71M6534H Demo Board User’s Manual
Page: 27 of 86
© 2005-2007 TERIDIAN Semiconductor Corporation
V2-0
If potential transformers (PTs) are used instead of resistor dividers, phase shifts will be introduced that will re-
quire negative phase angle compensation. TERIDIAN Demo Code accepts negative calibration factors for
phase.
1.9 CALIBRATION PARAMETERS
1.9.1 GENERAL CALIBRATION PROCEDURE
Any calibration method can be used with the 71M6534/6534H chips. This Demo Board User’s Manual presents
calibration methods with three or five measurements as recommended methods, because they work with most
manual calibration systems based on counting "pulses" (emitted by LEDs on the meter).
Naturally, a meter in mass production will be equipped with special calibration code offering capabilities beyond
those of the Demo Code. It is basically possible to calibrate using voltage and current readings, with or without
pulses involved. For this purpose, the MPU Demo Code can be modified to display averaged voltage and
current values (as opposed to momentary values). Also, automated calibration equipment can communicate
with the Demo Boards via the serial interface and extract voltage and current readings. This is possible even
with the unmodified Demo Code.
A complete calibration procedure is given in section 2.2 of this manual.
Regardless of the calibration procedure used, parameters (calibration factors) will result that will have to be
applied to the 71M6534/6534H chip in order to make the chip apply the modified gains and phase shifts
necessary for accurate operation. Table 1-5 shows the names of the calibration factors, their function, and their
location in the CE RAM.
Again, the command line interface can be used to store the calibration factors in their respective CE RAM
addresses. For example, the command
>]10=+16302
stores the decimal value 16302 in the CE RAM location controlling the gain of the current channel (
CAL_IA
) for
phase A.
The command
>]11=4005
stores the hexadecimal value 0x4005 (decimal 16389) in the CE RAM location controlling the gain of the
voltage channel for phase A (
CAL_VA
).
Constant
CE
Address
(hex)
Description
CAL_VA
CAL_VB
CAL_VC
0x11
0x13
0x15
Adjusts the gain of the voltage channels. +16384 is the typical value. The
gain is directly proportional to the CAL parameter. Allowed range is 0 to
32767. If the gain is 1% slow, CAL should be increased by 1%.
CAL_IA
CAL_IB
CAL_IC
0x10
0x12
0x14
Adjusts the gain of the current channels. +16384 is the typical value. The
gain is directly proportional to the CAL parameter. Allowed range is 0 to
32767. If the gain is 1% slow, CAL should be increased by 1%.
PHADJ_A
PHADJ_B
PHADJ_C
0x18
0x19
0x1A
This constant controls the CT phase compensation. No compensation
occurs when PHADJ=0. As PHADJ is increased, more compensation is
introduced.
Table 1-5: CE RAM Locations for Calibration Constants
Содержание 71M6534H
Страница 2: ...71M6534H Demo Board User s Manual Page 2 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...
Страница 8: ...71M6534H Demo Board User s Manual Page 8 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...
Страница 40: ...71M6534H Demo Board User s Manual Page 40 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...