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Vaisala LT31 User Manual Download Page 93

Chapter 4 _______________________________________________________________ Installation 

VAISALA _______________________________________________________________________ 93 

-  Weather protection hood 
-  Measurement head cover 
-  Upper interface unit cover 
-  Lower interface unit cover 

Later on these parts are also needed: 

- Maintenance 

cable 

- Optical 

blocker 

See Figure 46 below. 

 

 0401-071 

Figure 46 

Receiver Installation Parts 

For the receiver installation, the following parts are optional: 

-  Background Luminance Sensor LM21. 
-  Support arm, mounting bracket and cable for LM21. 
-  Junction box with enhanced overvoltage protection for signal and AC 

lines (type TERMBOX-1200). 

-  Obstruction Light (type LT31OBS) . 

-  Enhanced weather protection hood (for details, refer to LT31 

Enhanced Weather Protection Hoods Installation Guide in section 
Related Manuals on page 16) 

 

Summary of Contents for LT31

Page 1: ...USER S GUIDE Vaisala Transmissometer LT31 M210667EN C...

Page 2: ...nical 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 Plea...

Page 3: ...1 Patent Notice 21 Trademarks 21 Warranty 21 CHAPTER 2 PRODUCT OVERVIEW 23 Description and Purpose 23 LT31 Key Features 23 Range Extension 23 Auto calibration 23 Auto alignment 24 Window Contamination...

Page 4: ...Battery Backup LTBB111 63 CHAPTER 4 INSTALLATION 67 Preparing Installation 67 Selecting Location 70 Unpacking Instructions 70 Unpacking Procedure 71 Storage 71 Equipment Grounding and Lightning Prote...

Page 5: ...Power Cables 128 Connecting Communication Cable to Receiver Interface Unit 128 Connecting Power Cable to Receiver Interface Unit 128 Switching on LT31 System 128 Double checking Transmitter Alignment...

Page 6: ...e 9 Service Raw Values 181 Message Sending Modes 181 Automatic Mode 181 Polled Mode 182 METAR Messaging 183 System Configuration 184 Default Factory Settings 185 External Sensors Optional 186 Backgrou...

Page 7: ...r Module LTL212 213 Replacing Main Transmitter Module LTL112 216 Replacing Main Receiver Module LTD112 218 Replacing Blower Unit LTB111 220 Replacing Battery in Case of Optional LTBB111 222 Replacing...

Page 8: ...ncy Advanced Command Level only 256 Movement Advanced Command Level only 258 Scanning Advanced Command Level Only 259 Receiver Response Time Advanced Command Level Only 260 CHAPTER 7 TROUBLESHOOTING 2...

Page 9: ...3 Block Diagram LTC112 55 Figure 24 Interface Unit Receiver LTI211 56 Figure 25 Power Supply FSP102 57 Figure 26 Master CPU LTC212 58 Figure 27 PWD Forward Scatter Sensor 59 Figure 28 Installed Backgr...

Page 10: ...117 Figure 77 Final Connector Position for Measurement Unit 117 Figure 78 Fastening Measurement Unit 118 Figure 79 Mounting PWD 118 Figure 80 Connecting PWD 119 Figure 81 Transmitter Unit LTT111 Wiri...

Page 11: ...nu 233 Figure 133 Optical Blocker Mounted on Receiver Support Unit 235 Figure 134 Offset Calibration 236 Figure 135 Visibility Calibration 237 Figure 136 Choosing MOR Reading 238 Figure 137 Visibility...

Page 12: ...User s Guide ______________________________________________________________________ 12 __________________________________________________________________ M210667EN C This page intentionally left blank...

Page 13: ...22 LT31 Transmitter Status Byte Number 29 168 Table 23 LT31 Transmitter Main Transmitter Module Byte Number 30 168 Table 24 LT31 Transmitter Window Transmitter Module Byte Number 31 169 Table 25 LT31...

Page 14: ...User s Guide ______________________________________________________________________ 14 __________________________________________________________________ M210667EN C This page intentionally left blank...

Page 15: ...al Information provides general notes for the product Chapter 2 Product Overview introduces the features advantages and the product nomenclature Chapter 3 Functional Description describes the function...

Page 16: ...s Guide M210542EN PWD12 User s Guide M210543EN PWD22 User s Guide M211276EN LT31 Enhanced Weather Protection Hoods Installation Guide Feedback Vaisala Customer Documentation Team welcomes your comment...

Page 17: ...s failure to comply with these requirements Note the following precautions WARNING To minimize the electrical shock hazard the Vaisala Transmissometer LT31 chassis must be connected to a good electric...

Page 18: ...tions dangerous voltages may exist even with the power cable disconnected To avoid injuries disconnect the power and discharge all circuits before touching them CAUTION The component boards including...

Page 19: ...equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures reorient the receiving antenna relocate the device with respect to the receiver...

Page 20: ...ve to be disposed of separately as electronics waste material 6 Remove the complete mounting plate including all electrical components from the interface units LTI111 and LTI211 They have to be dispos...

Page 21: ...ansmissometer LT31 are protected by associated patents Trademarks Microsoft Windows and Windows NT are registered trademarks of Microsoft Corporation in the United States and or other countries Warran...

Page 22: ...User s Guide ______________________________________________________________________ 22 __________________________________________________________________ M210667EN C This page intentionally left blank...

Page 23: ...ded for the configuration and monitoring of the multiple LT31 functions During assembly and maintenance a laptop with a VT100 emulation terminal program is needed for checking the system parameters an...

Page 24: ...front of the LT31 windows to reduce the amount of window contamination caused by precipitation Alignment Quality Control Based on the auto calibration and window contamination measurement the alignme...

Page 25: ...f Vaisala MITRAS and Impulsphysik SKOPOGRAPH The emulation of related serial data messages is also a standard feature Introduction to LT31 The Transmissometer LT31 measurement system consists of one L...

Page 26: ...1 Vaisala Transmissometer LT31 The following numbers refer to Figure 1 above 1 LT31 receiver unit 2 Receiver measurement head 3 Mast 4 Receiver interface unit 5 LT31 transmitter unit 6 PWD forward sca...

Page 27: ..._____________________________________________ Product Overview VAISALA _______________________________________________________________________ 27 1104 087 Figure 2 Receiver Unit LTR111 with LM21 Backg...

Page 28: ...smitter Unit LTT111 with PWD Forward Scatter Sensor Both these units contain a similar mast construction with an inner and outer mast tube The measurement unit of the transmitter and the receiver is m...

Page 29: ...t unit from mechanical influences due to solar radiation or wind load This results in optimized alignment stability The transmitter and receiver units are equipped with an interface unit that contains...

Page 30: ...CPU Support unit including the blower unit weather protection hood support arm cover and an optional obstruction light Receiver measurement unit includes Enclosure with window heater and enclosure co...

Page 31: ...Figure 5 above 1 Blower 2 Support arm 3 Inner mast tube 4 Weather protection hood 5 Mounting frame 6 Outer mast tube The support unit is mounted to the outer mast tube of the LT31 mast construction I...

Page 32: ...closure with a cover and air duct Window heater Optics unit with Measurement CPU board including a window receiver Window transmitter module Main transmitter module for the transmitter measurement hea...

