USER'S GUIDE Vaisala Weather Transmitter WXT510 M210470EN-D
PUBLISHED BY Vaisala Oyj Phone (int.): +358 9 8949 1 P.O. Box 26 Fax: +358 9 8949 2227 FIN-00421 Helsinki Finland Visit our Internet pages at http://www.vaisala.com/ © Vaisala 2006 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice.
________________________________________________________________________________ Table of Contents CHAPTER 1 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Contents of This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Safety . . . . . . . . . . . . . . . . . . . . .
________________________________________________________________________________ CHAPTER 5 WIRING AND POWER MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . .35 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 Wiring Using the Screw Terminals . . . . . . . . . . . . . . . . . . .37 Wiring Using the 8-pin M12 Connector (Optional) . . . . . . .39 External Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 Internal Wiring . . . . .
________________________________________________________________________________ Start Concurrent Measurement (aC) . . . . . . . . . . . . . . . . . 72 Start Concurrent Measurement with CRC (aCC) . . . . . . . . 73 Send Data Command (aD) . . . . . . . . . . . . . . . . . . . . . . . . 74 Examples of aM, aC and aD Commands . . . . . . . . . . . . . . 75 Continuous Measurement (aR) . . . . . . . . . . . . . . . . . . . . . 77 Continuous Measurement with CRC (aRC) . . . . . . . . . . . .
________________________________________________________________________________ CHAPTER 10 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117 Self-Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119 Error Messaging/Text Messages . . . . . . . . . . . . . . . . . . .119 Rain and Wind Sensor Heating Control . . . . . . . . . . . . . .121 Operating Voltage Control . . . . . . . . . . . . . . . . . . . . . . . .121 Technical Support .
________________________________________________________________________________ List of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Vaisala Weather Transmitter WXT510. . . . . . . . . . . . . . . . . . . 15 Main Components of Weather Transmitter WXT510 . . . . . . . . 17 Cut Away View . . . . . . . . .
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________________________________________________________________________________ List of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Table 17 Table 18 Table 19 Table 20 Screw Terminal Pin-outs for WXT510 Serial Interfaces and Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Pin-outs for WXT510 Serial Interfaces and Power Supplies . . . .
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Chapter 1 ________________________________________________________ General Information CHAPTER 1 GENERAL INFORMATION This chapter provides general notes for the product. About This Manual This manual provides information for installing, operating, and maintaining Vaisala Weather Transmitter WXT510. Contents of This Manual This manual consists of the following chapters: - Chapter 1, General Information: This chapter provides general notes for the product.
User’s Guide ______________________________________________________________________ - Chapter 6, Communication Settings: This chapter contains the instructions for making the communication settings. - Chapter 7, Getting the Data Messages: This chapter presents the general and data message commands. - Chapter 8, Sensor and Data Message Settings: This chapter presents the sensor configuration and data message formatting commands for all communications protocols: ASCII, NMEA 0183 and SDI-12.
Chapter 1 ________________________________________________________ General Information CAUTION 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. NOTE Note highlights important information on using the product. ESD Protection Electrostatic Discharge (ESD) can cause immediate or latent damage to electronic circuits.
User’s Guide ______________________________________________________________________ Trademarks WINDCAP®, RAINCAP®, HUMICAP®, BAROCAP® and THERMOCAP® are registered trademarks of Vaisala. Microsoft®, Windows®, Windows NT®, and Windows XP® are registered trademarks of Microsoft Corporation in the United States and/or other countries. License Agreement All rights to any software are held by Vaisala or third parties.
Chapter 1 ________________________________________________________ General Information Warranty Vaisala hereby represents and warrants all Products manufactured by Vaisala and sold hereunder to be free from defects in workmanship or material during a period of twelve (12) months from the date of delivery save for products for which a special warranty is given.
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Chapter 2 __________________________________________________________ Product Overview CHAPTER 2 PRODUCT OVERVIEW This chapter introduces the unique features and advantages of the Vaisala Weather Transmitter WXT510.
User’s Guide ______________________________________________________________________ Weather Transmitter WXT510 is a small and lightweight transmitter that offers six weather parameters in one compact package. WXT510 measures wind speed and direction, precipitation, atmospheric pressure, temperature and relative humidity. WXT510 powers up with 5 ... 30 VDC and outputs serial data with a selectable communication protocol: SDI-12, ASCII automatic & polled and NMEA 0183 with query option.
Chapter 2 __________________________________________________________ Product Overview WXT510 Transmitter Components Figure 2 0505-190 Main Components of Weather Transmitter WXT510 The following numbers refer to Figure 2 on page 17: 1 = Top of the transmitter 2 = Radiation shield 3 = Bottom of the transmitter 4 = Screw cover VAISALA _______________________________________________________________________ 17
User’s Guide ______________________________________________________________________ Figure 3 0505-191 Cut Away View The following numbers refer to Figure 3 on page 18: 1 = Wind transducers (3 pcs) 2 = Precipitation sensor 3 = Pressure sensor inside the PTU module 4 = Humidity and temperature sensors inside the PTU module Figure 4 0505-192 Bottom of Transmitter 18 __________________________________________________________________ M210470EN-D
Chapter 2 __________________________________________________________ Product Overview The following numbers refer to Figure 4 on page 18: 1 = Alignment direction sign 2 = Service port 3 = Water tight cable gland (shown disassembled) 4 = Opening for cable gland (if unused, cover with hexagonal plug) 5 = 8-pin M12 connector for power/datacom cable (optional, cover with hexagonal plug if unused) 0505-193 Figure 5 Mounting Kit (Optional) Figure 6 Service Cable (Optional) 0505-194 VAISALA _
User’s Guide ______________________________________________________________________ The following numbers refer to Figure 6 on page 19: 1 = Battery connector 2 = D9-connector for PC serial port 3 = Connector for WXT510 service port (press the white flap while disconnecting cable) The service cable, while connected between the service port and PC, forces the service port to RS-232 / 19200, 8, N, 1.
Chapter 3 ______________________________________________________ Functional Description CHAPTER 3 FUNCTIONAL DESCRIPTION This chapter describes the measurement principles and heating function of Weather Transmitter WXT510. Wind Measurement Principle WXT510 uses Vaisala WINDCAP® sensor technology in wind measurement. The wind sensor has an array of three equally spaced ultrasonic transducers on a horizontal plane.
