ADE7760

Rev. 0 | Page 18 of 24

Calibration Concerns

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

arrangement shown in Figure 25, this may have implications for

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

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.

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

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.

AGND

CT

CT

RB

RB

0V

IB

IB

*RB + VR = RF

VR*

RB*

RA*

V

TEST

CURRENT

240V RMS

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