Rainbow Electronics 71M6542G - Manual (Page 135)

v1.1 © 2008–2011 Teridian Semiconductor Corporation 135
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
Name Default Description
0x10 CAL_IA 16384 These constants control the gain of their respective channels. The
nominal value for each parameter is 2
14
= 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.
0x11 CAL_VA 16384
0x13 CAL_IB 16384
0x14
†
CAL_VB 16384
0x12 PHADJ_A 0
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:
Φ ⋅ −
Φ ⋅
=
TAN
TAN
X PHADJ
0131 . 0 1487 . 0
02229 . 0
2 _ 20 at 60Hz
Φ ⋅ −
Φ ⋅
=
TAN
TAN
X PHADJ
009695 . 0 1241 . 0
0155 . 0
2 _ 20 at 50Hz
0x15 PHADJ_B 0
0x12 DLYADJ_A 0
The shunt delay compensation is obtained using the equation
provided below:
( )






+






+






∆ + ∆ =
s
s s
rees rees
f
f
c
b
f
f
ab
f
f
a
X DLYADJ
π
π π
π
2
sin
2
cos 2
2
cos
360
2
2 1 . 0 1 _
2 2
14
deg deg
where:
A a 2
=
1 2 + = A
b
𝑐 = 2𝐴 2 + 4𝐴𝑐𝑜𝑠 �
2𝜋𝑓
𝑓
𝑠
� + 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:
Channel
Value of A
(decimal)
Eq. 0 or 2 Eq. 1
DLYADJ_A 15811 / 2
14
6811 / 2
14
DLYADJ_B -1384 / 2 14 -1384 / 2 14
0x15 DLYADJ_B 0