MCP3909RD-3PH1 Microchip Technology, MCP3909RD-3PH1 Datasheet - Page 34

• 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

MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design
DS51723A-page 34
The energy pulse processing program only begins when the level is close to outputting
pulse level. To simplify the process and shorten the ISR execution time, a counter is
used in place of the energy accumulation function for each pulse and to determine if a
pulse will be outputted. When the count is greater than the threshold of pulse output,
an energy pulse will be outputted, and the appropriate amount of energy will be sub-
tracted from the energy accumulating register. Output toggling will then be processed.
Once the width of the output pulse exceeds 80 ms, the pulse output will be turned off.
The program flow chart is shown in Figure 3-4.
FIGURE 3-4:
IC1 Interrupt Service Routine.
ICI Interrupt Service
Call MCP3909 data
reactive energy?
falling edge of
active energy?
active energy?
active energy?
rising edge of
falling edge of
rising edge of
read program
Processing
Processing
Processing
Processing
routine
Return
No
No
No
No
Yes
Yes
Yes
Yes
Update pulse width
counter, if pulse
width > 80 ms, toggle
pulse output level.
End pulse output
process.
Update pulse width
counter, if counter >
flip threshold, output
pulse and update
energy accumulation
register.
Update pulse width
counter, if pulse
width > 80 ms, toggle
pulse output level.
End pulse output
process.
Update pulse width
counter, if counter >
flip threshold, output
pulse and update
energy accumulation
register.
© 2009 Microchip Technology Inc.