MCP39F511N datasheet(24/61 Pages) MICROCHIP

24 / 61 page

 2015-2018 Microchip Technology Inc.

DS20005473B-page 24

MCP39F511N

5.6

Energy Accumulation

Energy accumulation for all four energy registers

(import/export, active/reactive) occurs at the end of

each computation cycle if the energy accumulation has

been

turned

on.

See

Section 6.5

“System

Configuration Register” for the energy-control bits.

The accumulation of energy occurs in one of eight

64-bit energy counters, four for each channel (import

and export counters for both active and reactive

power).

5.6.1

NO-LOAD THRESHOLD

The no-load threshold is set by modifying the value in

the No-Load Threshold register. The unit for this

default value is 100 or 1.00W. Any power that is below

1W will not be accumulated into any of the energy

registers.

For scaling of the apparent power indication, the calcu-

lation engine uses the Apparent Power Divisor register.

This is described in the following register operations,

per Equation 5-4.

EQUATION 5-4:

APPARENT POWER (S)

5.7

Active Power (P)

The MCP39F511N has three simultaneous sampling

A/D converters monitoring two individual currents and

two individual active powers. For the Active Power cal-

culations, the instantaneous currents and voltage are

multiplied together to create instantaneous power. This

instantaneous power is then converted to Active Power

by averaging or calculating the DC component.

Equation 5-5 controls the number of samples used in

this accumulation prior to updating the Active Power

output register.

Please note that although this register is unsigned, the

direction of the Active power (import or export) can be

determined by the Active Power Sign bit located in the

System Status Register.

EQUATION 5-5:

ACTIVE POWER

FIGURE 5-4:

Channel 1 or Channel 2 Active Power Calculation Signal Flow.

CurrentRMS

VoltageRMS



ApparentPowerDivisor

---------------------------------------------------------------------

-------V



–





OffsetActivePower1,2:s32

ActivePower1,2:u32

GainActivePower1,2:u16

Range1,2:b32



ACCU

-1

÷ 2N

÷2RANGE

MCP39F511N Datasheet(PDF) 24 Page - Microchip Technology

MCP39F511N Datasheet(HTML) 24 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

Datasheet Download

Link URL