CDB5490U
24
DS923DB5
The
Refresh Screen
button will update the contents of the screen by reading all the register values from
the part. It is recommended to click the
Refresh Screen
button when entering the Calibration Window, or
after modifying any registers to reflect the current status of the CS5490.
2.6.1
Save Cal and Load Cal Buttons
Clicking the
Save Cal
button will save the calibration widow's configuration to a .txt file. Clicking the
Load
Cal
button will recall a saved configuration and store values into the CS5490.
2.6.2
Offset/Gain Register
In the
Offset
and
Gain Calibration
boxes, the offset and gain registers for all channels are displayed in
hexadecimal and decimal formats. These registers can be modified directly by typing the desired value in
the display boxes. There are three types of offset registers: DC offset, AC offset and power offset. The
AC offset registers only affect the RMS register values. The active and reactive power offset registers only
affect the active and reactive power register values, respectively. The DC, AC, and power offset registers
are two's complement numbers whose values ranges from -1 to +1. The gain register value ranges from
0 to 4.
2.6.3
Performing Calibrations
AC/DC offset and gain calibrations can be performed on both the voltage and current channels of the
CS5490. It is recommended to software-reset the CS5490 before running calibrations, because the initial
values in the calibration registers will affect the results of the calibration. A software-reset will reset these
registers back to the default values of zero offset and unity gain. AC/DC offset calibration should be per-
formed before gain calibration to ensure accurate results.
2.6.3.1
Offset Calibrations
1. Ground the channel(s) you want to calibrate directly at the channel header(s), J6 and J11 for the
voltage channel and J7 and J8 for the current channel. The channel(s) could also be grounded
directly at the screw-type terminals.
2. Press the corresponding AC or DC offset calibrate button (
Cal V
,
Cal I
, or
Calibrate All Channels
)
in the corresponding
Offset Calibration
box(es).
3. The offset register value(s) will automatically update when the calibration is completed.
2.6.3.2
Gain Calibrations
1. Attach an AC or DC calibration signal to the screw-type terminals, and make sure the correspond-
ing channel headers (J6, J7, J8, and J11) are set to the desired input position.
2. Press the corresponding gain calibrate button (
Cal V
,
Cal I
, or
Calibrate All Channels
) in the cor-
responding
Gain Calibration
box(es).
3. The gain register value(s) will automatically update when the calibration is completed.
The
Calibration
window also contains the
Active
and
Reactive Power Offset Register
display and adjust-
ment. The user can read and write the value in the CS5490 active and reactive power offset registers
(P
OFF
and Q
OFF
).
