71M6534H Demo Board User’s Manual
Page: 51 of 86
© 2005-2007 TERIDIAN Semiconductor Corporation
V2-0
Calibration Procedure for Rogowski Coils
Enter values in yellow fields!
Results will show in green fields…
Step 1: Enter Nominal Values:
Nominal CAL_V
16384
Resulting Nominal
REV
4.3
Nominal CAL_I
16384
Values: X
6
Date:
11/18/2005
PHADJ
-3973
Kh (Wh)
0.440
Author:
WJH
WRATE
179
VMAX
600
Calibration Frequency [Hz]
50
Angle Sensitivity (deg/LSB)
IMAX (incl. ISHUNT)
30.000
50Hz
5.60E-04
PULSE_FAST
-1
1
1
50
32768
PULSE_SLOW
-1
1
-1
60
-32768
NACC
2520
Step 2: VRMS Calibration:
Phase A
Phase B
Phase C
Enter old CAL_VA
16384
16384
16384
Input Voltage Applied
240
240
240
Measured Voltage
235.612
236.55
234.72
CAL_Vx
16689
16623
16753
Step 3: Current Gain and Phase Calibration
Deg/ct
5.60E-04
Phase A
Phase B
Phase C
old PHADJ
-3973
-3973
-3973
Old CAL_Ix
16384
16384
16384
%Error, 60°
-3.712
-3.912
-5.169
%Error, -60°
-3.381
-2.915
-4.241
%Error, 0°
-3.591
-3.482
-4.751
%Error, 180°
-3.72
-3.56
-4.831
Phase Error (°)
0.0547319 0.1647659 0.1533716
PHADJ
-4070.74
-4267.22
-4246.88
CAL_Ix
17005.641 16981.934 17208.457
Step 4: Crosstalk Calibration (Equalize Gain for 0° and 180°)
VRMS
240
IRMS
0.30
Phase A
Phase B
Phase C
Old VFEEDx
0
0
0
% Error, 0deg
1.542
1.61
1.706
%Error, 180deg
-1.634
-1.743
-1.884
VFEEDx
-13321
-14064
-15058
1. Rogowski coils have significant crosstalk from voltage to current. This contributes to gain and phase errors.
2. Therefore, before calibrating a Rogowski meter, a quick 0° load line should be run to determine
at what current the crosstalk contributes at least 1% error.
3. Crosstalk calibration should be performed at this current or lower.
4. If crosstalk contributes an E0 error at current Ix, there will be a 0.1% error in E60 at 15*Ix.
Figure 2-5: Calibration Spreadsheet for Rogowski coil
