PlantCare Mini-Logger User manual

PlantCare Mini-Logger
Soil moisture and soil temperature sensor
Operating Instructions
PlantCare Ltd.I Sennhof 13 I CH-8332 Russikon I Switzerland I [phone] I [email protected] I www.plantcare.ch

Table of contents
1. Introduction 3
Basic aspects 3
How the sensor measures soil moisture 3
Features 3
Quick guide 3
Scope of delivery 4
Optional accessories 4
2. Commissioning 5
Inserting / replacing the batteries 5
Switching on / switching off 5
LED display 5
Preparing the configuration file with the 6
PlantCare Mini-Logger Configurator
Configuring your Mini-Logger 7
3. Installation 7
Inserting a Mini-Logger sensor into the soil 7
Installing a Mini-Logger XL, cable version 8
4. Downloading and analyzing your data 10
Downloading your data 10
Data analyses with PlantCare DataViewer 10
5. Moisture output in hPa suction pressure 11
6. Maintenance 13
Replacing the sensor felt 13
7. Technical specifications 13
8. Warranty 14
9. Disclaimer 14
10. Support 14
PlantCare Ltd.I Sennhof 13 I CH-8332 Russikon I Switzerland I [phone] I [email protected] I www.plantcare.ch

1. Introduction
Please read through these instructions carefully before commissioning your PlantCare Mini-
Logger
3
Basic aspects
The PlantCare Mini-Logger is a maintenance-free sensor which records soil moisture and soil
temperature. Fields of application include scientific research and agriculture. Configuring a Mini Logger
as well as reading the data recorded is simple and easy to do using the data upload/download cable and
a USB stick. The data thus acquired can be analyzed on a PC using PlantCare DataViewer software.
How the sensor measures soil moisture
PlantCare’s worldwide patented sensor technology is based on the microthermic measurement of soil
moisture. Specially developed felt material in moisture balance with the soil acts as the interface
between the surrounding soil and the sensor. To measure the moisture level, the sensor is briefly
heated and the cooling-down time, which varies depending on soil moisture, is determined. The
sensor’s cooling-down time thus provides a reliable statement of the soil’s moisture content.
Features
The sensor measures soil moisture levels and soil temperature at freely selectable intervals.
The sensor reacts speedily to changes in moisture levels.
Reliable results even at minimum depths (from 5 cm).
Value measured is unaffected by salt or fertilizer content.
The mini-logger’s internal clock enables measurements to be precisely recorded with date and time.
Acquisition of up to 12.000 records.
A USB-interface allows programming the logger as well as readout the measured data.
PlantCare DataViewer software allows the optimal display and analysis of the data.
Quick guide
1. Check the scope and contents of delivery for completion according to your order.
2. Switch the unit(s) on and off to check whether batteries have been inserted. (Units are generally
supplied ex works with batteries installed). Install batteries if required (2 AA mono cell batteries).
3. If you wish to adjust the Mini-Logger’s factory settings, you must prepare the Mini-Logger’s
configuration file. To do so, open the "PlantCare Mini-Logger Configurator" software from your
CONFIG Stick and make the requested adjustments. Alternatively, the mentioned Configurator
Software can be downloaded from:
www.plantcare.ch/en Support.
4. Configure your Mini-Logger.
5. Immerse the sensor felt in water for about 1 minute and then insert the sensor with the protection cap
into the soil.
6. Thoroughly irrigate the soil around the sensor.
7. Read off the collected soil moisture and temperature data at intervals.
8. Use your PlantCare DataViewer software to view and analyze the data acquired.
PlantCare DataViewer software can be downloaded from:
www.plantcare.ch/en Support.
9. Maintenance: we recommend replacing the felt once a year or when reinserting the sensor into the
soil.
PlantCare Ltd.I Sennhof 13 I CH-8332 Russikon I Switzerland I [phone] I [email protected] I www.plantcare.ch

Scope of delivery
PlantCare Mini-Logger Sensor (version according to your order)
Software:
PlantCare DataViewer Software download from www.plantcare.ch/en Support.
