TDAS G5 DAS
User’s Manual
October 2019
10
11000-00010-MAN (Rev. 5)
Power Considerations
A good power source is of paramount importance. Each TDAS G5 DAS should be
powered from a fully-charged, 12 V battery or a high-quality power supply with a
nominal output voltage of 13.8 V (11-15 V range) and a capacity of 2 A. Be sure to
consider any power drop due to cable length.
Power Consumption and Management
When the TDAS G5 DAS is initially powered, all sensor excitation sources, signal condi-
tioning electronics, filter circuits and analog-to-digital converters are in a shutdown
state. The processor and support circuitry are always powered. The processor will
remain in a reduced power state when not performing tasks. When the user runs a test
set-up, the software automatically energizes all 32 channels. The current draw per TDAS
G5 DAS will increase from 190 mA at idle to as much as 800 mA when the system is
fully armed and powering 350 ohm bridges with 5 V excitation.
Once the system has been armed for data collection, all circuits remain in a full power
state until the system finishes storing data. After the data collection routine is complete,
the TDAS G5 DAS de-energizes several circuits to minimize power consumption. It takes
a maximum of 125 seconds (for 70 seconds of data at 10k samples/second) after the
end of the data storage window for the TDAS G5 DAS to return to the idle state, which
then allows communication and download. (Note: Data from multiple DAS units is
downloaded serially.)
Power Requirements and Memory Retention
RAM is the primary means for data storage. The flash memory is a back-up system used
to store a predetermined portion of the test data in case both primary and back-up power
is lost. (This data subset contains both pre- and post-trigger data up to 5 MB. Users
should select the pre-event time carefully to ensure that the post-event region-of-
interest is also included and written to flash.) If power is lost after flash memory has
been written, the data contained in the flash can be downloaded after power is restored.
External Power Provisions
The TDAS G5 DAS does not contain any internal power source, but has connector inputs
for both primary and back-up power sources. Actual useful back-up capacity will depend
upon the number of channels in use, the resistance of the connected sensors, the
supply
’s rating
and whether or not it was fully charged before testing.
