71M6534 MAXIM [Maxim Integrated Products], 71M6534 Datasheet - Page 15

• Manufacturer Part Number: 71M6534
• Description: Exceeds IEC 62053/ANSI C12.20 Standards
• Manufacturer: MAXIM [Maxim Integrated Products]

The CE is aided by support hardware to facilitate implementation of equations, pulse counters, and
accumulators. This hardware is controlled through I/O RAM locations EQU[2:0] (equation assist), the
DIO_PV and DIO_PW (pulse count assist) bits, and PRE_SAMPS[1:0] and SUM_CYCLES[5:0] (accumulation
assist).
PRE_SAMPS[1:0] and SUM_CYCLES[5:0] support a dual-level accumulation scheme where the first
accumulator accumulates results from PRE_SAMPS[1:0] samples and the second accumulator accumulates
up to SUM_CYCLES[5:0] of the first accumulator results. The integration time for each energy output is
PRE_SAMPS[1:0] * SUM_CYCLES[5:0] / 2520.6 (with MUX_DIV[3:0] = 6). CE hardware issues the
XFER_BUSY interrupt when the accumulation is complete.
1.3.1 Meter Equations
The 71M6533 and 71M6534 provide hardware assistance to the CE in order to support various meter
equations. This assistance is controlled through the I/O RAM field EQU[2:0] (equation assist). The
Compute Engine (CE) firmware for industrial configurations can implement the equations listed in
EQU[2:0] specifies the equation to be used based on the meter configuration and on the number of phases
used for metering.
Rev 2
EQU[2:0]
0
1
2
3
4
5
Not all CE codes support all equations.
1 element, 2 W,
1φ with neutral
current sense
1 element, 3 W, 1φ VA(IA-IB)/2
2 element, 3 W,
3φ Delta
2 element, 4 W,
3φ Delta
2 element, 4 W,
3φ Wye
3 element, 4 W,
3φ Wye
Description
Table 5: Inputs Selected in Regular and Alternate Multiplexer Cycles
Address (HEX)
Table 4: XRAM Locations for ADC Results
0x07 – 0x09
VA(IA-IB)/2
VA(IA-IB)/2 VB(IC-IB)/2
Element
VA ∙ IA
VA ∙ IA
VA ∙ IA
0x0A
0x0B
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0
Wh and VARh formula
Element
VA ∙ IB
VB ∙ IB
VB ∙ IB
N/A
N/A
1
Name
TEMP
VBAT
VA
VB
VC
IC
ID
IA
IB
–
Element
VC ∙ IC
VC ∙IC
N/A
N/A
N/A
N/A
2
Phase A voltage
Phase B voltage
Phase C voltage
Phase A current
Phase B current
Phase C current
Battery Voltage
Neutral current
Temperature
Description
Not used
Sequence is
programmable
with
SLOTn_SEL[3:0]
Sequence
Mux
Sequence is
programmable with
SLOTn_ALTSEL[3:0]
Sequence
ALT Mux
Table
15
5.