Design

As in the block diagram, the meter has a power supply, a metering engine, A processing and communication engine i.e a microcontroller, other add-on modules such as RTC, LCD display, communication ports/modules etc. Image File history File links Download high resolution version (637x747, 82 KB) Summary Basic Block Diagram of an Electronic Energy Meter. ... Image File history File links Download high resolution version (637x747, 82 KB) Summary Basic Block Diagram of an Electronic Energy Meter. ...

Metering engine

The metering engine is given the voltage and current inputs and has a voltage reference, samplers and quantisers followed by an ADC section to yield the digitised equivalents of all the inputs. These inputs are then processed using a Digital Signal Processor to calculate the various metering parameters such as powers, energies etc.


The largest source of long-term errors in the meter is drift in the preamp, followed by the precision of the voltage reference. Both of these vary with temperature as well, and vary wildly because most meters are outdoors. Characterizing and compensating for these is a major part of meter design.

Processing and communication section

This section has the responsibility of calculating the various derived quantities from the digital values generated by the metering engine. This also has the responsibility of communication using various protocols and interface with other addon modules connected as slaves to it.

RTC and other add-on modules

These are attached as slaves to the processing and communication section for various input/output functions. On a modern meter most if not all of this will be implemented inside the microprocessor, such as the Real Time Clock (RTC), LCD controller, temperature sensor, memory and analog to digital converters.