ADE9078ACPZ datasheet(47/108 Pages) AD

47 / 108 page

ADE9078

Data Sheet

Rev. 0 | Page 46 of 107

IRMS, VRMS, and Active Power VAR

The PSM1 mode uses a different computation method than is

done in PSM0. These measurements are computed over 20 ms.

Table 1 gives the expected accuracy achieved 40.5 ms after

setting the run register. Figure 66 shows the current channel

datapath for the ADE9078 PSM1.

To calibrate these measurements, write the xIGAIN, xVGAIN,

and xPGAIN registers before writing the run register to start

the calculation. Note that this measurement is updated every

10 ms. There is an option to enable the RMSRDY interrupt in

MASK0 to indicate when this result is ready. This interrupt

occurs every 10 ms; thus, several interrupts are required to

reach 40 ms for the specified accuracy.

Note that these PSM1 IRMS, VRMS, active power, and VAR

measurements are total bandwidth measurements—they are

done over the whole measurement bandwidth given in Table 1.

PSM1 Startup Flow from PSM2 and PSM3

To start up PSM1 from PSM2 and PSM3, follow these steps:

Wait for the RSTDONE interrupt indicated by the IRQ1

pin going low.

Configure the xIGAIN, xVGAIN, and xPGAIN registers

via the SPI to calibrate the measurements.

Write run = 1.

Wait 40.5 ms, then read the results in the xIRMS, xVRMS,

xWATT, and xVAR registers.

Optionally, enable the RMSRDY interrupt in MASK0 to

indicate when this result is ready. This interrupt occurs

every 10 ms; thus, several interrupts are required to reach

40 ms for the specified accuracy.

PSM1 Startup Flow from PSM0

To start up PSM1 from PSM0, follow these steps:

If the voltage sags, the host microcontroller changes the PM1

and PM0 pins to 0 and 1, respectively, to change to the PSM1

measurement mode.

The configured values in the xIGAIN, xVGAIN, and

xPGAIN registers remain valid.

Wait 40.5 ms, then read the results in the xIRMS, xVRMS,

xWATT, and xVAR registers.

Optionally, enable the RMSRDY interrupt in MASK0 to

indicate when this result is ready. This interrupt occurs

every 10 ms; thus, several interrupts are required to reach

40 ms for the specified accuracy.

xIGAIN

HPF

RESAMPLED WAVEFORM

DATA RANGE

CURRENTPEAK

DETECTION

REFERENCE

Σ-∆

MODULATOR

VIN

ADE9078 CURRENT CHANNE L (IA, IB, IC)

SINC4

LPF

4:1

LPF1

xIGAINx

PHASE

COMP

WAVEFORM

BUFFER

INTEGRATOR

WF_SRC

WF_CAP_SEL

MTEN

HPFDIS

INTEN

ICONSEL*

IB = –IA – IC

CURRENT CHANNEL (xI_PCF)

DATA RANGE

xI_PCF

ADC_

REDIRECT

MUX

NOTE: ICONSEL ONLY AFFECTS IB CHANNEL CALCULATION

PSM1TOTALACTIVEANDREACTIVE

POWERCALCUL ATION

PSM1 CURRENT RMS

CALCULATIONS

ZX_SRC_SEL

ZX DETECTION

NOT AVAILABLE IN ADE9078 PSM1

0xFBFF FB90 =

–67,110,000

0x0471 15C0 =

+74,520,000

SINC4 + IIR LPF (xI_LPF_DAT)

DATA RANGE

SINC4 OUTPUT (xI_SINC_DAT)

DATA RANGE

0x0400 0470 =

+67,110,000

0xFB8E EA40 =

–74,520,000

0x0474 E650 =

+74,770,000

0xFB8B 19B0 =

–74,770,000

4 kSPS

Figure 66. Current Channel PSM1 Datapath

ADE9078ACPZ датащи(PDF) 47 Page - Analog Devices

ADE9078ACPZ датащи(HTML) 47 Page - Analog Devices

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 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL