Delta-T WET-GP1 Logging Quick Start Guide

Delta-T WET-GP1 Logging is a data logger that can monitor soil moisture and conductivity using a WET sensor. It features multiple channels, allowing you to monitor various parameters. The device can also be used to control irrigation systems, leveraging readings from WET sensors.

PDF Download

Document

WET GP1 Logging
How to use a WET Sensor with a GP1 Data Logger
Quick Start Guide
Version 1.4
Delta-T Devices Ltd
1 Introduction
GP1 data loggers can read one WET sensor in addition to channels 1 to 6.
This guide explains how to use a WET sensor with a GP1 logger.
Read it in conjunction with the GP1 Quick Start Guide and the WET Sensor User
Manual online at www.delta-t.co.uk.
Features
Record

Water content or permittivity

Pore water conductivity or bulk conductivity

Temperature

Control irrigation or fertigation - WET readings can be used to trigger the GP1
Alarm, Control, and Dual Rate Logging functions, the same as for the other sensor
channels.

Read sensor calibrations directly from the WET sensor (see box below).

Specify soil types from a drop-down list which can be extended to include
specialist horticultural substrates.
Calibrations
WET sensors require two different types of calibration:
Sensor calibrations specify how to obtain accurate readings from individual
sensors. These sensor calibrations are now programmed into the WET sensor,
so that the GP1 can automatically load the correct calibration*. They are
supplied in two forms – a standard calibration that enables accurate readings
between 0 to 300 mS.m-1 bulk conductivity, and an extended range calibration
that increases the range to 0 to 500 mS.m-1, but at reduced accuracy.
Soil and substrate calibrations specify how to convert the WET readings
into water content measurements for a particular type of soil or substrate. The
GP1 software includes organic, mineral, clay and sand calibrations, and you can
also enter custom values obtained by soil specific calibration, or purchase soil
parameters for a range of artificial soil substrates commonly used in commercial
greenhouses (see: Soil Properties on page 6).
Please contact Delta-T if you wish to purchase these.
*Note: WET-1 and older versions of WET-2 sensors can be used with the GP1,
but you have to program the calibration into the GP1 from the calibration file
supplied on the CD or floppy disk. You can also download the file from our
website, if necessary.
&copy; 2019 Delta-T Devices Ltd
Page 2
Requirements
For the full functionality you need:
 WET-2 sensor serial number WET-27/001 or later
Earlier versions can be used, see * note on page 2
 DeltaLINK software version 2.3 or later
 GP1 logger with serial number GP1-06-001 or later
 GP1 firmware revision v1.45 or later.
For all WET sensor versions, if the sensor cable is &gt;5m the inbuilt calibration cannot
be read, so you must load the calibration from the USB stick, see instructions below.
Upgrades
To upgrade WET sensor or GP1
Please contact Delta-T if you want to upgrade your WET sensor or GP1 logger - you
may need to buy a replacement.
To update DeltaLINK and the GP1 firmware
Visit https://www.delta-t.co.uk/software/deltalink/ and install the current version of
DeltaLINK software on your PC.
Once that is installed, you can install the latest GP1 logger firmware:
1. Connect your GP1 to your PC using the serial cable provided along with a USB
convertor (USB-RS232), if necessary.
2. From the Windows Start menu select, DeltaLINK-PC, Firmware Upgrade.
*Note: this may vary depending on which version of Windows you have.
Cable Lengths
WET sensor
cable length
≤ 5m
&gt; 5m
Limitation
WET sensor can be read and the built-in sensor calibration
data can be retrieved, see Calibration Options (page 6).
WET sensor can be read but sensor calibration must be read
“From file” on the supplied USB memory stick, see Calibration
Options (page 6).
&copy; 2019 Delta-T Devices Ltd
Page 3
2 GP1 WET Sensor Wiring
Select the wiring diagram that corresponds with the serial number of your WET sensor.
Warning: All WET-1 Sensors: (IMAG sensors and serial numbers WET-01/001
to WET-15/099) must only be powered from the +5V ref reference and not from the
PWR (power) terminal (see diagram below).
Misconnection may cause permanent damage.
Such damage is not covered by the Delta-T warranty
WET-1 (IMAG)
GND
Braid
Blue
Green
Data7
Yellow
+5V (ref)
Brown
4-core
Braid
White
Green
Yellow
Brown
Screen
0V
0V
5V serial data out
+5V DC
WET-1 Serial numbers:
WET-01/000 to WET-15/099
GND
Braid
Blue
Green
Data7
Yellow
+5V (ref)
4-core
Braid
Blue
Green
Yellow
Red
Screen
0V
0V
5V serial data out
+5V DC
Red
WET-2 Serial numbers:
WET-16/001 to WET-26/070
GND
PWR
Data7
CalB
CalA
Black &amp; Screen
Red
Yellow
Turquoise
White
9-core
Braid
Black
Red
Yellow
Turquoise
White
Green
Brown
Blue
Screen
0V
+5 to +9V DC
5V serial data out
EEPROM - data
EEPROM - clock
Not used
Not used
Not used
Centre pin
size change
at
WET25.063
WET-2 Serial numbers:
WET-27/001+
GND
PWR
Data7
CalB
CalA
Blue &amp; Screen
Red
Yellow
Violet
White
&copy; 2019 Delta-T Devices Ltd
7-core
Braid
Blue
Red
Yellow
Violet
White
Grey
Green
Screen
Power 0V
+5 to +9V DC
5V serial data out
EEPROM - data
EEPROM - clock
Factory use
Not used
Page 4
3 Program the GP1
Connect your GP1 to your PC via the serial cable and run DeltaLINK.
Select the Program window and Click Change.
Select Edit, New Program and select Standard GP1 Program.
The Standard GP1 Program should appear, showing three channels labelled W. E.
and T. - configurable as WET sensor channels. See left hand figure below.
Right click on any of the W.E. or T. channels and select WET sensor to populate all
the WET sensor channels with default settings, as shown above. Alternatively, you
may set each channel individually.
Specify WET sensor properties
Double click on each of the WET sensor
channels to display a Properties dialog
and modify them to fit your requirements.
The figure at right shows the Properties
dialog for the W channel.
See the WET User Manual for information
on setting Measurement type, Units, and
Soil properties not covered here.
Similarly - for the Conductivity and
Temperature channels E &amp; T, refer to the
WET User Manual for an explanation of
settings not covered here.
&copy; 2019 Delta-T Devices Ltd
Page 5
Calibration options
From serial number WET 27/001 onwards, ALL WET sensors have sensor calibrations
supplied built in to the sensor memory.
Select from the available options:
 Calibration: Standard This uses the built-in Standard calibration which covers
the normal salinity range specified for the sensor in the WET User Manual.

