RXW EC-5 and 10H Soil Moisture Sensor (RXW-SMx-xxx) Manual
1-800-LOGGERS 5
www.onsetcomp.com
•
Make sure the mote is mounted a minimum of 1.8 m (6 ft)
from the ground or vegetation to help maximize distance
and signal strength.
•
Place the mote so there is full line of sight with the next
mote. If there is an obstruction between two sensor
motes or between the sensor mote and the RXW
Manager, then use an RXW Repeater (RXW-RPTR-xxx). For
example, if there is a hill between the sensor mote and
the RXW Manager, place a repeater at the top of the hill
between the sensor mote and the RXW Manager.
•
There should not be more than five motes in any direction
at their maximum transmission range from the RXW
Manager. Data logged by a wireless sensor must travel or
“hop” across the wireless network from one mote to the
next until it ultimately reaches the RXW Manager at the
RX3000 station. To make sure the data can successfully
travel across the network, the mote should not be more
than five hops away from the manager.
•
The RX Wireless Sensor Network can support a maximum
of 50 motes.
•
Use a #4-40 screw to attach a ground wire to the port on
the back of the mote if you are deploying the mote in a
location where lightning is a concern.
Sensor Installation Guidelines
This sensor measures the water content in the space
immediately adjacent to the probe surface. Air gaps or
excessive soil compaction around the probe can profoundly
influence soil water content readings. Do not mount the probes
adjacent to large metal objects, such as metal poles or stakes.
Maintain at least 8 cm (3 inches) of separation between the
probe and other objects. Any objects, other than soil, within 8
cm (3 inches) of the probe can influence the probe’s
electromagnetic field and adversely affect output readings. The
RXW-SMC sensor must be installed at least 3 cm (1.18 inches)
from the soil surface and the RXW-SMD sensor must be
installed at least 10 cm (3.94 inches) from the soil surface to
obtain accurate readings.
It is important to consider the particle size of the medium in
which you are inserting the sensor because it is possible for
sticks, tree bark, roots, or other materials to get stuck between
the sensor prongs, which will adversely affect readings. Be
careful when inserting these sensors into dense soil as the
prongs can break if excessive sideways force is used to push
them into the soil.
To install the soil moisture sensors, follow these guidelines:
•
Good soil contact with the sensor probes is required.
•
Install the sensor probes into undisturbed soil where there
aren’t any pebbles in the way of the probes.
•
Use a soil auger to make a hole to the desired depth (an
angled hole is best) and push the probes into undisturbed
soil at the bottom of the hole. Alternatively, dig a hole and
push the probes into the side of the hole.
•
If the probe has a protective cap on the end, remove it
before placing the probe into the hole.
•
To push the probe into the soil, use a PVC pipe with slots
for the sensor and a longer slot for the cable.
•
Thoroughly water the soil around the sensor after it is
installed with the hole partially backfilled to cause the soil
to settle around the sensor.
•
As the hole is back-filled, try to pack the soil to the same
density as the undisturbed soil.
•
Secure the sensor cable to the mounting pole or tripod
with cable ties.
•
Use conduit to protect the cable against damage from
animals, lawn mowers, exposure to chemicals, etc.
If you need to calibrate your probe for the soil, you may want
to gather soil samples from each sample depth at this time.
When removing the probe from the soil,
do not pull it out of
the soil by the cable!
Doing so may break internal connections
and make the probe unusable.
Maintenance
The soil moisture sensor does not require any regular
maintenance. If cleaning, rinse the sensor with mild soap and
fresh water.
The mote is designed for outdoor use, but should be inspected
periodically. When inspecting the mote, do the following:
•
Verify the mote is free of visible damage or cracks.
•
Make sure the mote is clean. Wipe off any dust or grime
with a damp cloth.
•
Wipe off any water before opening the mote.
•
Make sure the interior seal is intact and the latches are
fully locked when the mote door is closed.
Calibration
The soil moisture sensor comes pre-calibrated for most soil
types. If, however, your soil type has high sand or salt content,
the standard calibration will not be accurate. In such cases, you
will need to convert the data provided by the probe with a
specific calibration for your individual soil type. To determine
the soil specific calibration formula, refer to the
Calibrating
ECH
2
O Soil Moisture Probes
application note, available at
http://www.onsetcomp.com/support/tech-notes/calibrating-
ech2o-soil-moisture-sensors-application-note.
Updating Mote Firmware
If a new firmware version is available for the mote, use
HOBOlink to download the file to your computer.
1.
In HOBOlink, go to Devices > List and click your station
name.
2.
On the station page, click Overview and scroll down to
Device Information.
3.
Click the Wireless tab. This icon
appears next to the
mote if there is a new version of firmware available.
4.
Click the firmware
upgrade link. Click Download and
save the firmware .bin file to your computer.
5.
Connect the mote to the computer with a USB cable (open
the mote door and use the USB port to the right of the
LCD). The blue LED is illuminated while connected.
