Vaisala LT31 User manual

USER'S GUIDE
Vaisala Transmissomete
r
LT31
M210667EN-C

PUBLISHED BY
Vaisala Oyj Phone (int.): [phone]
P.O. Box 26 Fax: [phone]
FI-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2011
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.
Please observe that this manual does not create any legally binding obligations for
Vaisala towards the customer or end user. All legally binding commitments and
agreements are included exclusively in the applicable supply contract or Conditions of
Sale.
N17728

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VAISALA ________________________________________________________________________ 3
Table of Contents
CHAPTER 1
GENERAL INFORMATION.......................................................................... 15
About This Manual ................................................................. 15
Contents of This Manual ..................................................... 15
Version Information ............................................................. 16
Related Manuals ................................................................. 16
Feedback............................................................................. 16
Safety....................................................................................... 16
General Safety Considerations ........................................... 16
Product Related Safety Precautions ................................... 17
ESD Protection.................................................................... 19
Recycling ................................................................................ 20
Regulatory Compliances ....................................................... 21
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 Measurement........................... 24
Contamination Prevention.............................................. 24
Alignment Quality Control .............................................. 24
Double-mast Construction ............................................. 24
LED Light Source........................................................... 24
Self-diagnostics.............................................................. 24
Compatibility................................................................... 25
Introduction to LT31............................................................... 25
Mast with Support Unit ........................................................ 30
Measurement Unit............................................................... 32
Interface Unit....................................................................... 34
Equipment Nomenclature...................................................... 35
CHAPTER 3
FUNCTIONAL DESCRIPTION..................................................................... 39
Operating Principles .............................................................. 39
Concept of Visibility............................................................. 39
Meteorological Optical Range............................................. 40
Visibility Measurement ........................................................ 41
Auto-calibration ................................................................... 41
Auto-alignment .................................................................... 42

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Alignment Quality Control....................................................43
Preventing Contamination ...................................................44
Measuring Window Contamination ................................44
Hardware Descriptions ..........................................................45
Measurement Unit LTM112/212..........................................47
Optics Unit LTO112/212.................................................48
Main Transmitter Module LTL112 ..................................49
Main Receiver Module LTD112......................................50
Window Transmitter Module LTL212 .............................52
Measurement Head CPU LTC112 .................................53
Interface Unit LTI111/211....................................................55
Power Supply FSP102 ...................................................56
Master CPU LTC212......................................................58
Present Weather Detector Forward Scatter Sensor............59
Software Descriptions............................................................60
Master CPU.........................................................................60
Measurement CPUs ............................................................60
Optional Equipment Descriptions.........................................61
Background Luminance Sensor LM21 ................................61
TERMBOX-1200/TERMBOX-9000 .....................................62
Obstruction Light LT31OBS ................................................62
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 Protection .................72
Cable Selection ...................................................................73
Line Power Cable ...........................................................74
Communication Cable....................................................76
Communication Options........................................................78
Serial Communications Settings .........................................78
Serial Transmission with RS-232 ...................................78
Serial Multipoint Transmission with RS-485...................79
Modem DMX501 (optional) .................................................81
Multipoint Modem Connection........................................85
Installation Procedure............................................................85
Foundation...........................................................................86
Dowel mounting..............................................................87
Molded Screw Mounting.................................................89
Preparing Assembly of LT31.................................................92
On-site Receiver Installation ...............................................92
Setting up Receiver Mast to Foundation........................94
Setting Up Weather Protection Hood to Support Unit....95
Mounting Optional LM21 ................................................98
On-site Transmitter Installation .........................................109
Setting up Transmitter Mast to Foundation..................110
Setting up Weather Protection Hood to Support Unit ..110
Foundation Level Differences ......................................111
Tilting Transmitter Mast...........................................111
Mounting Optional Obstruction Light LT31OBS...........112

