Electronic power metering made easy

The utility-metering industry has grown and matured enormously. Power meters, specifically, have been a major driving force, going beyond the simple replacement of traditional mechanical solutions. By fully embracing new electronic technologies, the power-meter segment stands to reap substantial benefits, including automated meterreading capabilities, sophisticated anti-tampering solutions, and time-of-use and pre-paid billing options.

Generally, the faster the growth rate in a particular region, the more urgent the demand for metered power. Fortunately, new advanced analogue and digital solutions are available from leading embeddedcontrol manufacturers to make the most of electronic power metering.

The flexibility of electronic meters allows for the implementation of three important collection (billing) strategies not available with previous mechanical solutions. Time-of-use technology is based on the ability of the meter to record energy consumption during different segments of the day and to apply different rates for each segment. Pre-pay technology, on the other hand, requires the meter to actually control the delivery of energy as soon as proof of payment is provided (via magnetic cards, smart cards and other technologies) in the exact amount allowed by the available credit. Automated Meter Reading (AMR) technology refers to the capability of the meter to communicate its reading to a fully-automated collection and communication center, via the use of dedicated lines and/or existing networking infrastructure.

 

 

Electronic meters made easy

Several semiconductor manufacturers have developed new solutions that provide ever greater simplicity and flexibility in the design of energy meters. Analogue Front-End (AFE) devices, such as the MCP3905A/6A and MCP3909 devices from Microchip Technology (see Figure 1) offer full functionality with 24-pin SSOP packages, including additional features such as an automatic tampering alert when a negative power condition is detected.

The MCP3905A/6A and MCP3909 can be used with a few external components to implement a complete and inexpensive mono-phase meter, but its performance can be augmented by pairing it with advanced Flash microcontrollers, such as the PIC18F8490. Additionally, the MCP3909 can be used in 3-phase meters by accessing the A/D converters data directly and sending it to the microcontroller for additional post-processing (see Figure 2).

 

 

 

www.microchip.com/meter