Attachment_4_-_PPNM_Stabilization_-_Appendix_C_Part3.pdf

M211840EN-E

User Guide

Vaisala Weather Transmitter WXT530 Series

PUBLISHED BY

Vaisala Oyj Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland P.O. Box 26, FI-00421 Helsinki, Finland +358 9 8949 1

Visit our Internet pages at www.vaisala.com.

© Vaisala 2020

No part of this document may be reproduced, published or publicly displayed in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be modified, translated, adapted, sold or disclosed to a third party without prior written permission of the copyright holder.

Translated documents and translated portions of multilingual documents are based on the original English versions. In ambiguous cases, the English versions are applicable, not the translations.

The contents of this document are subject to change without prior notice.

Local rules and regulations may vary and they shall take precedence over the information contained in this document.

Vaisala makes no representations on this document’s compliance with the local rules and regulations applicable at any given time, and hereby disclaims any and all responsibilities related thereto.

This document does not create any legally binding obligations for Vaisala towards customers or end users. All legally binding obligations and agreements are included exclusively in the applicable supply contract or the General Conditions of Sale and General Conditions of Service of Vaisala.

This product contains software developed by Vaisala or third parties. Use of the software is governed by license terms and conditions included in the applicable supply contract or, in the absence of separate license terms and conditions, by the General License Conditions of Vaisala Group.

Table of contents

1. About this document

1.1 Version information

1.2 Documentation conventions

1.3 Trademarks

2. Product overview

2.1 WXT530 Series weather transmitters

2.1.1 WXT536

2.1.2 WXT535 and WXT534

2.1.3 WXT533 and WXT532

2.1.4 WXT531

2.2 Components

2.3 Optional features

2.3.1 USB cables

2.3.2 Mounting kit

2.3.3 Surge protector

2.3.4 Bird kit

2.3.5 Vaisala Configuration Tool

2.3.6 Sensor heating

2.4 Backward compatibility

2.5 ESD protection

2.6 Regulatory compliances

3. Functional description

3.1 Wind measurement principle

3.2 Precipitation measurement principle

3.3 PTU measurement principle

3.4 Heating

3.5 Analog input interface

3.6 Analog output interface

4. Installation

4.1 Installing WXT530

4.1.1 Maritime installations

4.2 Placing WXT530

4.3 Unpacking WXT530

4.4 Mounting WXT530

4.4.1 Mounting WXT530 on vertical pole mast without mounting kit

4.4.2 Mounting WXT530 on vertical pole mast with mounting kit

4.4.3 Mounting WXT530 on sensor support arm

4.5 Grounding

4.5.1 Grounding with bushing and grounding kit

4.6 Aligning WXT530

4.6.1 Aligning WXT530 with compass

4.6.2 Configuring wind direction offset

4.7 Installing Vaisala Configuration Tool

4.8 Installing USB cable driver

4.9 Updating WXT530 firmware

4.10 Changing from CLI mode to Modbus mode

4.11 Changing from Modbus mode to CLI mode

4.12 Using Modbus with old WXT530

5. Power management

5.1 Power supplies

5.2 Power management

5.3 Wiring with 8-pin M12 connector

5.3.1 External wiring

5.3.2 Internal wiring

5.4 Wiring with screw terminals

5.5 Data communication interfaces

6. Connection options

6.1 Communication protocols

6.2 Connection cables

6.3 Connecting with service cable

6.3.1 Connecting through M12 bottom connector or screw terminal

6.4 Communication setting commands

6.4.1 Checking current communication settings (aXU)

6.4.2 Settings fields

6.4.3 Changing the communication settings (aXU)

7. Retrieving data messages

7.1 General commands

7.1.1 Reset (aXZ)

7.1.2 Precipitation counter reset (aXZRU)

7.1.3 Precipitation intensity reset (aXZRI)

7.1.4 Measurement reset (aXZM)

7.2 Modbus protocol

7.3 ASCII protocol

7.3.1 Abbreviations and units

7.3.2 Device address (?)

7.3.3 Acknowledge active command (a)

7.3.4 Wind data message (aR1)

7.3.5 Pressure, temperature and humidity data message (aR2)

7.3.6 Precipitation data message (aR3)

7.3.7 Supervisor data message (aR5)

7.3.8 Combined data message (aR)

7.3.9 Composite data message query (aR0)

7.3.10 Polling with CRC

7.3.11 Automatic mode

7.3.12 Automatic composite data message (aR0)

WXT530 Series User Guide M211840EN-E

7.4 SDI-12 protocol

7.4.1 Address query command (?)

7.4.2 Acknowledge active command (a)

7.4.3 Change address command (aAb)

7.4.4 Send identification command (aI)

7.4.5 Start measurement command (aM)

7.4.6 Start measurement command with CRC (aMC)

7.4.7 Start concurrent measurement (aC)

7.4.8 Start concurrent measurement with CRC (aCC)

7.4.9 Send data command (aD)

7.4.10 Examples of aM, aC and aD commands

7.4.11 Continuous measurement (aR)

7.4.12 Continuous measurement with CRC (aRC)

7.5 NMEA 0183 v3.0 protocol

7.5.1 Device address (?)

7.5.2 Acknowledge active command (a)

7.5.3 MWV wind speed and direction query

7.5.4 XDR transducer measurement query

7.5.5 TXT text transmission

7.5.6 Automatic mode

7.5.7 Automatic composite data message (aR0)

8. Sensor and data message settings

8.1 Sensor configuration and data message formatting

8.1.1 Wind sensor

8.1.2 Pressure, temperature, and humidity sensors

8.1.3 Precipitation sensor

8.1.4 Supervisor message

8.1.5 Composite data message (aR0)

8.1.6 Analog input

8.1.7 Analog output

9. Maintenance

9.1 Cleaning

9.1.1 Cleaning the radiation shield

9.2 Replacing PTU module

10. Troubleshooting

10.1 Self-diagnostics

10.1.1 Error messaging/text messages

10.1.2 Rain and wind sensor heating control

10.1.3 Operating voltage control

10.1.4 Missing readings and error indication

11. Technical specifications

11.1 Performance

11.2 Inputs and outputs

11.3 Environmental conditions

11.4 Mechanical specifications

11.5 Options and accessories

11.6 Type label

11.7 Dimension

Appendix A: Networking A.1 Connecting several transmitters on same bus A.2 SDI-12 serial interface

