Campbell Scientific 229 Water Matric Potential Sensor and CE4/CE8 - Manual (Page 8)

229 Heat Dissipation Matric Water Potential Sensor
2. Specifications
229
Measurement range: -10 to -2500 kPa
Measurement 30 seconds typical time:
hermocouple type:
cylinder
nsor
tance: 34 ohms plus cable resistance
n: 00 kPa
T copper / constantan (type T)
Dimensions: 1.5 cm (0.6”) diameter
3.2 cm (1.3”) length of ceramic
6.0 cm (2.4”) length of entire se
Weight: 10 g (0.35 oz) plus 23 g/m (0.25 oz/ft) of cable
Heater resis
Resolutio ~1 kPa at matric potentials greater than -1
CE4/CE8
Output: 50 mA ±0.25 mA per channel, regulated
Output channel CE4: 4 CE8: 8 s:
urrent drain(while active):
Dimensions: CE4: 11.5 cm (4.5”) x 5.4 cm (2.1”) x 2.7 cm (1.1”)
CE8: 16.5 cm (6.5”) x 5.4 cm (2.1”) x 2.7 cm (1.1”)
ght: CE4: 131 g (4.6 oz) CE8: 184 g (6.5 oz)
3. Installation
3.1 Orientation
For best measurement results, the 229 should be installed horizontally at the
r
3.2 Contact
en the two. Adequate contact will
lings.
arse sand can
fine silica
metimes referred to as silica flour).
C 25 mA + 50 mA * no. of 229’s connected to the
CE4 or CE8 output channels.
Wei
desired depth of the soil. This will reduce distortion of typical vertical wate
flux.
Good contact must exist between the ceramic matrix and the soil since the
measurement relies on water flux betwe
result if the sensor is ‘planted’ in a manner similar to that used for seed
Sufficient contact in coarse texture soils such as medium and co
be obtained by surrounding the ceramic portion with a slurry of
(so
4