Calibration: Extended This uses the built-in Extended calibration which
enables the WET to read with reasonable accuracy over a higher conductivity
range, up to 500 mS.m -1.

Calibration: From file This uses a WET sensor calibration file that can be
downloaded from our website www.delta-t.co.uk. For sensors with cable lengths
longer than 5m, the calibration file will be supplied on a USB memory stick.
Standard calibration files are named WETxxyyy.CAL.
Extended salinity range files are named WEXxxyyy.CAL.
When prompted, select the calibration file that you want to use.
Note: Use of the built-in Standard and Extended option requires:
 Serial number WET-27/001 or later.
 Cable ≤5m.
Note: the built-in WET sensor calibration is only read when you click Apply or do a
Warm Reset (i.e. briefly press Reset). So, if you do change the WET sensor, briefly
press Reset. See the GP1 Quick Start Guide for more about Reset.
Note: all three W.E.T. channels share the same calibration data, so you only need to
specify the source once for any given WET sensor.
Soil properties: Soil type
For best accuracy select the Soil type, which best matches your soil. DeltaLINK
includes WET sensor soil properties for organic, mineral, clay and sandy soils.
Special soil substrate calibrations
You can also purchase soil properties for several artificial growing media:
 WET-ST-1G for measurements in Stonewool (vertical and horizontal)

