ADE9153AACPZ datasheet(21/50 Pages) AD

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Data Sheet

ADE9153A

Rev. 0 | Page 21 of 50

THEORY OF OPERATION

mSURE AUTOCALIBRATION FEATURE

The ADE9153A offers mSure autocalibration technology,

enabling the automatic calibration of the current and voltage

channel accurate, automatic calibration. Autocalibration features

have two main components: absolute accuracy and the speed of

convergence (see the Terminology section for more details).

When performing autocalibration, the current channels, AI and

BI, can be run in two power modes: turbo mode and normal mode.

The power mode is a trade-off between the speed of convergence

and current consumption. In turbo mode, the speed of conver-

gence is 4× faster and the current consumption is only 2× higher

when compared to normal mode, which means that the average

consumption over a full run is less than in low power mode, but

the instantaneous consumption is higher, as shown in Figure 38.

POWER

CONSUMPTION

NORMAL

MODE

LOW POWER MODE

p0 + 2 × p1

p0 + p1

0t1

4 × t1 TIME

ADE9153 A

Sure DISABLED

Figure 38. mSure Autocalibration Power Modes to Same Certainty

The ADE9153A can perform the autocalibration of a meter

without requiring an accurate source or reference meter. By

powering up the meter, the CC of each channel can be measured,

and that requirement alone is enough to perform the auto-

calibration.

After the meter is powered, the autocalibration feature can be run

on each channel, one at a time, by using the MS_ACAL_CFG

channel finishes a run, the certainty of the measurements are

confirmed with the MS_ACAL_xCERT registers. Then, the

MS_ACAL_xCC register can be used to calculate a gain value

that calibrates the meter.

mSure System Warning Interrupts

A set of interrupts in the ADE9153A are dedicated to alerting

the user regarding any issues during an mSure autocalibration.

These alerts are all indicated as a bit in the MS_STATUS_IRQ

Interrupts/Events section.

The MS_CONFERR bit is set if a run of mSure is incorrectly set up

with the MS_ACAL_CFG register. Clear these registers to 0 and

check the settings being written before starting another run.

The MS_ABSENT bit is set if the mSure signal is not detected. If

this bit is triggered, wiring in the meter may be incorrect or broken.

The MS_TIMEOUT bit is set if autocalibration is left to run for

more than the 600 sec limit of the system. If this interrupt is

triggered, ensure that the runs of mSure are being correctly

handled in terms of enabling and disabling mSure when

appropriate.

The MS_SHIFT bit is set when there is a shift in the CC value

that occurs in the middle of a run. This setting means that an

event at the meter level changed the CC before the run finished

and another run must be performed to achieve a more accurate

value. The certainty in this case is high, >50,000 ppm.

Figure 39 to Figure 41 show the speed of convergence of the mSure

result (the CC value). As the value of the shunt increases, or as the

gain of the PGA increases, the speed of convergence also increases

due to the signal size being larger. These are both parameters

that must be set based on the overall system, taking into account

factors such as the maximum current being measured. Figure 39

to Figure 41 show how the speed of convergence is influenced

from factors in a system.

300µΩ

500µΩ

1000µΩ

2000µΩ

20406080

100

120

CALIBRATION TIME TO REACH ACCURACY (Seconds)

140

150

180

200

1.000

0.800

0.600

0.400

0.353

0.250

0.200

Figure 39. Speed of Convergence for Autocalibration (Shunt Channel,

Normal Mode) Based on Shunt Value

300µΩ

500µΩ

1000µΩ

2000µΩ

1020

3040

CALIBRATION TIME TO REACH ACCURACY (Seconds)

0.600

0.353

0.500

0.400

0.250

0.300

0.200

0.100

Figure 40. Speed of Convergence for Autocalibration (Shunt Channel, Turbo

Mode) Based on Shunt Value

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