ICT PSY1 User manual

Contents
System Requirements ....................................................................................... 4
Charging the PSY1 Internal Battery................................................................... 5
Connecting a Power Supply to the Instrument............................................. 6
Connecting Power Directly via Solar Panel ................................................... 7
Connecting Power Directly via CH24 Power Supply ..................................... 8
Cleaning the Psychrometer Chamber ............................................................... 9
Installing ICT Combined Instrument Software and USB Driver....................... 10
Turning the Instrument On ............................................................................. 11
Connecting to the Instrument......................................................................... 12
Connect via MCC Mini................................................................................. 13
Setting Measurement Parameters.................................................................. 14
Configuration .............................................................................................. 15
Cooling Time and Waiting Time .............................................................. 15
Chamber Heating .................................................................................... 16
Calibration................................................................................................... 16
Diagnostics .................................................................................................. 17
Reverse Peltier (Warming)...................................................................... 17
SD Card Logging Options............................................................................. 18
View Options............................................................................................... 18
PSY Logger Mounting and Sensor Installation ................................................ 19
Selecting a Site ............................................................................................ 19
Preparing a Site........................................................................................... 21
Sealing the Exposed Site ............................................................................. 22
Downloading Data........................................................................................... 23

Introduction
The PSY1 Stem Psychrometer is a powerful tool integrating all the ambient
environmental parameters acting upon the plant, such as solar radiation,
temperature, humidity, wind speed and water availability, into a single
continuously measurable variable.
Stem water potential directly reflects the energy required to access water, an
indication of the stress the plant is undergoing.
Note: This manual should be used in conjunction with the instructional
videos on the ICT YouTube channel:
https://www.youtube.com/c/ICTinternational
Note: The psychrometer thermocouples are made from 25 µm
Chromel/Constantan wire, you will require a microscope to view the
thermocouples. You cannot see them or manipulate their position with the
naked eye. The thermocouples can easily be broken if handled incorrectly.
Please watch the video Adjusting the Thermocouples
(https://youtu.be/kNsZnSYDBPE) before removing the chamber lid.
Photo: 25 µm Chromel/Constantan thermocouples viewed under a dissection
microscope at 20x magnification.

System Requirements
The ICT Combined Instrument Software does not require a powerful
computer.
Minimum Recommended System Specifications:
Intel Atom 1.66 GHz and 1GB RAM or higher.
Software:
The ICT Combined Instrument Software is compatible with the following
operating systems:
a) Windows 7
b) Windows 8 & 8.1
c) Windows 10
d) Mac OS X
Screen Resolution
ICT Combined Instrument Software works best on computers with a screen
resolution of 1366 x 768 or larger.

Charging the PSY1 Internal Battery
The PSY1 is a self-contained instrument that incorporates a lithium polymer
battery. Before using the instrument, this battery should be charged. To
choose from a range of charging options, see Connecting a Power Supply to
the Instrument (Pages 6 to 8).
An external power supply should be connected to the PSY1 in the field.
The unique power bus-plug design was developed by ICT International to
simplify the electrical wiring process. It minimises the need for custom tools
in the field, requiring only that the outer cable sheath be stripped back to
expose the copper wire.
As shown on Page 6, no other tools are required, with all necessary
components and fixings fully incorporated into the instrument design.
Retaining straps ensure the power bus-plugs do not separate from the
instrument when removed during wiring preparation and connection of
external power.

Connecting a Power Supply to the Instrument

Connecting Power Directly via Solar Panel
Note: The PSY1 is non-polarised.

Connecting Power Directly via CH24 Power Supply
Note: The PSY1 is non-polarised
Note: Continuous connection of an external battery or constant power
supply (for days to months at a time) is not recommended as this can shorten
the life of the internal battery. ICT International recommend using a solar
panel directly connected (with no external battery backup in parallel)
wherever possible; or a timer switch to turn off external power for 8-12
hours daily to simulate a solar panel during the day and night.

Cleaning the Psychrometer Chamber
The Stem Psychrometer consists of two very small welded thermocouples
made of very fine 25µm wire.
This makes the sensor very sensitive for measuring water potential, but
equally sensitive to dirt and mild oxidation. It is recommended that before
starting any measurements you clean the thermocouples. The cleaning
process involved using an organic solvent such as chloroform, or electronics
contact cleaner.
Watch the Video: https://www.youtube.com/watch?v=sUe2leJzxE0

Installing ICT Combined Instrument Software and USB
Driver
Insert the supplied USB drive and run Autorun.exe.
Select Software (a) then choose ICT Combined Instrument Software (b).
Follow the on-screen prompts until the finished installation screen appears.
To install the USB driver, choose USB Driver (c) and then wait for the
installation to complete.
(b)
(a) (c)
Alternatively, the individual installers (Windows and Mac) are available in the
Instrument Software folder on the USB drive.
The most recent versions of all ICT software are available from:
http://www.ictinternational.com/support/software/

Turning the Instrument On
To turn on your PSY1, connect the instrument to a computer via a USB cable.
Alternatively, the PSY1 can be turned on manually by pressing the power
button, and automatically turns on if a power supply is connected to the bus-
plugs.

