Delta-T Devices Ltd WS-GP1 Quick Start Manual

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WS-GP1 Weather Station

WS-GP1 Weather Station for wind speed and direction, relative humidity, air temperature, rain and solar radiation

Quick Start Guide

Version 2.0

Delta-T Devices Ltd

Introduction

The WS-GP1 Weather Station measures wind speed and direction, air temperature, relative humidity, solar radiation and rainfall.

Apart from the wind vane tail, the sensors are already attached to the cross-arm and connected to a GP1 Logger with a weather station program installed.

This guide explains how to choose a site, install the mast, mount and align the cross arm, add the wind-vane tail and align it to North. Then, using a PC or Windows Mobile Device we show how to change the weather station program, check the sensor readings, then acquire and display readings.

1 Unpacking

Check your contents against your order. You should have a cross arm fitted with a GP1 logger pre-wired to:

Wind speed and direction sensor D-034B-CA RH and air temperature sensor RHT3nl-CA Solar energy flux sensor PYRPA-03 Rain gauge RG2+WS-CA

You should also find the following:

Sensor user manuals GP1 Quick Start Guide and screwdriver Allen keys - 5/64 inch for the wind vane and 2.5 mm for light sensor levelling mount Spanner for the mast GP1-RS232 serial cable Delta-T Software and Manuals CD including DeltaLINK PC version 2.3 or later

You may also have the following:

Tripod mast M2-TRPD or some other mast to mount on Guy wire support kit WS-GWSK

Other tools you may need:

Spirit level for ensuring mast is vertical Pick axe and shovel if the site needs preparing for the mast Mallet for ground stakes if used Steps, box to stand on, or mirror, to see bubble level on light sensor PC running DeltaLINK-PC or PDA running Pocket DeltaLINK version 2.3 or later

2 Choose the Location

Results depend not just on sensor accuracy and reliability but also on how representative the site is – so choose the site carefully.

Where data is to be compared to a “standard” meteorological site, the sensors should be exposed in a similar way to sensors at the standard sites, i.e. over a level surface of short grass and away from trees or buildings.

These are rough guidelines. Refer to meteorological publications for further advice. e.g. http://www.wmo.int/web/www/IMOP/WebPortal-AWS/Index02.html

Rules of thumb

Near a building, mount the sensors outside the zone of influence. Horizontally this extends roughly twice the height of the building upstream and ten times downstream. Vertically it extends to about twice the height of the structure.

If the requirement is to measure the true local conditions, e.g. a field of newly planted corn, select a relatively uniform area of the terrain. Be aware that, as a crop grows up towards the sensors, the measured wind speed decreases as the canopy approaches.

Sensors are also influenced by the changing local thermal and humidity microclimate above the crop. There are no simple rules to follow – but be aware of the following:

Clothes line effect: vegetation upwind may

affect vapour gradients and heat transfer.

Oasis effect: If an isolated source of water,

e.g. a lake or glacier, is surrounded by a relatively arid area, then the relative humidity may be affected if the wind direction draws air from the water source.

Leading Edge effect: When air moves over

the boundary between two surfaces that differ in temperature, moisture content, roughness or some other characteristic, it takes time for the air to adjust. The line of discontinuity is known as the leading edge. The boundary layer will vary in vertical extent with distance from the leading edge as it adjusts to the new conditions.

Thermal plume effect: Avoid placing objects directly under the air humidity and

temperature sensor, such as a solar panel, which can create a rising thermal plume when warmed by the sun.

3 Attach wind vane

1 Fully insert vane arm into hub. 2 Align vane with centre axis of sensor. 3 Use the hex 5/64” Allen key to tighten

the set screw at the top of the hub.

4 Install mast and cross arm

The cross arm can be mounted on any sturdy vertical (or horizontal) mast of diameter: 42 to 52 mm (1⅝ to 2 inches).

