229 Heat Dissipation Matric Water Potential Sensor
3.3 Equilibratio
Installation
d the
e ceramic
pores with liquid water will optimize the hydraulic conductivity between the
ceramic and soil.
the
water
llowed by soaking under a vacuum of
≥
71 kPa (0.7 atm)
atmosphere for 1 hour results in complete saturation of the sensor.
4. Wiring
Table 4-1 shows wiring information for the 229 sensor and CE4 or CE8
excita
directly to the datalogger without
the us
sim
tic of these
conne
e m
5 for de
multiplexer wiring.
BLE 4- 229 Sensor and CE4/CE8 Wiring
n and Saturation of the Sensor Before
The smaller the difference in water potential between the 229 ceramic an
surrounding soil, the sooner equilibrium will be reached. Filling th
Simple immersion of the sensors in water can leave some entrapped air in
pores. Complete saturation can be closely approached if (1) deaerated water is
used, and (2) saturation occurs in a vacuum. Soaking the ceramic in free
for 12 hours fo
tion module when connecting sensors
e of a multiplexer. Figure 4-1 shows a
ctions.
ple schema
See th
ultiplexer program in Section
tails on
TA
1.
229 Wire Color
10(X), CR23X, CR800, CR850,
1000, CR3000
E4/CE8
Function
CR
CR
C
Blue
gh
side of differential channel
Thermocouple Hi
High
Red
w side of differential channel
Thermocouple Low
Lo
Green
excitation channel
Heater High
Current
Black Heater
Low
Clear Shield G
CE4/CE8
Power
12V
+12V
CE4/CE8
Ground
G
CE4/CE8
Enable
Control
Port
CTRL
5
Summary of Contents for 229
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