Connecting to the Instrument
Connect a USB cable to the instrument. The PSY1 will be detected by the
computer automatically, as with any USB device.
Open ICT Combined Instrument Software and Search for Devices.
Double-click the instrument in the list to connect to it or select it and click
‘Connect’.

Connect via MCC Mini
Ensure that the PSY1 is on. Connect the MCC Mini to your computer, open
ICT Combined Instrument Software. Tick ‘Auto RF Discover’ and then Search
for Devices.
The MCC Mini should appear on the list, it will then automatically search for
nearby ICT Instruments.
You can double click the instrument, or select it and Connect, as with USB.
You may need to install the MCC Mini USB driver from the ICT International
website: http://www.ictinternational.com/support/software/

Setting Measurement Parameters
When you connect to an instrument, the Channels screen will be displayed.
This shows the current measurement status, when the next measurement
will take place, instrument serial number/name/comment, battery status,
external power status, SD card status, and instrument date and time.

Configuration
Normally, all instruments provided by ICT International come pre-configured,
calibrated and tested. All that you need to do is select a logging interval. This
is done from the Configuration screen:
Note: Click ‘Update Measurement Option Changes’ after changing any
settings to send them to the logger.
A range of standard Measurement Modes are available, from every 10
minutes to every 60 minutes. In manual mode a measurement will be taken
whenever the Start Measurement button on the Channels screen is clicked.
Cooling Time and Waiting Time
The default settings are a cooling time of 10 seconds and a wait time of 6
seconds. This ensures that water in the atmosphere of the chamber
condenses and cools the thermocouple. A wait time of six seconds allows for
stabilisation of the psychrometric wet bulb depression.

Chamber Heating
Chamber heating should be used whenever the psychrometer is subjected to
very cold temperatures at night that could induce condensation. If such
conditions are expected, a good protocol to follow is to employ chamber
heating between 5 pm and 10 am to prevent the chamber from becoming
colder than the stem.
Calibration
It is highly recommended that the psychrometer is calibrated before each
installation.
The calibration employs a 6-point measurement protocol using NaCl solutions
of known molalities. The calibration must be done under isothermal
conditions at a controlled temperature of 25°C to generate a specific slope
and intercept that characterises the specific response of the individual
thermocouples.
A detailed calibration function is provided in the software that can be used to
generate the new calibration.

Watch the Stem Psychrometer Calibration videos SP08, SP09 and SP10 from:
https://www.youtube.com/playlist?list=PL4F3FBBF0881B16D7 for more
details.
Diagnostics
Temperature Correction Constants (C1 and C2) should not be changed unless
advised to do so by an ICT Technician.
Reverse Peltier (Warming)
Reverse Peltier is not normally required for a clean psychrometer. This is
typically only required for very humid conditions.

SD Card Logging Options
These settings allow you to select what is recorded to the SD card. By default,
everything except Raw Data is logged.
Raw Data creates a separate data file on the SD card in addition to the
standard .csv file.
View Options
Enables the display of diagnostic measurement results during measurement.

PSY Logger Mounting and Sensor Installation
Installation is an important aspect best explained by watching the SP03, SP04
and SP05 installation videos.
Care must be taken to prepare the site for installation:
(a) Latex exudates seeping from the stem. It would not be acceptable to
install the Psychrometer under these conditions.
(b) A stem that has been prepared appropriately. The xylem under the latex
source is exposed. The Psychrometer can be successfully installed.
Note: Any living tissue left behind will grow into the chamber and cause
damage to the thermocouples.
The stem psychrometer can be installed on woody, herbaceous and hollow
(bamboo) stems of greater than 10mm diameter. With additional care,
preparation and specific clamps, the stem psychrometer can also be used on
fruits and leaves.
When attaching the psychrometer it is important not to over tighten the
clamping mechanism on softer plant issues to prevent damage to the
installation site.
Selecting a Site
Stems with flattened portions are more conductive to efficient sealing. In
situations where it is not possible to easily or safely access appropriate small
diameter branches (ie: branches of an appropriate size for the clamp used),
the psychrometer can be installed on large diameter trunks or on leaves.

Example installation of a small clamp on an herbaceous stem.
Large clamp on a woody stem.