Make the ground sufficiently level, firm and stable to secure your mast. If using the M2-TRPD tripod mast use the optional guy wire kit with ground stakes to further stabilise it.

Install the mast securely and as vertical as possible using a sprit level.

Shield the logger from direct sun by mounting the cross arm East to West with the logger away from the Equator.

If using a solar panel, ensure it is not immediately below the RH and air temperature sensor.

Bolt cross arm to the mast - using the U-bolts and box wrench, and make it horizontal.

5 Orient the wind vane

Find true north

It is best to set the wind direction sensor to true north, not magnetic north.

Compass Method: Get a compass and the local angle of magnetic declination – either from a map, local airport - or use an online calculator e.g.

http://www.ngdc.noaa.gov/seg/geomag/jsp /struts/calcDeclination

...and enter your latitude and longitude. Magnetic declination (or variation) is the

angle between magnetic north and true north. It is positive when the angle measured is east of true north and negative when west. So, if the declination is positive, true north is left of magnetic north.

Attach wind vane

South in the

northern

hemisphere

South in the

southern

hemisphere

Orient the cross arm East-West

MAGNETIC

NORTH = 360M

TRUE NORTH = = 270 M

TRUE NORTH = 0-(-30) = 30 M

+ -

PLUS

MINUS

Example: How to find true north given a compass

and the angle of magnetic declination

180 180

270

0-30

Typical map of magnetic declination for year 2000 (reproduced courtesy of NOAA)

From this map you can see the magnetic variation around the world can be quite large. Magnetic north also drifts over time, so it is best to refer wind direction to true north. Star Method: Find the North Star or the Southern Cross. Whichever method you use, establish where True North intersects the horizon.

Orient the wind vane

1. Ensure that the locking shoulder screw #231 is in place on the hub. The wind vane cannot rotate and, if read, the sensor should indicate 180 degrees, i.e. south.

2. Using the spanner provided, loosen the clamp holding the O34B to the cross arm,

3. Rotate the housing body until the counterweight and the black arrow on the housing actually point to true south (and the wind vane tail points to true north).

4. Tighten the clamp and remove the shoulder screw to release the wind vane and allow it to rotate freely.

6 Level the light sensor

Adjust the tripod of screws supporting the light sensor to centre the bubble level, using the 2.5 mm hexagonal socket wrench provided .

Note: You may need to stand on steps or a box or use a mirror to see the bubble level.

See the D-034-CA Technical Manual on the Software and Manuals CD

7 Install and Start GP1 Software

Install and start the GP1 software DeltaLINK on your PC as instructed in the GP1 Quick Start Guide and connect to the Weather Station GP1 logger using the GP1-RS232 cable provided.

8 Examine the GP1 Program

1. Select the Program window. Factory installed weather stations will have the

WS-GP1 Weather Station Program pre-installed as shown

2. If missing, to reinstall this program Click Change on the Program window and

select File, New Program, WS-GP1 Weather Station Program and click OK.

3. Click on and examine the Air, Wind Sun and Rain sensor tabs.

4. Examine the context sensitive online Help for each tab.

5. Note the default 1 hour Recording Rate in the Main tab and the choice of faster

sampling rates for individual sensors in the Sensor tabs, and modify them as required.

6. Note the various recording options such

as Average, Maximum, Time of maximum and so on, and click the check boxes as required.

7. Note the choice of units for wind run

and radiation integral.

8. Make any change you deem necessary

to the program and click Apply to install it to the logger.

For definitions e.g. for the various wind rose options: see the online Help.

9 Check sensors & 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.

3. Check the wind vane

reads 360 degrees at north and 180 at south.

4. Spin the anemometer and

blow on the radiation shield and check the readings look plausible.

5. Illuminate the light sensor

then cover it, and check the readings seem plausible.

6. Pour water into the rain

gauge funnel to simulate rainfall.

7. Click the Cancel button

when finished.

8. Select the Logger

window and click Start to commence logging.

