Cirrus Logic CDB5484U - Manual (Page 26)

CDB5484U
26 DS919DB5
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 CS5484.
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 CS5484.
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 range 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
CS5484. It is recommended to software-reset the CS5484 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) that need to be calibrated directly at the channel header(s), J6, J10, J11, and
J9 for the voltage channels and J7, J8, J13, and J14 for the current channels. 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 corresponding
channel headers (J6, J7, J8, J9, J10, J11, J13, and J14) are set to the desired input position.
2. Press the corresponding gain calibrate button (Cal V, Cal I, or Calibrate All Channels) in the corre-
sponding 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 1 and Register 2
display and adjustment. The user can read and write the values in the CS5484 active and reactive power
offset registers (P1
OFF
, P2
OFF
, Q1
OFF
, and Q2
OFF
).