MCP3909RD-3PH3 Microchip Technology, MCP3909RD-3PH3 Datasheet - Page 48

• Manufacturer Part Number: MCP3909RD-3PH3
• Description: REF DESIGN FOR MCP3909 W/18F2520
• Manufacturer: Microchip Technology

Specifications of MCP3909RD-3PH3

• Main Purpose: Power Management, Energy/Power Meter
• Utilized Ic / Part: MCP3909, PIC18F2520, PIC18F4550
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

MCP3909 3-Phase Energy Meter Reference Design
DS51643B-page 44
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 4 equations apply for calculating the proper output frequency of the CF output.
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 val-
ues when calibrating a standard phase:
EQUATION 5-5:
The following equations apply for calculating the proper GLSB registers when calibrat-
ing 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 18F2520 register and
firmware calculations.
Convert to 16-bit signed integer for compatibility with 18F2520 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
PHY_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
,
⎞
⎠
•
•
© 2008 Microchip Technology Inc.
V
----------- -
1000
CFDEN
B
I
B
•
32768
•
+
1