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"CIRCUIT FUNCTION AND BENEFITS

The circuit shown in Figure 1 is a complete smart industrial, loop powered field instrument with 4 mA to 20 mA analog output and a highway addressable remote transducer (HART®) interface. HART is a digital 2-way communication in which a 1 mA peakto- peak frequency-shift-keyed (FSK) signal is modulated on top of the standard 4 mA to 20 mA analog current signal. This allows features such as remote calibration, fault interrogation, and transmission of process variables, which are necessary in applications such as temperature and pressure control.

This circuit has been compliance tested, verified, and registered by the HART Communication Foundation (HCF). This successful registration provides circuit designers with a high level of confidence using one or all of the components in the circuit.

The circuit uses the ADuCM360, an ultralow power, precision analog microcontroller, the AD5421, a 16-bit, 4 mA to 20 mA, loop powered digital-to-analog converter (DAC), and the AD5700, the industry’s lowest power and smallest footprint HARTcompliant IC modem."

The AD5700 is a single-chip solution, designed and specified to operate as a HART® FSK half-duplex modem, complying with the HART physical layer requirements. The AD5700 integrates all of the necessary filtering, signal detection, modulating, demodulating and signal generation functions, thus requiring few external components. The maximum supply current consumption of 115 µA and the small 4mm x 4mm housing, makes the AD5700 an optimal choice for low power loop-powered applications. Transmit waveforms are phase continuous 1200 Hz and 2200 Hz sinusoids. The AD5700 contains accurate carrier detect circuitry and uses a standard UART interface.



Это реально технологии 21 века.