The AS8218 and AS8228 1-phase energy metering ICs from austriamicrosystems offer the meter manufacturer a highly integrated meter system solution that contains all the anti-tamper requirements specified by utilities.
The AS8218 and AS8228 ICs provide all the required functional blocks for 1-phase metering, a precision energy measurement front-end, an industry standard 8-bit 8051 microcontroller, real-time clock, up to 96-segment LCD driver and up to 12 programmable multi-purpose inputs/ outputs.
The precision energy measurement front-end consists of the analogue front-end (AFE) and digital signal processor (DSP) and incorporates all the anti-tamper requirements specified by utility companies.
The AFE has three analogue inputs for measuring the mains voltage and both the phase and neutral currents. The voltage and current inputs provide for full bi-directional energy measurement. This configuration ensures that the meter can measure and record energy when all the tamper connection configurations are applied, including incoming and outgoing interchanged, phase and neutral interchanged and load is connected to earth, as well as combinations of these.
Furthermore, when current is measured and the mains voltage signal is not available for calculation, the DSP provides for a simulated mains voltage input to ensure energy consumption can still be metered.
Up to 12 multi-purpose inputs/outputs (MPIO) are fully programmable for data direction, pull-up or pull-down resistors and for drive strength. This provides for direct connection of LEDs for the display of current reversal, phase availability and earthing of the load, besides all other standard display requirements such as LED pulse output for calibration and consumption monitoring. The fully programmable on-chip liquid crystal display driver (LCDD) can also be used for the display of the various tamper conditions.
The on-chip microcontroller allows for the recording of tamper conditions and the real-time clock/calendar provides the time and date stamp for such events.
The AS8218 IC with its 80 segments has nine independently programmable inputs/outputs; the AS8228 IC, with its 96-segment LCD display and 12 programmable inputs/outputs, far surpasses the utility specification requirements laid out in the IEC1036 and ANSI standards, and requires a minimum of external components.