71M6541D Datasheet, PDF (135/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
5.3.11 CE Calibration Parameters
Table 92 lists the parameters that are typically entered to effect calibration of meter accuracy.
Table 92: CE Calibration Parameters
CE
Address
0x10
0x11
0x13
0x14^†
0x12
0x15
Name
CAL_IA
CAL_VA
CAL_IB
CAL_VB
PHADJ_A
PHADJ_B
Default Description
16384
16384
16384
16384
0
0
These constants control the gain of their respective channels. The
nominal value for each parameter is 2¹⁴ = 16384. The gain of each
channel is directly proportional to its CAL parameter. Thus, if the
gain of a channel is 1% slow, CAL should be increased by 1%.
Refer to the 71M6541 Demo Board User’s Manual for the equations
to calculate these calibration parameters.
† _{71M6542 only.}
These constants control the CT phase compensation. Compensation
does not occur when PHADJ_X = 0. As PHADJ_X is increased,
more compensation (lag) is introduced. The range is ± 215 – 1. If
it is desired to delay the current by the angle Φ, the equations are:
PHADJ _ X = 2^{20 0.02229 ⋅TANΦ at 60Hz}
0.1487 − 0.0131⋅TANΦ
PHADJ _ X = 2²⁰
0.0155 ⋅ TANΦ
at 50Hz
0.1241− 0.009695⋅TANΦ
The shunt delay compensation is obtained using the equation
provided below:
0x12 DLYADJ_A
0
( ) DLYADJ
_
X
=
∆_{deg rees}
1 + 0.1∆_degrees
2¹⁴
2π
360
a²
cos
2

2πf
f_s

+
2ab
cos_{}
2πf
f_s
c sin_{}
2πf
f_s

 ^{+ b}
where:
a = 2A
b = A² +1
0x15 DLYADJ_B 0
𝑐
=
2𝐴²
+
4𝐴𝑐𝑜𝑠
2𝜋𝑓
� _{í µí±“í µí±}  �
+
2
Where, f is the mains frequency and f_s is the sampling frequency.
The table below provides the value of A for each current channel:
Value of A
Channel
(decimal)
DLYADJ_A
DLYADJ_B
Eq. 0 or 2
15811 / 2¹⁴
-1384 / 2¹⁴
Eq. 1
6811 / 2¹⁴
-1384 / 2¹⁴