Page 33: ...___________________________________________________ 33 0401 023 Figure 7 Measurement Unit Opened The following numbers below refer to Figure 7 above 1 Window heater 2 Window transmitter module 3 Optic...

Page 34: ...weather protection cover of the interface unit is split into two pieces The lower part covers the optional junction box and the upper part protects the interface unit electronics box The interface un...

Page 35: ...urement head terminal box LTB111 115 Blower unit 115 VAC version LTB111 230 Blower unit 230 VAC version LTI111 Interface unit transmitter Incorporates the power supply FSP102 Power supply LTAM250 LT31...

Page 36: ...ld climates with snow and frost LTEH211 115 Enhanced weather protection hood with heating 115VAC Enhanced weather protection hood for cold demanding climates with snow or ice storms LTEH211 230 Enhanc...

Page 37: ...able 6 LT31 Spare Parts for Options Code Common Name Description DMX501 Modem LM21F Background luminance sensor Complete spare unit LM21 spare parts Refer to LM21 User s Guide OBS24DSSP Obstruction li...

Page 38: ...User s Guide ______________________________________________________________________ 38 __________________________________________________________________ M210667EN C This page intentionally left blank...

Page 39: ...individual perceptive and interpretative abilities as well as the light source characteristics and transmission factors Any visual estimation of visibility is therefore subjective Human observations o...

Page 40: ...ce t and the threshold value of the luminance contrast The optical state of the atmosphere depends directly on meteorological conditions its basic parameter being the visual extinction coefficient Of...

Page 41: ...ween the light transmitter and the light receiver It makes an assessment of the mean extinction coefficient including both the scattering and absorption contributions to the measurement The LT31 provi...

Page 42: ...visibility readings above the auto calibration threshold typically 10 km The atmospheric situation is homogenous meaning that the deviation of the visibility reading is below a certain threshold for t...

Page 43: ...elow 0401 026 Figure 9 Alignment Mechanism The user must manually initiate the auto alignment sequence after the installation when the realignment is requested or after maintenance activities For more...

Page 44: ...Contamination In general precipitation increases the window contamination when the precipitation particles reach the transmissometer windows The long and narrow weather protection hoods of LT31 reduce...

Page 45: ...ectronics which are part of the measurement CPU board This principle is described in Figure 11 below LT31 uses the measurement CPU board s measurement for the following Measuring the real transparency...

Page 46: ...U main receiver module and window transmitter module PWD forward scatter sensor Background luminance sensor LM21 optional At least four of the intelligent units of the measurement system master CPU tr...

Page 47: ...n transmitter module window transmitter module and measurement CPU board including window receiver The measurement unit of the LT31 receiver unit is named LTM212 and consists of the following Measurem...

Page 48: ...he LT31 transmitter is named LTO112 see Figure 14 below 1104 089 Figure 14 Optics Unit Transmitter LTO112 The following numbers refer to Figure 14 above 1 Mounting chassis with an alignment mechanism...

Page 49: ...n 2 Window transmitter module 3 Measurement CPU including window receiver 4 Main receiver module Main Transmitter Module LTL112 The main transmitter module LTL112 is mounted to the optics tube of the...

Page 50: ...itter module is also equipped with a temperature measurement and EEPROM These components are connected to the measurement CPU through the IIC Bus interface Individual calibration parameters are stored...

Page 51: ...S 422 technology The measurement CPU circuitry converts the signal to TTL and then it is sent to the main receiver module With this technology it is possible to achieve an optimal signal to noise rati...

Page 52: ...mitter module LTL212 see Figure 20 below is mounted to the optics unit and is secured by two screws It is connected to the measurement CPU using two connectors 1104 093 Figure 20 Window Transmitter Mo...

Page 53: ...LTL212 is shown in Figure 21 below Transmitter LED Intensity Measurement Regulator Driver Temperature Measurement EEPROM CPU Transmitter Clock CPU Derating CPU Transmitter Intensity CPU CPU 0401 034 F...

Page 54: ...ransmitter approximately 250 Hz Modulation frequency generation for the main transmitter in case of transmitter configuration approximately 1 kHz Window receiver including the optics tube and adapted...

Page 55: ...ure Measurement EEPROM Power Supply Interface Enclosure Temperature Measurement WinReceiver Temperature Measurement 2 channel 20bit ADC Window Receiver Detector DC Measurement Window Transmitter Modul...

Page 56: ...LM21 and the transmitter interface unit LTI111 provides an interface and power supply for the PWD Forward Scatter Sensor The external power inputs and the communication interfaces of LT31 are located...

Page 57: ...y has been tested to sustain 2 kV level transient surges generated according to the EN 61000 4 5 testing standard According to the test results 2 kV level transient surges should not affect the operat...

Page 58: ...________________ M210667EN C Master CPU LTC212 The master CPU LTC212 see Figure 26 below is located in the receiver interface unit LTI211 0808 003 Figure 26 Master CPU LTC212 The CPU module is equippe...

Page 59: ...support arm of the LT31 transmitter unit It is used for auto calibration and for present weather detection optional 0401 043 Figure 27 PWD Forward Scatter Sensor The key functions of the PWD forward...

Page 60: ...itter The measurement CPU of the receiver Master CPU The master CPU is located in the interface unit of the LT31 receiver limit The main tasks of the master CPU are as follows Collect raw data from al...

Page 61: ...ensor offers the means for measuring ambient light level or background luminance in RVR applications The sensor is mounted to the LM21 support arm which is attached to the mast construction of the LT3...

Page 62: ...d surge protector device for AC power and signal line cables An AC power cable with a maximum diameter of 25 mm can be taken inside the termination box The connector contacts are proper for cable lead...

Page 63: ...11 The optional battery backup LTBB111 see Figure 30 on page 64 is installed in the interface units of LT31 transmitter and receiver unit A proper and fully charged battery ensures operation for a per...

Page 64: ..._______________________ M210667EN C 0401 041 Figure 30 Installed Battery Charger Module QBR101 The following numbers refer to Figure 30 above 1 Battery charger module QBR101 2 DC switch The battery is...

Page 65: ...______________ 65 0810 074 Figure 31 Installed Backup Battery The DC switch is used to interrupt the battery based power supply for storage transportation and maintenance of the instrument CAUTION Do...

Page 66: ...User s Guide ______________________________________________________________________ 66 __________________________________________________________________ M210667EN C This page intentionally left blank...

Page 67: ...ded to help you install this product NOTE If LT31 is equipped with enhanced weather protection hoods follow the instructions given in the document LT31 Enhanced Weather Protection Hoods Installation G...

Page 68: ...generate modem signal cabling layout and cable type 3 Order the construction materials and cables 4 Do the digging for the cables and foundation 5 Cast the concrete foundations 6 Prepare the cables C...

Page 69: ...upply of the interface unit 11 Finalize the receiver installation Install the receiver measurement unit Mount the optional LT31OBS Connect the optional LT31OBS Make intercommunication connections to t...

Page 70: ...ouch down or mid position the related location along the runway is defined by ICAO as well The typical measurement height must meet approximately 2 3 m above the runway surface level LT31 is prepared...

Page 71: ...rial optional Third box PWD forward scatter sensor Optional material is packed separately NOTE The case containing the optical parts should be handled carefully Do not drop either end of the case for...

Page 72: ...ng rod to the local grounding rods Depending on the need one to four copper sheathed steel rods are driven into the ground In case several rods are needed the alignment from the foot of the base plate...