User’s Guide ______________________________________________________________________ The wind speed is calculated from the measured transit times using the following formula: V w = 0.5 u L u 1 e t f – 1 e t r 0505-216 where Vw = Wind speed L = Distance between the two transducers tf = Transit time in forward direction tr = Transit time in reverse direction Measuring the six transit times allows Vw to be computed for each of the three ultrasonic paths.
Chapter 3 ______________________________________________________ Functional Description Precipitation Measurement Principle WXT510 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.
User’s Guide ______________________________________________________________________ - Time mode: Transmitter sends automatically a precipitation message in the update intervals defined by the user. - Polled mode: Transmitter sends a precipitation message whenever requested by the user. More information about the precipitation sensor operation modes can be found in section Precipitation Sensor on page 103.
Chapter 3 ______________________________________________________ Functional Description Three fixed temperature limits, namely +4 °C, 0 °C, and -4 °C (+39 °F, +32 °F, +25 °F)control the heating power as follows: Th > +4 °C: heating is off, 0 °C < Th < +4 °C: 50 % heating power, -4 °C < Th < 0 °C: 100 % heating power, Th < -4 °C: 50 % heating power. When the heating function is disabled the heating is off in all conditions, see Supervisor Message on page 108.
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Chapter 4 _______________________________________________________________ Installation CHAPTER 4 INSTALLATION This chapter provides you with information that is intended to help you install Weather Transmitter WXT510. Unpacking Instructions Weather Transmitter WXT510 comes in a custom shipping container. Be careful when removing the device from the container. CAUTION Beware of damaging any of the wind transducers located at the top of the three antennas.
User’s Guide ______________________________________________________________________ Assembling WXT510 1. Loosen the three fixing screws at the sensor bottom assembly. 2. Turn out the top of the transmitter. 3. Remove the vacuum bag protecting the PTU module. Connect the new PTU module. Make sure the module goes all the way in and is locked into its position with the small white latch (see section A in Figure 7 on page 28). 4.
Chapter 4 _______________________________________________________________ Installation Installation Procedure At the measurement site, WXT510 needs to be mounted, aligned, and connected to the data logger and the power source. Mounting Weather Transmitter WXT510 can be mounted either onto a vertical pole mast or onto a horizontal cross arm. When mounting WXT510 onto a pole mast, an optional mounting kit can be used to ease mounting.
User’s Guide ______________________________________________________________________ Mounting with Mounting Kit (Optional) 1. Insert the mounting kit adapter to the transmitter bottom in the position shown in the picture. 2. Turn the kit inside the bottom firmly until you feel that the adapter snaps into the locked position. 3. Mount the adapter to the pole mast, do not tighten the fixing screw (provided). 4. Align the transmitter in such a way that the arrow points to north. 5.
Chapter 4 _______________________________________________________________ Installation Mounting To Horizontal Cross Arm 1. Remove the screw cover. 2. Align the horizontal cross arm in south-north-direction, see Aligning WXT510 on page 32.In case the cross arm cannot be aligned, make the wind direction correction as instructed in section Wind Direction Correction on page 34. 3.
User’s Guide ______________________________________________________________________ Figure 11 0505-200 Mounting Screw Location in Cross Arm Aligning WXT510 To help the alignment, there is an arrow and the text "North" on the bottom of the transmitter. WXT510 should be aligned in such a way that this arrow points to the north. 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.
Chapter 4 _______________________________________________________________ Installation Figure 12 0003-011 Sketch of Magnetic Declination Compass Alignment To align Weather Transmitter WXT510, proceed as follows: 1. If WXT510 is already mounted, loosen the fixing screw on the bottom of the transmitter so that you can rotate the device. 2. Use a compass to determine that the transducer heads of WXT510 are exactly in line with the compass and that the arrow on the bottom of WXT510 points to the north.
User’s Guide ______________________________________________________________________ Wind Direction Correction Make a wind direction correction in case WXT510 cannot be aligned in such a way that the arrow on the bottom points to the north. In this case, the deviation angle from the true north should be given to WXT510. 1. Mount the transmitter to a desired position, see section Mounting on page 29. 2. Define the deviation angle from the north-zero-alignment.
Chapter 5 _______________________________________________ Wiring and Power Management CHAPTER 5 WIRING AND POWER MANAGEMENT This chapter provides you with instructions on how to connect the power supply and the serial interfaces. WXT510 can be accessed through four different serial interfaces: RS232, RS-485, RS-422 and SDI-12. Each of them can be wired either through the internal screw terminal or the 8-pin M12 connector (optional). Only one serial interface can be used at a time.
User’s Guide ______________________________________________________________________ In most occasions the average consumption is less than 10 mA. Typically, the higher the voltage the lower the current, but with voltages above 18 V the current will gradually increase, adding to the usual consumption an extra 4 mA at 24 V (see Figure 14 on page 36).
Chapter 5 _______________________________________________ Wiring and Power Management Figure 15 0505-203 Heating Current and Power vs Vh CAUTION To avoid exceeding the maximum ratings in any condition, the voltages must be checked with no load at the power supply output. WARNING Make sure that you connect only de-energized wires. Wiring Using the Screw Terminals 1. Loosen the three long screws at the bottom of WXT510. 2. Pull out the bottom part of the transmitter. 3.
User’s Guide ______________________________________________________________________ 0505-204 Figure 16 Screw Terminal Block Table 1 Screw Terminal Pin-outs for WXT510 Serial Interfaces and Power Supplies Screw Terminal Pin RS-232 SDI-12 RS-485 RS-422 1 RX2 RX+ 3 TX4 TX+ 5 RXD 6 SGND 17 HTG18 HTG+ 19 VIN20 VIN+ Data out (TxD) Data in (RxD) GND for data GND for Vh+ Vh+ (heating) GND for Vin+ Vin+ (operating) Data in/out (Tx) Data in/out (Rx) GND for data GND for Vh+ Vh+ (heating) GND for Vin+ Vin
Chapter 5 _______________________________________________ Wiring and Power Management Wiring Using the 8-pin M12 Connector (Optional) External Wiring If WXT510 is provided with the optional 8-pin M12 connector, the connector is located on the bottom of the transmitter, see Figure 4 on page 18. The pins of the 8-pin M12 connector as seen from outside the transmitter are illustrated in the following figure.