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Mounting Transmitter Measurement Unit .................... 114
Mounting PWD to Support Arm.................................... 118
Connecting Signal Lines to Transmitter Interface Unit 119
Mounting and Connecting Optional TERMBOX-9000
(Junction Box) .............................................................. 121
Connecting Power Cable to Transmitter Interface Unit122
Finalizing On-site Receiver Assembly .............................. 123
Orientation of Support Unit .......................................... 123
Foundation Level Differences ...................................... 123
Tilting the Receiver Mast ........................................ 123
Mounting Optional Obstruction Light LT31OBS........... 124
Mounting Receiver Measurement Unit......................... 124
Connecting Signal Lines to Receiver Interface Unit .... 125
Mounting and Connecting Optional TERMBOX-1200
(Junction Box) .............................................................. 127
Connecting Communication and 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...................... 131
Startup Procedure ................................................................ 132
LT Maintenance Interface ................................................. 132
Connection to Maintenance Terminal .......................... 132
Settings for Maintenance Terminal .............................. 134
Entering and Exiting Command Mode ......................... 134
OPEN Command .................................................... 135
CLOSE Command .................................................. 135
Initial Settings.................................................................... 135
Checking Operation .......................................................... 138
Final Alignment ................................................................. 139
Calibration ......................................................................... 139
Finalizing Installation........................................................... 140
Mounting Measurement Head Cover................................ 140
Closing Interface Units ...................................................... 142
Mounting Interface Unit Covers ........................................ 142
Disassembly for Transportation ......................................... 144
CHAPTER 5
OPERATION............................................................................................... 145
LT31 Commands .................................................................. 145
Entering and Exiting Command Mode .............................. 145
OPEN Command ......................................................... 145
CLOSE Command ....................................................... 147
Available Commands ........................................................ 147
Command Completion ................................................. 147
Terminal Line Adjustment ................................................. 153
Command Polling.............................................................. 153
CRC16 Checksum ....................................................... 155
Menu-driven Operation........................................................ 156
Submenus ......................................................................... 157
Configuration................................................................ 157
Item List .................................................................. 158
Free-form Input ....................................................... 158
System Status .............................................................. 158

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Alignment .....................................................................159
Calibration ....................................................................159
Linearity Test................................................................159
Simulation.....................................................................159
PWD Sensor.................................................................160
Service..........................................................................160
Events...........................................................................160
Message Formats .................................................................161
MESSAGE Command .......................................................162
Message 1 - LT31 Standard Message ..............................162
Status Codes................................................................164
LT31 System ...........................................................164
Message 2 - LT31 Message Including PW Data
(optional)............................................................................174
Message 3 - Status Message............................................175
Message 4 - Vaisala System Standard Message .............176
Message 5 and 6 - FD12 Emulation..................................177
Message 5 - FD12 Message 2 .....................................177
Message 6 - FD12 Message 7 .....................................178
Message 7 - MITRAS Emulation.......................................179
Message 8 - Flamingo Emulation......................................180
Message 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
Background Luminance Sensor LM21.........................186
RVR System Test Commands .............................................186
Fixed Test Messages ........................................................187
Message 1....................................................................187
Message 2....................................................................187
Message 4....................................................................187
Message 5 - FD12 Message 2 Emulation....................187
Message 6 - FD12 Message 7 Emulation....................188
Message 7 - MITRAS Emulation..................................188
Message 8 - SKOPOGRAPH II Flamingo....................188
Manual Simulation Message .............................................188
Simulation Sequences.......................................................189
Message 1...............................................................191
Message 2...............................................................191
Message 4...............................................................191
Message 7 (MITRAS)..............................................191
Message 8 (SKOPO 2) ...........................................191
CHAPTER 6
MAINTENANCE..........................................................................................193
Periodic Maintenance...........................................................193
Cleaning Instructions.........................................................194
Cleaning LT31 Windows and Weather Protection Hoods.194
Cleaning PWD Forward Scatter Sensor............................195
Cleaning Lenses and Hoods ........................................195
Cleaning RAINCAP®....................................................197
Cleaning Window of Optional LM21..................................197

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Inspection and Cleaning Winter Dirt ................................. 198
Blower System .................................................................. 198
Checking Operation ..................................................... 199
Replacing Particle Filter ............................................... 199
Optional Heated Weather Protection Hoods..................... 200
Checking Operation ..................................................... 201
Repair Instructions............................................................... 201
Replacing Fuses ............................................................... 201
Replacing Power Supply FSP102..................................... 203
Replacing Master CPU LTC212........................................ 203
Replacing Optional Modem DMX501................................ 204
Replacing Receiver Measurement Unit LTM212 .............. 205
Replacing Transmitter Measurement Unit LTM112 .......... 206
Replacing Receiver Optics Unit LTO212 .......................... 207
Replacing Transmitter Optics Unit LTO112 ...................... 209
Replacing Measurement CPU/Window Receiver
LTC112.............................................................................. 211
Replacing Window Transmitter 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 PWD Sensor .................................................... 223
Replacing optional LM21 Sensor ...................................... 224
Alignment.............................................................................. 225
Raw and Fine Alignment................................................... 226
Fine Alignment .................................................................. 231
Calibration............................................................................. 232
Calibration Menu ............................................................... 233
Offset and Visibility Calibration ......................................... 234
Visibility Calibration ........................................................... 238
Command Line Calibration................................................ 240
Visibility Calibration...................................................... 240
PWD Sensor.......................................................................... 241
CLEAN Command............................................................. 241
ZERO Command............................................................... 242
CAL Command..................................................................243
CHEC Command .............................................................. 243
Other Commands.............................................................. 244
Spare Unit Init ................................................................... 244
Full Command Set Access................................................ 244
Linearity Test ........................................................................ 245
Service Menu ........................................................................ 250
Displayed Values .............................................................. 251
Transmitter/Receiver Measurement Unit ..................... 251
Blow ........................................................................ 251
Heat......................................................................... 252
Beep........................................................................ 252
Status...................................................................... 252
Freq (Advanced Command Level only) .................. 252
mRdc (Receiver only)
(Advanced Command Level only)........................... 252
mTint (Transmitter only)
(Advanced Command Level only)........................... 252
mTdera (Transmitter only)
(Advanced Command Level only)........................... 252