Page 73: ...plying the power and signal cables and conduits for the cables In all field cabling the following should be remembered Use armored field cables Cables must be suitable for underground use Check the ca...

Page 74: ...e wire ends If a local terminal with the power supply of 115 230 VAC is not available an extended AC cable from LT31 to the nearest power source is needed This cable should be armored and suitable for...

Page 75: ...75 0210 026 Figure 33 TERMBOX 1200 Junction Box for Receiver 0210 021 Figure 34 TERMBOX 9000 Junction Box for Transmitter The distance between the equipment and the AC distribution transformer and th...

Page 76: ...es should be armored suitable for underground use and led to the equipment through conduits Unless the cables are armored they have to be led through pipes The signal cable shields should be grounded...

Page 77: ...cluding the plastic cylinder Slide the cap with the plastic cylinder onto the cable 4 Add shrinkable tubes to increase the cable diameter of thin cables diameters less than 5 mm 5 Slide the plastic cy...

Page 78: ...the line 50 m RS 232 RS 485 RS 485 modem only 300 bps 1200 m RS 485 modem RS 485 modem only 300 bps 1200 m Modem Modem only 300 bps Serial Communications Settings NOTE The default serial communication...

Page 79: ...232 VB VB RS 485 RS 485 9 10 11 12 Sensor line 12V Out GND 5 6 7 8 1 2 3 4 Reset Status RXD TXD Reset Button 0401 055 Figure 36 RS 232 Communication Option Serial Multipoint Transmission with RS 485...

Page 80: ...t line RS 232 RS 485 RS 485 18 19 Data line CTS RTS RXD TXD GND 13 14 15 16 17 Data line RS 232 VB VB RS 485 RS 485 9 10 11 12 Sensor line 12V Out GND 5 6 7 8 1 2 3 4 Reset Status RXD TXD Reset Button...

Page 81: ...long distance communications 10 km using a leased telephone grade cable Since the modem is not approved by the PTT Post Telephone and Telegraph it should not be used in public telephone networks Howe...

Page 82: ...1 22 23 24 25 26 27 Module modem modem Maint line RS 232 RS 485 RS 485 18 19 Data line CTS RTS RXD TXD GND 13 14 15 16 17 Data line RS 232 VB VB RS 485 RS 485 9 10 11 12 Sensor line 12V Out GND 5 6 7...

Page 83: ...kup switch if installed 0401 146 Figure 40 AC and Battery Backup Switch 2 Disconnect all the connectors from the LTC212 board 3 Open the four screws holding the cover plate and remove it see Figure 41...

Page 84: ...urself before attempting to touch the boards NOTE Do not let the boards get wet NOTE Note the correct orientation of the DMX501 module 6 After installing the DMX501 modem push the LTC212 board back to...

Page 85: ...ent identifiers For details see Chapter 5 Operation on page 145 When using the multipoint modem connection mode have the limited transfer capability of the 300 bps V 21 mode in mind For an example see...

Page 86: ...required The recommended dimensions for the foundations are illustrated in Figure 42 below This size generates sufficient space to place a ladder safely near the transmissometer transmitter and recei...

Page 87: ...st point towards the opposite foundation NOTE Set the foundation screws to ensure secure fixing of the equipment For the foundation screws the following tools are required Torque wrench size 24 Hammer...

Page 88: ...s and hammer them down until their edges are on the foundation level Recommended dowels HILTI HKD S M16 x 65 4 Use the HILTI tool HSD G M16 x 65 respectively a 14 mm mandrel bar and hammer the expandi...

Page 89: ...licon rubber so that no water can access the drilling hole 7 Tighten the foundation screws using the welded nut 60 Nm maximum 80 Nm 8 Check using the drilling template that the screw positions fit Mol...

Page 90: ...ect position has been found destroy the threads above and below them by hammering 2 Fix the drilling template to the upper ends of the foundation screws with six M16 nuts 3 Embed the assembly in the c...

Page 91: ...n VAISALA _______________________________________________________________________ 91 0906 095 Figure 45 LT31 Foundation Construction The following numbers and letter refer to Figure 45 above 1 Drillin...

Page 92: ...bling LT31 the following tools are required Screwdrivers sizes 3 1 6 x 10 Crosstip screwdrivers sizes 1 x 3 1 x 4 Wrenches sizes 40 24 20 18 17 Allen key hex socket sizes 3 4 5 Flat pliers Edge cutter...

Page 93: ...enance cable Optical blocker See Figure 46 below 0401 071 Figure 46 Receiver Installation Parts For the receiver installation the following parts are optional Background Luminance Sensor LM21 Support...

Page 94: ...eceiver mast on the prepared foundation screws The interface unit at the mast base must be oriented backwards from the baseline between the two installation places 4 Secure this preliminary mast posit...

Page 95: ...the instructions below Alternatively the enhanced weather protection hood if ordered part of the optional material is mounted according to a separate instruction For details see the document LT31 Enh...

Page 96: ...n hood 3 Fix the hoods with two screws hex socket head size 3 at each rear end corner of the hood See Figure 50 below 0401 073 Figure 50 Mounting Weather Protection Hood WARNING Death or serious injur...

Page 97: ...on of the support unit 6 Loosen the two fastening screws hex socket size 4 at the right side operator s view of the mast top The complete support unit must now be turnable See Figure 52 below 0401 076...

Page 98: ...210667EN C 0401 077 Figure 53 Aligning with Sight Hole 8 Fix the two fastening screws of the support unit at the mast top Mounting Optional LM21 Background Luminance Sensor LM21 is provided together w...

Page 99: ...Option Installed The following numbers refer to Figure 54 above 1 Transmissometer LT31 2 Background Luminance Sensor LM21F 3 Mounting bracket 4 Support arm 5 Fastener assembly To install the optional...

Page 100: ...rface unit 3 Route the open wire ends of the LM21 cable through the upper end of the LM21 support arm See Figure 56 below 1104 098 Figure 56 Routing LM21 Cable through LM21 Support Arm 4 Canalize the...

Page 101: ...onnector The following numbers refer to Figure 57 above 1 LM21 2 LM21 fastening screws 3 mounting bracket 4 connector of LM21 cable 6 Install the LM21 mounting bracket assembly to the LM21 support arm...

Page 102: ...________________________________________________________ M210667EN C 1104 100 Figure 58 Mounting LM21 to Support Arm The following numbers refer to Figure 58 above 1 LM21 2 Support arm 3 LM21 fastenin...

Page 103: ...runway end in approach direction is possible Direct sunlight into the sensor must be avoided Verify that no artificial light sources illuminate the LM21 in its viewing direction For details refer to B...

Page 104: ...ntal fine alignment is done using the rotation plate of the mounting bracket Loosen the two hex socket size 4 screws of the rotation plate rotate the LM21 as intended and tighten the rotation plate sc...

Page 105: ...ed The elevation angle should meet approximately 30 above the horizon Verify that no artificial light sources illuminate the LM21 in its viewing direction For details refer to Background Luminance Sen...

Page 106: ...______ 106 _________________________________________________________________ M210667EN C 1104 104 Figure 62 LM21 Vertical Alignment The following numbers refer to Figure 62 above 1 Mounting bracket 2...

