CDB5464U Datasheet, PDF (15/38 Pages) Cirrus Logic – CDB5464U Engineering Borad and GUI Software

CDB5464U
2.5.1 Offset / Gain Register
In the offset and gain register boxes, the offset and gain registers for all channels are displayed in hexa-
decimal and decimal. These registers can be modified directly by typing the desired value in the hexadec-
imal 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 power offset registers only affect the active
power register values. The DC/AC/power offset register is a two's complement number whose value rang-
es from -1 to +1. The gain register value ranges from 0 to 4.
2.5.2 Performing Calibrations
AC/DC offset and gain calibrations can be performed on both the voltage and current channels of the
CS5464. It is generally a good idea to software-reset the CS5464 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 performed before gain calibration to ensure accurate results.
2.5.2.1 Offset Calibrations
1. Ground the channel(s) you want to calibrate directly at the channel header(s), J17 and J22 for the voltage
channel, J24 and J26 for current channel 1, and J20 and J19 for current channel 2. 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) beside or
below the offset register boxes.
3. The offset register value(s) will automatically update when the calibration is completed.
2.5.2.2 Gain Calibrations
1. Attach an AC or DC calibration signal to the screw-type terminals, and make sure the corresponding chan-
nel headers (J17, J22, J24, J26, J20, and J19) are set to the input position.
2. Press the corresponding AC or DC gain calibrate button (Cal V, Cal I, or Calibrate All Channels) beside or
below the gain register boxes.
3. The gain register value(s) will automatically update when the calibration is completed.
The Calibration window also contains the Power Offset Register1 / 2 display and adjustment. The user
can read and write the values in the power offset registers (P1off / P2off).
DS847DB1
15