User’s Guide ______________________________________________________________________ The terms "Default wiring" and "RS-422 wiring" refer to the two internal wiring options, see the diagrams on the next page. Internal Wiring The 8-pin M12 connector is optional and hence may not be readily installed. For retrofitting, make the wiring between the connector and the screw terminal block according to one of the following pictures.
Chapter 5 _______________________________________________ Wiring and Power Management directly readable with PC's Received Data line. In this case Signal Ground for PC ComPort is taken from screw terminal pin #6 SGND (for testing purposes pin #19 VIN- will also do). For configuration work, the Service Port is most practical, since it has constant and convenient line parameters: RS232/19200, 8, N, 1. See Chapter 6, Communication Settings, on page 45 and Figure 4 on page 18).
User’s Guide ______________________________________________________________________ With RS-485 and RS-422 interfaces, termination resistors should be used at both ends of the line, if data rate is 9600 Bd or higher and distance is 600 m (2000 ft) or longer. Resistor range 100 ... 180 Ω is suitable for twisted pair lines. Resistors are connected across RX- to RX+ and across TX- to TX+ (with RS-485 only one resistor needed).
Chapter 5 _______________________________________________ Wiring and Power Management - Wind measurement is absolutely the most consuming operation in the system. So, it all depends on how the wind is to be reported. If long time averages are needed, the wind must be constantly measured - then it makes no big difference, which requesting period or mode is used. Fully continuous wind measurement with 4 Hz sampling rate adds 2 ...
User’s Guide ______________________________________________________________________ NOTE - SDI-12 Native mode (M=S, C=1) has the lowest standby consumption, about 0.07 mA. Note that it can also be used with RS-232 terminals (PC or equivalent), see the SDI-12 connection diagram in Figure 19 on page 41. In this case the commands must be in SDI-12 format, but no special line break signals are required. The SDI-12 mode is for polling only.
Chapter 6 ____________________________________________________ Communication Settings CHAPTER 6 COMMUNICATION SETTINGS This chapter contains the instructions for making the communication settings. Communication Protocols As soon as WXT510 has been properly connected and powered the data transmission can be started. The communication protocols available in each of the serial interfaces are shown in the following table.
User’s Guide ______________________________________________________________________ NOTE The RS-485 and RS-422 interfaces cannot be directly accessed with a standard PC terminal. They require a suitable converter. NOTE RS-232 and SDI-12 can be accessed with a standard PC terminal, presuming that, for SDI-12, the Data in/out lines have not been combined inside WXT510.
Chapter 6 ____________________________________________________ Communication Settings NOTE Changes in the serial interface/communication protocol/baud settings take place when disconnecting the service cable or when resetting the sensor. If these settings are not changed during the service connection session, original main port settings (at M12 and screw terminals) are returned, as soon as the service cable is disconnected from either end.
User’s Guide ______________________________________________________________________ Communication Setting Commands NOTE Hereafter the commands to be typed are presented in normal text while the responses of the transmitter are presented in italic. Checking the Current Communication Settings (aXU) With this command you can request the current communication settings of WXT510.
Chapter 6 ____________________________________________________ Communication Settings Setting Fields a = Device address XU = Device settings command in ASCII and NMEA 0183 XXU = Device settings command in SDI-12 [A] = Address: 0 (default) ... 9, A ... Z, a ... z [M] = Communication protocol: A = ASCII, automatic a = ASCII, automatic with CRC P = ASCII, polled p = ASCII, polled, with CRC N = NMEA 0183 v3.0, automatic Q = NMEA 0183 v3.0, query (= polled) S = SDI-12 v1.3 R = SDI-12 v1.
User’s Guide ______________________________________________________________________ NOTE [L] = RS-485 line delay: 0 ... 10000 ms Defines the delay between the last character of the query and the first character of the response message from WXT510. During the delay, the WXT510's transmitter is disabled. Effective in ASCII, polled and NMEA 0183 query protocols. Effective when RS-485 is selected (C = 3). [N] = Name of the device: WXT510 (read only) [V] = Software version: for example, 1.
Chapter 6 ____________________________________________________ Communication Settings Changing the Communication Settings Make the desired setting with the following command. Select the correct value/letter for the setting fields, see Setting Fields on page 49. See also the examples.
User’s Guide ______________________________________________________________________ Example (ASCII and NMEA 0183, device address 0): Changing the device address from 0 to 1: 0XU,A=1 1XU,A=1 Checking the changed settings: 1XU 1XU,A=1,M=P,T=1,C=2,I=0,B=19200,D=8,P=N,S=1,L=25, N=WXT510,V=1.
Chapter 7 __________________________________________________ Getting the Data Messages CHAPTER 7 GETTING THE DATA MESSAGES This chapter presents the general and data message commands. Each communication protocol has its own section for data message commands. For changing the message parameters, units and other settings, see Chapter 8, Sensor and Data Message Settings, on page 93. NOTE Type commands in CAPITAL letters.
User’s Guide ______________________________________________________________________ where a = Device address XZ = Reset command = Command terminator in ASCII and NMEA 0183 ! = Command terminator in SDI-12 The response depends on the communication protocol, see the examples.
Chapter 7 __________________________________________________ Getting the Data Messages Example (ASCII): 0XZRU 0TX,Rain reset Example (SDI-12): 0XZRU!0 (= device address) Example (NMEA 0183): 0XZRU $WITXT,01,01,10,Rain reset*26 Precipitation Intensity Reset (aXZRI) This command is used to reset the rain and hail intensity parameters Ri, Rp, Hi and Hp.
User’s Guide ______________________________________________________________________ OTX,Inty reset Example (SDI-12): 0XZRI!0 (= device address) Example (NMEA 0183): 0XZRI $WITXT,01,01,11,Inty reset*39 Measurement Reset (aXZM) This command is used to interrupt all ongoing measurements of the transmitter and start them from the beginning.