A.2.1 Wiring SDI-12 A.2.2 SDI-12 communication protocol

A.3 RS-485 serial interface A.3.1 RS-485 wiring A.3.2 RS-485 communication protocol A.3.3 ASCII, polled A.3.4 NMEA 0183 v 3.0 query A.3.5 NMEA 0183 v 3.0 query with ASCII query commands

Appendix B: Modbus protocol B.1 Register maps

Appendix C: SDI-12 protocol C.1 SDI-12 electrical interface

C.1.1 SDI-12 communications protocol C.1.2 SDI-12 timing

Appendix D: CRC-16 computation D.1 Encoding the CRC as ASCII characters D.2 NMEA 0183 v3.0 checksum computation

Appendix E: Wind measurement averaging method

Appendix F: Factory configurations F.1 General unit settings F.2 Wind configuration settings F.3 PTU configuration settings F.4 Rain configuration settings F.5 Supervisor settings

Appendix G: Connecting external sensors to WXT536 G.1 Connecting ultrasonic level sensor to WXT536 G.2 Connecting pyranometer to WXT536 G.3 Connecting resistance temperature sensor G.4 Connecting rain gauge to WXT536

Appendix H: Complete set of accessories

Appendix I: Configuration parameters

Appendix J: Recycling instructions

Index

Warranty

Recycling

Technical support

List of figures

Figure 1 WXT536 Figure 2 WXT535 and WXT534 Figure 3 WXT533 and WXT532 Figure 4 WXT531 Figure 5 WXT536 components Figure 6 Cut-away view of WXT536 Figure 7 Bottom of WXT536 Figure 8 WXT536 with bird kit Figure 9 Vaisala Configuration Tool Figure 10 Analog inputs for external sensors Figure 11 Contents of shipping container Figure 12 Mounting WXT531 on vertical pole mast Figure 13 WXT530 North arrow Figure 14 Sketch of magnetic declination Figure 15 Average operational current consumption (with 4Hz wind sensor sampling) Figure 16 Heating instant current and power vs Vh (WXT536, WXT535, WXT533, and WXT532) Figure 17 Heating instant current and power vs Vh (WXT531) Figure 18 PTU power consumption in RS-232, RS-485, RS-422, and SDI-12 continuous modes Figure 19 PTU power consumption in SDI-12 native mode Figure 20 Pins of 8-pin M12 connector Figure 21 Internal wiring for RS-232, SDI-12, and RS-485 Figure 22 Screw terminal block Figure 23 Data communication interfaces Figure 24 Termination jumper positions Figure 25 Service cable connection Figure 26 Analog input connector pins Figure 27 Analog input settings in Vaisala Configuration Tool Figure 28 Type label Figure 29 WXT536 dimensions Figure 30 WXT535 and WXT534 dimensions Figure 31 WXT533 and WXT532 dimensions Figure 32 WXT531 dimensions Figure 33 WXT530 series mounting kit (212792) dimensions Figure 34 Mounting accessory (WMSFIX60) for connecting mounting kit (212792) and 60-mm tube Figure 35 Timing diagram Figure 36 Wind measurement averaging method Figure 37 Connecting external sensors to WXT536 Figure 38 Connecting ultrasonic level sensor to WXT536 Figure 39 Wiring ultrasonic level sensor to WXT536 Figure 40 Connecting pyranometer to WXT536 Figure 41 Peeling pyranometer cable sheath

Figure 42 Wiring pyranometer to WXT53 Figure 43 Pt1000 connected to WXT536 M12 connector Figure 44 Wiring temperature sensor Pt1000 to WXT536 Figure 45 Wiring temperature sensor TM-Pt1000 to WXT536 Figure 46 TM-Pt1000 connector Figure 47 Wiring RG13/RG13H to WXT536 Figure 48 Complete set of accessories Figure 49 WXT536 with surge protector WSP150 Figure 50 WXT536 with surge protector WSP152

List of figures

List of tables

Table 1 Document versions Table 2 WXT530 series features Table 3 Available options Table 4 WXT536 measurements Table 5 WXT534 and WXT535 measurements Table 6 WXT533 and WXT532 measurements Table 7 WXT531 measurements Table 8 Precipitation sensor modes Table 9 Heater resistance Table 10 Standby power consumption Table 11 Economic power management Table 12 Pinouts for WXT530 Series serial interfaces and power supplies Table 13 Screw terminal pinouts Table 14 WXT532 mA output option screw terminal pinouts Table 15 RS-232 wiring Table 16 RS-485 wiring Table 17 SDI-12 wiring Table 18 RS-422 wiring Table 19 mA output wiring Table 20 Screw terminal pinouts for serial interfaces and power supplies Table 21 Available serial communication protocols Table 22 Connection cable options Table 23 Default serial communication settings for M12/screw terminal connection Table 24 Abbreviations and units Table 25 Transducer IDs of measurement parameters Table 26 Transducer table Table 27 Wind parameters bits 1-8 Table 28 Wind parameters bits 9-16 Table 29 PTU parameters bits 1-8 Table 30 PTU parameters bits 9-16 Table 31 Precipitation parameters Bits 1-8 Table 32 Precipitation parameters Bits 9-16 Table 33 Supervisor parameters bits 1-8 Table 34 Supervisor parameters bits 9-16 Table 35 Analog input signals Table 36 Analog input setting definitions Table 37 aIU setting fields [R] Table 38 Analog output scaling Table 39 aWU setting fields [R] Table 40 Data validation Table 41 Communication problems Table 42 Error messaging/text messages Table 43 Barometric pressure measurement performance Table 44 Air temperature measurement performance