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wRdc (Advanced Command Level only).................252
wTint (Advanced Command Level only) .................252
wTdera (Advanced Command Level only)..............253
ver (Advanced Command Level only).....................253
hor (Advanced Command Level only).....................253
mRac (Receiver only)
(Advanced Command Level only)...........................253
wRac (Advanced Command Level only).................253
PWD Sensor.................................................................253
Visi...........................................................................253
WMO1min ...............................................................253
LM Sensor ....................................................................253
BGL .........................................................................253
Commands ........................................................................254
Blower...........................................................................254
Heater...........................................................................255
Beeper..........................................................................255
Frequency (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................................................................................261
Status Messages ..................................................................261
Miscellaneous Problems......................................................273
Technical Support ................................................................275
Return Instructions ..............................................................276
CHAPTER 8
TECHNICAL DATA ....................................................................................277
Operational Specifications ..................................................277
Optical Specifications..........................................................278
Electrical Specifications ......................................................279
Mechanical Specifications...................................................279
Environmental Specifications .............................................279
Electromagnetic Compatibility............................................280
APPENDIX A
OPTIONS INSTALLATION.........................................................................281
Extension Poles Installation................................................281
LTEP100/200 Extension Pole Unit....................................281
Prerequisites......................................................................281
Installing LTEP100/200 .....................................................282
Drilling Instructions.......................................................282
Setting Up Receiver/Transmitter Mast to Foundation .......284
INDEX .........................................................................................................291

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List of Figures
Figure 1 Vaisala Transmissometer LT31 ............................................... 26
Figure 2 Receiver Unit LTR111 with LM21 Background Luminance
Sensor ...................................................................................... 27
Figure 3 Transmitter Unit LTT111 with PWD Forward Scatter Sensor .. 28
Figure 4 Measurement Head.................................................................. 29
Figure 5 Support Unit ............................................................................. 31
Figure 6 Measurement Unit .................................................................... 32
Figure 7 Measurement Unit Opened ...................................................... 33
Figure 8 Interface Unit ............................................................................ 34
Figure 9 Alignment Mechanism .............................................................. 43
Figure 10 Window Contamination Prevention Principle ........................... 44
Figure 11 Window Contamination Measurement Principle ...................... 45
Figure 12 Communication Principle.......................................................... 46
Figure 13 Measurement Unit .................................................................... 47
Figure 14 Optics Unit Transmitter LTO112 .............................................. 48
Figure 15 Optics Unit Receiver LTO212 .................................................. 49
Figure 16 Main Transmitter Module LTL112 ............................................ 49
Figure 17 Block Diagram LTL112............................................................. 50
Figure 18 Main Receiver Module LTD112................................................ 51
Figure 19 Block Diagram LTD112 ............................................................ 52
Figure 20 Window Transmitter Module LTL212 ....................................... 52
Figure 21 Block Diagram LTL212............................................................. 53
Figure 22 Measurement Head CPU LTC112 ........................................... 53
Figure 23 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 Background Luminance Sensor LM21 ...................... 61
Figure 29 Installed Obstruction Light LT31OBS....................................... 63
Figure 30 Installed Battery Charger Module QBR101.............................. 64
Figure 31 Installed Backup Battery........................................................... 65
Figure 32 LT31 Equipment Grounding ..................................................... 73
Figure 33 TERMBOX-1200/Junction Box for Receiver ............................ 75
Figure 34 TERMBOX-9000/Junction Box for Transmitter ........................ 75
Figure 35 Cable Grounding Instruction .................................................... 77
Figure 36 RS-232 Communication Option ............................................... 79
Figure 37 RS-485 Communication Option ............................................... 80
Figure 38 RS-485 Option.......................................................................... 81
Figure 39 Modem Wiring .......................................................................... 82
Figure 40 AC and Battery Backup Switch ................................................ 83
Figure 41 Installing DMX501 .................................................................... 84
Figure 42 Casting Concrete Foundation .................................................. 86
Figure 43 Positioning Drilling Holes.......................................................... 88
Figure 44 Foundation Screws................................................................... 89
Figure 45 LT31 Foundation Construction................................................. 91
Figure 46 Receiver Installation Parts........................................................ 93
Figure 47 Foundation Screws................................................................... 94
Figure 48 Vertical Mast Alignment............................................................ 94
Figure 49 Tightening Nuts ........................................................................ 95
Figure 50 Mounting Weather Protection Hood ......................................... 96
Figure 51 Cable Routing for Optional Heated Hood................................. 96
Figure 52 Fastening Screws of Support Unit............................................ 97
Figure 53 Aligning with Sight Hole............................................................ 98
Figure 54 LT31 with LM21 Option Installed.............................................. 99

