Configuration Tab - Analog Devices AD8452 User Manual

UG-1181

CONFIGURATION TAB

Click Configure System to open the configuration tab. This tab
contains several options described in the following sections.
Sample Timing Controls
Sample Interval sets the rate at which the system updates the
battery voltage and current measurements. The sample interval
is the rate at which the screen updates, and is completely
independent of the analog control loop.
Graphing Sampling Rate Multiple sets the update rate for the
main window as a ratio of the sample interval. For example,
setting the Sample Interval to 1 sec and the Graphing Sample
Rate Multiple to 1 results in chart updates every second. Setting
the Graphing Sampling Rate Multiple to 5 results in graph
updates only every 5 sec.
Calibration Controls
The gain correction and offset controls allow the user to
perform system level calibration. The measurements displayed
in the main window are the nominal output from the ADC
scaled with the following equation:
Output Measurement = (Nominally Scaled Measurement −
Offset Correction) × Gain Correction
where Nominally Scaled Measurement uses the typical values for
the sense resistor, the ADC reference, the AD8452 gain, and so on.
Current Gain Correction is the gain correction constant for
the current measurement. The default is 1.
Current Offset (A) is the offset correction constant for the
current channel, in units of amps. The default is 0.
AD8452
Voltage Gain Correction is the gain correction constant for the
voltage measurement. The default is 1.
Voltage Offset (V) is the offset correction constant for the
voltage channel, in units of volts. The default is 0.
Hardware Configuration Controls
As indicated in the main window, the hardware configuration
controls must reflect the actual configuration of the power
module and analog interface boards. If there is a mismatch
between the settings in these controls and the actual hardware
configuration, excessive current can be sourced into (or sunk
from) the battery.
ADC Range (V) is the nominal ADC input range, with a
default of 2.5 V.
DAC Range (V) is the nominal DAC output range, with a
default of 2.5 V.
Sense Resistor (Ohms) is the nominal value of the sense resistor
on the power module board. The default is 0.003 Ω (3 mΩ).
Current Sense Gain is the gain setting for the AD8452
programmable gain current sense instrumentation amplifier.
The default value is 66.
Voltage Sense Gain is the gain setting for the AD8452
programmable gain differential voltage sense amplifier.
The default is 0.4.
Full Scale Current is the setting to change the scaling of the
current setpoint range. This value matches the full-scale current
of the power module.
Clicking Reset Ahr Meter resets the amp-hour counter in the
main window to 0.
Figure 16. Configuration Tab
Rev. 0 | Page 12 of 32
System Demo User Guide