Chapter 7 _____________________________________________________________ Technical Data
VAISALA _______________________________________________________________________ 183
Soil Moisture Sensor
Table 57
ML2x Soil Moisture Sensor Specifications
Property
Description/Value
Full Range
0 ... 1.0 m
3
.m
-3
Accuracy
±
0.02 m
3
.m
-3
after calibration to a specific soil
type, or,
±
0.05 m
3
.m
-3
using the supplied soil
calibration, in all 'normal' soils, over range
0.05 to 0.6 m
3
.m
-3
and 0 to 40
°
C ambient
temperature.
Soil conductivity range
Accuracy figures apply over a soil conductivity
range of 0 to 100 mS.m
-1
. Calibratable up to
2000 mS.m
-1
.
Soil sampling volume
90% influence within cylinder of 2.5 cm diam.,
6 cm long, (approx 30 cm
3
), surrounding
central rod.
Environment
Can be buried to wide ranging soil types or
water for long periods without malfunction or
corrosion.
Stabilization time
1 to 5 sec. from power-up, depending on
accuracy required.
Response time
Less than 0.5 sec. to 99% of change
Duty cycle
100 % (continuous operation possible)
Input requirements
5 ... 15 VDC unregulated
Current consumption
19 mA typical, 23 mA max.
Output signal
Approx. 0 ... 1 VDC for 0 ... 0.5 m
3
.m
-3
Dimensions
Measuring rods 60 mm, overall length 207 mm
including pins (see Figure 130 below).
Extension Tubes (optional) For convenient placement and removal when
burying. Choice of 50 cm or 100 cm (can be
joined).
Case material
PVC
Rod material
Stainless steel
Cable length
Standard 5m (maximum length 100m)
Weight
350 g (with 5m cable)
0105-058
Figure 130
Soil Moisture Sensor Dimensions