Page 107: ...through one fitting cable feed through at the bottom of the box 11 The cable shield of the Background Luminance Sensor cable must be properly grounded into the cable gland See Figure 35 on page 77 12...

Page 108: ...Figure 64 Wiring of LM21 to Receiver Interface Unit The following numbers refer to Figure 64 above 1 Pink wire connected to Master CPU pin 9 2 Gray wire connected to Master CPU pin 10 3 Green wire co...

Page 109: ...ing parts are required Transmitter mast type LTT111 including the mounted interface unit type LTI111 at the mast base and support unit at the mast top Transmitter measurement unit type LTM112 Weather...

Page 110: ...complete mast construction by turning the nut below the base plate See Figure 48 on page 94 6 When the mast is aligned perpendicular secure the base plate again fix the nuts to ensure a stable mast p...

Page 111: ...unit at the mast top carefully The support unit will not be moved again 9 The sight must show now the measurement head of the receiver Otherwise the support unit position and or the vertical alignment...

Page 112: ...foundation nuts must be fixed as tight as possible to allow for a safe positioning of the mast A torque of 60 80 Nm is recommended Mounting Optional Obstruction Light LT31OBS 1 Place the ladder behind...

Page 113: ...Mounting LT31OBS 5 LT31OBS must be electrically connected to the power supply voltage inside the interface unit 6 Route the obstruction light cable inside the support unit below the blower system thr...

Page 114: ...nterface unit box See Figure 63 on page 107 10 Wire the cable through one cable feed through at the bottom of the box 11 Do the connection as shown in Figure 81 on page 120 12 Tighten the cable feed t...

Page 115: ...ut the transportation lock see Figure 73 below and remove it from the measurement unit Do not damage any of the module cables 0401 084 Figure 73 Cutting Transportation Lock 3 Finally remove the transp...

Page 116: ...ble must be routed below the small junction box near the blower 8 Make sure that the measurement unit has completely settled on the inner mast tube of the transmitter mast The air duct inlet on top of...

Page 117: ...om the support unit 11 Place the connectors at the rear of the support unit right side from the small junction box For an illustration see Figure 77 below 0401 097 Figure 77 Final Connector Position f...

Page 118: ...PWD to Support Arm 1 The ear on the support arm is foreseen for the mounting of the PWD Forward Scatter Sensor See Figure 79 below 0401 098 Figure 79 Mounting PWD 2 Use two hex socket screws size 5 w...

Page 119: ...ire the cables through the cable feed throughs at the bottom of the box 3 Make the connection of cables that are shown circled in Figure 81 on page 120 4 The interface unit of the transmitter must be...

Page 120: ..._______________________________________________________ M210667EN C 1104 106 Figure 81 Transmitter Unit LTT111 Wiring 5 Tighten the cable feed through carefully wind the rest of the cable length to a...

Page 121: ...rounding cable 4 mm2 to the grounding clamp at the left bottom side of the box See Figure 82 below 0401 102 Figure 82 Grounding Cable for TERMBOX 3 Screw the box onto the transmitter mast below the in...

Page 122: ...o the Vaisala TERMBOX 9000 see section Mounting and Connecting Optional TERMBOX 9000 Junction Box on page 121 or routed straight through the opening in the base plate of the mast and further into a lo...

Page 123: ...tical alignment of the mast have to be checked Probably a slight tilting of the mast is necessary due to foundation level differences 6 If the sight shows the measurement head of the transmitter the f...

Page 124: ...Loosen the two fastening screws at the side of the measurement unit flange hex socket size 4 See Figure 74 on page 116 6 Place the measurement unit on top of the inner mast tube windows pointing left...

Page 125: ...ox 3 Connect the cables that are shown circled in Figure 84 on page 126 4 The receiver interface unit must be connected to the two wire RS 485 module bus terminals 8 and 10 which connects all intellig...

Page 126: ...Guide ______________________________________________________________________ 126 _________________________________________________________________ M210667EN C 1104 107 Figure 84 Receiver Unit LTR111...

Page 127: ...rounding bolt at the base plate below the box The wrench size is 17 See Figure 82 on page 121 6 Use a short 3 conductor power cable 3 x 1 5 mm2 with free wire ends Connect this power cable to the corr...

Page 128: ...t the interface unit with the local junction box 2 Route the cable through a fitting cable feed through at the bottom of the interface unit 3 For details see section Communication Options on page 78 C...

Page 129: ...ion VAISALA ______________________________________________________________________ 129 0401 146 Figure 85 Power Supply Switches 0808 005 Figure 86 Power Supply LEDs The green LED on the master CPU LTC...

Page 130: ...s Guide ______________________________________________________________________ 130 _________________________________________________________________ M210667EN C 0806 038 Figure 87 Master CPU LTC212 L...

Page 131: ...R class 1 product do not stare directly into the bright light beam Double checking Transmitter Alignment 1 Place the ladder behind the receiver mast 2 The main bright transmitter light beam must be ob...

Page 132: ...S 232 serial interface can be used as a maintenance terminal for LT31 The maintenance cable QMZ101 included in the delivery provides a 9 pin D connector for the computer and a connector for LT31 The e...

Page 133: ...face The maintenance cable for Vaisala MILOS 500 can also be used but in this case the door of the receiver interface unit LTI211 must be opened and the original maintenance line connector in the LTC2...

Page 134: ...tion line 17 Data line RS 232 VB VB RS 485 RS 485 9 10 11 12 Sensor line 12V Out GND 5 6 7 8 1 2 3 4 Reset Status RXD TXD Reset Button 0401 120 Figure 91 Maintenance Line connector on LTC212 Settings...

Page 135: ...f no ID is configured LT31 answers as follows LT31 line closed For details see Chapter 5 Operation on page 145 Initial Settings Vaisala Transmissometer LT31 is typically interfaced to a host computer...

Page 136: ...ic mode message 2 interval 10 seconds Message port Data Baseline 30 m Sensor ID No ID set In multipoint communication where several sensors share the same communication line RS 485 Modem LT31 must be...

Page 137: ...stallation situation The default is 30 In terms of the system change LM sensor to the On position if Background Luminance Sensor LM21 is installed In terms of the system PWD Sensor must be switched on...

Page 138: ...installed NOTE To exit the MENU pages press ESC Checking Operation Pressing B on the keyboard on the MAIN MENU page gives access to the LT31 System Status page see Figure 94 below 0401 131 Figure 94...

Page 139: ...e final alignment see section Alignment on page 225 NOTE Always select Raw and Fine Alignment mode for the final alignment during installation Calibration As the achievable measurement signal depends...

Page 140: ...ansmitter Mounting Measurement Head Cover When the measurement head cover is attached to the support unit a special fast locking mechanism is utilized to secure the hood in its intended position using...

Page 141: ...nd align the lock screw so that the screw slot is in an upright position which ensures that the screw stud fits into the associated receptacle of the support unit see Figure 97 a below NOTE The figure...

Page 142: ...up before it can be removed from the support unit Closing Interface Units When all wiring activities are finalized and the cable feed throughs are carefully tightened the interface units can be close...

Page 143: ...y tools Hook in the upper interface unit cover by lowering the cover vertically so that the screws in the cover slide into the corresponding notches of the mast construction See Figure 100 below 0906...

