Vaisala CT25K - Page 4

Ceilometer CT25K
User’s Guide CT25K-U059en-2.1
ii
4.4.1 Data Message No. 1 ...................................................................33
4.4.2 Data Message No. 2 ...................................................................36
4.4.3 Data Message No. 3 ...................................................................38
4.4.4 Data Message No. 4 ...................................................................39
4.4.5 Data Message No. 5 ...................................................................39
4.4.6 Data Message No. 6 ...................................................................39
4.4.7 Data Message No. 7 ...................................................................40
4.4.8 (Spare) .......................................................................................41
4.4.9 (Spare) .......................................................................................41
4.4.10 DMX611 operation (option) .........................................................41
4.4.11 Status Message "S" ....................................................................42
4.4.12 Manual Message.........................................................................45
4.5 Polling mode ................................................................................................45
4.6 Prevailing parameter settings.....................................................................46
4.7 Manual angle setting ...................................................................................47
5. FUNCTIONAL DESCRIPTION ................................................................................49
5.1 Theory of Operation.....................................................................................49
5.2 Technical Description..................................................................................53
5.2.1 General.......................................................................................53
5.2.2 LIDAR Measurement...................................................................55
5.2.3 Internal Monitoring and Control...................................................58
5.3 Module Descriptions....................................................................................58
5.3.1 Optical Subassembly CTB22.......................................................58
5.3.2 Laser Transmitter CTT21............................................................59
5.3.3 Receiver CTR21 .........................................................................60
5.3.4 Optics Monitor CTL21 .................................................................61
5.3.5 Board Frame DMF51 ..................................................................62
5.3.6 Processor Board DMC50B ..........................................................63
5.3.7 DC Converter DPS52..................................................................67
5.3.8 Ceilometer Interface Board DCT51 .............................................69
5.3.9 Line and Power Interface Subassembly CTP241 ........................70
5.3.10 Internal Heaters Subassembly CT25039.....................................72
5.3.11 Tilt Angle Sensor CT3675 ...........................................................73
5.3.12 Window Conditioner CT2614 / CT2688 .......................................74
5.3.13 Maintenance Terminal PSION3 (Option) .....................................75
5.3.14 Modem DMX55 (Option) .............................................................76
5.3.15 Modem DMX50 (Option) .............................................................78
5.3.16 DMX611 ANet

Interface (Option)..............................................80
5.4 Sky Condition Algorithm .............................................................................83
5.4.1 General.......................................................................................83
5.4.2 Option code ................................................................................83
5.4.3 Activation....................................................................................83
5.4.4 Algorithm overview......................................................................84
6. PERIODIC MAINTENANCE ....................................................................................87
6.1 Alarms and warnings...................................................................................87
6.2 Window Cleaning.........................................................................................87
6.3 Battery check ...............................................................................................88
6.4 Storage .........................................................................................................88
7. TROUBLESHOOTING ............................................................................................89
7.1 Normal Operation.........................................................................................89
7.1.1 Equipment ..................................................................................89