Chapter 7 __________________________________________________ Getting the Data Messages ASCII Protocol This section presents the data commands and data message formats for the ASCII communication protocols. Abbreviations and Units For changing the units, see Chapter 8, Sensor and Data Message Settings, on page 93.
User’s Guide ______________________________________________________________________ Device Address (?) This command is used to query the address of the device on the bus. Command format: ? where ? = Device address query command = Command terminator The response: b where b = Device address (default = 0) = Response terminator. Example: ? 0 If more than one transmitter is connected to the bus, see Appendix A, Networking, on page 131.
Chapter 7 __________________________________________________ Getting the Data Messages The response: a where a = Device address = Response terminator Example: 0 0 Wind Data Message (aR1) With this command you can request the wind data message. Command format: aR1 where a = Device address R1 = Wind message query command = Command terminator Example of the response (the parameter set is configurable): 0R1,Dn=236D,Dm=283D,Dx=031D,Sn=0.0M,Sm=1.
User’s Guide ______________________________________________________________________ Sx = Wind speed maximum (M = m/s) = Response terminator To change the parameters and units in the response message and to make other sensor settings, see section Wind Sensor on page 93. Pressure, Temperature and Humidity Data Message (aR2) With this command you can request a pressure, temperature and humidity data message.
Chapter 7 __________________________________________________ Getting the Data Messages Precipitation Data Message (aR3) With this command you can request the precipitation data message. Command format: aR3 where a = Device address R3 = Precipitation message query command = Command terminator Example of the response (the parameter set is configurable): 0R3,Rc=0.0M,Rd=0s,Ri=0.0M,Hc=0.0M,Hd=0s,Hi=0.0M,Rp=0.0M, Hp=0.
User’s Guide ______________________________________________________________________ Supervisor Data Message (aR5) With this command you can request a supervisor data message containing self-check parameters of the heating system and power supply voltage. Command format: aR5 where a = Device address R5 = Supervisor message query command = Command terminator Example of the response (the parameter set is configurable): 0R5,Th=25.9C,Vh=12.0N,Vs=15.2V,Vr=3.
Chapter 7 __________________________________________________ Getting the Data Messages where a = Device address (default = 0) R = Combined message query command = Command terminator Example of the response: 0R1,Dm=027D,Sm=0.1M 0R2,Ta=74.6F,Ua=14.7P,Pa=1012.9H 0R3,Rc=0.10M,Rd=2380s,Ri=0.0M,Hc=0.0M,Hd=0s, Hi=0.0M 0R5,Th=76.1F,Vh=11.5N,Vs=11.5V,Vr=3.
User’s Guide ______________________________________________________________________ Polling with CRC Use the same data query commands as in the previous sections but type the first letter of the command in lower case and add a correct threecharacter CRC before the command terminator. The response contains also a CRC. For more information about the CRC-computation see Appendix C, CRC-16 Computation, on page 143.
Chapter 7 __________________________________________________ Getting the Data Messages Response: atX,Use chksum GoeIU~ where 0 = Device address tX,Use chksum = Text prompt Goe = Correct three-character CRC for the ar1 command IU~ = Three-character CRC for the response message = Response terminator Example of the other data query commands with CRC (when the device address is 0): Pressure, humidity and temperature message query = 0r2Gje Precipitation query = 0r3Ki
User’s Guide ______________________________________________________________________ Example: 0R1,Dm=027D,Sm=0.1M 0R2,Ta=74.6F,Ua=14.7P,Pa=1012.9H 0R3,Rc=0.10M,Rd=2380s,Ri=0.0M,Hc=0.0M,Hd=0s, Hi=0.0M 0R5,Th=76.1F,Vh=11.5N,Vs=11.5V,Vr=3.510V Example (with CRC): 0r1,Sn=0.1M,Sm=0.1M,Sx=0.1MGOG 0r2,Ta=22.7C,Ua=55.5P,Pa=1004.7H@Fn 0r3,Rc=0.00M,Rd=0s,Ri=0.0MIlm 0r5,Th=25.0C,Vh=10.6#,Vs=10.8V,Vr=3.
Chapter 7 __________________________________________________ Getting the Data Messages SDI-12 Protocol There are two different modes available for providing all the functionality of the SDI-12 v1.3 standard. The lowest power consumption is achieved with the Native SDI-12 mode (aXU,M=S), as it makes measurements and outputs data only when requested. In this mode all the commands presented in this chapter are available except those for the Continuous measurement.
User’s Guide ______________________________________________________________________ The response: a where a = Device address (default = 0) = Response terminator Example (device address 0): ?!0 Acknowledge Active Command (a) This command is used to ensure that a device is responding to a data recorder or another SDI-12 device. It asks a device to acknowledge its presence on the SDI-12 bus.
Chapter 7 __________________________________________________ Getting the Data Messages Change Address Command (aAb) This command changes the device address. After the command has been issued and responded to, the sensor is not required to respond to another command for one second time in order to ensure writing the new address to the non-volatile memory.
User’s Guide ______________________________________________________________________ where a = Device address I = Send identification command ! = Command terminator The response: a13ccccccccmmmmmmvvvxxxxxxxx where a = Device address 13 = The SDI-12 version number, indicating SDI-12 version compatibility; for example, version 1.
Chapter 7 __________________________________________________ Getting the Data Messages Command format: aMx! where a = Device address M = Start measurement command x = The desired sensor to make the measurement 1 = Wind 2 = Temperature, humidity, pressure 3 = Precipitation 5 = Supervisor If x is left out, the query refers to the combined data message used for requesting data from several sensors with just one command. See Examples of aM, aC and aD Commands on page 75.
User’s Guide ______________________________________________________________________ NOTE When the measurement takes less than one second, the response part two is not sent. In WXT510 this is the case in the precipitation measurement aM3. NOTE The maximum number of parameters that can be measured with aM and aMC commands is nine (9).
Chapter 7 __________________________________________________ Getting the Data Messages x = The desired measurement 1 = Wind 2 = Temperature, humidity and pressure 3 = Precipitation 5 = Supervisor If x is left out, the query refers to combined data message in which the user can request data from several sensors with just one command. See the examples below.
