REV. 0

–38–

ADE7754

Watt Mode Register (0Dh)

The phases involved in the active energy measurement of the ADE7754 are defined by writing to the WATMODE register. Table XIV

summarizes the functionality of each bit in the WATMODE register.

Table XIV. WATMODE Register

Bit

Bit

Default

Location

Mnemonic

Value

Description

0-2

LWATSEL

7

These bits are used to select each part of the formula separately, depending on the line active

energy measurement method. The behavior of these bits is the same as WATSEL bits. Bit 2

selects the first term of the formula and so on.

3-5

WATSEL

7

These bits are used to select each part of the formula separately, depending on the active

energy measurement method. These bits are also used to enable the negative power detection

available in Bits 12 to 14 of CFNUM register. See Table XI. Setting Bit 5 to Logic 1 selects

the first term of the formula (VA

IA or VA

(IA – IB)). Setting Bit 4 to Logic 1 selects the

second term of the formula (VB

IB or 0 depending on WATMOD configuration). Setting

Bit 3 to Logic 1 selects the last term of the formula (VC

IC or VC

(IC – IB)). Any combi-

nation of these bits can address calibration and operational needs.

6-7

WATM

0

These bits are used to select the formula used for active energy calculation.

WATM1

WAVM0

Active Energy Calculation

00

VA

IA + VB

IB + VC

IC

01

VA

(IA – IB) + 0 + VC

(IC – IB)

10

VA

(IA – IB) + 0 + VC

IC

11

Reserved.

VA Mode Register (0Eh)

The phases involved in the apparent energy measurement of the ADE7754 are defined by writing to the VAMODE register. Table XV

summarizes the functionality of each bit in the VAMODE register.

Table XV. VAMODE Register

Bit

Bit

Default

Location

Mnemonic

Value

Description

0-2

LVASEL

7

These bits are used to select each part of the formula separately, depending on the line appar-

ent energy measurement method. The behavior of these bits is the same as VASEL bits. Bit 2

selects the first term of the formula, and so on.

3-5

VASEL

7

These bits are used to select separately each part of the formula, depending on the apparent

energy measurement method. Setting Bit 5 to Logic 1 selects the first term of the formula

bits can address calibration and operational needs.

6-7

VAMOD

0

These bits are used to select the formula used for active energy calculation.

VAMOD1

VAMOD0

Apparent Energy Calculation

00

01

10

11

Reserved.