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dc2259af
DEMO MANUAL DC2259A
prevents any voltage drop errors caused by the discharge
current flowing through the cell interconnection wiring. An
accurate indication of the true cell voltage is then obtained.
The LTC6811 offers the option of keeping the discharge
transistors steadily on while measuring the cell voltages.
This is done using the STARTCELL DCC command button.
The command button is illuminated blue when this com-
mand has been executed. This lower voltage reading also
includes I•R errors introduced by cabling and connectors.
6. Other Control Features
Additional command buttons are provided on the control
screen. The POLL ADC command button is used to test
if the ADC is busy making conversions of any LTC6811
devices in a system. The result of this command can be
observed by monitoring the serial data output line of the
SPI interface to the Bottom Port, J2. There is no indication
provided on the control screen.
The START OPEN (WIRE) command button connects
the built-in open wire detection circuitry to all cells. This
command must be followed by any command buttons
inside the READ CELLS box click to see the result. The
OPEN WIRE TEST CURRENT box provides options to use
either PULLUP or PULLDOWN Open Wire Test Currents.
An open wire connection to any cell will be indicated by an
abnormally high voltage measurement for the cell above
the open wire and a near zero measurement for the cell
with the open wire in the PULLDOWN case.
7. Continuous Operation
OPERATING THE CONTROL SCREEN
For convenience, the control panel allows for continuous
operation of the DC2259A board. When the command
button labeled START CONTINUOUS READ CELLS is se-
lected, the GUI operates in a continuous loop executing
the following command sequence automatically:
n
Start cell voltage
n
Read cell voltage groups A (1 – 3) , B (4 – 6), C (7 – 9),
and D (10 – 12)
n
Read flags
Options available are the READ DISPLAY box, ADC SETTINGS
box, OPEN WIRE TEST CURRENT box, and the CONTINU-
OUS box. The CONTINUOUS box allows the selection of
STARTCELL, STARTOPEN, STARTCELL DCC, and STAR-
TOPEN DCC commands to be executed during continuous
operation. The options are useful for monitoring the cell
voltage measurements under different ADC Test Conditions.
All values are updated continually (update rate is ~500ms).
While running, the configuration can be changed on-the-fly.
Simply changing a configuration item (discharge cells for ex-
ample) and clicking the WRITE CONFIG button will implement
the new configuration and return to continuous operation.
A green box with the label ON in the lower right corner
of the GUI indicates that the system is running continu-
ously. A red box with the label OFF means that the system
is stopped and waiting for a new command to be sent.
DATALOGGING OPERATION
The GUI program can “datalog” or store cell voltage re-
sults in a CSV (Comma Separated Value *.csv) file. This
feature is useful in characterizing cell voltages over time.
Datalogging operates similarly to continuous operation but
has the added functionality of storing results in a CSV file.
1. At the upper left of the GUI, click on the Datalog Menu
then Enable Datalog.