User’s Guide ______________________________________________________________________ Send Data Command (aD) This command is used to request the measured data from the device. See Examples of aM, aC and aD Commands on page 75. NOTE Start measurement command tells the number of parameters available. However, the number of the parameters that can be included in a single message depends on the number of characters in the data fields.
Chapter 7 __________________________________________________ Getting the Data Messages NOTE In SDI-12 v1.3 Continuous measurement mode (aXU,M=R) the sensor makes measurements at configurable update intervals. The aD command following the aM, aMC, aC or aCC command always returns the latest updated data. Thus in aXU,M=R mode issuing consecutive aD commands may result in different data strings if the value(s) happen to be updated between the commands.
User’s Guide ______________________________________________________________________ Example 3: Start a precipitation measurement and request the data: 0M3!00006 (6 parameters available immediately, thus the device address is not sent) 0D0!0+0.15+20+0.0+0.0+0+0.0 Example 4: Start a supervisor measurement with CRC and request the data: 0MC5!00014 (measurement ready in one second and 4 parameters available) 0 (measurement completed) 0D0!0+34.3+10.5+10.7+3.
Chapter 7 __________________________________________________ Getting the Data Messages 0 (measurement completed) 0D0!0+069+079+084+0.1+0.6+1.1+21.1+21.7+32.0+1000.3+0.02 +20+0.0+0.0 0D1!0+0+0.0+1.3+0.0+0+77.1 Continuous Measurement (aR) The device can be configured so that all the parameters can be requested instantly with the command aR instead of the two phase request procedure of commands aM, aMC, aC, aCC + aD.
User’s Guide ______________________________________________________________________ The response: a+ where a = Device address = The measured parameters in selected units, separated with '+' marks (or '-' marks in case of negative parameter values). The maximum number of parameters to be measured with one reqeust is 15. = Response terminator Examples (device address 0): 0R1!0+323+331+351+0.0+0.4+3.0 0R3!0+0.15+20+0.0+0.0+0+0.0+0.0+0.
Chapter 7 __________________________________________________ Getting the Data Messages NMEA 0183 V3.0 Protocol This section presents the data query commands and data message formats for the NMEA 0183 v3.0 query and automatic protocols. For changing the message parameters, units and other settings, see Chapter 8, Sensor and Data Message Settings, on page 93. A two-character checksum (CRC) field is transmitted in all data request sentences.
User’s Guide ______________________________________________________________________ Acknowledge Active Command (a) This command is used to ensure that a device is responding to a data recorder or another device. It asks a sensor to acknowledge its presence on the bus.
Chapter 7 __________________________________________________ Getting the Data Messages Command format: $--WIQ,MWV*hh where $ = Start of the message -- = Device identifier of the requester WI = Device type identifier (WI = weather instrument) Q = Defines the message as Query MWV = Wind speed and direction query command * = Checksum delimiter hh = Two-character checksum for the query command. = Command terminator The response format: $WIMWV,x.x,R,y.
User’s Guide ______________________________________________________________________ Example: Typing the command $--WIQ,MWVxxx (xxx arbitrary characters) WXT510 responds $WITXT,01,01,08,Use chksum 2F*72 which tells that *2F is the correct checksum for the $--WIQ,MWV command. Example of the MWV Query: $--WIQ,MWV*2F $WIMWV,282,R,0.1,M,A*37 (Wind angle 282 degrees, Wind speed 0.
Chapter 7 __________________________________________________ Getting the Data Messages NOTE The parameter order in the output is as shown in the parameter selection setting field, see Chapter 8, sections Setting the Fields. The response format: $WIXDR,a1,x.x1,u1,c--c1, ... ... ..an,x.
User’s Guide ______________________________________________________________________ 1. NMEA-format transmits only numbers as transducer ids. If WXT510 address is given as a letter, it will be shown as a number (0 ... 9, A = 10, B = 11, a = 36, b = 37 etc.) The checksum to be typed in the query depends on the device identifier characters and can be asked from WXT510, see example below.
Chapter 7 __________________________________________________ Getting the Data Messages Table 6 Transducer IDs of the Measurement Parameters (Continued) Measurement Transducer ID Internal temperature Relative humidity Rain accumulation Rain duration Rain current intensity Hail accumulation Hail duration Hail current intensity Rain peak intensity Hail peak intensity Heating temperature Supply voltage Heating voltage 3.
User’s Guide ______________________________________________________________________ The structure of the wind sensor response message: where $ = Start of the message WI = Device type (WI = weather instrument) XDR = Transducer measurement response identifier A = Transducer id 0 type (wind direction), see the following Transducer table 302 = Transducer id 0 data (min wind direction) D = Transducer id 0 units (degrees, min wind direction) 0 = Transducer id for min wind direction A = Tra
Chapter 7 __________________________________________________ Getting the Data Messages = Response terminator The structure of the pressure, temperature and humidity sensor response message: where $ = Start of the message WI = Device type (WI = weather instrument) XDR = Transducer measurement response identifier C = Transducer id 0 type (Temperature), see the following Transducer table 23.
User’s Guide ______________________________________________________________________ WI = Device type (WI = weather instrument) XDR = Transducer measurement response identifier V = Transducer id 0 type (Accumulated rainfall), see the following Transducer table 0.
Chapter 7 __________________________________________________ Getting the Data Messages M = Transducer id 1 units (hits/cm2, Hail peak intensity) 3 = Transducer id for Hail peak intensity * Checksum delimiter 51 = Two-character checksum for the response = Response terminator The structure of the supervisor response message: where $ = Start of the message WI = Device type (WI = weather instrument) XDR = Transducer measurement response identifier C = Transducer id 2 type (tem
User’s Guide ______________________________________________________________________ 1. See Chapter 8, section Supervisor Message, Setting Fields for definitions of the Heating voltage field.
Chapter 7 __________________________________________________ Getting the Data Messages xx = Text identifier (see text message table) c---c = Text message (see text message table) * Checksum delimiter hh = Two-character checksum for the query command. = Response terminator Examples: $WItXT,01,01,01,Unable to measure error*6D (wind data request when all the wind parameters were disabled from the wind message). $WITXT,01,01,03,Unknown cmd error*1F (unknown command 0XO!).