Page 144: ...upper and lower interface unit covers 2 Remove measurement head cover 3 Remove measurement unit and store it carefully in a separate box 4 Remove weather protection hood 5 Store interface unit covers...

Page 145: ...e which is entered by the MENU command in the command line mode Other commands can be used to display the system status and other maintenance data All commands can be given either via the maintenance...

Page 146: ...n example of the command OPEN LT If there are other sensors on the line with the same ID the command mode of LT31can be opened by including the device type LT with the ID This command is similar to th...

Page 147: ...vel use the LEVEL 1 command The command prompt shows the current command set level For the user level it is 0 and for the advanced level it is 1 Command Completion The operator only needs to remember...

Page 148: ...EVENTS string page The reduced event list is given by separate pages HELP Lists available command HELPcommand Shows information about a specific command LEVEL 1 or LEVEL 1 password Changes the operati...

Page 149: ...age is directed to the Data port default SET MESSAGE PORT MAINTENANCE Message is directed to the Maintenance port SET MESSAGE PORT MODULE Message is directed to the optional communication module for e...

Page 150: ...e spaces SET PORT_TIMEOUT number Sets the command mode time out to 0 30 in minutes Zero disables the time out and the default is 10 minutes SET TERMINAL_LINES number Adjusts printouts used for termina...

Page 151: ...ckground luminance sensor LM21 data polling and photo switch reading in the LT31 system default SET CONTAMINATION_COMPENSATION LM OFF Disables the compensation function of LM21 SET CONTAMINATION_COMPE...

Page 152: ...ORT DATA The Second Message is directed to the Data port SET MESSAGE SECOND PORT MAINTENANCE The Second Message is directed to the Maintenance port SET MESSAGE SECOND PORT MODULE The Second Message is...

Page 153: ...message type for system testing purposes See section Fixed Test Messages on page 187 Terminal Line Adjustment The printout of the command response can be adjusted to the screen size of the used termin...

Page 154: ...n Line feed The response for the command is framed similarly see below LT1 LT31 RESPONSE CSUM where Start of heading LT1 Start of text LT31 RESPONSE Response of LT31 End of text CSUM Checksum End of t...

Page 155: ...ort Word16 Calculate CRC 16 value as used in LT31 protocol Word16 crc16 const unsigned char buf int len Word16 crc int i j crc 0xffff for i 0 i len i crc buf i 8 for j 0 j 8 j Word16 xmask crc 0x8000...

Page 156: ...ation the terminal height in lines used by the terminal application must be configured to LT31 with the command SET TERMINAL_LINES number minimum 24 In addition any line wrap and translate CR or CR LF...

Page 157: ...ader analog to SET HEADER B Configure identifier analog to SET UNIT_ID C Configure baseline length analog to SET BASELINE D Configure PWD sensor analog to SET PWD E Configure LM sensor analog to SET L...

Page 158: ...r in this case E for 9600 bps 0401 128 Figure 104 Configuration Menu Data Port Speed Free form Input In Figure 105 below the configuration is completed by giving a valid value for the message interval...

Page 159: ...le 15 on page 165 Alignment The Alignment menu offers a two step alignment Raw and fine alignment can be started or fine alignment separately For details see section Alignment on page 225 Calibration...

Page 160: ...in depth view to the transmitter and receiver units Raw data values are shown and a set of direct impact commands are available If the MENU command has been given at the user level the possibilities...

Page 161: ...event happened 0 years 0 months 0 days 4 hours 16 minutes and 33 seconds ago 31031436 The event occurred after 31 031 436 seconds of powered operation S An event can be Single Bad or Good A single ev...

Page 162: ...n page 180 LT31 also accepts MITRAS FD12 and Flamingo type of polling by the RVR computer when the emulation is on MESSAGE Command The MESSAGE command is used for displaying messages The command forma...

Page 163: ...5 Start of the text ASCII 2 6 VIS 10000 0 MOR value unit m 1 min average 18 AL 00000000000000000000 Alarm status of the LT31 system see Table 13 on page 164 42 BL 01000 Background luminance identifier...

Page 164: ...transmitter measurement CPU 33 LT31 transmitter misc 34 LT31 receiver status 35 LT31 receiver master CPU status 36 LT31 receiver main receiver module 37 LT31 receiver window transmitter module 38 LT31...

Page 165: ...ly to the above described default behavior it is possible to disable the use of PWD MOR in error situations The intended respective behavior can be configured using the PWD_MOR_ON_ERROR ON OFF command...

Page 166: ...see Table 17 below Table 17 LT31 Auto calibration Byte Number 24 Code Explanation Comment 0 OK 1 Auto calibration situation Auto calibration situation detected Auto calibration in process 4 Auto cali...

Page 167: ...Alignment Byte Number 26 Code Explanation Comment 0 OK 1 Automatic alignment in process 2 Reduced alignment quality level 1 3 Reduced alignment quality level 2 New fine alignment should be carried ou...

Page 168: ...ed in the transmitter measurement unit LTM112 of the LTT111 LT31 transmitter Table 23 LT31 Transmitter Main Transmitter Module Byte Number 30 Code Explanation Comment 0 OK normal operation 2 Light sou...

Page 169: ...it will lead to code 3 The byte shown in Table 25 below indicates the status of the measurement CPU LTC112 which is located in the transmitter measurement unit LTM112 of the LTT111 LT31 transmitter T...

Page 170: ...ode 2 occur at the same time it will lead to code 3 The byte shown in Table 27 below indicates the overall status of the LTR111 LT31 receiver unit Table 27 LT31 Receiver Status Byte Number 34 Code Exp...

Page 171: ...rect solar radiation 4 Hardware warning Internal monitoring alarm signal exceeded limit 8 Hardware error Examples Self test failed EEPROM and or temperature sensor failure NOTE The listed status codes...

Page 172: ...warning Internal monitoring alarm signal exceeded limit 8 Hardware error Examples EEPROM and or temperature sensor failure NOTE The listed status codes do not cover all possible cases Combinations ar...

Page 173: ...rror Hardware error C Communication error Device not responding X Not configured LT31 is not configured to handle PWD auto calibration is off The byte shown in Table 34 below indicates the status of t...

Page 174: ...M 999 TMP 23 4 AL 0 CSUM Start at Byte No Content Description 1 Start of the heading ASCII 1 2 LT LT31 sensor identifier 4 1 Unit identifier if the ID is not defined it is replaced by a space characte...

Page 175: ...check message which contains a short clear language report of the system status can be requested with the STATUS CHECK command The following is an example of a status message LT1 LT31 SYSTEM OK Statu...

Page 176: ...ed by a space character Start of the text MESSAGE BODY End of the text CSUM Checksum CRC16 End of the transmission CR LF The amount of characters in the message is approximately 975 The transmission t...

Page 177: ...LT31 also supports the message format frames and polling format of Vaisala Visibility Meter FD12 The FD12 polling format is accepted only when the FD12 message emulation is selected The FD12 polling f...

Page 178: ...format of the emulated Vaisala FD12 message number 7 is presented below Message with framing FD A 00 10000 10000 L 52 61 61 0 33 12 16 0 13 2 01000 Message contents 00 10000 10000 L 52 61 61 0 33 12 1...

Page 179: ...eceiver 1 status ___transmitter status ____S status heading background luminance value ___B background luminance heading _____ visibility m 1 min average ________V visibility heading ________unit ID o...

