MCP3909RD-1PH1 Microchip Technology, MCP3909RD-1PH1 Datasheet - Page 38

• 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

MCP3909/PIC18F85J90 Single Phase Energy Meter Reference Design
DS51884A-page 38
5.3.3
The following equations represent the proper method for calculating the calibration and
correction factors after configuration C1. The PC calibration software handles these
calculations automatically.
The following equations only apply when calibrating a standard phase.
The first four equations apply for calculating the proper output frequency of the CF out-
put. See Figure 5-3 for meter input conditions.
EQUATION 5-1:
EQUATION 5-2:
EQUATION 5-3:
EQUATION 5-4:
The gain matching registers for the standard phase need to be set to the following
values when calibrating a standard phase:
EQUATION 5-5:
The following equations apply for calculating the proper GLSB registers when
calibrating both a standard phase, and a non-standard phase. See flow chart for meter
input conditions.
Note:
Note:
CFDEN
Equations for Configuration C1 Calibration
Convert to 8-bit signed integer for compatibility with PIC18F2520 register
and firmware calculations.
Convert to 16-bit signed integer for compatibility with PIC18F2520 register
and firmware calculations.
CFNUM
=
LOG
-------------------------------------------------------------------------------------------------------------------------- -
CF_IMP_S
=
LINE_CYC_NUM
--------------------------------------------------------------- - 2
⎛
⎝
2
---------------------------------------- LINE_CYC_NUM 256
--------------------------------------------------------- -
LINE_CYC_NUM 256
Line Freq 128
32
ENERGY_W_L_RAW
PHA_W_GAIN
⎛
⎝
•
2
----------------------------------------
Line Freq 128
32
CF_IMP_S
•
=
CF_IMP_S
•
Meter Constant
------------------------------------ -
•
LOG(2)
=
3600
=
•
--------------------------------------------------------- -
2
ENERGY_W_L_RAW
⎞
⎠
LINE_CYC
16 384
,
⎞
⎠
•
•
© 2009 Microchip Technology Inc.
V
----------- -
1000
CFDEN
B
I
B
•
32768
•
+
1