User’s Guide ______________________________________________________________________ Example (the parameters included can be chosen from the full parameter set of the commands aR1, aR2, aR3 and aR5): 0R0,Dx=005D,Sx=2.8M,Ta=23.0C,Ua=30.0P,Pa=1028.2H, Hd=0.00M,Rd=10s,Th=23.6C For selecting the parameter set in the response message, see Chapter 8, Sensor and Data Message Settings, on page 93.
Chapter 8 ____________________________________________ Sensor and Data Message Settings CHAPTER 8 SENSOR AND DATA MESSAGE SETTINGS This chapter presents the sensor configuration and data message formatting commands for all communications protocols: ASCII, NMEA 0183 and SDI-12. Sensor and data message settings can also be done by using the Vaisala Configuration Tool software.With this software tool you can change the device and sensor settings easily in Windows® environment. See Table 20 on page 127.
User’s Guide ______________________________________________________________________ where a = Device address WU = Wind sensor settings command in ASCII and NMEA 0183 XWU = Wind sensor settings command in SDI-12 = Command terminator in ASCII and NMEA 0183 ! = Command terminator in SDI-12 The response in ASCII and NMEA 0183: aWU,R=[R],I=[I],A=[A],U=[U],D=[D],N=[N],F=[F] The response in SDI-12: aXWU,R=[R],I=[I],A=[A],U=[U],D=[D],N=[N],F=[F] where [R][I][A][U][D][N] are
Chapter 8 ____________________________________________ Sensor and Data Message Settings Setting Fields [R] = Parameter selection: This field consists of 16 bits defining the precipitation parameters included in the data messages. The bit value 0 disables and the bit value 1 enables the parameter.
User’s Guide ______________________________________________________________________ [N] = NMEA wind formatter: T = XDR (Transducer syntax), W = MWV (Wind speed and angle) Determines whether the wind message in NMEA 0183 (automatic) is sent in XDR or MWV format. [F] = Sampling rate: 1, 2, or 4 Hz Defines how often the wind measurement is performed.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Command format in ASCII and NMEA 0183: aWU,R=x,I=x,A=x,U=x,D=x,N=x,F=x Command format in SDI-12: aXWU, R=x,I=x,A=x,U=x,D=x,N=x,F=x! where NOTE R, I, A, U, = D, N, F The wind sensor setting fields, see Setting Fields on page 95.
User’s Guide ______________________________________________________________________ Changing the wind parameter selection: 0WU,R=0100100001001000 0WU,R=01001000&00100100 NOTE Character '&' is not allowed in the command. The response after the change: 0R1 0R1,Dm=268D,Sm=1.8N Example (SDI-12, device address 0): Changing the measurement interval to 10 seconds: 0XWU,I=10!0 In SDI-12 mode a separate enquiry (0XWU!) must be given to check the data content.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Pressure, Temperature, and Humidity Sensors Checking the Settings With this command you can check the current pressure, temperature and humidity sensor settings.
User’s Guide ______________________________________________________________________ Setting Fields [R] The bits 1-8 determine the parameters included in the message obtained with the following commands: -ASCII: aR2 and ar2 -NMEA 0183: $--WIQ,XDR*hh -SDI-12: aM2, aMC2, aC, and aCC2 -SDI-12 continuous: aR2 and aRC2 = Parameter selection: This field consists of 16 bits defining the PTU parameters included in the data messages. The bit value 0 disables and the bit value 1 enables the parameter.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Changing the Settings You can change the following settings: - parameters included in the data message, - update interval, - pressure unit, and - temperature unit. Make the desired setting with the following command. Select the correct value/letter for the setting fields, see Setting Fields on page 100. See the examples.
User’s Guide ______________________________________________________________________ Changing the update interval: 0TU,I=30 0TU,I=30 The response after the change: 0R2 0R2,Ta=23.9C,Ua=26.7P Example (SDI-12, device address 0): Changing the temperature unit to Fahrenheit: 0XTU,U=F!0 In SDI-12 mode a separate enquiry (0XTU!) must be given to check the data content.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Precipitation Sensor Checking the Settings With this command you can check the current precipitation sensor settings.
User’s Guide ______________________________________________________________________ Setting Fields [R] = Parameter selection: This field consists of 16 bits defining the precipitation parameters included in the data messages. The bit value 0 disables and the bit value 1 enables the parameter.
Chapter 8 ____________________________________________ Sensor and Data Message Settings [S] = Units for surface hits: M = metric (accumulated hailfall in hits/cm2, Hail event duration in s, Hail intensity in hits/cm2h) I = imperial (the corresponding parameters in units hits/in2, s, hits/in2h), H = hits (hits, s, hits/h) Changing the unit resets the precipitation counter.
User’s Guide ______________________________________________________________________ NOTE The autosend mode parameter is significant only in ASCII automatic (+CRC) and NMEA 0183 automatic protocols. NOTE Changing the counter reset mode or precipitation/surface hits units also resets precipitation counter and intensity parameters. The accumulation counter resets automatically when the accumulation value exceeds 655.35 mm (or 65.535 inch).
Chapter 8 ____________________________________________ Sensor and Data Message Settings where R, I, U, S, M, Z = The precipitation sensor setting fields, see Setting Fields on page 104.
User’s Guide ______________________________________________________________________ Supervisor Message Checking the Settings With this command you can check the current supervisor settings.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Setting Fields [R] = Parameter selection: This field consists of 16 bits defining the supervisor parameters included in the data messages. The bit value 0 disables and the bit value 1 enables the parameter.
User’s Guide ______________________________________________________________________ Example (ASCII and NMEA 0183, device address 0): 0SU 0SU,R=11110000&11000000,I=15,S=Y,H=Y Example (SDI-12, device address 0): 0XSU!0XSU,R=11110000&11000000,I=15,S=Y,H=Y Changing the Settings You can change the following settings: - parameters included in the supervisor data message, - update interval, - error messaging on/off, and - heating control.
Chapter 8 ____________________________________________ Sensor and Data Message Settings Example (ASCII and NMEA 0183, device address 0): Disabling the heating and error messaging: 0SU,S=N,H=N 0SU,S=N,H=N Example (SDI-12, device address 0): Changing the update interval to 10 seconds: 0XSU,I=10!0 In SDI-12 mode a separate enquiry (0XSU!) must be given to check the data content.