Table 45 Relative humidity measurement performance Table 46 Precipitation measurement performance Table 47 Wind measurement performance Table 48 Inputs and outputs Table 49 WXT536 analog input options Table 50 WXT532 analog mA output options Table 51 Operating environment Table 52 Electromagnetic compatibility Table 53 Mechanical specifications Table 54 Options and accessories Table 55 Holding registers Table 56 Device status Table 57 Commonly used unit system independent values Table 58 Measurement values in metric units (°C, m/s, mm, mm/h) Table 59 Measurement values in imperial units (°F, mph, in, in/h) Table 60 Other measurement values Table 61 Temperature Table 62 Humidity Table 63 Pressure Table 64 Air density Table 65 Precipitation Table 66 External analog inputs Table 67 PTU measurement Table 68 General unit settings Table 69 Wind configuration settings Table 70 PTU configuration settings Table 71 Rain configuration settings Table 72 General unit settings Table 73 Ultrasonic level connections Table 74 Pyranometer connections Table 75 Temperature sensor connections Table 76 Rain gauge connections Table 77 General parameters Table 78 Pressure, temperature and humidity parameters Table 79 Wind parameters Table 80 Precipitation parameters Table 81 Auxiliary sensor parameters Table 82 Analog mA output parameters

List of tables

1. About this document

1.1 Version information

Table 1�Document versions

Document code Date Description

M211840EN-E August 2020 Added information on Modbus protocol.

Updated information on PTU module.

Updated cable information.

Added recycling information.

M211840EN-D April 2017 Added information about external sensors. Updated technical drawings. Added grounding information.

Added index.

1.2 Documentation conventions

Warning alerts you to a serious hazard. If you do not read and follow instructions carefully at this point, there is a risk of injury or even death.

WARNING!

Caution warns you of a potential hazard. If you do not read and follow instructions carefully at this point, the product could be damaged or important data could be lost.

CAUTION!

Note highlights important information on using the product.

Tip gives information for using the product more efficiently.

Lists tools needed to perform the task.

Chapter 1 – About this document

Indicates that you need to take some notes during the task.

1.3 Trademarks

Vaisala , BAROCAP , HUMICAP , RAINCAP , and WINDCAP are registered trademarks of Vaisala Oyj.

Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and other countries.

All other product or company names that may be mentioned in this publication are trade names, trademarks, or registered trademarks of their respective owners.

2. Product overview

2.1 WXT530 Series weather transmitters

The WXT530 series transmitters are suitable for several purposes, such as:

• Agro-meteorological applications

• Building control systems

• Cruisers

• Energy applications

• Environmental monitoring

• Fire weather

• Meteorological test beds

• Noise monitoring

• Researchers

• Sport events

• Weather stations

The WXT530 models offer the following measurement combinations.

Chapter 2 – Product overview

WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

P Pressure T Temperature U Humidity R Rain W Wind

Table 2�WXT530 series features

Feature Value / Description

Transmitter power-up 5 … 32 VDC

Communication protocols • SDI-12

• ASCII automatic and polled

• NMEA 0183 with query option

Serial interface options • RS-232

• RS-485

• RS-422

• SDI-12

Connectors • 8-pin M12 connector for installation

• 4-pin M8 connector for service use

Transmitter housing IP rating IP65, with mounting kit IP66

Table 3�Available options

Available options WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

Service pack 2: Windows-based Vaisala configuration tool software with USB service cable (1.4 m)

USB RS-232/RS-485 cable (1.4 m)

Mounting kit

Surge protector

Available options WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

Bird kit

Shielded cables (2 m, 10 m, 40 m)

Bushing and grounding kit

Heating �

Analog input option � mA output option

2.1.1 WXT536

Table 4�WXT536 measurements

Sensor Pressure Temperature Humidity Rain Wind speed Wind direction

WXT536

WXT536 offers an analog input option.

Figure 1�WXT536

1 Analog input option 2 Analog input option not ordered

2.1.2 WXT535 and WXT534

Table 5�WXT534 and WXT535 measurements

Sensor Pressure Temperature Humidity Rain Wind speed Wind direction

WXT535

WXT534

Figure 2�WXT535 and WXT534

2.1.3 WXT533 and WXT532

Table 6�WXT533 and WXT532 measurements

Sensor Pressure Temperature Humidity Rain Wind speed Wind direction

WXT533

WXT532

WXT532 offers an mA output option.

Figure 3�WXT533 and WXT532

2.1.4 WXT531

Table 7�WXT531 measurements

Sensor Pressure Temperature Humidity Rain Wind speed Wind direction

WXT531

Figure 4�WXT531

2.2 Components

Figure 5�WXT536 components

1 Fixing screw and chassis grounding point 2 Screw cover 3 Top of the transmitter 4 Radiation shield 5 Bottom of the transmitter

Figure 6�Cut-away view of WXT536

1 Wind transducers (3 pcs) 2 Precipitation sensor 3 Pressure sensor inside the PTU module 4 Humidity and temperature sensors inside the PTU module 5 Service port

Figure 7�Bottom of WXT536

1 Opening for cable gland (if unused, cover with a hexagonal plug).

Watertight cable gland (optional, included in the Bushing and Grounding Kit)

2 4-pin M8 connector for service port 3 8-pin M12 connector for power or data communications cable 4 Alignment direction indicator arrow 5 Fixing screw and chassis grounding point

2.3 Optional features

The WXT530 series includes the following optional features:

• USB cables

• Mounting kit

• Surge protector

• Bird kit

• Vaisala Configuration Tool

• Heating

You must select these options when placing the order.

More information

Options and accessories (page 166)

2.3.1 USB cables

The service cable, while connected between the service port and PC, forces the service port to

RS-232 / 19200, 8, N, 1.

You need a driver for the USB cable.

More information

Installing USB cable driver (page 53)

2.3.2 Mounting kit

The optional mounting kit (212792) helps mounting the transmitter on a pole mast. If you use the mounting kit, you only need to align the transmitter when mounting for the first time.

