ITRON ACE6000, User Manual

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The main components of the ACE6000 meter are assembled onto two printed circuit boards (PCBs):
the PSU board contains all the metrology voltage divider circuitry and the switched-mode power supply
the top I/O board contains all the other meter circuitry including the I/O and communication ports,
microcontroller, memory devices and LCD display
The block diagram below shows the main functional elements of the meter:
7.1. Metrology
The meter current sensors are integral Mutual Conductance Transformers, which provide a wide dynamic range
and guarantee high stability over the operating temperature range of the meter.
The three current sensors generate a signal per phase that is proportional to the instantaneous current, while
voltage signals are derived by dividing the distribution-network line voltages through a resistive divider.
The current and voltage input signals are sampled and digitised 40 times per cycle (50Hz) by an analogue to
digital (A-to-D) converter, then processed by a microcontroller to derive various energy values. The
microcontroller records these values in a suite of registers that are independent of any meter configuration and
are always available.
These registers accumulate their respective energy values in an incremental fashion, until they reach the register
limit. At that point they are automatically reset to zero in the same way as roll-over electromechanical meter
types.
The contents of these registers can be displayed at any time as instantaneous values on the meter LCD.
The microcontroller also controls the data transfer to the various inputs and outputs, visible metrological LEDs
and infrared port.
7. Technical description