MCP3909RD-3PH1 Microchip Technology, MCP3909RD-3PH1 Datasheet - Page 15

• Manufacturer Part Number: MCP3909RD-3PH1
• Description: REF DESIGN MCP3909 3PH ENGY MTR
• Manufacturer: Microchip Technology

Specifications of MCP3909RD-3PH1

• Main Purpose: Power Management, Energy/Power Meter
• Embedded: No
• Utilized Ic / Part: MCP3909, PIC18F2520, PIC18F4550
• Primary Attributes: 3-Ph, 220 VAC, In Case, LCD, USB, GUI
• Secondary Attributes: Opto-Isolated Interface for Safety
• Operating Voltage: 220 V
• Operating Current: 5 A
• Description/function: Energy Meter
• For Use With/related Products: MCP3909
• Lead Free Status / RoHS Status: Not applicable / Not applicable

2.1
FIGURE 2-1:
© 2008 Microchip Technology Inc.
CTA-1
CTA-2
INPUT AND ANALOG FRONT END
PHA-L
PHA-N
T-4
J6:1
J6:2
Note:
This meter comes populated with components designed for 220V line voltage. At the
bottom of the main board are the high voltage line and load connections. The
connections to the current transformers for each phase are labelled CTA, CTB and
CTC. The three screw terminals to the right of these are the connections to be wired
into the line side of the CT for the voltage input and power supply transformer
connections. These are labelled PHA, PHB and PHC. The line and neutral connections
are labelled “L” and “N”.
Each phase will use a current transformer and a resistor divider on the voltage channel
input. Anti-aliasing low-pass filters will be included on both differential channels. The
voltage channel uses 221 kΩ resistors to achieve a divider ratio of 453:1. For a line
voltage of 230 V
channel of each phase uses current transformer with a turns ratio of 2000:1 and burden
resistance of 56.4 kΩ. The resulting channel 0 signal size is 340 mV
twice the rated maximum current of the meter, still within the input range of the A/D
converter of the MCP3909.
Analog Front End, Phase A Connections and Reference Designators shown.
Note:
FB = ferrite beads. Ferrite beads have an impedance of the
specified value at 100 MHz.
150 FB (Note)
Revision 2 of the hardware uses current transformers, P/N: SCT954.
none
Chapter 2. Hardware
RMS
, the channel 1 input signal size will be 718 mV
23.2Ω
23.2Ω
1000:1
221 kΩ 221 kΩ
METER REFERENCE DESIGN
MCP3909 3-PHASE ENERGY
1.0 kΩ
1.0 kΩ
1.0 kΩ
1.0 kΩ
0Ω
68 nF
68 nF
68 nF
68 nF
PEAK
CH0-
CH0+
CH1+
CH1+
PEAK
DS51643B-page 11
MCP3909
. The current
for 20A, or