PlantCare Mini-Logger Configurator Software on white CONFIG Stick or download from
www.plantcare.ch/en Support.
Manuals:
PlantCare Mini-Logger Sensor Manual on white CONFIG Stick or download from
www.plantcare.ch/en Support.
PlantCare Mini-Logger Configurator Manual on white CONFIG Stick or download from
www.plantcare.ch/en Support.
Optional accessoires
Mini-Logger ST Insertion depth max. 18 cm
Mini-Logger M Insertion depth max. 35 cm
Mini-Logger XL Insertion depth max. 60 cm
Mini-Logger XXL Insertion depth max. 100 cm
Replacement tip with felt
Mini-Logger XL cable Insertion depth max. 60 cm
Mini-Logger XXL cable Insertion depth max. 250 cm
Data upload /download cable with
USB interface incl. 2 USB Sticks
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Sensor with protection cap
(Shipments from September 2012 on)

2. Commissioning
Mini-Loggers are generally supplied with batteries fitted.
Inserting/replacing the batteries
Switch the unit off if it has been switched on.
1. Only release the fastening screw on the Mini-Logger
cover as far as is necessary to open the cover.
2. Carefully withdraw the battery holder from the casing.
Dispose of old batteries appropriately if new ones are to
be fitted. Empty batteries will not cause your Mini-Logger
to lose its settings.
3. Insert 2 AA mono cells. Ensure that the polarity is correct
as you will otherwise damage your Mini-Logger.
4. Reinsert the battery holder into the casing with care.
5. Replace the cover so that it fits over the white inner
casing. Ensure that the cover seal is located in the groove
provided in the cover and that no dirt is present. Re-attach
the cover by tightening the fastening screw.
(Warning: do not overtighten!).
6. Switch on your Mini-Logger.
IMPORTANT: After a battery change, please download
the data and ensure that the date and the time are still
correct. If they are not, proceed in accordance with the
details given in the sections “Preparing the configuration
file” and “Configuring your Mini-Logger”.
Do not remove the
fastening screw
LED display
Switch on: LED flashes briefly
Switch off: LED will light up and then go out
Uploading the configuration file or downloading data: the LED will light up until downloading or
uploading is complete.
LED flashes continuously: the batteries need replacing.
The LED will not light up when the Mini-Logger is making a measurement. In a case like this, wait
for about 3-4 minutes.
Switching on/switching off
Switching on: Press the ON/OFF button
briefly. The LED will flash briefly.
Switching off: Hold the ON/OFF button down
until the LED lights up and then goes out.
IMPORTANT: A Mini-Logger cannot be
switched off when it is taking a measurement.
Wait for 3-4 minutes if this happens.
LED window
ON/OFF button
Fastening
screw
Protective cap
Mini-Logger
cover
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Preparing the configuration file with the PlantCare Mini-Logger Configurator
The PlantCare Mini-Logger Configurator automatically generates a file (MLConfig.txt) that
you save on the white CONFIG Stick and then read in into the Mini-Logger.
If you would like to keep the factory settings, you must not configure the Mini-Logger.
If you would like to configure the Mini-Logger according to your needs, proceed as follows:
Open the "PlantCareMLConfigurator.exe" software. This software is either
delivered on the white "CONFIG Stick" from PlantCare or
can be downloaded from: www.plantcare.ch/en Support.
The software does not need any installation. Just copy
the exe.file either on your desktop or preferably save it directly
on an empty USB Stick (e.g. PlantCare white CONFIG Stick).
A help file is integrated in the PlantCare Mini-Logger Configurator software.
Initial configuration: If you leave a field empty, the factory setting will be retained.
Re-configuring: Adjust the required parameters and ignore (leave empty) those fields that are
not to be adjusted. The box for date and time should not be clicked, if you do not wish to
update them.
Save your configuration by clicking "Save to stick". This will generate automatically a
configuration file in the corresponding CONFIG Stick.
