Incotex Co. Ltd, Moscow, has selected Texas Instruments' ultra-low power MSP430 microcontrollers (MCU), power-efficient TMS320VC54x(TM) digital signal processors (DSP) and analog technologies for its e-meter, data collection and power line communication (PLC) system for power distribution networks. Each Mercury PLC system reads up to 3000 e-meters and is designed to overcome the presence of high noise and signal loss when communicating over electrical distribution networks. By combining digital e-meters and a PLC-modem, power utilities can now replace less accurate mechanical meters and manual meter reading for greater flexibility, control and cost savings for power distribution and measurement.
"By leveraging TI's processors and analog technologies, designers can tap into less than 50 mW power consumption, high noise immunity with a signal-to-noise ratio of -20 dB and a low system cost," said Yuri Sokolov, president of Incotex Holdings.
Low-power technologies like TI's MSP430 MCUs, C54x DSPs and analog components reduce overall power consumption on all meters within a distribution system. Utility companies monitoring e-metering data that are transmitted via long-distance electrical distribution networks have traditionally faced significant technical challenges due to the "unfriendly" environment that utility networks -- which were never designed for data transmission -- represent. Issues such as changing load characteristics from connected household electrical appliances often makes data transmission almost impossible. Alternatively, communication via broadband modulation implemented by the patented Mercury PLC system overcomes the noisy environment, allowing e-meter communications data to be read at signal-to-noise ratios (SNR) of down to minus 20 decibels (dB) and at a signal attenuation of down to -60 dB, although not simultaneously.
Data can be transmitted at up to 100 frequencies in two directions -- both to read data from the e-meter and also to communicate, control and adjust the meter. Accurate, two-way communication enables utility companies to easily adjust rates based on time of day, update software or be alerted in the event of user tampering or mechanical malfunction. This two-way communication is based on two types of broadband modulation: orthogonal frequency division multiplexing (OFDM), which transmits multiple signals simultaneously over a single path, and phase shift keying (PSK) of the frequency hopping carrier, in which the phase of a transmitted signal is varied to convey information. TI's MSP430F155 MCU enables PSK communication while the VC5409 DSP handles complex OFDM signal processing through the implementation of Fast Fourier Transform calculations that analyze the frequencies contained in a sampled signal.
Measuring only 40 x 60 x 20 mm including the power supply, Incotex' PLC solution integrates the MSP430F155 MCU in the modem daughter board. The MCU features a powerful 16-bit RISC CPU, 16-bit registers and a digitally controlled oscillator (DCO) that allows wake-up from low-power modes to active mode in less than 6 microseconds. The PLC system also incorporates a concentrator that combines up to 3000 meter readings and is controlled by a low-power TMS320VC5409 DSP. TI analog technologies include a THS6093 high-speed line driver for driving signals from the remote terminal to the central office, and a TPS3828 for circuit initialization and timing supervision, as well as a TL431 shunt regulator.
The Incotex "Mercury" e-meter is enabled by a highly integrated MSP430FE423 MCU e-meter solution that eliminates the need for multiple external components traditionally used to measure and calculate energy, provide an accurate real time clock and drive an LCD, including high-precision analog to digital converters (ADCs), crystals, EEPROMs, LCD drivers, external real time clocks or 5 V power supplies. The ESP430CE1 module is embedded in the MSP430FE42x series of devices and integrates a hardware multiplier, three independent 16-bit Sigma-Delta ADC (SD16) and an embedded signal processor (ESP430). The ESP430CE1 module measures two or three-wire, single-phase energy and automatically calculates parameters that are made available to the MSP430 CPU. The module can be calibrated and initialized to accurately calculate energy, power factor and other parameters for a wide range of metering sensor configurations.