WET-GH-1G for measurements in horticultural media: coir, peat-based, mineral
green-house and pot soils.
In the Soil types list you can choose one of the standard DeltaLINK soil properties, or
for any artificial growing media which has been installed in the GP1.
Special soil types have to be pre-installed in the GP1 at the factory.
Please contact Delta-T if you wish to purchase these for your GP1.
Note: If you program the GP1 offline i.e. with no GP1 attached, DeltaLINK initially
displays and accepts all soil types. But, when you try to Apply the program to the GP1,
it will report an ‘Incompatible Program’ error if you have selected a soil type not
installed in the GP1.
&copy; 2019 Delta-T Devices Ltd
Page 6
Comparing WET sensor readings to other sensors
In many situations it's convenient to use the supplied general soil substrate
calibrations (e.g. for &quot;mineral&quot;, &quot;organic&quot;, &quot;sand&quot; or &quot;clay&quot; soils, or one of the special
greenhouse substrates) as these calibrations provide reasonable accuracy and enable
changes in water content to be monitored or controlled effectively.
When comparing readings between different types of sensors it's more appropriate to
use a soil-specific calibration for each sensor, so that each provides readings as close
as possible to the true (gravimetric) reading. For example, when comparing readings
from a WET Sensor and an SM150T soil moisture sensor:
Accuracy
Typical accuracy with soil-specific
calibration
Typical accuracy with general calibration
WET
sensor
&plusmn; 3%
&plusmn; 5%
&plusmn; 3%
Typical reading
difference*
&plusmn; 5%
&plusmn; 6%
&plusmn; 8%
SM150T
* This is a rough estimate - the reading errors are not independent variables,
particularly for generalised calibrations where the errors will often be in the same
direction.
In addition, note there are some substrates for which the usual relationship between
dielectric measurement and water content does not apply. It is still possible to obtain
good comparisons between WET sensor and other sensor readings when used with
appropriate substrate calibrations, but it is more difficult to derive the substrate
calibrations for each sensor, and they may only apply over a more restricted range.
This seems to occur with a few peat or coir-based composts and some artificial
substrates.
Finalise the Program
Having configured the WET sensor channels in DeltaLINK, specify the rest of the
program to meet your requirements. This may include control of the relay dependent
on the WET or other sensor readings
See also: the GP1 Quick Start Guide, the Irrigation Control Quick Start Guide, the
DeltaLINK on-line Help and Applications Notes from our website www.delta-t.co.uk.
&copy; 2019 Delta-T Devices Ltd
Page 7
4 Check Sensors and Start Logging
1.
Select the Sensors window and click the Read now button.
The sensor readings will continually refresh on a scrolling time graph.
2.
Observe the sensor reading display in the scrolling charts and value panels while
adjusting sensor wiring and/or installation conditions.
Note: WET sensors will not read theta or EC in air.
3.
Click the Cancel button when finished.
4.
Select the Logger Window and click Start to commence logging.
5 Retrieve, View and Save Logged Data
1.
Select the Dataset window. All
stored data in the logger will be
retrieved and displayed on the
screen (it may take a few seconds
to upload the data).
Click Refresh if required.
2.
Select File, Save to save the data
to a dataset file.
3.
Select File, Open to open and
view a previously saved dataset
file.
4.
To save a dataset file as an ASCII
file for importing into other
programs, open the file in
DeltaLINK, and select File, Save
As… selecting the appropriate file
type to save.
Delta-T Devices Ltd
130 Low Road, Burwell
Cambridge CB25 0EJ
UK
Tel:
+44 1638 742922
Fax: +44 1638 743155
e-mail: [email protected]
[email protected]
web: www.delta-t.co.uk
">

Hello! I am an AI chatbot specifically trained to assist you with the Delta-T WET-GP1 Logging Quick Start Guide. I have thoroughly reviewed the document and can help you locate the exact information you need or explain the content in clear and simple terms. Whether you’re looking for guidance on specific features, troubleshooting steps, or general usage, feel free to ask your questions. The more details you provide about your concerns or needs, the more accurately and effectively I can assist you!

Show related prompts

Assistant typing

Assistant terminated

Key features

Soil Moisture Monitoring
Conductivity Measurement
Irrigation Control
Multiple Sensor Channels
Calibration Options
Data Logging
DeltaLINK Software Compatible

Frequently asked questions

The latest WET sensors have built-in calibrations, but you can also load them from a file. Consult the manual for details on calibration options and file downloads.

Yes, the GP1 can trigger its alarm, control, and dual-rate logging functions based on the WET sensor readings.

The GP1 supports organic, mineral, clay, and sandy soils. You can also purchase special calibrations for artificial growing media like stonewool and horticultural substrates.