Configuration field
Factory setting
Description
Device Name
PlantCare Mini-Logger
(From version 1.20 on,
a 4-digit serial number)
Mini-Loggers can be given any name and/or number
(at least 4-digits. No ü / ö / é, etc. or special characters
or space). The first 4 digits will appear on readout file
name. The full device name will appear on readout data.
Measuring Cycle Start
60min
The factory setting entered is 60min and a Mini-Logger
carries out the first measurement 60 minutes after being
switched on. Enter the time here (0…23) if you would like
to have the first measurement taken at a certain time.
Measuring Cycle Time
60
With the factory setting, a Mini-Logger takes a moisture
measurement every 60 minutes. This measurement cycle
can be adjusted.
* Moisture Output
rel%
The factory setting is rel%. This means that the output of
measured moisture values are in relative moisture
percentage. From Mini-Logger Version 1.15 (apparent on
housing), the moisture values can be read out also in hPa
suction pressure. If you select hPa, you can choose out of
6 different soil types the one, which matches best with
your soil. Alternatively, if your specific soil has been
calibrated by PlantCare, the corresponding parameters for
converting the measurement data into hPa can be entered
here. See also Chapter "Moisture output in hPa suction
pressure“.
Set Date-Time
Central European Time
(can be up to 15 minutes
plus to the actual time)
Erase Data Memory
If you wish to delete the previous measurement data, click
this box. This does not delete your settings.
* The measurements stored in the Mini-Logger, for example in rel%, can be (after reconfiguration) read at
any time for the same measurement period in hPa and vice versa.
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Uploading the configuration file:
1. Carefully remove the protective cap over the Mini-Logger
socket.
2. Connect the round plug on the data upload/download cable to
the Mini-Logger.
3. Upload the configuration file: Attach the CONFIG Stick to the
data upload/download cable.
4. If the Mini-Logger has not yet been switched on, switch it on
(press the ON/OFF button briefly).
5. Press the ON/OFF button briefly. The LED on the Mini-Logger
will light up and then go out when the configuration process
has been completed.
6. Now disconnect the cable from the Mini-Logger and firmly
replace the protective cap.
7. Check the configuration q.v. “Downloading data”. The
downloaded file displays all the parameters that you entered
in PlantCare Mini-Logger Configurator.
Configuring your Mini-Logger
You will require the following components to configure your Mini-Logger:
USB stick with PlantCare
Mini-Logger Configurator
software and an automatically
generated configuration file
Data upload
/download cable
Inserting a Mini-Logger Sensor into the soil - quick guide
(see also next pages)
1. Dip the tip of the sensor with the felt in water for approx. 30 seconds.
2. Put on the protection cap, in order to protect the sensor electronics.
3. Place the sensor tip at a position at which the sensor must measure the
moisture level. This is usually in the area of the roots. It is a good idea to make
a suitable hole in advance into which the sensor can be inserted. The sensor tip
should be in contact with the soil on all sides.
4. Avoid forming a preferential water path along the sensor channel.
5. Irrigate the immediate surrounding area of the soil moisture sensor with a
sufficient amount of water. Dependent on the soil and the depth at which the
sensor is located, it can take up to a few hours before the soil moisture sensor
records the actual soil moisture level.
Caution!
The tip of the sensor will only measure the soil moisture correctly if the sensor tip
is in full contact with the ground on all sides! Entrapped air in the surrounding of
the sensor may cause false measuring results.
Never rotate the sensor when inserting or pulling out as this may unscrew the
yellow sensor tip.
3. Installation
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Sensor with protection cap

Guide for the correct placement of the soil moisture sensors
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Dripper
Not ideal
Fig. 1
Placing at the right depth
The sensors should measure the moisture there,
where the plants absorb the water, namely in the
root zone (Fig. 1). As the size of the root ball
change significantly during the growth phase, it is
recommended to re-place the sensors deeper after
the initial growth phase.
Sensors in stick version
1. For longer sensors in stick version, drilling of a hole is reasonable. Use an auger or a drilling machine
with a bore diameter of 16 mm.
