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CT25K User Guide in English

1. 128 Receiver CTR241 ndo need 132 Removal eder D er ERE Ee ats 132 Replacement sss 134 Coaxial Cable 136 actuum 136 137 Compensation nnn 138 Compensation Fiber 138 Optics Monitor CTL214 139 REMOVAL PE 139 memet 140 Boards of Board Frame DMF 51 141 Removing 141 Replacing 142 Parameter Settings of Ceilometer Interface Board DCT52142 Line amp Power Subassembly 241 143 Renmioval een dert e ats 143 User s Guide Replacement ed nete 144 Internal Heater Subassembly CT25039 Replacement 145 Battery 4592 Replacement Instructions 147 Getting Help 5 148 Return 149 CHAPTER 9 TECHNICAL DAT 5 151
2. 39 VAISALA User s Guide User Commands eeeeeseeseeeeeseee ennt nnne 41 Data Messages erret eet ect cte rne oerte 45 Data Message No 1 46 Data Message No 2 48 Data Message No 3 51 Data Message No 4 52 Data Message No 5 52 Data Message No 6 52 Data Message No 7 54 Status Message S pm t Mene REED Mazes 55 Manual Message eiie b et tied etate 58 Pollino Mode eraran nhe 58 Prevailing Parameter Settings eeeeee 59 Manual Angle Setting 61 CHAPTER 5 FUNCTIONAL DESCRIPTION 63 Theory of Operation eese nnn 63 Basic Principle of Operation 63 Practical Measurement 63 Noise Cancellation ssssssssseeeee 64 Return Signal Strength 65 Height Normalization seen 65 The Backscatter 66 Extinction Normalization and Vertical Visibility 67 Technical Description 68 General 552 5 eto eaa ite eq EE 68 LIDAR Measurement
3. sss 70 Internal Monitoring and 73 Module Descriptions 74 Optical Subassembly 22 74 Description zs etie ten aoi oie ae 75 Laser Transmitter CTT21 sessssssssssseee 76 Description eniin 76 Easer Safety eun ime te ei ties 7T Receiver CT R21 iscsi dnte teen gea 77 Optics Monitor 21 78 Board Frame 51 79 Processor Board 5 82 PrOCeSSOEF teh ee ut e toiture cumin 83 A to D Converter e e aa aan aean a baaaie 83 Serial Communication 83 Technical Information 84 DC Converter DPS52 sss 85 Ceilometer Interface Board 52 89 Line and Power Interface Subassembly CTP241 90 Internal Heaters Subassembly CT25039 92 Tilt Angle Sensor CT3675 94 Window Conditioner CT2614 2688 96 Maintenance Terminal 97 Modem DMX55 98 Modem 5
4. Open the command set by first typing OPEN JJ at the command prompt and then typing the password ADVANCED JI Interrupt autoadjustments with the command STOP I Then give the following commands SET PORT TIMEOUT 204 Sets the timeout of the dialog to 20 minutes SET DATA INTERVAL 154 Sets minimum measurement interval Give the command GET STATUS J Wait until the SENS parameter under the title Receiver in the status message gets a value It may take a couple of minutes because the automatic receiver self check 15 performed during the fourth measurement cycle Check that the SENS value is OK The receiver sensitivity tells you the present measured receiver value compared to the factory setting If the SENS value is OK the receiver installation is ready and you can skip steps g and h If the SENS value is not within range i e FAIL is shown type the following command GET VALUE OTHERS RECVALUE J which prints the measured receiver test value and the value compared to the present factory setting in on your screen Note the RECEIVER TEST VALUE and write it down Then give a new receiver factory value with the command SET FACTORY RECVALUE and type the recent value first value of the two NOT the percentage of the output RECEIVER TEST VALUE 135 User s Guide WARNING h Wait until a few measurement cycles have been completed Give the command GET STATUS J Check in the status message the
