6
dc2259af
DEMO MANUAL DC2259A
3. Program the Cell Monitoring Voltage Thresholds
The essential function of the LTC6811 is to measure and
report the voltage on each battery cell when commanded.
First click on the STARTCELL button. This commands an
A/D conversion of all 12-cell voltages in the bit-resolution
configured from the selected CONV MODE (Conversion
Mode) in the ADC SETTINGS box. The actual cell voltage
measurements are displayed in groups of 3 when each
command button inside the READ CELLS box is clicked.
NOTE:
The READ DISPLAY box has options to display
Cell Voltages in VOLTS or HEXadecimal. First select
VOLTS or HEX then click on one of the command but-
tons inside READ CELLS box. Every time a command
button inside the READ CELLS box is clicked; new data
is downloaded from the board and displayed as selected
in VOLTS or HEX.
5. Discharge Cells
OPERATING THE CONTROL SCREEN
In the section labeled SET VOLTAGE LIMITS, click on the
boxes and enter voltage values for the overvoltage and
undervoltage thresholds appropriate for the cells being
monitored. The voltage value entered will be rounded to
the actual value used by the LTC6811 and displayed in
the box. The voltage ranges for these thresholds is 0V to
6.5520V.
These monitor thresholds can be applied globally to each
and every cell in the system or customized for the cells
connected to an individual board by clicking the desired
option button. Individual boards are selected for program-
ming by the left hand tabs in multiple board systems.
4. Read Cell Voltages
The LTC6811 includes the ability to remove energy from
individual cells to help equalize the cell charges within a
stack of batteries. DC2259A contains a P-channel MOSFET
in series with a 33Ω resistor across each cell connection.
When enabled, a cell is loaded and charge is pulled from
the cell with energy dissipated in the switch and resistor.
A check box is provided for each cell to be discharged.
Checking this box (Cell 6 in the above example screen
shot) and then writing the new configuration with a WRITE
CONFIG button click will load the cell.
The discharge transistors are automatically turned off
momentarily while the A/D converter is measuring the
cell voltage using the normal STARTCELL command. This
