Energy meter suitable for counting pulses of an external device

Abstract

The invention relates to an energy meter (1) suitable for counting pulses of an external device, which comprises a logic gate adapted to receiving pulses from external equipment through an interface module. The pulses are transmitted through a switch. The logic gate is associated with a minimum high threshold and a maximum low threshold corresponding to a comparison threshold. The logic level of the logic gate triggered by the comparison threshold is 1 or 0. The module comprises a filter circuit with a filter resistor connected in series with a filter capacitor. The logic gate is electrically connected between the filter resistor and the filter capacitor. The logic gate receives a voltage level corresponding to the voltage of the filter capacitor. A counter comprises a software means, wherein the level of the logic gate is kept to be 1 at a first predefined duration T1. After the filter capacitor is fully charged, the logic gate is set to receive the voltage level of the filter capacitor. After a second predefined duration T2, the voltage level of the logic gate is sampled. Whether the level of the logic gate is 1 or 0 depending on whether the sampled voltage level is greater than the minimum high threshold or below the maximum low threshold. The the level of the logic gate is set to be 0 for a third predetermined duration T3.

Description

technical field [0001] The present invention relates to the field of energy meters, in particular thermal energy meters, and more particularly to the processing of pulse count inputs for counting pulses from other meters. Background technique [0002] In the field of heat meters of the water meter type, such a meter may be required to perform the task of counting pulses from other devices or other meters to which the meter may be connected. For this purpose they are equipped with one or more pulse inputs or "water meter" ("WM") inputs designed to receive such external pulses. [0003] figure 1 is a schematic block diagram showing a configuration in which a heat meter 1 is connected to respective pulse outputs of two pieces of external equipment schematically represented by two switches 2, 3 of reed switch type. These two switches 2, 3 work like relays, each switch having their two terminals connected by cables to a pair of the two inputs 10 and 11 and 12 and 13 of the term...

AI Technical Summary

Problems solved by technology

This longer time corresponds to the duration during which the microprocessor 18 may be unstable, increasing the risk of excessive counting

Furthermore, during periods of instability, considerable short-term over-consumption at the input port 18 of the microprocessor may occur

[0022] Finally, this period of instability also generates over-consumption by an external load of 0Ω

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