For help diagnosing sensor behaviour - from the Help menu (Alt H) select Document Library (Alt D), and then WS-GP1 to display the Weather Station Document Library and refer to the individual sensor technical manuals.

Weather Records 10 Collect 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 download 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 a ASCII file for importing into other programs, open the file

in DeltaLINK, and select File, Save As… selecting the appropriate file type to save.

11 View Weather

Display Options in Dataset View

Right-click on the timescales axis to select from the preset timescale options.

Left click and drag on a chart to mark out a zoom region. Then right-click to zoom.

Right click on the value axis to restore the default zoom.

Left click and drag top and bottom chart borders then click to resize the chart

Right click on the chart region to pop up a menu of display options including Hide, Show all Charts and Details options

See also the online Help

Example Dataset

From the Help menu (Alt H) select Document Library (Alt D), and then WSGP1 to display the Weather Station

Document Library

Double click on the file “Example WSGP1 Weather Station data.dt6 to

display a typical record. Examine the display options as outlined above.

Average

Maximum

+1 standard

deviation

Minimum

Key to statistical symbols

Time of

maximum

Time of

minimum

% of time wind was from each direction:

% of windrun from each direction % of wind energy from each direction

Class Rose: % of time speed was in each Beaufort scale range

1 2

5 6 and greater

-1 standard deviation

Note – Statistical symbols are only available if selected in the program

Further processing your weather data

Dataset Import Wizard helps you seamlessly import data into MS Excel spreadsheets. Multiple dataset files may be imported and the data interleaved.

See GP1 Quick Start Guide for instructions on using the Dataset Import Wizard. Once your data is in Excel, many third-party Excel add-ins are available to help you

process your database. Note: at the time of writing this document Excel can only graph up to 32000 lines of data.

Moving the station

For its protection, remove the wind sensor vane before moving the weather station. The blue box is NOT drop proof, so carry it carefully. Do not ship it by commercial

carrier without further protective packing.

Battery Life

Replace the battery before the battery voltage indicator drops below 5.5V.

At 1 reading/ minute on all sensors a 9V Alkaline battery may last 90 days. To increase this, reduce the reading frequency, and/or use a lithium battery or external lead acid battery.

The RH sensor dominates the current consumption reducing RH sensor readings to once every 5 minutes will more than double battery life.

You might expect an external 10 Ahr lead acid battery to last longest, but internal self discharge may limit this to 12 months at 25C or only 3 months at 40C. So unless it is periodically recharged – for example by a solar panel - a lead acid battery may not outlast a Lithium battery with its longer shelf life.

Note: When retrieving data, keep an eye on your logger battery. Its status is reported by the logger software, and you can also log it along with the sensor readings. The voltage reported is that presented to the sensors, and is slightly less than that at the battery terminals.

Battery Life Estimator

200

400

600

800

0 10 20 30 40 50 60 70 80 90 100

Frequency of RH readings (minutes)

Life (days)

9V Lithium 9V alkaline

Specifications

Specification Range/Notes

Logger GP1

± (0.3mV+0.01% reading)

typical at 20C

± (1.63mV+0.05% reading) max over -20°C to + 60°C

± 0.07°C typical at 20°C

± 0.13°C max. (-20°C to +60°C)

Readings > 600,000

Logging frequency 1s to 24 hr

Data collection To PC or Pocket PC Logging status Flashing LED

Environmental -20°C to +60°C, IP67

Wind speed

± 0.1m.s

-1

up to 10m.s-1 (22.7 mph)

± 1.1% of reading

over 10m.s

-1

(22.7 mph)

Range

0 to 75m.s

-1

(0 to 167 mph)

Starting threshold

0.4 m.s-1 (0.9 mph)

Wind direction

Accuracy

± 4

0 to 356

electrical

0 to 360

mechanical

Starting threshold

0.4 m.s-1 (0.9 mph)