2. If the soil is dry, moisten.
3. Immerse entire sensor tip (yellow part) in water (felt must be wet).
4. Insert the sensor cautiously. Never rotate the sensor when inserting or pulling out as this may
unscrew the yellow sensor tip.
5. Water the area around the sensor with sufficient water.
Sensors in cable version
Depending on the placement depth, the installation
of sensors in cable version requires a different
approach.
If the sensor is placed in turf, it is virtually
impossible to accommodate the electronics within
the lawn, as this would disrupt the use of the lawn.
In this case, sensors with extension cable are
available. This allows to embed just the sensor tip
in the lawn. The electronics on the other hand is
placed on the edge of the lawn (Fig. 2).
If the sensor has to be buried deeper in the soil, it
is inevitable to excavate soil first. Fig. 2
Ideal
Plastic clamp for the
Mini-Logger, cable version
Installing cable version
Use any plastic or metal rod or tube of the required length and a diameter of approx.16 mm.

Porous, permeable soil
Dripper
Humus rich garden soil Clayey soil
Fig. 3
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Placing the sensor in drip irrigation applications
The following recommendations are particularly important when the Mini-Logger is used within an irrigation system.
However, this section also contains important information when the Mini-Logger is used for general moisture
investigations.
The sensors must be placed in a way that it can register the water. This is more or less critical, depending
on the type of irrigation. If sprinklers are used, the distribution uniformity is usually homogeneous enough,
unless the root zone and thus the sensor is not shielded by leafs.
If a drip irrigation is used, the water is supplied very locally and it will diffuse more or less evenly and
quickly within the soil over a certain volume range. Therefore, especially in drip irrigation it is important to
pay attention to the following points:
Depending on the permeability of the soil or substrate, differently shaped moisture zones are formed
(Fig. 3).
If the soil is porous and permeable, it is advisable to use several dripper with a correspondingly lower
water outlet per plant, in order to achieve a better distribution of water. Plants are very adaptive and the
roots will grow into those areas, where water is available. However, the yield respectively the health of a
plant is improving, the bigger a water saturated soil volume is available for the roots. Using this type of soil
- especially in pot cultures - may result in the formation of so-called preferential water paths. This will
always occur, whenever a dripper with a high water output is used. Since the water in the substrate runs
off quite rapidly downward, fine particles are washed out, resulting in a preferred water path. In such a
case, the water barely has time to spread horizontally, and this inevitably leads to an insufficient water
supply to the plants. Once such a water path is formed, an initially correct placed sensor may not be able
to register the applied water.
To avoid this problem, you can use drippers with a lower water output rate. However, such drippers may
clog faster or calcify. The best remedy against the formation of preferred water paths is to use a piece of
felt which is laid onto the substrate, so that the water drops first onto the felt and is distributed horizontally.

Downloading your data:
Note: Downloading data leads to high battery consumption.
Only download data, when necessary. When LED flashes
continuously during download, the batteries need replacing.
1. Carefully remove the protective cap over the Mini-Logger socket.
2. Connect the round plug on the data upload/download cable to
the Mini-Logger.
3. Download the data: Attach the DATA Stick for downloading the
data to the data upload/download cable.
IMPORTANT: The data cannot be downloaded if the USB
stick contains a configuration file ("MLConfig.txt).
4. If the Mini-Logger has not yet been switched on, switch it on
(press the ON/OFF button briefly).
5. Press the ON/OFF button briefly. The LED on the Mini-Logger
will light up and then go out when the process has been
completed.
6. Now disconnect the cable from the Mini-Logger and firmly
replace the protective cap.
4. Downloading and analyzing your data
The following components are required to download the data from your Mini-Logger:
USB stick on which to
download the data files Data upload/download cable
7. Downloaded data: Connect the DATA Stick with the downloaded data to your computer and open
it. An automatically generated file structure will be displayed. This contains the folder “ML-
DATA”, which contains the downloaded data file. The filename consists of the first four letters of
the name of the Mini-Logger as well as the download time (minutes/seconds). You can now open
this file either in an editing program or with PlantCare DataViewer software. Alongside the soil
moisture data and the soil temperature data, the file also displays all the parameters that you
entered in the configuration file. Each new download creates a new data file. The old files remain
unaffected by this.
