Rainbow Electronics 78M6631 - Manual (Page 5)

DS_6631_056 78M6631 Data Sheet
Rev 1 5
1 Hardware Functional Description
1.1 Hardware Overview
The Teridian 78M6631 single-chip power measurement and monitoring device integrates all the primary
AC measurement and control blocks required to implement the 3-phase power measurement and
monitoring system.
The 78M6631 includes:
• Six input analog front-end (AFE) (3 Differential Current/3 Voltage)
• Independent digital computation engine (CE)
• 8051-compatible microprocessor (MPU) which executes one instruction per clock cycle (80515)
• Precision voltage reference
• Temperature sensor
• RAM and flash memory
• A variety of I/O pins
• Communication Interfaces: UART, SPI, and I 2 C (Master)
Various current sensor technologies are supported including Current Transformers (CT), Resistive
Shunts, and Rogowski coils.
The 32-bit compute engine (CE) of the 78M6631 sequentially process the samples from the analog inputs
on pins IA, IB, IC, VA, VB, and VC and performs calculations to measure active power (Watts), reactive
power (VARs), apparent power (VAs), power factor, fundamental power, and harmonic power for three
independent phases. RMS, fundamental, and harmonic currents and voltages are also computed for each
phase. Totals are available for most results.
Figure 1 provides a block diagram of the 78M6631 IC. A detailed description of the various functional
blocks follows.
Refer to the applicable Firmware Description Document for additional supported functionality.