Page 180: ...FF BIT 7 8 CONSISTENCY OFF For example status 4101 means that I 4 BL sensor ON II 1 ON IV 1 ON In other words Background Luminance Sensor LM21 is set as the background luminance sensor Message 8 Flami...

Page 181: ...e cd m 2 _ln Et 104 _Visibility m _Transmission _STILBUS II indication _Header The total amount of characters in the message is 80 The transmission times are 2 7 s at 300 bps 10 bit char 0 33 s at 240...

Page 182: ...the LT31 system sends a data message when the host computer transmits a polling command The automatic message sending mode is disabled by setting the message interval to zero with the following comma...

Page 183: ...ats respectively METAR Messaging In order to support host systems in generating comprehensive Weather Reports LT31 is able to provide additional information on the prevailing weather situation When ME...

Page 184: ...zero ASCII 0x30 There is no crosscheck for whether the message interval and port settings are able to offer a bandwidth large enough to transmit all the data for example 300 bps 15 s LT31 message 9 M...

Page 185: ...t speed 9600 mode rs 485 data format 8n1 2nd port none 2nd type 0 maintenance port speed 9600 system modem off LM on PWD on 12V out off PW option enabled PWD Pitch 1 Internal Filter 1 Blow on WMO 0 He...

Page 186: ...O 0 PWD pitch 1 000 Internal Filter 1 00 Heat on Battery Yes Base Length 30 meters MOR Range 10 to 10 000 meters BL Range 1 to 100 000 cd sqm External Sensors Optional Background Luminance Sensor LM21...

Page 187: ...simulation off by giving the SIMULATE OFF command in the advanced level and then change the message type with the SET MESSAGE TYPE number command Turn the simulation on again by giving the SIMULATE TE...

Page 188: ...aracter and the E X end of the text character The message string must be given after the SIMULATE MANUAL_MESSAGE command in the following way SIMULATE MANUAL_MESSAGE string The LT31 sensor does not ma...

Page 189: ...in the Simulation menu To enter the Simulation menu it is necessary to open the maintenance terminal see section Entering and Exiting Command Mode on page 145 and then enter the menu driven operation...

Page 190: ...yping 1000 CR will change background luminance data to 1000 cd m2 Sequence A AL 0 Typing CR will keep the background luminance status data unchanged The summary of sequence data is displayed in Figure...

Page 191: ...The LT31 sensor does not make any validity checks to the sequence data contents As all messages do not have the capability to give all the defined data some message formats use only parts of the defin...

Page 192: ...____________________________ M210667EN C Flags for MOR and background luminance overrange are replaced by the first two characters of the overall status Other characters of the overall status are omit...

Page 193: ...ilt in self check processes will generate related status messages if any maintenance and or repair activity is required besides the periodic maintenance for example window cleaning or alignment Period...

Page 194: ...need to be cleaned occasionally either due to a window contamination warning see section Status Messages on page 261 or during the periodic maintenance In this frame the inner surface of the weather...

Page 195: ...isibility Calibration on page 238 Cleaning PWD Forward Scatter Sensor The structure of the PWD forward scatter sensor is explained in Figure 112 below 1 4 6 6 5 3 2 0401 121 Figure 112 PWD Hardware St...

Page 196: ...weather protection hood is free of ice or snow deposits 4 Wipe the dust from the inner and outer surfaces of the hoods NOTE Do not use any sharp tools to remove ice or snow from the hoods especially f...

Page 197: ...ance In this frame the inner surface of the weather protection hood should be cleaned as well To access the LM21 window no parts have to be removed 1 Wipe the window with a soft lint free cloth and no...

Page 198: ...nt housings of the transmissometer 1 Use a soft cloth and warm water with a household cleaning agent and clean especially the following Measurement head covers of the transmitter and receiver Masts an...

Page 199: ...d off the blowers of the receiver and transmitter Now a significant blower air stream must be noticeable in front of the window panes of the measurement units of the LT31 transmitter and receiver Duri...

Page 200: ...ow be removed See Figure 115 below 0401 166 Figure 115 Particle Filter 4 After checking and replacing the filter material the securing screw of the particle filter holder has to be tightened and the m...

Page 201: ...ver Repair Instructions Replacing Fuses The FSP102 Power Supply Board contains two glass tube fuses in the AC line in both the phase and return lines The secondary side of the transformer also holds t...

Page 202: ...__________________________________ M210667EN C 6 Turn the AC power switch back on and verify that both LEDs are lit on the FSP102 board to indicate that both output power supply lines are OK 5 0808 00...

Page 203: ...connect all the connectors carefully and re install the plastic protector shield properly 4 Turn on the AC power switch and also the battery backup switch if installed 5 Close the interface unit and m...

Page 204: ...t 5 Push the replacement LTC212 board back to its place and attach the two screws securing it into the correct position 6 Attach the cover plate by tightening the four screws holding it 7 Insert the c...

Page 205: ...212 Carry out the re assembling like described for LTC212 above Replacing Receiver Measurement Unit LTM212 To replace the complete receiver measurement unit the AC power has to be switched off first a...

Page 206: ...nt and calibration is finalized Replacing Transmitter Measurement Unit LTM112 To replace the complete transmitter measurement unit the AC power has to be switched off first and then the measurement he...

Page 207: ...urement unit and carry out the replacement on a clean workbench in a dry room To remove the complete receiver measurement unit the AC power has to be switched off first and then the measurement head c...

Page 208: ...tics unit should be mounted in parallel to the enclosure 6 Reconnect the three plugs at the rear end of the LTC112 board 7 Tighten the two fastening screws and the bolt carefully 8 The complete optics...

Page 209: ...ve the upper interface unit cover and open the interface unit with the provided key NOTE Switch the AC switch off before you proceed with the next steps In case of the optional LTBB111 switch the batt...

Page 210: ...t the rear end of the LTC112 board 7 Tighten the two fastening screws and the bolt carefully 8 The complete optics unit consists of fully adjusted and tested modules For that reason no adjustments are...

Page 211: ...ment unit the AC power has to be switched off first and then the measurement head cover has to be removed 1 Remove the upper interface unit cover and open the interface unit with the provided key NOTE...

Page 212: ...4 110 Figure 122 Fastening Screws of LTC112 CAUTION Handle the board carefully Do not touch the components on the board to avoid ESD damage to them Ground yourself before attempting to touch the board...

Page 213: ...age 232 15 Re install the measurement head cover and lock it carefully 16 Close the interface unit and mount the upper interface unit cover after fine alignment and calibration is finalized Replacing...

Page 214: ...following steps should be carried out in a closed room The measurement unit cover has to be opened carefully 1 Loosen the four fastening screws of the cover plate hex socket size 5 and remove the cove...

Page 215: ...he rear end of the LTC112 board 9 Tighten the two fastening screws and the bolt carefully 10 Close the measurement unit carefully Pay attention to the position of the cover seal 11 The repaired measur...

Page 216: ...s to be switched off first and then the measurement head cover has to be removed 1 Remove the upper interface unit cover and open the interface unit with the provided key NOTE Switch the AC switch off...

Page 217: ...nnect the cabling tighten the securing screw carefully and secure the cables with a cable tie Pay attention not to damage the optical tube of the main transmitter module while tightening the screw 4 T...

