Vaisala AWS330 - Manual (Page 88)

User's Guide ______________________________________________________________________
86 __________________________________________________________________ M211296EN-B
Installing Soil Temperature Sensor QMT110
Vaisala Soil Temperature Probe QMT110 is used for precision
measurement of ground and soil temperatures. In AWS330, you can have
up to two QMT110 sensors. Positioning of the sensor and insulation of
the sensor cable are essential for the measurements; see steps 3 and 4.
1. Choose a location. The measurement site should be undisturbed
ground, 1 m², and typical of the surface of interest. The ground
surface should be level with respect to the immediate (10 m radius)
area.
2. Make a hole with a shovel to a depth slightly deeper than the
desired installation depth of the sensor.
3. To have good sensor contact with the soil, push the sensor into the
wall of the hole horizontally until set firmly. Do not place the
sensor at the bottom of the hole. Fill the hole with the dug-up soil.
4. Lead the sensor cable from the sensor to the enclosure. For thermal
insulation, do either of the following:
- If possible, wrap 1–2 m of the sensor cable into a coil and bury
it in the ground.
- Lead the sensor cable from the enclosure to the sensor via
insulated tube that you have buried in the ground.
5. Connect the sensor cable to the Soil T1 connector on the bottom of
the enclosure. For two QMT110 sensors, use the Soil T2 connector
as well; see section Connecting Sensor Cables on page 95.
1108-009
Figure 44 Installing Soil Temperature Sensor QMT110