Datasheet

MAX71020
Single-Chip Electricity Meter AFE
29Maxim Integrated
Table 11. CESTATUS Register
Table 12. Sag Threshold and Gain Adjust Control
a transition on the YPULSE output. The CE controls
the pulse rate based on WSUM_X (register 0x084) and
VARSUM_X (register 0x088).
CE Transfer Variables
When the host controller receives the INTZ interrupt, it
knows that fresh data is available in the transfer vari-
ables. They remain constant throughout each accumula-
tion interval. In this data sheet, the names of CE transfer
variables always end with “_X”. The transfer variables
can be categorized as:
U Fundamental energy measurement variables
U Instantaneous (RMS) values
U Other measurement parameters
Fundamental Energy Measurement Variables
Table 13 describes each transfer variable for fundamen-
tal energy measurement. All variables are signed 32-bit
integers. Accumulated variables such as WSUM are
internally scaled so that internal values are no more than
50% of the full-scale range when the integration time is
Table 13. CE Transfer Variables
CE ADDRESS NAME DESCRIPTION
0x80 CESTATUS See the description of CESTATUS bits in Table 7
CE
ADDRESS
NAME DEFAULT DESCRIPTION
0x24 SAG_THR 2.39 x 10
7
The voltage threshold for sag warnings. The default value is equivalent to
113Vpk or 80V
RMS
if V
MAX
= 600V
RMS
.
−
×
=
××
RMS
9
MAX
V2
üüü
V 7.8798 10
0x40 GAIN_ADJ0 16384
This register scales the voltage measurement channels VA and VB. The default
value of 16384 is equivalent to unity gain (1.000).
0x41 GAIN_ADJ1 16384
This register scales the IA current channel for Phase A. The default value of
16384 is equivalent to unity gain (1.000).
0x42 GAIN_ADJ2 16384
This register scales the IB current channel for Phase B. The default value of
16384 is equivalent to unity gain (1.000).
CE
ADDRESS
NAME DESCRIPTION
0x84 WSUM_X
The signed sum: W0SUM_X + W1SUM_X. Not used for EQU[2:0] = 0 (register
0x30D[14:12]) and EQU[2:0] = 1.
0x85 W0SUM_X
The sum of Wh samples from each wattmeter element.
LSB
W
= 6.08040 x 10
-13
x V
MAX
x I
MAX
Wh
0x86 W1SUM_X
0x88 VARSUM_X
The signed sum: VAR0SUM_X + VAR1SUM_X. Not used for EQU[2:0] = 0 and
EQU[2:0] = 1.
0x89 VAR0SUM_X
The sum of VARh samples from each wattmeter element.
LSB
W
= 6.08040 x 10
-13
x V
MAX
x I
MAX
VARh
0x8A VAR1SUM_X