Campbell Scientific 229 Water Matric Potential Sensor and CE4/CE8 - Manual (Page 9)

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