5. Introduction to CT25K Ceilometer VAISALA Ceilometer CT25K measures cloud heights and vertical visibilities The small and lightweight measurement unit suits well for mobile operation The CT25K Ceilometer employs pulsed diode laser LIDAR technology LIDAR Light detection and ranging where short powerful laser pulses are sent out in a vertical or near vertical direction The reflection of light backscatter caused by haze fog mist virga precipitation and clouds is measured as the laser pulses traverse the sky The resulting backscatter profile i e signal strength versus height is stored and processed and the cloud bases are detected Knowing the speed of light the time delay between the launch of the laser pulse and the detection of the backscatter signal indicates the cloud base height The CT25K is able to detect three cloud layers simultaneously Besides cloud layers it detects whether there is precipitation or other obstructions to vision No adjustments in the field are needed The embedded software includes several service and maintenance functions and gives continuous status information from internal monitoring The software is designed to give the full backscatter profile 17 User s Guide 18 Figure 1 CT25K Ceilometer The following numbers refer to Figure 1 above 1 Shield 2 Measurement Unit 3 Pedestal 0208 065 M210345en A Chapter 2 Product Nomenclature VAISALA Prod
6. Height Bin width 0 5000 ft 100 ft 5000 15000 ft 500 ft 15000 25000 ft 1000 ft 103 User s Guide 104 The counts are summed starting from the lowest bin The bins where the sum exceeds 1 33 3 8 5 8 and 7 8 of the maximum value are recorded as layer heights The corresponding cloud amounts for these layers are 1 3 5 and 7 oktas In addition the minimum number of counts hits for each layer has to be exceeded Table 14 Minimum Number of Counts Hits for Each Layer 1st layer 17 3 4 hits 2nd layer 10 2 hits 3rd layer 25 5 hits 4th layer 25 5 hits In case the minimum count is not exceeded in the assigned bin the algorithm seeks three bins upwards and then three bins downwards if one of these bins has the required number of counts However if none of the bins contains enough counts the original bin is used as the layer height If the resulted layers are close to each other it is reasonable to combine them rather than define them as separate layers If the distance between two cloud layers is less than the minimum distance shown in Table 15 below the layers are combined The height of the combined layer is that of the lower layer and the cloud amount of the combined layer is that of the upper layer Table 15 Minimum Distance Between Different Cloud Layers Layer Height Minimum Distance 1 000 ft 100 ft 1 000 2 000 200 ft 2 000 3
7. 17 kg 37 Ib 10 kg 22 Ib 8 kg 17 Ib 13 kg 28 Ib 1170 x 740 x 430 mm 46 x 29 x 17 in 51 kg 111 Ib 1240 x 760 x 450 mm 49 x 30 x 18 in 70 kg 152 Ib 151 User s Guide 152 External Connector J1 Window conditioner Table 20 Window Conditioner Property Description Value Connector J1 Type Binder series 693 09 4228 00 07 female Mating connector type Type Binder series 693 99 4225 70 07 7 pin male elbow External Connector J2 Power input Table 21 Power Input Property Description Value At nominal line voltage 100 115 230 V Power consumption typical Total 365W Measurement unit 15W Internal heater 120W Window conditioner heater 200 W Window blower 30W Frequency 45 65 Hz Power connector J2 Type Binder series 693 09 4223 00 04 4 pin male Mating connector type Type Binder series 693 99 4222 70 04 female elbow No break power supply 12V Sealed Lead Acid Battery 2 1 Ah Overvoltage Protection Low press filter VDR Output Interface The data port can operate according to the following serial line standards RS 232 RS 422 RS 485 multidrop 2 wire 4 wire M210345en A Chapter 9 Technical Data The data port can also be operated through DMX55 and DMX50 modems The maintenance port is an RS 232 serial line except when the data line is set to RS 422 or RS 485 then the maintenance line voltage lev
8. 250 mV 25 mV 7 5 mV Filtering By hardware software or both Serial Communication Ports Multistandard Ports 2 configurable ports to comply with RS 232D RS 422 RS 423 and RS 485 or MIL STD 188 114 standards Data Port P8 Maintenance Port P7 Data Transfer Rate 110 to 19 200 baud 300 to 9600 baud used in CT25K Programmable rate frame handshake and port standard Electrostatic Discharge Protection 8 kV per each port pin Overvoltage protection Bipolar 30 A 1 ms TRANSZORBS Environmental specifications Temperature Humidity Vibration Electromagnetic compatibility Conducted emissions Conducted susceptibility Conducted susceptibility Radiated emissions MIL STD 810D 501 2 amp 502 2 50 C to 70 C MIL STD 810D 507 20 to 100 RH not condensing IEC 68 2 6 Fc 10 500 Hz up to 2 2 g IEC 801 4 MIL STD 461C CE03 MIL STD 461C CS02 power leads IEC 801 4 fast transient burst MIL STD 461 REO2 Radiated susceptibility MIL STD 461 RS03 See Figure 21 on page 85 and Table 11 on page 85 for DMC50 DIP switch settings M210345en A Chapter 5 Functional Description 9502 042 Figure 21 DIP Switch Settings of the DMC50 Table 11 DIP Switch Settings of the DMC50 Board Switch Switch Function Position Setting DMC50 52 1 OFF Disconnect digital GND from CASE