User’s Guide ______________________________________________________________________ Change the maximum wind direction (Dx) and speed (Sx) to average wind direction (Dm) and average wind speed (Sm): 0RU,R=&01001000 0RU,R=11110000&01001000 Remove the heating voltage (Vh) and temperature (Th) data from the composite data message: 0SU,R=&00000000 0SU,R=11110000&00000000 Remove the accumulated rainfall (Rc) from the composite data message: 0RU,R=&00000000 0RU,R=11111100&0
Chapter 9 ______________________________________________________________ Maintenance CHAPTER 9 MAINTENANCE This chapter contains instructions for the basic maintenance of Weather Transmitter WXT510 and contact information for Vaisala Service Centers. Cleaning To ensure the accuracy of measurement results, Weather Transmitter WXT510 should be cleaned when it gets contaminated.
User’s Guide ______________________________________________________________________ 4. Avoid contacting the white filter cap with your hands while inserting the PTU module. 5. Replace the top and tighten the three fixing screws that fasten the top and the bottom. When turning the top back in, make sure that the flat cable does not get stuck or squeezed between the top and the funnel for the flat cable.
Chapter 9 ______________________________________________________________ Maintenance Factory Calibration and Repair Service Send the device to Vaisala Instruments Service Centers for calibration and adjustment, see contact information below. Vaisala Service Centers NORTH AMERICAN SERVICE CENTER Vaisala Inc., 10-D Gill Street, Woburn, MA 01801-1068, USA. Phone: +1 781 933 4500, Fax: +1 781 933 8029 E-mail: us-customersupport@vaisala.
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Chapter 10 __________________________________________________________ Troubleshooting CHAPTER 10 TROUBLESHOOTING This chapter describes common problems, their probable causes and remedies, and includes contact information for technical support. Table 8 Data Validation Problem Interpretation Action Wind measurement failure. Both the speed and direction units are replaced by a # sign or the data values are irrelevant. Blockage (trash, leaves, branches, bird nests) between the wind transducers.
User’s Guide ______________________________________________________________________ Table 9 Communication Problems Problem Interpretation Action No response to any commands. Wrong wiring or operation voltage not connected. Baud rate/start bits/parity/stop bit settings do not match between the device and the host. Check the wiring and operation voltage, see Chapter 5, Wiring and Power Management, on page 35. Connect the service cable, use the communication settings 19200,8 N,1.
Chapter 10 __________________________________________________________ Troubleshooting Table 9 Communication Problems (Continued) Problem Interpretation Action Data messages are not in expected format. The communication protocol may not be the one you want. Some parameters are missing from the data messages. The formatting of the data messages is not what you expect. An error message as a response to a command. WXT510 keeps sending the message "TX Sync/address error".
User’s Guide ______________________________________________________________________ 0xUabc!0TX,Use chksum CCb (wrong checksum applied to the 0xU command) Table 10 Error Messaging/Text Messages Table Text message identifier (in Text Message NMEA 0183 v3.
Chapter 10 __________________________________________________________ Troubleshooting Rain and Wind Sensor Heating Control The supervisor message aSU (see Supervisor Message on page 108) shows you continuously monitored information about rain and wind sensor heating (heating temperature Th and heating voltage Vh). The heating temperature should stay above 0 °C when the heating is on (except in extremely cold conditions where the heating power is not sufficient).
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Chapter 11 ____________________________________________________ Technical Specifications CHAPTER 11 TECHNICAL SPECIFICATIONS This chapter provides the technical data of Weather Transmitter WXT510. Performance Table 11 Barometric Pressure Property Description/Value Range Accuracy Output resolution Units available 600 ... 1100 hPa ±0.5 hPa at 0 ... 30 °C (+32 ... +86 °F) ±1 hPa at -52 ... +60 °C (-60 ...
User’s Guide ______________________________________________________________________ °C 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 °C -0.1 -0.2 -0.3 -0.4 -0.5 -0.6 -0.7 -80 -60 -40 -20 0 20 40 60 80 0505-209 Figure 21 Accuracy Over Temperature Range Table 13 Relative Humidity Property Description/Value Range Accuracy 0 ... 100 %RH ±3 %RH at 0 ... 90 %RH ±5 %RH at 90 ... 100 %RH 0.1 %RH 1 ...
Chapter 11 ____________________________________________________ Technical Specifications Table 14 Wind (Continued) Property Description/Value Measurement frame averaging time update interval Table 15 1 ... 3600 s (= 60 min), at 1 s steps, on the basis of samples taken at 4, 2 or 1 Hz rate (configurable) 1 ... 3600 s (= 60 min), at 1 s steps Precipitation Property Description/Value Rainfall cumulative accumulation after the latest auto or manual reset collecting area 60 cm2 0.01 mm (0.
User’s Guide ______________________________________________________________________ Inputs and Outputs Table 16 Inputs and Outputs Property Description/Value Operation voltage 5 ... 30 VDC1 Average power consumption minimum typical maximum Heating voltage recommended ranges 0.07 mA @ 12 VDC (SDI-12) 3 mA @ 12 VDC (with default measuring intervals) 13 mA @ 30 VDC (constant measurement of all parameters) Options: DC, AC, full-wave rectified AC 12 VDC ± 20 %, 1.1 A max 24 VDC ± 20 %, 0.
Chapter 11 ____________________________________________________ Technical Specifications Materials Table 18 Materials Property Description/Value Radiation shield, top, and bottom parts Precipitation sensor plate Weight Polycarbonate + 20 % glass fibre Stainless steel (AISI 316) 650 g (1.43 lbs.
User’s Guide ______________________________________________________________________ Dimensions Figure 22 0505-210 WXT510 Dimensions in mm [inches] 128 _________________________________________________________________ M210470EN-D
Chapter 11 ____________________________________________________ Technical Specifications Figure 23 0505-211 Mounting Kit Dimensions in mm [inches] The following numbers refer to Figure 23 on page 120: 1 = Mounting kit with adapter sleeve for ø26.
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Appendix A ______________________________________________________________ Networking APPENDIX A NETWORKING Connecting Several WXT510s on the Same Bus Connecting several WXT510s on the same bus is possible in two ways: 1. Using SDI-12 serial interface and communication protocol, and 2. Using RS-485 serial interface and one of the following communication protocols: ASCII or NMEA 0183 v3.0. SDI-12 Serial Interface Wiring 1.