Page 218: ...for replacement purposes NOTE To replace the main receiver module LTD112 the measurement unit has to be opened For this reason it is highly recommended to dismount the complete measurement unit and c...

Page 219: ...air duct See Figure 72 on page 115 2 Loosen one hex socket set screw size 1 5 see Figure 125 below and remove the main receiver module from the optics unit Use an edge cutter to cut the cable tie care...

Page 220: ...onon page 232 10 Re install the measurement head cover and lock it carefully 11 Close the interface unit and mount the upper interface unit cover after finalizing fine alignment and calibration Replac...

Page 221: ...citor and particle filter Take care of the cable routing through the feed through hole in the support unit and the cable feed through of the junction box 8 Tighten the four blower fastening screws car...

Page 222: ...e fine alignment and calibration is finalized Replacing Battery in Case of Optional LTBB111 In case of the optional battery backup LTBB111 a battery loader module QBR101 and a 2 Ah battery are located...

Page 223: ...ery backup switch 8 Close the interface unit and mount the upper interface unit cover after exchange work is finalized Replacing PWD Sensor The PWD sensor is mounted to the support arm of the LT31 tra...

Page 224: ...upport arm at the LT31 receiver unit To replace the LM21 sensor the AC power has to be switched off first 1 Remove the upper interface unit enclosure and open the interface unit of the LT31 receiver u...

Page 225: ...rocedure is heavily supported by the Alignment menu To enter the Alignment menu it is necessary to open the maintenance terminal see section Entering and Exiting Command Mode on page 134 and enter the...

Page 226: ...All status information has to be read as OK for proper operation during the alignment During the raw alignment all axes of the transmitter or receiver measurement unit are set to the mid position When...

Page 227: ...r has to give a confirmation See Figure 129 below and the example below HAS THE TRANSPORT PROTECTION IN THE T R OPTIC UNITS BEEN REMOVED yes no To confirm type yes CR To abort the action type no CR As...

Page 228: ...image is exactly visible through the sight hole and if the measurement unit is turned in line with the support unit refer to Figure 53 on page 98 If this is not the case the receiver alignment has to...

Page 229: ...n the two fastening screws of the support unit lower two hex socket screws size 4 and turn the support unit slightly until the orientation is perfect 2 Tighten the support unit securing screws 3 Loose...

Page 230: ...ignal available one by one Indication of the process is given on the left of the menu On the right the current positions and the main receiver signal are changing according to the ongoing process In t...

Page 231: ...o the procedure in weather conditions that are stable without precipitation and with visibility above 10 km To make sure that the transport protection in the transmitter and receiver measurement unit...

Page 232: ...yes no To confirm type yes CR To abort the action type no CR Calibration The LT31 subsystems such as transmitter receiver measurement units and PWD sensor are calibrated at the factory As the achievab...

Page 233: ...Menu driven Operation on page 156 0401 136 Figure 132 Calibration Menu As shown in Figure 132 above the Calibration menu consist of three areas On the left side the available actions are displayed Pr...

Page 234: ...emaining Main Receiver signal as the offset value During the menu guided procedure the zero signal level offset without any receiver signal receiver optical system blocked and the signal level in acco...

Page 235: ...Least 20 Min yes no To confirm type yes CR To abort the action type no CR For offset calibration the optical path has to be blocked This will have to be done at the receiver location The user has to...

Page 236: ...clearance of the optical path Unblock Receiver Done yes no To confirm type yes CR To abort the action type no CR NOTE For a proper visibility calibration all the optical surfaces of the transmitter r...

Page 237: ...er 6 ______________________________________________________________ Maintenance VAISALA ______________________________________________________________________ 237 0401 139 Figure 135 Visibility Calibr...

Page 238: ...ill prompt for an extra input Give Observer s Visibility Estimation In Meter Type the value and terminate the input by pressing CR The new calibration data is displayed on the right side The new value...

Page 239: ...enu see Figure 137 below 0401 141 Figure 137 Visibility Calibration The taken Main Receiver Signal has to be linked to an MOR reading see Figure 138 below 0401 142 Figure 138 Choosing MOR Reading Type...

Page 240: ...When using the command line for visibility calibration it can only be performed on the advanced user level NOTE For a proper visibility calibration all the optical surfaces of the transmitter receive...

Page 241: ...he LT31 system maintenance port namely the PWD Sensor menu The menu is shown in Figure 139 below 0401 116 Figure 139 PWD Sensor Menu CLEAN Command After cleaning the optical surfaces of the PWD sensor...

Page 242: ...To calibrate the PWD sensor offset signal the optical path of the receiver has to be blocked When the optical path of the receiver is blocked the ZERO command can be executed The ZERO command does not...

Page 243: ...nd needs the Calibrator Signal Value which is printed on the opaque plates as a parameter Give Calibrator_Signal_Value Enter the Calibrator Signal Value and terminate the input by CR The PWD sensor re...

Page 244: ...n be given Enter the command string Enter the command and parameters and terminate the input by CR The PWD sensor response is displayed Spare Unit Init CAUTION When the PWD forward scatter sensor is r...

Page 245: ...r helpful to create visibility situations in order to evaluate or verify the measurement performance of the LT31 system Creation of visibility namely reduced transmittance can be done by applying opti...

Page 246: ...ceiver Support Unit The filter holder is able to hold up to three optical filters By combining optical filters a wide variety of filter values can be applied to the optical path 0401 120 Figure 143 Li...

Page 247: ...down and maximum up visibility compared to the current Measured data The 2 minutes Variation versus current Measurement is given only when the latest action entering the menu page applying the filter...

Page 248: ...holder is mounted to the receiver support unit and an optical filter has been chosen to be applied to the optical path the user has to give the filter value to the system Enter Filter Value e g 0 5 E...

Page 249: ...asured values are 1 minute averages After applying an optical filter the system needs its response time to handle the new situation NOTE The 2 minutes Variation versus current Measurement is given onl...

Page 250: ...topology the transmitter receiver measurement units are connected to the module bus and are thus hidden for user access For the users convenience a subset of commands for the measurement unit mainten...

Page 251: ...u on User Command Level 1104 114 Figure 147 Service Menu on Advanced Command Level Displayed Values All displayed values are updated every five seconds Every sub unit transmitter receiver measurement...

Page 252: ...tion Status Codes on page 164 Freq Advanced Command Level only Transmitter Generated Main Transmitter Modulation Frequency Receiver Detected Synchronization Signal Frequency This may differ from the g...

Page 253: ...ertical Position value 0 1023 hor Advanced Command Level only Horizontal Position value 0 1023 mRac Receiver only Advanced Command Level only Main Receiver AC value 0 1048575 Receiver Response Mode is...

Page 254: ...lower The blower can be switched on or off for the transmitter or receiver unit Select the command by pressing A The user has to select whether to handle the transmitter or receiver unit BLOWER R ECEI...

Page 255: ...ATER R ECEIVER T RANSMITTER The transmitter unit heater is selected by pressing T The receiver unit heater is selected by pressing R The user has to select whether the heater shall be switched on or o...

Page 256: ...tem Only trained or advised users shall use this feature The Main Transmitter Modulation Frequency can be increased decreased set to a fixed value or written to the EEPROM of the main transmitter modu...

Page 257: ...ansmitter measurement unit is able to realise due to the restricted frequency generator resolution The result can be read at the displayed values at Freq Example On the advance command level the Main...

