Elektricitetsmåler med variabel forstærkning og med sigma-delta omsætter

摘要

An electricity metering device including at least one sigma-delta converter (20) adapted to output a series of digital pulses, a digital counter means (21) for summing the output of the sigma-delta converter and a signalling means (32) to deliver an output signal (38) when the sum reaches a predetermined value, characterised in that the metering device further comprises a means (32, 33) for digitally adjusting the gain of the sigma-delta converter comprising programmable digital memory means (33) adapted to store a parameter representing the gain of the metering device, the value of the parameter being externally programmable, and a digital logic means (32) for logically combining the gain parameter with the digital sum stored in the counter means to determine the number of pulses required before the predetermined value is reached and an output pulse delivered.