9
Calibration Screen
9.1
How to Calibrate
9.2
To Calibrate the bq20z95
9.3
Board Offset Calibration
9.4
Pack Voltage Calibration
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Calibration Screen
The data flash configuration can be saved to a file by selecting | File | Export | and entering a file name. A
data flash file also can be retrieved in this way, imported, and written to the bq20z95 using the | Write All |
button.
The configuration information of the bq29z95 and module calibration data also is held in the bq20z95 data
flash.
The bq20z95 allows for an automatic data flash export function, similar to the SBS Data logging function.
This feature, when selected via | Options | Auto Export |, exports Data Flash to a sequential series of files
named as
FilenameNNNNN.gg
where N = a decimal number from 0 to 9.
The AutoExport interval is set under the | Options menu | with a minimum value of 15 s. The AutoExport
filename also is set under the | Options menu |.
When a check mark is next to | AutoExport |, the AutoExport is in progress. The same menu selection is
used to turn on / off AutoExport.
If the data flash screen is blank, then the bq20z95 that is being used may not be supported by the
bqEVSW version that is being used. An upgrade may be required.
Before the bq20z95 is calibrated:
•
Connect a load to Pack- and Pack+ that draws approximately 2 A and measures discharge current to
use the FETs.
•
Connect a current source to Batt- and Pack- to calibrate without using the FETs.
•
Measure the pack voltage from Batt+ to Batt- (Total of Cell voltages).
•
Measure the temperature of the pack.
•
These steps may not be required, depending on the type of calibration being performed.
Note that voltage calibration with cells attached requires special consideration. Cells must be in a resting
state. For additional information, go to the TI Web site (
www.ti.com
) and access the TI Knowledge Base
and search for
bq20zxx Calibration Using EV Software
.
Select the types of calibration to be performed (see
Figure 10
).
Enter the measured values for the types selected.
If
Voltage Calibration
is selected, then enter the number of cells on the pack.
If
Temperature Calibration
is selected, then select the sensor that is to be calibrated.
If the load is connected between Pack+ and Pack-, then select the
Use FETs
check box.
Press the
Calibrate Part
button.
This performs the offset calibration for the current offset of the board.
Remove load/external voltage and short Pack- to Batt-.
Press the
CC Board Offset Calibration
button.
This calibrates the voltage at the AFE Pack pin.
Make sure
Voltage Calibration
has been performed for the pack. If
Voltage Calibration
is not performed,
then
Pack Voltage Calibration
calibrates incorrectly.
SLUU275 – October 2006
bq20z95EVM-001 SBS 1.1 Impedance Track™ Technology
13
Enabled Battery Management Solution Evaluation Module
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