Data analyses with PlantCare DataViewer
PlantCare DataViewer software enables the optimal display and
analysis of your data. After a short registration process, this
software can be downloaded free of charge and used to obtain a
graphic view of the moisture and temperature levels on one or
several Mini-Loggers as well as data averages.
PlantCare DataViewer analysis software can be downloaded
using the following link: www.plantcare.ch/en Support
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The PlantCare moisture sensor technology is based on a micro-thermal measuring principle. A cooling
time is measured, which allows a statement about the water content of the soil.
To permit a conversion to a suction pressure (hPa), a calibration must therefore be made. This can be
achieved by parallel measurements with a tensiometer. Here, a soil sample at different moisture levels is
measured with both sensors, the PlantCare sensor as well as with a tensiometer and the measured
values are set into a relation according to the accepted van Genuchten equation. However, such a
calibration is valid for the used soil type only.
As there can also occur quite large variations in moisture measurements between two tensiometers, a
tensiometer-independent calibration was performed by the Zurich University of Applied Sciences (ZHAW)
in Wädenswil. For the calibration, a pF-pressure chamber was used.
To cover the most important soil types, 6 standard soils were obtained from the "Agricultural Research
Institute (LUFA) Speyer" in Germany. The data from these standard soils can be seen on the table below.
The results are primarily two parameters, alpha and n, which have to be inserted into the van Genuchten
equation, in order to convert from the measured time to hPa. Moreover, a scaling factor K can be entered.
van Genuchten equation:
5. Moisture output in hPa suction pressure
Note: Only applicable for sensors with a hard felt or part-number endings "H" and from
Mini-Logger Version 1.15 on (apparent on housing).
 
 
n
m
nm tK 1
111
1 


Standard soils from the „Agricultural Research Institute (LUFA) Speyer”:
nm /11
Standard Soils - Analyses Data Sheet (9/11)
Mean values of different batch analyses +- standard deviation. All values refer to dry matter
Standard soil type no.
1
2
3
4
5
6
organic carbon
0,62+- 0,07
1,87 +- 0,20
0,94+- 0,10
2,42 +- 0,5
1,05 +- 0,20
1,64 +- 0,12
in % C
Nitrogen in % N
0,05 +- 0,01
0,17 +- 0,02
0,08 +- 0,02
0,20 +- 0,04
0,12 +- 0,03
0,20 +- 0,02
pH-value
5,1+- 0,4
5,5 +- 0,2
6,8 +- 0,2
7,1 +- 0,2
7,3 +- 0,1
7,1 +- 0,1
(0.01 M CaCl2)
cation exchange capacity
4,0 +- 0,7
10,1 +- 0,5
10,3 +- 1,3
30,8 +- 6,2
15,3 +- 2,9
24,5 +- 7,0
( meq / 100g)
Particle size (mm) distribution according to German DIN (%):
<0.002
2,4 +- 0,4
6,5 +- 0,8
8,7 +- 1,6
27,0 +- 1,9
10,4 +- 1,1
42,1 +- 1,2
0.002 - 0.006
2,0 +- 0,9
3,3 +- 0,7
4,2 +- 0,9
8,7 +- 0,7
5,1 +- 0,5
10,4 +- 1,0
0.006 - 0.02
3,1 +- 0,8
4,1 +- 0,7
8,8 +- 0,8
14,7 +- 1,3
9,1 +- 1,0
12,3 +- 1,4
0.02 - 0.063
6,9 +- 0,5
6,9 +- 0,9
17,6 +- 2,8
23,0 +- 1,3
21,2 +- 1,0
14,3 +- 2,0
0.063 - 0.2
27,4 +- 2,2
34,5 +- 1,9
30,1 +- 4,0
19,1 +- 0,3
38,1 +- 1,2
8,6 +- 0,4
0.2 - 0.63
55,8 +- 3,1
43,9 +- 1,6
27,9 +- 2,1
5,8 +- 0.3
14,7 +- 1,5
8,9 +- 0,5
0.63 - 2.0
2,4 +- 0,6
0,8 +- 0,3
2,7 +- 0,7
1,7 +- 0,3