With the mounting kit, WXT530 IP rating is IP66. Without the mounting kit, the rating is IP65.

More information

Mounting WXT530 on vertical pole mast with mounting kit (page 41)

2.3.3 Surge protector

Vaisala recommends using surge protectors:

• When weather instruments are installed in areas with an elevated risk of lightning strike, such as on top of high buildings or masts, or in open areas.

• If your cable length exceeds 10 m.

• If you have unshielded, open-wire lines.

Vaisala provides the following surge protectors:

• Vaisala Surge Protector WSP150.

A compact transient overvoltage suppressor designed for outdoor use. It can be used with all Vaisala wind and weather instruments. Install WSP150 close to the protected instrument (maximum 3 m).

• Vaisala Surge Protector WSP152.

Designed for use with Vaisala WXT transmitters and WMT sensors. WSP152 protects the host PC against surges entering through the USB port. Install WSP152 close to the PC, no further than the USB cable can reach (1.4 m).

2.3.4 Bird kit

The optional bird kit reduces the interference that birds cause to the wind and rain measurement.

The kit consists of a metallic band with spikes pointing upward. The kit is installed on top of the transmitter. The shape and location of the spikes has been designed so that the interference with wind and rain measurement is minimal.

Figure 8�WXT536 with bird kit

The spikes do not hurt the birds; they are simply a barrier that makes it difficult for birds to land on top of the transmitter. The bird spike kit does not provide complete protection against birds, but it does render the transmitter unsuitable for roosting and nest building.

When the kit is in place, more snow can accumulate on the transmitter, and the snow can melt away more slowly.

2.3.5 Vaisala Configuration Tool

Vaisala Configuration Tool is a Windows-based, user-friendly parameter setting software for WXT530 transmitters. It is also fully compatible with WMT52 and WXT520.

Figure 9�Vaisala Configuration Tool

2.3.6 Sensor heating

Heating helps to improve the measurement accuracy.

More information

Heating (page 33)

2.4 Backward compatibility

Always use the latest version of Vaisala Configuration Tool.

The WXT530 series transmitters are fully compatible with WXT520 and WMT52. This applies to mounting, cable options, and communication.

When you upgrade from WMT52 to WXT532 or from WXT520 to WXT536, you must use the same profile and communication option as you had before. Regenerate the setup files (WXC files) for WXT530 with the latest version of Vaisala Configuration Tool .

Because the WXT530 series has several product variants, the old configuration code does not apply to the new WXT530 sensor. You must generate and apply a new order code for it.

More information

Vaisala Configuration Tool (page 27)

2.5 ESD protection

Electrostatic Discharge (ESD) can damage electronic circuits. Vaisala products are adequately protected against ESD for their intended use. However, it is possible to damage the product by delivering electrostatic discharges when touching, removing, or inserting any objects in the equipment housing.

To avoid delivering high static voltages to the product:

• Handle ESD sensitive components on a properly grounded and protected ESD workbench or by grounding yourself to the equipment chassis with a wrist strap and a resistive connection cord.

• If you are unable to take either precaution, touch a conductive part of the equipment chassis with your other hand before touching ESD sensitive components.

• Hold component boards by the edges and avoid touching component contacts.

2.6 Regulatory compliances

The electromagnetic compatibility of the WXT530 series has been tested according to the following product family standard:

• EN 61326-1 Electrical equipment for measurement, control and laboratory use - EMC requirements - for use in industrial locations.

• The WXT530 series has been enhanced for marine use according to the appropriate sections of the IEC 60945 Maritime Navigation and Radiocommunication Equipment and Systems - General requirements - Methods of testing.

• The WXT530 series is in conformance with the provisions of the RoHS directive of the European Union:

• Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (2002/95/EC)

3. Functional description

3.1 Wind measurement principle

The transmitters use Vaisala WINDCAP sensor technology for wind measurement.

The wind sensor has an array of 3 equally spaced ultrasonic transducers on a horizontal plane.

The unit determines wind speed and wind directions by measuring the time it takes the ultrasound to travel from one transducer to the other two.

The wind sensor measures the transit time (in both directions) along the 3 paths established by the array of transducers. The transit time depends on the wind speed along the ultrasonic path. For zero wind speed, both the forward and reverse transit times are the same. With wind along the sound path, the up-wind direction transit time increases and the down-wind transit time decreases.

The unit calculates wind speed from the measured transit times using the following formula:

Vw = 0.5 × L × (1/tf – 1/tr)

Vw Wind speed

L Distance between the two transducers tf Transit time in forward direction tr Transit time in reverse direction

Measuring the 6 transit times allows Vw to be computed for each of the 3 ultrasonic paths. The computed wind speeds are independent of altitude, temperature, and humidity, which are cancelled out when the transit times are measured in both directions, although the individual transit times depend on these parameters.

The Vw values of 2 array paths are enough to compute wind speed and wind direction. A signal processing technique ensures that wind speed and wind direction are calculated from the 2 array paths with the best quality.

The wind speed is represented as a scalar speed in selected units (m/s, kt, mph, km/h). The wind direction from which the wind comes is expressed in degrees (°). North is represented as 0°, East as 90°, South as 180°, and West as 270°.

The wind direction is not calculated when the wind speed drops below 0.05 m/s. In this case, the last calculated direction output remains until the wind speed increases to the level of

0.05 m/s.

The average values of wind speed and direction are calculated as a scalar average of all samples over the selected averaging time (1 ... 3600 s) with a selectable updating interval. The sample count depends on the selected sampling rate: 4 Hz (default), 2 Hz, or 1 Hz. The minimum and maximum values of wind speed and direction represent the corresponding extremes during the selected averaging time.

You can select the computation of the wind speed extreme values in one of 2 ways:

• Traditional minimum/maximum calculation

• 3-second gust & calm calculation recommended by the World Meteorological

Organization (WMO). In this case the highest and lowest 3-second average values (updated once a second) replace the maximum and minimum values in reporting of wind speed, while the wind direction variance is returned in the traditional way.

