MCP3909RD-1PH1 Microchip Technology, MCP3909RD-1PH1 Datasheet - Page 17

• Manufacturer Part Number: MCP3909RD-1PH1
• Description: BOARD DES MCP3909 ENERGY METER
• Manufacturer: Microchip Technology

Specifications of MCP3909RD-1PH1

• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP3909, PIC18F85J90
• Primary Attributes: Single Phase Shunt Energy Meter
• Secondary Attributes: 16 Bit ADC
• Ic Function: Single Phase Energy Measurement IC
• Supply Voltage Range: 4.5V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 24
• Interface Type: SPI
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

3.1
© 2009 Microchip Technology Inc.
REGISTER OVERVIEW
Chapter 3.
The PIC18F85J90 contains registers that are used during calibration and registers that
can be read through the UART. The registers are named to describe each phase,
specific measurement, and in the case of the calibration registers, the calibration
function.
The intent of the calibration process is to yield output registers that are decimal
representation of the final energy, power, current or voltage value.
Instantaneous Power Registers
The PHy_W and PHy_VA registers contain the decimal representation of the active
power (W) and apparent power (VA) post calibration. The reactive power calculation is
not implemented at this time.
The final correction factors to convert these registers to units of energy are located in
the _GLSB registers. These correction factors can be automatically calculated and
loaded by using the PC calibration software. The exact representation depends on the
meter values that are entered in the software. For example, at 10A and 220V, power in
the PHy_W register is 0.1 mW/LSB.
Calibration Registers
The calibration registers fall into one of three categories: offset, gain, and LSB, denoted
by _OFF, _GAIN and _GLSB register names.
In addition there are two registers, CFNUM and CFDEN, that calibrate the output pulse,
CF.
Calculation and Register Description
MCP3909/PIC18F85J90 SINGLE PHASE
ENERGY METER REFERENCE DESIGN
DS51884A-page 17