Damping ratio .25

Resolution

< 0.5

Temperature

Accuracy at 25°C

± 0.2°C

sensor and logger

IP65

0.5 °C

at 3 m.s

-1

1.0 °C

at 2 m.s

-1

2.0 °C

at 1 m.s

-1

± 2% RH 5 to 95% RH ± 2.5% RH < 5% and > 95% RH

Envronmental -20 to 80°C, 0-100%RH IP65

Response time < 10s

90% of scale for a step change from 11% to 75% RH

Rainfall

Sensitivity 0.2mm per tip

up to 360 mm.hr

-1

Solar Radiation

Calibration Uncertainty ± 5%

Spectral Range 360 to 1120 nm response exceeds 10% of maximum

Cosine response ± 5%

75 zenith angle

Drift <2% per year

Environmental -40 to 70°C, 0 to100%RH can be immersed up to 30m in water

Accuracy at 25°C

Accuracy analog

Temperature accuracy

for 10K thermistor (at -20 to + 60C)

Accuracy

Range

Radiation Shield error

Sensor Wiring

Service & Recalibration

Before returning parts please contact Delta-T or your local agent for instructions.

Wind speed and direction D-034B-CA

Recalibrate: every year. Service: 6-12 months: look & listen to see if the vane and cups are running freely, are undamaged, and are not loose. 12-24 months: replace anemometer bearings. 24-36 months: complete factory overhaul of sensor. Most parts are replaceable in the field.

Note: the Windvane, though connected to GP1 terminal Temp3, is actually read as a voltage output sensor (0-2.5V equals 0-360 degrees). The internal circuit differs from the standard MetOne O34B, see panel at right. See also D-034B-CA Technical Manual on the Delta-T Software and Manuals CD.

10K

5V (ref)

GND

Temp3 (IN) Temp3 (GND)

green

yellow

white

Windvane circuit schematic

Rain gauge RG2

Can be recalibrated in the field. See also the RG2+WS-CA Technical Manual on the Software and Manuals CD

Light sensor D-PYRPA-CA

Typical drift 1% per year. Recalibrate every 2 years. Keep it clean and level. Manufacture’s Warranty: 1 year parts and labour. See also the D-PYR-PA Technical Manual on the Software and Manuals CD

RH & air temp sensor RHT3nl-CA

Typical drift -1.5 to -2% in the first year, -1% in the second year and -0.5% in the third. No adjustment of the RH or temperature element is possible. Inaccurate sensors must be replaced with new module which can be plugged in the field. Replace every two years in clean atmospheric conditions or every year if the atmosphere is polluted.

Replacing the RH Sensor

Note: the RHT3nl uses a 10K Betatherm 10K3A1B thermistor and a 6 plate radiation shield but is otherwise similar to the RHT2nl sensor. See also the RHT3nl-CA Technical Manual on the Software and Manuals CD.

Notices

This product uses software code. It should not be used in safety-critical applications or where consequential loss may occur. It is the responsibility of the user to ensure appropriate safeguards are in place for regularly monitoring and checking the equipment.

In no event shall Delta-T’s liability exceed the selling price of the product. Delta-T is not liable for indirect, incidental or consequential damages in connection with the use of equipment, including but not limited to: data loss, vegetation loss, loss of energy or water, cost of substitute equipment

or services, property damage, or personal injury that results from installer’s negligence. The

customer agrees to the limitations and exclusions of liability by purchase or use of this product. See also the GP1 Product Usage.pdf in the online Document Library folder.

The WS-GP1 Weather Station is CE compliant, See WS-GP1 EC Certificate.pdf in the online

Document Library folder.

Delta-T Devices Ltd 130 Low Road, Burwell Cambridge CB25 0EJ UK

Tel: +44 1638 742922 Fax: +44 1638 743155 e-mail: sales@delta-t.co.uk

tech.support@delta-t.co.uk

web: www.delta-t.co.uk

Delta-T Devices Ltd WS-GP1 Quick Start Manual

Specifications and Main Features

Frequently Asked Questions

User Manual