FIELD: measuring equipment.
SUBSTANCE: invention relates to measurement equipment, in particular to heat meters comprising a primary flow converter based on electromagnetic flow meters (EFM), and can be used to determine flow rate in pipeline completely filled with electroconductive liquid medium, at objects remote from industrial power supply. Heat meter is supplied from autonomous power supply comprising two series-connected batteries. EFM supply is carried out by current of two polarities of rectangular shape. To select the optimum power supply unit there determined are thermal noise voltages in the circuit of the primary flow converter, in a wide range of change of active resistance, frequency band and temperature. Current consumption in heat meter circuit is defined. Dependences of thermal noise EFM on the temperature much higher than 20 °C are determined at different resistances of EFM winding and frequency band. In quiescent mode, initial value of thermal noise voltage is determined depending on change of frequency band, from discrete values of active resistances for different circuits of measuring system, from noise temperature coefficient. Current value of thermal noise voltage is determined depending on change of frequency band, temperature is measured by temperature sensor, then amplified, digitized and registered in memory unit of computer unit. Operator monitors working mode of self-contained heat meter. Under commands of control signal of microcontroller, also after amplification, matched digitized signals from outputs of matching amplifier, voltage amplifier, bearing information on flow rate of fluids and temperature, are stored and registered in memory unit of computer unit.
EFFECT: technical result is reduction of electric energy consumption, improvement of signal/noise ratio by three orders.
2 cl, 5 dwg, 4 tbl