User’s Guide ______________________________________________________________________ Communication Protocol Set the communication protocol SDI-12 v 1.3 (aXU,C=1,M=S) or SDI12 v1.3 continuous (aXU,C=1,M=R). WXT510s on the bus shall be assigned with different addresses (for example: aXU,A=0,1,2, ... ). Thereafter WXT510s on the bus do not respond to the commands not assigned to them nor to the data messages sent by the other WXT510s.
Appendix A ______________________________________________________________ Networking Communication Protocol Set the communication protocol to ASCII polled (with or without CRC) or NMEA query. When using NMEA query, the wind message should be set to XDR (aWU,N=T).
User’s Guide ______________________________________________________________________ for receiving data from several transmitters on the bus, just with a single query command. To generate different time slots, each WXT510 is given an individual delay for its query response, by using the RS-485 line delay parameter aXU,L. This parameter defines the time (in milliseconds) between the last character of the query and the first character of the response from WXT510.
Appendix A ______________________________________________________________ Networking The maximum transducer ID is three when WXT510 address is 0. Hence, assigning address 4 for the second and address 8 for the third WXT510 on the bus the following responses to the XDR-query $-WIQ,XDR*2D will be obtained from these transmitters (same message parameter configuration): The second transmitter (address 4): $WIXDR,A,330,D,4,A,331,D,5,A,333,D,6,S,0.1,M,4,S,0.1,M,5,S,0.2, M,6*55 $WIXDR,C,23.
User’s Guide ______________________________________________________________________ NMEA 0183 v3.0 Query with ASCII Query Commands You can use ASCII query commands aR1, aR2, aR3, aR5, aR, aR0 and their CRC-versions ar1, ar2, ar3, ar5, ar and ar0 also in NMEA 0183 protocol. The responses to these commands will be in standard NMEA 0183 format. and the transmitters shall be assigned with different addresses (for example: aXU,A=0,1,2, ... ). The RS-485 line delays are not needed.
Appendix A ______________________________________________________________ Networking $WIXDR,C,23.5,C,1,C,24.3,C,2,H,49.3,P,1,P,1010.1,H, 1*59 $WIXDR,V,0.000,I,1,Z,0,s,1,R,0.00,I,1,V,0.0,M,2,Z,0,s,2,R,0.0,M, 2*67 $WIXDR,C,25.8,C,3,U,10.6,N,1,U,10.9,V,1,U,3.362,V,2*78 The query for WXT510 #3 and the response: 2R $WIXDR,A,341,D,2,A,347,D,3,A,357,D,4,S,0.1,M,2,S,0.2,M,3,S,0.2, M,4*53 $WIXDR,C,23.5,C,2,C,24.3,C,3,H,49.3,P,2,P,1010.1,H, 2*5F $WIXDR,V,0.
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Appendix B __________________________________________________________ SDI-12 Protocol APPENDIX B SDI-12 PROTOCOL SDI-12 is a standard for interfacing data recorders with microprocessorbased sensors. The name stands for serial/digital interface at 1200 baud. More information of the complete SDI-12 standard text is available from the SDI-12 web-site in the following address: www.sdi-12.org.
User’s Guide ______________________________________________________________________ the data line for at least 12 milliseconds. The data recorder then sends a command. The sensor, in turn, returns the appropriate response. Each command is for a specific sensor. The first character of each command is a unique sensor address that specifies with which sensor the recorder wants to communicate. Other sensors on the SDI-12 bus ignore the command and return to low-power standby mode.
Appendix B __________________________________________________________ SDI-12 Protocol - When receiving a break, a sensor must detect 8.33 milliseconds of marking on the data line before it looks for an address. - A sensor must wake up from a low-power standby mode and be capable of detecting a start bit from a valid command within 100 milliseconds after detecting a break. - After a data recorder transmits the last character of a command, it must relinquish control of the data line within 7.
User’s Guide ______________________________________________________________________ NOTE The low-power standby mode, in addition to being a low-power consumption state, is a protocol state and a break is required to leave that state.
Appendix C ______________________________________________________ CRC-16 Computation APPENDIX C CRC-16 COMPUTATION The computation of the CRC is performed on the data response before parity is added. All operations are assumed to be on 16 bit unsigned integers. The least significant bit is on the right. Numbers preceded by 0x are in hexadecimal. All shifts shift in a zero. The algorithm is: Initialize the CRC to zero.
User’s Guide ______________________________________________________________________ Encoding the CRC as ASCII Characters The 16 bit CRC is encoded to three ASCII characters by using the following algorithm: 1st character = 0x40 OR (CRC shifted right 12 bits) 2nd character = 0x40 OR ((CRC shifted right 6 bits) AND 0x3F) 3rd character = 0x40 OR (CRC AND 0x3F) The three ASCII characters are placed between the data and . Parity is applied to all three characters, if selected for the character frame.
Appendix D ________________________________________ Wind Measurement Averaging Method APPENDIX D WIND MEASUREMENT AVERAGING METHOD The following three figures represent the wind measurement averaging for different selections of communication protocol, wind measurement update interval (I) and averaging time (A). Scalar averaging is used for both wind speed and direction. For direction, zero degree crossing, when present, is taken correctly into account in averaging.
User’s Guide ______________________________________________________________________ Case 1 I > A, all other communication protocols than SDI-12 (aXU,M=S). In this example I=5 sec and A=3 sec. A A ... ... 1 sec Case 2 I time I I < A, all other communication protocols than SDI-12 (aXU,M=S). In this example I=2 sec and A=5 sec. A A A A ... ... time 1 sec Case 3 I I I I Communication protocol SDI-12 (aXU,M=S). In this example A =3 sec. I does not have any function in this protocol. A A ...
Appendix D ________________________________________ Wind Measurement Averaging Method NOTE Grey boxes indicate that the measurement is in progress during the corresponding second. Update (= internal calculation) is always made in the end of the update interval. In the auto sending protocols (ASCII automatic (+ CRC) and NMEA automatic) outputting the data messages is synchronized to take place immediately after the update.
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