ADE7760 Ver la hoja de datos (PDF) - Analog Devices

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componentes Descripción

Fabricante

ADE7760

Energy Metering IC with On-Chip Fault Detection

Analog Devices 

ADE7760

Calibration Concerns

Typically, when a meter is being calibrated, the voltage and

current circuits are separated as shown in Figure 25. This means

that current passes through only the phase or neutral circuit.

Figure 25 shows current being passed through the phase circuit.

This is the preferred option, because the ADE7760 starts billing

on the input V1A on power-up. The phase circuit CT is con-

nected to V1A in the diagram. Because there is no current in the

neutral circuit, the FAULT indicator comes on under these

conditions. However, this does not affect the accuracy of the

calibration and can be used as a means to test the functionality

of the fault detection.

RF

V1A

IB

CT

RB

AGND

IB

TEST

CURRENT

RB

CT

RA*

RB*

CF

VR*

V

240V RMS

*RB + VR = RF

V1A

0V

RF

RF

CT

CF

V1N

CF

V1B

V2P

V2N

Figure 25. Fault Conditions for Inactive Input Greater than Active Input

If the neutral circuit is chosen for the current circuit in the

arrangement shown in Figure 25, this may have implications for

the calibration accuracy. The ADE7760 powers up with the V1A

input active as normal. However, because there is no current in

the phase circuit, the signal on V1A is zero. This causes a fault to

be flagged and the active input to be swapped to V1B (neutral).

The meter can be calibrated in this mode, but the phase and

neutral CTs might differ slightly. Because under no-fault condi-

tions all billing is carried out using the phase CT, the meter

should be calibrated using the phase circuit. Of course, both

phase and neutral circuits can be calibrated.

Rev. 0 | Page 18 of 24

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