Campbell Scientific TDR100 Time Domain Reflectometry Systems - Manual (Page 19)

TDR100
5.5 Power Supply
The system operates on 12 V power. A user supplied deep cycle 12 V lead
acid battery is commonly used in remote installations. Two terminal strip
adapters for the battery posts are provided with the ENCTDR100 (see Figure
5-3). These terminal strips will mount to wing nut battery posts found on most
deep cycle lead acid batteries. Installations with AC power available should
use it to continuously charge the system battery. Remote installation without
AC power should keep the battery charged with an SP10R or SP20R solar
panel. See the applications note at
ftp://ftp.campbellsci.com/pub/outgoing/apnotes/pow-sup.pdf for discussion of
power supplies.
FIGURE 5-3. Terminal Strip Adapters for Connections to Battery
Campbell Scientific recommends using datalogger switched 12 volts to power
the TDR100. This will provide power savings and will automatically reset the
TDR100 and provide automatic recovery from system malfunctions. This
practice can reduce loss of measurement data when a problem exists.
Typically the switched 12 volts is turned on at the beginning of the datalogger
program table that contains the TDR measurement instructions, and it is turned
off at the end of the table. CRBasic Instruction “SW12” can be used to switch
12 volt power on the CR800, CR850, CR1000, or CR3000 datalogger. See
CR1000 programming example in the program example section of this manual.
CR10X and CR23X datalogger Instruction 86 can be used to set a control port
for the switched 12 volt power. PC208W or LoggerNet HELP provide
guidance for controlling switched 12 volts with both the CR10X and CR23X.
See CR10X/CR23X programming example 1 in program example section of
this manual.
5.5.1 Grounding
The TDR system should be installed with a single ground point. A good earth
ground should be established close to the datalogger/TDR100.
A copper clad grounding rod comes with the model CM6 or CM10 tripod. The
UTGND kit provides hardware needed for grounding rod use.
The dataloggers, TDR100 and SDMX50SP multiplexer have grounding lugs.
These lugs should be tied together with short pieces of grounding wire no
smaller than 12 AWG. The ENCTDR100 has a grounding lug in the lower left
corner of the enclosure. A piece of 10 AWG is provided for connection to the
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