Cirrus Logic CDB5460AU - Manual (Page 14)

CDB5460AU
14 DS487DBU1
2.5 Calibration Window
The Calibration window is used to display and write to the CS5460A offset and gain calibration registers.
The user is also able to initiate the CS5460A's calibration sequences that are used to set the calibration
values. Both AC and DC calibrations can be run for offset and gain, for either the voltage channel or the
current channel, or both simultaneously. The user should refer to the CS5460A data sheet for more details
on calibration.
The Refresh Screen button will update the contents of the screen by reading all the register values from
the part. It is a good idea to press the Refresh Screen button when entering the Calibration window, or
after modifying any registers to reflect the current status of the CS5460A.
Figure 9. Calibration Window
2.5.1 Offset / Gain Register
In the Offset and Gain boxes, the offset and gain registers for all channels are displayed in hexadecimal
and decimal. These registers can be modified directly by typing the desired value in the hexadecimal dis-
play boxes. There are two types of offset registers: DC offset and AC offset. The AC offset registers only
affect the RMS register values. The power offset registers only affect the active power register values.
The offset register is a two's complement number whose value ranges from -1 to +1. The gain register
value ranges from 0 to 4.
2.5.2 Performing Calibrations
Offset and gain calibrations can be performed on both the voltage and current channels of the CS5460A.
Because the initial values in the calibration registers will affect the results of the calibrations, it is generally
a good idea to software reset the CS5460A before running calibrations. A software reset will reset these
registers back to the default values of zero offset and unity gain. Offset calibration should be performed
before gain calibration to ensure accurate results.