The transmitter constantly monitors the wind measurement signal quality. If poor quality is detected, the wind values are marked as invalid. If over half of the measurement values are considered invalid, the last valid wind values are returned as missing data. In the SDI-12 protocol, the invalid values are marked as zero.

More information

Wind measurement averaging method (page 193)

3.2 Precipitation measurement principle

The transmitter uses Vaisala RAINCAP Sensor 2 technology in precipitation measurement.

The precipitation sensor comprises of a steel cover and a piezoelectrical sensor mounted on the bottom surface of the cover.

The precipitation sensor detects the impact of individual raindrops. The signals from the impact are proportional to the volume of the drops. The signal of each drop can be converted directly to accumulated rainfall. An advanced noise filtering technique filters out signals originating from other sources than raindrops.

The measured parameters are:

• Accumulated rainfall

• Rain current and peak intensity

• Duration of a rain event

Detecting each drop enables the computing of rain amount and intensity with high resolution.

Chapter 3 – Functional description

Precipitation current intensity is internally updated every 10 seconds and represents the intensity during the 1-minute period before requesting/automatic precipitation message sending (for fast reactions to a rain event, during the first minute of the rain event, the intensity is calculated over the period rain has lasted in 10-second steps instead of a fixed period of 1 minute). Precipitation peak intensity represents the maximum of the calculated current intensity values since last precipitation intensity reset.

The sensor can also distinguish hail stones from raindrops. The measured hail parameters are the cumulative number of hail stones, current and peak hail intensity and the duration of a hail shower.

The precipitation sensor operates in 4 modes.

Table 8�Precipitation sensor modes

Mode Description

Precipitation start/end mode

The transmitter automatically sends a precipitation message 10 seconds after the recognition of the first drop. The messages are sent continuously and they stop when the precipitation ends.

Tipping bucket mode The mode emulates tipping bucket type precipitation sensors. The transmitter sends automatically a precipitation message when the counter detects 1 unit increment (0.1 mm/0.01 in).

Time mode The transmitter sends automatically a precipitation message in the update intervals defined by the user.

Polled mode The transmitter sends a precipitation message when requested by the user.

More information

Precipitation sensor (page 131)

3.3 PTU measurement principle

WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

The PTU module contains separate sensors for pressure, temperature, and humidity measurement.

The PTU module includes:

• Capacitive silicon BAROCAP sensor for pressure measurement,

• Resistive thin-film Pt1000 sensor for air temperature measurement

• Capacitive thin-film polymer HUMICAP R2 sensor for humidity measurement.

In case of capacitive sensors, the measurement principle of the transmitter is based on an advanced RC oscillator and reference capacitors against which the capacitance of a sensor is continuously measured. The resistive Pt1000 sensors are measured with a voltage divider circuit incorporating a reference resistor and a stable voltage source. Using mathematical sensor response models and the information from sensor calibrations, the microprocessor of the transmitter performs transformations from measured electrical parameters to reported environmental parameters. These calculations include compensation for the temperature dependency of the pressure and humidity sensors.

3.4 Heating

When operating the sensor in temperatures below 0 °C (32 °F), select a model with an internal heater and enable the heater for operation.

The heating elements located below the precipitation sensor and inside the wind transducers help keeping the sensors clean from snow and ice. A heating temperature (Th) sensor underneath the precipitation sensor controls the heating. Note that Th is measured inside the equipment, where temperature is much higher than the ambient temperature (Ta).

The heating control tries to keep Th at +15 °C by adjusting the heating power. The heater control switches heating resistors on and off based on heating voltage and Th.

Table 9�Heater resistance

Transmitter model Heater resistance when Vh

< 15 V

Heater resistance when Vh

> 15 V

WXT536, WXT535, WXT533, WXT532 15 57

WXT531 27

The instant current depends on the heater voltage. You must select the power supply with the instant current in mind. The average heating power and heater performance do not depend on the heating voltage.

When the heating function is disabled, the heating is off in all conditions.

Snow accumulation can cause temporary wind measurement problems even when heating is enabled.

Chapter 3 – Functional description

Supervisor message (page 136)

3.5 Analog input interface

WXT536 offers an analog input option for solar radiation, external temperature, level measurement, and tipping bucket.

Figure 10�Analog inputs for external sensors

1 Analog input 1 Sensor A: Solar radiation

2 Analog input 2 Sensor B: Temperature Sensor C: Level sensor Sensor D: Tipping bucket

3.6 Analog output interface

WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

WXT532 offers an analog output option for wind speed and wind direction measurement.

The output settings are preconfigured at the factory according to your order. WXT532 takes measurements according to the configured averaging time and synthesizes the analog outputs of wind speed and wind direction with an update interval of 0.25 seconds.

4. Installation

Do not store the transmitter outdoors. Make sure you switch on the transmitter right after installation.

CAUTION!

4.1 Installing WXT530

At the measurement site, you must mount, ground, align, and connect the transmitter to the data logger and the power source.

You can install the instrument on top of a pole mast or on a sensor support arm.

For the most reliable measurements:

• Avoid trees or other objects nearby which could disturb wind flow.

• Install the sensor to the height that best represents the prevailing wind conditions on site.

To prevent equipment damage, install an air terminal so that the tip is as high above the instruments and sensors as possible.

CAUTION!

To prevent corrosion and oxidation, use copper paste or equivalent on screws and connector threads.

4.1.1 Maritime installations

In maritime installations according to IEC 60945, the WXT530 series belongs to the installation category C, which means that it is exposed to weather. When making maritime installations, pay attention to the following:

• Do not install WXT530 near a magnetic compass. The compass safe distance is 5 m. The transmitter must be installed in open space to avoid disturbance in measurements.

• Do not place WXT530 directly in front of a radar.

• Do not install WXT530 next to a powerful RF-transmitter antenna.

4.2 Placing WXT530

Select a site that represents the general area of interest to ensure representative ambient measurements. Make sure that the site that is free from turbulence caused by nearby objects, such as trees and buildings.