1,4 +- 0,2
3,4 +- 0,7
soil type
silty sand (uS)
loamy sand (lS)
silty sand (uS)
clayey loam (tL)
loamy sand (lS)
clayey loam (tL)
Particle size (mm) distribution according to USDA (%)
<0.002
2,7 +- 1,1
6,8 +- 1,3
8,7 +- 1,7
26,9 +- 0,3
11,2 +- 1,0
41,0 +- 1,9
0.002 - 0.05
10,0 +- 1,6
12,6 +- 1,7
27,6 +- 3,8
40,3 +- 1,1
28,5 +- 3,3
36,8 +-2,0
0.05 - 2.0
87,3 +- 1,2
80,6 +- 2,6
63,7 +- 4,4
32,8 +- 1,1
60,3 +- 4,1
22,2 +- 1,6
soil type
sand
loamy sand
sandy loam
loam
sandy loam
clay
water holding capacity
(g/100g)
31,2 +- 2,0
44,4 +- 6,0
35,6 +- 3,0
44,1 +- 1,5
40,4 +- 2,7
38,9 +- 4,6
weight per volume
(g/1000ml)
1462 +- 39
1257 +- 43
1295 +- 30
1305 +- 12
1280 +- 89
1372 +- 60
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Clay
Silt
Sand
Swiss soil texture pyramid classification with positioning of the LUFA Speyer standard soils
5
1
6
2 2
fine textured soils
medium textured soils
coarse
sand
4
European Union soil texture pyramid classification
German soil texture pyramid classification FAO soil texture pyramid classification
(Food and Agriculture Organization of the United Nations)
gray area has no significance
5. Moisture output in hPa suction pressure
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6. Maintenance
Replacing the sensor felt
7. Technical specifications
PlantCare Mini-Logger
Description
Measuring principle
MHP: Micro-Heat-Pulse measurement of soil moisture and soil temperature
Operating temperature
-20° C to +50° C
Measuring range
Moisture: 0 -100% at 0° - 37°C soil temperature
Temperature: -20 - +50°C
Reading accuracy
Moisture: Relative %: 1% / hPa: 1hPa
Temperature: 0.1 °C
Measuring accuracy
Moisture: +/- 3%
Temperature: +/- 0.3°C
Frost resistant
Yes
Type of soil
All
Weight
130 gr.
Power supply
2 AA 1.5V mono-cells
Battery life
Approx. 1 year depending on measuring cycle and frequency of data
readout
Logging capacity
approx. 12.000 records
Data-Export
Export cable and USB stick
Programming
Via configuration file on USB stick
Possible settings
Device name
Start-time for first measurement
Measuring cycle time: 10 –360 min
Moisture output in relative % or hPa
Date and time
Data erase
Data analysing
PlantCare DataViewer software (included)
Sealing electronics and sensor
IP67
Maintenance
None
Accessories
Sensor tip with felt / Data upload/download cable with 2 USB Sticks
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8. Warranty
Your dealer will issue a two-year warranty for this product (from date of purchase). This warranty covers
all substantial defects of the unit that are demonstrably attributable to faulty material(s) or manufacturing
faults. It will be implemented either by replacement with a unit in perfect condition or by repair (free of
charge) of the returned unit at our discretion if the following conditions are met:
The unit was treated properly and in accordance with the recommendations in the operating
instructions.
Neither the buyer nor any third party has attempted to repair the unit themselves.
9. Disclaimer
No liability can be assumed for any consequential damage resulting from the incorrect operation of or any
malfunctioning by this product.
10. Support
If you have any questions, please contact us by e-mail: [email protected]
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