Datasheet

71M6515H
Energy Meter IC
DATA SHEET
JULY 2011
Page: 52 of 60 © 2005−2011 Teridian Semiconductor Corporation 1.6
A Maxim Integrated Products Brand
APPLICATION INFORMATION
Meter Circuits
Bits 7 through 5 (EQU) of the CONFIG register allow the selection of the metering equation that is to be implemented by the
71M6515H. The equation to be used depends on the meter configuration.
Figure 15 shows how the 71M6515H is connected for the most common configuration, the three-phase, four-wire WYE. The
neutral wire connects to V3P3A. For this configuration, equation 5 must be selected.
LOAD A
A
N
CT
71M6515H
IA
V3P3A
VA
Distribution
transformers
ANSI: Form 16S
EQU = 5
B
LOAD B
IC
P=VA*IA+VB*IB+VC*IC
CT
C
LOAD C
CT
IB
VB
VC
Figure 15: 4-Wire 3-Phase WYE Connection
In many three-phase three-wire configurations, one phase can be grounded, as shown in Figure 16. Again, the grounded wire
is connected to V3P3A. For this configuration, equation 2 must be selected.
The four-wire three-phase delta configuration is shown in Figure 19. In this case, the center tap of the transformer that
provides the A-C voltage is grounded. the grounded wire is connected to V3P3A. For this configuration, equation 2 must be
selected. For this configuration, equation 3 must be selected, i.e. P = VA*(IA-IB)/2 + VC*IC.