Chapter 4 – Installation

To protect personnel and the transmitter, install an air terminal with the tip at least one meter above the transmitter. It must be properly grounded, compliant with all applicable local safety regulations.

WARNING!

Installations on top of high buildings or masts and in sites on open grounds are vulnerable to lightning strikes. A nearby lightning strike can induce a high-voltage surge not tolerable by the internal surge suppressors of the instrument.

Additional protection is needed in regions with frequent, severe thunderstorms, especially when long line cables (> 30 m / 98 ft ) are used. Vaisala recommends using a surge protector, such as WSP150 and WSP152, in all sites with an elevated risk of lightning strike.

CAUTION!

4.3 Unpacking WXT530

The transmitter comes in a custom shipping container. The following figure shows the contents of the carton.

Figure 11�Contents of shipping container

1 Protective packaging top 2 Shipping carton 3 Inner box 4 Manual, cables, mounting kit (optional) 5 Installation note 6 Protective packaging bottom 7 Transmitter 8 Bird kit (optional)

Be careful not to damage the wind transducers located at the top of the 3 antennas. Dropping the device can break or damage the transducers. If the antenna bends or twists, re-aligning can be difficult or impossible.

CAUTION!

Do not remove the top of the package protecting the transducer until you have installed the transmitter. The polypropylene cushion protects the transducers during installation.

CAUTION!

Save the container and the packaging materials for future transportation and shipping.

4.4 Mounting WXT530

The transmitter is easy to install as it does not have any moving parts.

The transmitter can be mounted on:

• Vertical pole mast

• Sensor support arm

Install the transmitter upright.

The transmitter radiation shield reflects light. If you install the transmitter next to a pyranometer or a temperature and humidity sensor, the pyranometer or temperature and humidity sensor can give incorrect measurements. Install the transmitter on the same level with the pyranometer or temperature and humidity sensor so that the distance between the units is approximately 800 mm (31.5 in).

4.4.1 Mounting WXT530 on vertical pole mast without

mounting kit

2.5 mm Allen key

1. Remove the screw cover and insert the transmitter to the pole mast.

2. Align the transmitter so that the arrow points to North.

3. Tighten the fixing screw and replace the screw cover.

4. Connect the sensor cable.

4.4.2 Mounting WXT530 on vertical pole mast with mounting

kit

2.5 mm and 5 mm Allen keys

When mounting a transmitter on a pole mast, you can use an optional mounting kit to ease mounting.

Figure 12� Mounting WXT531 on vertical pole mast

Handle with care. Any impact on the instrument or sensor array may cause damage and lead to incorrect measurements.

CAUTION!

1. Remove the adapter sleeve from the mounting kit.

2. Lead the sensor cable through the mounting kit, and connect the cable to the bottom part of the sensor.

3. Insert the mounting kit adapter to the transmitter bottom.

1 Protective cushion 2 Transmitter 3 Mounting kit 4 Pole

4. Turn the kit firmly until you feel the adapter snap into the locked position.

5. Holding the sensor from its body, run the sensor cable through the mounting adapter, and slide the sensor onto the adapter. Do not tighten the fixing screw yet.

1 Fixing screw 2 Mounting accessory between mounting kit and 60 mm tube

(WMSFIX60)

3 Mounting kit (212792)

6. Align the transmitter so that the arrow on the bottom of the transmitter points North.

7. To attach the adapter to the pole mast, tighten the fixing screw of the mounting adapter.

8. Remove the protective cushion.

When removing a transmitter from the pole, turn the transmitter so that it snaps out from the mounting kit. Realignment is not needed when replacing the device.

4.4.3 Mounting WXT530 on sensor support arm

10 mm wrench

If you use the optional mounting kit, you only need to align the sensor when mounting it for the first time.

Handle with care. Any impact on the instrument or sensor array may cause damage and lead to incorrect measurements.

CAUTION!

1. Remove the screw cover.

2. Align the sensor support arm in South–North direction.

If you cannot align the sensor support arm, adjust the wind direction offset.

3. Mount the transmitter on the sensor support arm.

1 Nut M6 DIN 934 2 Mounting bolt M6 DIN 933 3 Screw cover

1 Mounting bolt M6 DIN 933

2 Nut M6 DIN 934

4.5 Grounding

A transmitter is typically grounded by installing it on a mast or a cross arm that provides a good connection to earth ground.

As grounding is provided through the fixing screw (or mounting bolt), it is important that it makes a good ground connection.

4.5.1 Grounding with bushing and grounding kit

If the surface of the mounting point is painted or has some other finishing that prevents a good electrical connection, consider using the Bushing and Grounding Kit (222109) and a cable to ensure ground connection.

Use the Bushing and Grounding Kit to run a cable from the fixing screw to a grounding point.

The kit does not include a grounding cable. The minimum grounding conductor size is 4 mm2

(AWG 11).

1. Assemble the grounding kit so that the connector for the grounding cable is between the washers and nuts.

1 Connector for grounding cable 2 Abiko connector 3 Washer (2 pcs) 4 Nut (2 pcs) 5 Fixing screw

2. Connect a grounding cable to the connector. Use a 16 mm2 conductor to achieve a good ground connection.

3. Remove the transmitter fixing screw.

4. Insert the grounding kit through the hole in the seal. Make sure the nuts are tight so that the connector has a good connection.

1 Seal 2 Fixing screw

5. Connect the other end of the cable to a good grounding point.

4.6 Aligning WXT530

WXT536 WXT535 WXT534 WXT533 WXT532 WXT531

To help the alignment, there is an arrow and the text North on the bottom of the transmitter.

Align the transmitter so that the arrow points North.

Figure 13�WXT530 North arrow

Wind direction can be referred either to true North, which uses the Earth’s geographic meridians, or to the magnetic North, which is read with a magnetic compass. The magnetic declination is the difference in degrees between the true North and magnetic North. The source for the magnetic declination should be current as the declination changes over time.