9. 35 Character code CLOSE command Coaxial cable Removal Replacement Compensation adjustments Compensation fiber Replacement Contrast threshold CPU Board CT VIEW D Data messages Data message No Data message No Data message No Data message No Data message No Data message No Data message No Status message S DC Converter DPS52 Internal switch settings LED functions Output voltages Specifications Detector Digital display DD50 E EEPROM Electrostatic discharge Environmental conditions ESD External connections External connector J1 External connector J2 NOOR INDEX 159 User s Guide External connector J3 153 External connector J4 155 Extinction coefficient 66 Extinction normalization 67 F Failure diagnosis 119 Fiberglass pedestal 151 Focal length 157 Foundation screws 23 Frame DMF51 79 G GET GET ALGORITHM 59 GET DATA AQC 60 GET FACTORY 60 GET MESSAGE 60 GET OPER MODE 61 GET PORT 61 GET STATUS 55 61 GET UNIT ID 61 GET command 35 H Hard target test 115 Height normalization 65 Infrared interference filter 72 Internal heaters subassembly CT25039 92 Internal voltages 56 Inversion 67 L Laser 156 Laser classification 156 Laser diode 76 Laser safety 77 Laser transmitter CTT21 76 Removal 124 Replacement 125 Specifications 156 Technical description 76 Letter case in commands 40 LIDAR 17 70 89 Lidar equation 65 LIDAR measurement 70 Lidar ratio 66 Line amp
10. 9 Attach the cables to External Connectors J1 J4 10 Turn the Ceilometer to vertical position and tighten the screws of the pedestal 11 Verify that the Ceilometer is operating properly Internal Heater Subassembly CT25039 Replacement 1 Remove the following connectors Optics Monitor CTL21 connector P2 Laser Transmitter CTT21 connector P3 Receiver CTR21 connector P1 Coaxial Cable CT3696 connector P1 VAISALA 145 User s Guide 2 Take a good hold on the CTB22 Optical Subassembly from the black part with one hand Do not touch the transmitter receiver or the black cone on the opposite side of the receiver Open the two screws shown in Figure 38 on page 147 using a 6 mm hex key with the other hand 3 Carefully remove the optics subassembly Do not touch the compensation fiber Place the optics subassembly carefully on the table so that the laser transmitter and the receiver do not touch the table 4 Open the four nuts at the corner of the internal heater Disconnect the wires and replace the heater with a new subassembly 6 Assemble CTB22 Optical Subassembly and cables back in their original positions 146 M210345en A Chapter 8 Repair 9805 011 Figure 38 Internal Heater Replacement Battery 4592 Replacement Instructions 1 Open the screw from the ba
11. M210345en A Chapter 5 VAISALA Functional Description All voltage and two temperature channel measurements along with several internal and external functions are controlled by a two wire serial 2 bus Identification and other board specific parameters are also saved in EEPROM via this bus The internal battery charger keeps the sealed lead acid battery in maximum charge and ready for power back up The battery is charged in four phases or states trickle charge while battery voltage is below normal bulk charge while battery is charged with maximum current over charge while battery voltage is raised over its temperature compensated level float charge charge is complete and battery voltage is floating at the temperature compensated level LED functions Two LEDs are located in the upper part of the front panel POWER OK LED D2 is lit when battery circuit is connected and charge is at least in bulk charge state and all voltages are ok ACCESS LED D1 is lit every two seconds indicating a voltage channel read cycle Internal switch settings The following table describes the internal switch settings of DPS52 For normal operation all switches shall be OFF Switch Switch Function Switch Function position setting s w controlled setting manual 51 1 OFF Not used ON Not used 1 2 OFF Digital analog voltages ON ON Digital analog voltages OFF 1 3 OFF 5