Page 258: ...transmitter and receiver measurement unit have been removed The user has to give a confirmation HAS THE TRANSPORT PROTECTION IN THE T R OPTIC UNITS BEEN REMOVED yes no To confirm type yes CR To abort...

Page 259: ...moving any optics Make sure that the transport protection in the transmitter and receiver measurement unit have been removed The user has to give a confirmation HAS THE TRANSPORT PROTECTION IN THE T...

Page 260: ...command by pressing G The user has to select whether to switch the Main Receiver Response Time to slow or fast RECEIVER F AST S LOW The Main Receiver Response Time switched to fast by pressing F The M...

Page 261: ...erous voltage of 230 115 100 VAC Status Messages With each standard message Message 1 and 2 a 20 character overall status word is transmitted The overall status word describes the current status of th...

Page 262: ...errange MOR value is above upper MOR measurement range limit Normal operation A3 AutoCal autocalsituation Preconditions for auto calibration are valid A new auto calibration factor is build Normal ope...

Page 263: ...quality has been evaluated to be below level 2 Fine Alignment has to be carried out in short term range see section Alignment on page 225 LT31 system is able to cope this situation A12 Alignment redu...

Page 264: ...module wTdera wTint see section Service on page 250 Replace window transmitter module see section Replacing Window Transmitter Module on page 213 C6 Receiver Measurement CPU LTC112 window receiver AC...

Page 265: ...Execute Other Command STA on the PWD Sensor Menu see section PWD Sensor on page 241 and refer to PWD User s Guide P6 PWD not responding PWD Sensor does not respond to LT31 system polling request Chec...

Page 266: ...er LTL212 LED aged The derating value of the Window Transmitter LED has been evaluated as to be high Replacement of the Window Transmitter Module in mid term range see section Replacing Window Transmi...

Page 267: ...nge R20 Receiver Optics Unit LTO212 alignment mechanism horizontal overrange Position values are out of range for normal operation Check if movement of all axes is possible and position values are val...

Page 268: ...ee sections starting from Repair Instructions on page 201 R30 Receiver Optics Unit LTO212 alignment mechanism horizontal error R31 Receiver Optics Unit LTO212 alignment mechanism vertical error The Re...

Page 269: ...lue of Main Transmitter LED has been evaluated as to be off Replacement of the Main Transmitter Module is necessary see section Replacing Main Transmitter Module on page 216 T5 Transmitter Main Transm...

Page 270: ...of the Window Receiver Try to eliminate the influence T15 Transmitter Measurement CPU LTC112 window receiver AC off Window Receiver Signal is lower than the underrange level During start up this even...

Page 271: ...ce appropriate module see sections starting from Repair Instructions on page 201 T24 Transmitter Window Transmitter LTL212 EEPROM error T25 Transmitter Main Transmitter LTL112 EEPROM error T26 Transmi...

Page 272: ...ensor Check for proper cabling between Transmitter Measurement CPU and heating elements T34 Transmitter Unit LTT111 not responding Transmitter Unit does not respond to LT31 system polling request Chec...

Page 273: ...r switch is on and the LEDs on the FSP102 power board are lit and the status LED on the interface unit is blinking If the AC switch is on but no LED is lit check the fuses on the FSP102 board and veri...

Page 274: ...s blown Check and replace the blown fuse on the FSP102 board Status LED inside LTI211 is giving a fast flash instead of a long flash of 1 Hz LTC212 indicates an indication Check the content of the ind...

Page 275: ...name to identify the respective LT31 later on for example installation site code date and time c Use the OPEN respectively OPEN to enter the command mode see section LT Maintenance Interface on page 1...

Page 276: ...n of a technically competent person who can provide further information on the problem 3 On the Problem Report please explain What failed what worked did not work Where did it fail location and enviro...

Page 277: ...ine length 75 m baseline length Purchased option 25 m baseline length MOR measurement range 1 3 x baseline length to 10 000 m 1 2 x baseline length to 10 000 m 10 m to 10 000 m 25 m to 10 000 m 37 5 m...

Page 278: ...ice pellets 49 different codes from WMO 4680 code table Optical Specifications Table 39 LT31 Transmitter Optical Specifications Property Description Value Light source White Light Emitting Diode Cert...

Page 279: ...e line RS 232 Mechanical Specifications Table 42 LT31 Mechanical Specifications Property Description Value Dimensions h w d 1 2 685 mm 420 mm 1022 mm Weight Transmitter Unit LTT111 Receiver Unit LTR11...

Page 280: ...ce Verification Subject Standard Electrical Safety IEC 60950 22 EN 60950 22 A11 IEC 60950 1 EN 60950 1 UL 60950 1 Radiated Emissions CISPR 22 EN 55022 Conducted Emissions AC CISPR 22 EN 55022 Harmonic...

Page 281: ...extension One grounding cable Three frangible threaded mounting rods foundation screws with contraction area according to the extension pole length Mounting rod contraction diameter 8 mm for usage wi...

Page 282: ...Installing LTEP100 200 In this section LTEP100 200 specific installation instructions are given which replace the sections Setting up Receiver Mast to Foundation and Setting up Transmitter Mast to Fou...

Page 283: ...il their edges are on the foundation level Recommended dowels HILTI HKD S M16 x 65 5a Use the HILTI tool HSD G M16 x 65 respectively a 14 mm mandrel bar and hammer the expanding mechanism of the wedge...

Page 284: ...drilling hole 9 Tighten the frangible mounting rod foundation screws using the welded nut 60 Nm maximum 80 Nm 10 Make sure that the screw positions fit by using the drilling template Setting Up Recei...

Page 285: ...n pole base and top plate is oriented backwards from the baseline between the two installation places See Figure 157 on page 288 4 Secure this preliminary extension pole position Use a washer and nut...

Page 286: ...5 Vertical Extension Pole Alignment 7 When the extension pole is aligned perpendicular secure the base plate again and fix the nuts to ensure a stable mast position 8 If the level of receiver and tran...

Page 287: ...above WARNING Use only appropriate utilities to lift the LT31 for installation on extensions poles Take all necessary precautions to avoid any harm to involved personnel when lifting and mounting the...

Page 288: ...s Guide ______________________________________________________________________ 288 _________________________________________________________________ M210667EN C 1001 099 Figure 157 LTEP100 200 Install...

Page 289: ...Installation VAISALA ______________________________________________________________________ 289 The following numbers refer to Figure 157 on page 288 1 Extension pole LTEP100 200 2 Bolt M16x80 3 Washe...

Page 290: ...User s Guide ______________________________________________________________________ 290 _________________________________________________________________ M210667EN C This page intentionally left blank...

Page 291: ...ption 45 Heated weather protection hood 110 193 200 Host interface 59 I Installation 67 Installation procedure 85 Interface unit LTI111 55 Interface unit LTI211 55 Introduction to LT31 25 L Linearity...

Page 292: ...Return instructions 276 RVR system test commands 186 S Safety 16 Service 250 Software 60 Spare parts 36 Spare parts for options 37 Startup procedure 132 Status messages 261 Submenus 157 Alignment 159...

Page 293: ...___________________________________________________________________________INDEX VAISALA ______________________________________________________________________ 293 This page intentionally left blank...

Page 294: ...www vaisala com M210667EN...

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