Figure 14�Sketch of magnetic declination

4.6.1 Aligning WXT530 with compass

• 2.5 mm Allen key

• Compass

Do not remove the instrument or sensor from the mounting kit during alignment.

1. If the transmitter is mounted, loosen the fixing screw on the bottom of the transmitter so that you can rotate it.

2. Use a compass to determine that the transducer heads of the transmitter are exactly in line with the compass and that the arrow on the bottom of the transmitter points North.

3. Tighten the fixing screw. Tightening torque 1.5 Nm.

4.6.2 Configuring wind direction offset

If the transmitter cannot be aligned so that the arrow on the bottom points North, make a wind direction offset by configuring the deviation angle in the transmitter.

1. Mount the transmitter to a desired position.

2. Define the deviation angle from the North (zero) alignment. Use the ± sign indication to express the direction from the North line.

3. Enter the deviation angle in the device using the wind message formatting command aWU,D (direction offset).

Now the transmitter transmits the wind direction data using the changed zero alignment.

More information

Mounting WXT530 (page 39) Mounting WXT530 on sensor support arm (page 44)

4.7 Installing Vaisala Configuration Tool

1. Insert the WXT530 driver memory stick in the USB port.

2. Go to the WXT_Series_Conf_Tool folder and run WXTConf-2.41 r.3Setup.exe.

3. When Vaisala Configuration Tool Setup Wizard opens, select Next.

4. In the User Information window, fill in the User Name, Organization, and License Key fields. The license key is shown on the sticker on the memory stick. Select Next.

5. In the Select Destination Location window, select a folder and select Next.

6. In the Select Start Menu Folder window, select a folder for shortcuts and select Next.

7. In the Select Additional Tasks window, select Additional Tasks and select Next.

8. In the Ready to Install window, select Install. Installing window opens.

9. Select Launch Vaisala Configuration Tool and select Finish to launch the tool.

Backward compatibility (page 28)

4.8 Installing USB cable driver

Before taking the USB cable into use, you must install the USB cable driver on your PC. The driver is compatible with Windows 7, Windows 8, and Windows 10.

1. Make sure that the USB cable is not connected.

2. Insert the WXT530 driver memory stick in the USB port.

3. Go to the USB-driver folder and start installation by running setup.exe.

4. When Vaisala USB Device Driver Setup Wizard opens, select Next.

5. In the Select Additional Tasks window, select the tasks you want to perform and select Install.

6. Select Display Vaisala USB Device Finder > Finish. The driver is started.

7. Plug in the cable.

Remember to use the correct port in the settings of your terminal program. Windows recognizes each individual cable as a different device, and reserves a new COM port.

There is no reason to uninstall the driver for normal use. However, if you wish to remove the driver files and all Vaisala USB cable devices, uninstall the entry for Vaisala USB Instrument Driver from the program manager tool in the Windows Control Panel.

4.9 Updating WXT530 firmware

WXT530 must be in the CLI mode before the firmware update. CLI is the command line interface, such as ASCII, NMEA and SDI-12. Firmware update is not possible in the Modbus mode.

1. Connect WXT530 service cable to the USB port of your computer and to WXT530 service connector.

2. To make sure that WXT530 is in the CLI mode, open the terminal software, such as Tera Term, with settings 19200, 8, N, 1 and type the command ?!.

If the sensor is in the CLI mode, the terminal program prints the sensor address.

Alternatively, open Vaisala Configuration Tool. If you can communicate with it, WXT530 is in the CLI mode. If not, see Changing from Modbus mode to CLI mode (page 57)

3. Start WxtLoader.exe.

4. To change the serial port settings, select Configuration.

• Select the COM port in use.

• Select serial port settings: 19200, 8 bit, none, 1 bit.

5. When Status is Connected to device, select Upload.

When Upload Status is 100 %, the firmware update is completed.

To change to the Modbus mode, see Changing from CLI mode to Modbus mode (page 56).

When WXT530 starts up in Modbus mode, communication with the terminal software is no longer possible.

4.10 Changing from CLI mode to Modbus mode

Before changing to the Modbus mode, save the settings with Vaisala Configuration Tool.

1. Set the computer terminal software, such as Tera Term, communication parameters to 19200 8N1.

2. Connect WXT530 service cable to the USB port of your computer and to WXT530 service connector.

3. In the terminal software, type the command ?XU,M=M!.

WXT530 starts up in the Modbus mode. Communication with the terminal software is no longer possible.

4.11 Changing from Modbus mode to CLI mode

When you change from the CLI mode (ASCII, NMEA, SDI-12) to the Modbus mode, or the other way round, also the accumulated values are reset. The parameter ranges in the CLI mode are sometimes bigger than what is allowed in the Modbus mode. WXT530 enforces the narrower range when the device is turned to the Modbus mode.

1. Set the computer terminal software (such as Tera Term) communication parameters to 19200 8N1 and select and open a COM port in the terminal software.

You can find the COM port reserved for the connected USB cable with Vaisala Instrument Finder provided with the drivers. The reserved COM ports are also listed in the Ports section of Windows® Device Manager.

2. Press SPACE and keep it pressed down.

3. Connect WXT530 service cable to the WXT530 service connector.

4. Release SPACE and press it down again. Keep the it pressed down for 5 seconds. WXT530 starts in the CLI service port default mode (RS-232, Standard ASCII polled, 19200, 8, N, 1).

Alternatively, you can change from the Modbus mode to the CLI mode by typing the value 0x0F to register number 11 (0x000A).

4.12 Using Modbus with old WXT530

If you already have WXT530, you need an RS-485 connection to use the Modbus protocol. You can change the communication parameters with the Vaisala Configuration Tool software, or, by using WXT530 command line with a terminal software.

When you update to Modbus, WXT530 settings roll back to default settings. You can save WXT530 settings with Vaisala Configuration Tool.

CAUTION!

To use the Modbus protocol:

• Make sure the firmware is 3.85, or newer. If not, update the firmware.

See Updating WXT530 firmware (page 56).

• Change from the CLI mode to the Modbus mode See Changing from CLI mode to Modbus mode (page 56).