12. The message is meant mainly for testing and maintenance purposes The internal diagnostics part of the Status Message can also be displayed by giving the command GET STATUS An example of the status message is presented below Line Characters d CTA3880Q l 1 11 ow 00400200 2 31 VOLTAGES UNIT 0 1V JJ 3 22 P12 125 M12 126 P5G 54 M5G 54 VCA 2254 4 41 P13 128 M13 124 P5R 50 M5R 50 BAT 098 5 41 P18 178 PHV 2306 17 P65 674 CHA 144 6 41 d 7 2 RECEIVER TRANSMITTER 8 27 GAIN H PLEN Ld 9 22 BAND N POTY 64K l 10 24 SAMP 10MHz OUT 1416mV l 11 27 SENS OK SENS 101 12 25 COMP 013 125 IN 1901 13 24 d 14 2 TEMPERATURES ENVIRONMENT 15 27 BLOWER 20C WINDOW 210mV 102 16 36 CPU 34C RADIANCE 60mV 17 31 LASER 29C ANGLE 3DEG M 2 18 35 LENS 34C HUMIDITY NONE 19 29 OUTSIDE 23 20 14 INHEATER ON OUTHEATER OFF BLOWER OFF l 21 39 8 22 3 Total554 characters NOTE An asterisk in front of a variable indicates that an alarm or warning limit of that variable is exceeded In the example above the battery voltage is too low M is shown after the ANGLE value only if the manual angle setting is used VAISALA 55 User s Guide 56 Interpretation of the status message is as follows IST LINE Identical to that of message no 1 except that the second to last character which identifies the message number is always S 2ND LINE Identical to that of message no 1 LINES 3
13. 9600 bits s modem mode with error correction and data compression V 22bis V 42bis SET PORT DATA INTERFACE RS232 Use RS 232 serial line SET PORT DATA INTERFACE RS422 Use RS 422 4 wire serial line SET PORT DATA INTERFACE RS485_2W Use RS 485 2 wire serial line SET PORT DATA INTERFACE RS485_4W Use RS 485 4 wire serial line SET PORT DATA BAUD B300 Set data port serial line baud rate to 300 SET PORT DATA BAUD B1200 Set data port serial line baud rate to 1200 SET PORT DATA BAUD B2400 Set data port serial line baud rate to 2400 SET PORT DATA BAUD B4800 Set data port serial line baud rate to 4800 SET PORT DATA BAUD B9600 Set data port serial line baud rate to 9600 SET UNIT ID 0 2 Unit identifier Alphanumerical character for message and polling identification GET ALGORITHM Print values of algorithm parameters GET DATA ACQ Print settings of data acquisition GET FACTORY Print values of factory settings GET INFO Print identifying information for this equipment configuration GET MESSAGE Print message setting GET OPER MODE Print operating mode GET OPTIONS Print installed modem and active options GET PORT Print values of port setting GET STATUS Print STATUS message GET UNIT 1 Print unit identification string GET VALUE OTHERS ANGLE Print value of tilt angle sensor range 15 90 degr
14. 999 146 Window contamination millivolts at internal ADC input 0 2500 2 Tilt angle degrees from vertical 15 90 621 background light millivolts at internal ADC input 0 2500 7 Measurement Dune pulse Long Short freq F const pulse qty 47 1 gain High Low bandwidth Narrow Wide sampling 10 20 MHz 139 SUM of detected and normalized backscatter 0 999 Multiplied by scaling factor times 104 At scaling factor 100 the SUM range 0 999 corresponds to integrated backscatter 0 0 0999 srad 1 4TH 19TH LINE Backscatter profile sensitivity and range normalized at 100 ft 30 m resolution normally scaled to units of 10000 srad km Example of 8th line 064FDFDFDFDFDFCFCFCFCFCFCFCFCFBFBFBFBFBFBFBFAFBFAFBFBFAFAFBFAF9FAF9 lt where 064 Is start distance height of line backscatter data items decimal unit is 100ft 30m 200ns two way FDFC FBFA Are 16 four character data items per line at 100ft 30m 200ns resolution 16 bit HEX ASCII msb nibble and bit first 2 s complement Data is range and sensitivity normalized backscatter units 10000 srad km unless otherwise scaled by parameter SCALE 20TH LINE Od End of Text and CRLF M210345en A Chapter 4 VAISALA Operation Data Message No 3 This message contains a line which has one bit for each range gate at 100 ft resolution It is intended for printer type black and white graphical rec
