JPS57519A - Electronic type flowmeter - Google Patents

Abstract

PURPOSE:To warn the use of water meters conforming to the rate of use to consumers by generating an overflow alarm when the repetitive time intervals of an object rotating repeatedly according to measuring flow rates is below a prescribed value. CONSTITUTION:The revolutions of the impeller of a flowmeter are detected at two points to obtain signals (a), (b), and in an input circuit 11, the forward-backward discrimination signal (c) of the signals (a), (b), and a stepping pulse signal (d) by AND are obtained. The intervals T of the stepping pulse signal (d) are time- measured 21, and a correction table 23 storing the instrumental error correction coefficients for respective flow rates and a controller 22 corresponding to the forward-backward discrimination signal (c) cause addition and subtraction in an adder-subtractor 12 by way of a gate circuit 24, and these are integrated in a reversible integrating counter at every overflow or underflow. The controller 22 generates an overflow alarm when the measurement intervals are smaller than the minimum time interval T, and at the same time, it changes over the gate circuit 24 to an externally set constant in lieu of the correction table and therefore the correct use of water meters is warned.