If you want to return from the Modbus mode to the CLI mode, see Changing from Modbus mode to CLI mode (page 57).

5. Power management

This chapter describes how to connect the power supply and the serial interfaces and how to manage and estimate power consumption.

You can access the transmitter through the following serial interfaces:

• RS-232

• RS-485

• RS-422

• SDI-12

• mA output (WXT532)

You can wire them either through the internal screw terminal or the 8-pin M12 connector. You can use only one serial interface at a time.

The cable opening in the transmitter bottom assembly is covered with hexagonal rubber plugs. If you are not using the cable gland (included in the bushing and grounding kit), keep the opening covered.

CAUTION!

More information

Wiring SDI-12 (page 174)

5.1 Power supplies

WXT530 and the cable must be protected with a fuse or a circuit breaker from the supply side. A fuse or a circuit breaker protects the cable from overheating if there is a short circuit in the cabling.

The maximum size for the fuse or circuit breaker is 2 A. 1.6 A is also enough for guaranteed operation. Over current limitation or protection can also be built into the power supply. This limitation applies to Vaisala cables with 0. 25 mm2 conductors. The minimum conductor cross section area is 0,25 mm2 for WXT530 series instrument with heating.

The minimum consumption graph is for SDI-12 standby mode.

Figure 15�Average operational current consumption (with 4Hz wind sensor sampling)

The input power supply must be capable of delivering 60 mA (at 12 V) or 100 mA (at 6 V) instant current spikes with duration of 30 ms. These are drawn by the wind sensor (whenever enabled) at 4 Hz rate, which is the default value for wind sampling. Wind sampling at 2 Hz and 1 Hz rate is also available.

Because wind measurement is the most consuming operation in the system, the average current consumption decreases almost in proportion to the sampling rate.

Typically, the average consumption is less than 10 mA. The higher the voltage, the lower the current.

Heating voltage Vh+ (one of the following two alternatives):

• 12 … 24 VDC (-10 % … + 30 %)

• 12 … 17 VACrms (-10 % … +30 %)

The typical DC voltage ranges are:

• 12 VDC ± 20 % (max 1.1 A)

• 24 VDC ± 20 % (max 0.6 A)

Nominally at 15.7 V heating voltage level, the transmitters automatically change the heating element combination to reduce instant current. The input resistance (Rin) is radically increased with voltages above 16 V as shown in the following graph. The average (5s) power does not depend on the input voltage.

The recommended range for AC is:

Chapter 5 – Power management

• 12 … 17 VACrms (-10 % … +30 %) max 1.1 A for AC

Figure 16�Heating instant current and power vs Vh (WXT536, WXT535, WXT533, and WXT532)

Figure 17�Heating instant current and power vs Vh (WXT531)

The power supply must meet the values shown above.

Make sure that you connect only de-energized wires.WARNING!

To avoid exceeding the maximum ratings in any condition, the voltages must be checked with no load at the power supply output.

CAUTION!

More information

Power management (page 61)

5.2 Power management

The power consumption varies significantly, depending on the selected operating mode or protocol, the data interface type, the sensor configuration, and the measurement and reporting intervals.

Lowest consumption is achieved with the native SDI-12 mode, typically about 1 mW in standby (0.1 mA at 12 V), while with ASCII RS-232 or continuous SDI-12 modes it is about 3 mW in standby. Any activated sensor measurement adds its own extra consumption to the standby power.

Some hints for economic power management are given below. The consumption values are all defined for 12 V supply. For 6 V supply, multiply the values by 1.9. For 24 V supply, multiply the values by 0.65.

Table 10�Standby power consumption

Mode Standby Wind

4 Hz sampling rate 1 Hz sampling rate

Continuous measurement

10 s average every 2 min

Continuous measurement

10 s average every 2 min

RS-232

RS-485

RS-422

SDI-12

continuous

1.5 mA +4.5 mA + 0.6 mA +1.3 mA +0.2 mA

SDI-12 native 0.1 mA N/A +1 mA N/A +0.7 mA

Analog output (mA)

N/A 16 … 90 mA 16 ... 90 mA 16 ... 90 mA 16 ... 90 mA

Mode Standby PT1000 Level Tipping bucket

Solar radiation

Precipitation

Continuous rain

RS-232

RS-485

RS-422

SDI-21

continuous

1.5 mA +0.1 mA +0.4 mA +0.1 mA +0.4 mA +0.4 mA

SDI-12 native 0.1 mA +0.1 mA (interval 5 s)

+0.4 mA (interval 5 s)

+0.1 mA (interval 1 s)

+0.4 mA (interval 5 s)

+0.4 mA (interval 5 s)

Analog output (mA)

N/A N/A N/A N/A N/A N/A

SDI-12 native mode power save is based on measurements only when requested.

Due to SDI-12 polling mode operation, only periodic wind measurement results are comparable with other communication modes. Continuous measurement is not relevant for SDI-12 mode. Every measurement request increases power consumption for the first time measurement. The total SDI-12 power consumption can be changed by changing measurement request intervals.

Figure 18�PTU power consumption in RS-232, RS-485, RS-422, and SDI-12 continuous modes

Figure 19�PTU power consumption in SDI-12 native mode

Table 11�Economic power management

Measurement Consumption

Wind measurement The most consuming operation in the system, with extra variations depending on how the wind is reported. If you need long time averages and measure wind constantly, there are no large differences between requesting periods or modes. Fully continuous wind measurement with a 4 Hz sampling rate adds about 4.5 mA to the standby current, depending on the wind and some other climatic conditions. A 10-second average requested every 2 minutes consumes 8 times less. 1 Hz sampling rate decreases it to about one fourth.

Continuous precipitation

Adds approximately 0.4 mA to the standby consumption. A single, isolated raindrop increases current consumption for about 10 seconds (continued, if more raindrops are detected within the 10-second period).

ASCII RS-232

Standby consumption

Typically 1.5 mA. The jumper wires across TX+/RX+ and TX-/RX- (only necessary…