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Figure 55 Routing LM21 Cable through Mounting Bracket ....................100
Figure 56 Routing LM21 Cable through LM21 Support Arm ..................100
Figure 57 Installing LM21 to Mounting Bracket and Attaching
Connector ...............................................................................101
Figure 58 Mounting LM21 to Support Arm..............................................102
Figure 59 Coarse Horizontal LM21 Alignment........................................103
Figure 60 Securing Support Arm ............................................................103
Figure 61 LM21 Fine Horizontal Alignment ............................................104
Figure 62 LM21 Vertical Alignment.........................................................106
Figure 63 Opening Interface Unit Box ....................................................107
Figure 64 Wiring of LM21 to Receiver Interface Unit..............................108
Figure 65 Parts for Transmitter Installation.............................................109
Figure 66 Front Nut Adjustment to Tilt Mast...........................................111
Figure 67 LT31OBS Mounting Preparation ............................................112
Figure 68 Mounting LT31OBS ................................................................113
Figure 69 Cable Routing of LT31OBS....................................................113
Figure 70 Cable Hole below Interface Unit.............................................114
Figure 71 Cable Comb for Securing LT31OBS Cable............................114
Figure 72 Measurement Unit Cover Screws...........................................115
Figure 73 Cutting Transportation Lock ...................................................115
Figure 74 Fastening Screws of Measurement Unit ................................116
Figure 75 Height of Measurement Unit...................................................116
Figure 76 Parallel Position of Measurement Unit ...................................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 Wiring .............................................120
Figure 82 Grounding Cable for TERMBOX ............................................121
Figure 83 LT31 System Wiring with TERMBOX Option .........................122
Figure 84 Receiver Unit LTR111 Wiring.................................................126
Figure 85 Power Supply Switches..........................................................129
Figure 86 Power Supply LEDs................................................................129
Figure 87 Master CPU LTC212 LEDs ....................................................130
Figure 88 Measurement Unit LEDs ........................................................131
Figure 89 External Maintenance Line Connector ...................................132
Figure 90 LT Maintenance Interface.......................................................133
Figure 91 Maintenance Line connector on LTC212 ...............................134
Figure 92 Main Menu..............................................................................136
Figure 93 Configuration Menu ................................................................137
Figure 94 System Status.........................................................................138
Figure 95 Lock-Screws at Measurement Head Cover............................140
Figure 96 Receptacle Inside the Measurement Head Cover..................140
Figure 97 Using Lock Screws at Measurement Head Cover..................141
Figure 98 Interface Unit Locks................................................................142
Figure 99 Lower Interface Unit Cover.....................................................143
Figure 100 Hooking-in Upper Interface Unit Cover ..................................143
Figure 101 Upper Interface Unit Cover.....................................................144
Figure 102 Main Menu..............................................................................156
Figure 103 Configuration Menu ................................................................157
Figure 104 Configuration Menu: Data Port Speed ...................................158
Figure 105 Configuration Message Interval..............................................158
Figure 106 Status Menu............................................................................159
Figure 107 Event Log................................................................................160
Figure 108 Event Log: Reduced List ........................................................161
Figure 109 Simulation Menu.....................................................................189
Figure 110 Summary of Sequence Data ..................................................190
Figure 111 LT31 Windows........................................................................194