SERIAL MICROPROCESSOR METER FOR MEASURING ENERGY

摘要

The proposition applies to electronics, namely to instruments of consumed electrical energy measurement - electrical energy meters, and may be used for the calculation of electrical power of an alternating 50 Hz frequency current. In the electric energy meter box installed are; terminals of a phase and zero input, that are connected to the relevant output terminals by two relevant busbars. Between the busbars there is, switched-on a voltage division resistor with a middle point contact. Also in the box there is a microprocessor with data inputs, a timer and an external programmable memory. The microprocessor is connected to a digital indicator for the readings and that is placed behind the box front wall window. Additionally between the input and output phase terminals, in the cut of the phase busbar, there is a current resistor switched-on, the contacts of which are connected to contacts of a current amplifier, which has output contacts connected to the input contacts of the first digital analogue converter (DAC), and the middle point contact of the voltage division resistor and zero busbar are connected to input contacts of the second DAC. Outputs of the first and second DAC are connected to the microprocessor data inputs. In the second version, instead of the voltage division resistor there is a switched-on primary voltage transformer winding, the secondary winding of which is connected to the zero busbar and the input of the second DAC, and instead of the current resistor there is switched-on, a short-circuitry, which has a circular magnetic circuit with a current excitation winding that is connected to the input of the current amplifier.