a first output and a lower frequency is extracted as a second output, through a low pass filter having a large time constant. A predetermined operation, such as addition, zero correction, response correction, etc, is carried out on the first and second outputs to produce a flow rate output. The invention has quick response, stable zero point and reduced susceptibility to noises.

Abstract: A capacitive displacement type transducer, wherein the oscillation frequency of a self-excited oscillator circuit including a pair of differential capacitors formed with a movable electrode disposed between two outer electrodes is counted by a counter, the output level of the counter is reversed each time a certain count is attained to cause the differential capacitances to be switched alternatively, and to make identical the respective reversal periods, and application voltage to be applied to the differential capacitors being controlled by an integrator, and a voltage relating to the output of the integrator being applied through a fixed impedance to the movable electrode, thereby eliminating fixed capacitances formed across the difference capacitors. Also, a voltage generated by dividing and averaging the output level of the counter by use of a certain pulse duration of a monostable circuit operating in synchronism with a counter, is used to compensate for static pressure changes.

Abstract: H and L logic signals are written in a memory in a ratio between the numbers of the H and L logic signals corresponding to the magnitude of an analog signal. The memory is cyclically read out and the output therefrom is smoothed by a smoothing circuit to provide an analog output.

Abstract: A capacitance type displacement conversion device is provided in which a physical displacement resulted from a change of a physical value such as pressure or tension is converted into an electrical signal. The device is comprised of a capacitance sensor and an improved circuitry whereby conversion characteristics are linear and free from erroneous measurements caused by distributed capacitances and other circuit elements related thereto. The type of the sensor may be either a single capacitance or a differential capacitance type.

Abstract: A process control system for multiplex operation of several process control loops. The system includes process input and process output units, analog and computer operation units and operator's interface stations, the exchange of process information between these units and stations being carried out by a time-sharing technique. The system is provided with a first data trunk through which process information through the data trunk is carried out in synchronism with address signals supplied to the address trunk in accordance with a cyclic control routine. Also included is a second data trunk which makes it possible at one's option to modify the cyclic control routine to select a desired mode of operation, the analog and computer operation units and the interface stations signalling whether operation in the manual control, analog control, or control mode is possible. State signals are generated at the operator's interface stations to the respective units to control their signal transmitting or receiving state.