15. CEILO gt GET STATUS 4l Status format example VOLTAGES UNIT 0 1V P12 125 M12 126 P5G 54 56 54 VCA 225 P13 128 124 P5R 50 M5R 50 BAT 098 P18 178 PHV 2306 PFB 17 P65 674 CHA 144 RECEIVER TRANSMITTER GAIN H PLEN L BAND N POTY 64K SAMP 10MHz OUT 1416mV SENS OK SENS 101 TEMPERATURES ENVIRONMENT BLOWER 20C WINDOW 210 mV 101 CPU 34C RADIANCE 60 mV LASER 29C ANGLE 3 DEG LENS 34C HUMIDITY NONE OUTSIDE 23C M210345en A Chapter 7 Troubleshooting INHEATER ON OUTHEATER OFF BLOWER OFF NOTE If there are variables showing xxx values in the status message the power up routines are not finished Wait for a while and ask for the status again VAISALA 6 Check the status message All the VOLTAGES RECEIVER and TRANSMITTER values are within predefined limits if no asterisks appear An asterisk in front of a variable indicates that an alarm or warning limit of that variable is exceeded In the status example above the battery voltage is too low Check the TEMPERATURES The OUTSIDE temperature should be close to the environment temperature The CPU LASER and LENS temperatures are typically 10 15 degrees higher than the OUTSIDE temperature Compare the ANGLE If the ceilometer is in a vertical position i e pointing upwards the ANGLE should be 2 2 degrees 7 Check the message line operation Give the commands SET MESSAGE PORT MAINTENANCE l CLOSE The followin
16. ESD can cause immediate or latent damage to electronic circuits Vaisala products are adequately protected against ESD for their intended use However it is possible to damage the product by delivering electrostatic discharges when touching removing or inserting any objects inside the equipment housing To make sure you are not delivering high static voltages yourself Handle ESD sensitive components on a properly grounded and protected ESD workbench When this is not possible ground yourself to the equipment chassis before touching the boards Ground yourself with a wrist strap and a resistive connection cord When neither of the above is possible touch a conductive part of the equipment chassis with your other hand before touching the boards Always hold the boards by the edges and avoid touching the component contacts VAISALA 15 User s Guide Warranty 16 For certain products Vaisala normally gives a limited one year warranty Please observe that any such warranty may not be valid in case of damage due to normal wear and tear exceptional operating conditions negligent handling or installation or unauthorized modifications Please see the applicable supply contract or conditions of sale for details of the warranty for each product M210345en A Chapter 2 CHAPTER 2 Product Overview PRODUCT OVERVIEW This chapter introduces the CT25K Ceilometer features advantages and the product nomenclature
17. Switch OFF in addition to the line power switch Having the unit ON with battery supply only will drain the battery NOTE Do not attempt to carry a fully assembled unit alone Lift the CT25K from Measurement Unit Base or Pedestal only not from the shield The three main parts Measurement Unit Shield and Pedestal can be lifted and carried separately by one person 34 WARNING Verification of Proper Operation Proper operation of the Ceilometer can be checked with help of the maintenance terminal Turn the power on After 30 45 seconds ask for the status message with the command GET STATUS Information about commands can be found in chapter 4 Operation The message should not contain any warnings or alarms In the opposite case see Chapter 7 Troubleshooting on page 111 If a solid stable cloud base is present at a range of 1 000 5 000 ft and no fog or precipitation is present a quick check of the detection and the unit sensitivity can be carried out by observing the variable SUM on the third line of data message No 2 SUM indicates the sum of detected and normalized backscatter and its value should be in the range 150 200 if parameter SCALE has the standard value 100 See section Data Message No 2 on page 48 for details If suitable clouds are not present for proper operation verification the unit may be tilted towards a hard target at known distance The minimum distance to the hard target should be at least 300 met
18. correct Check that the line voltage is present and correct Blower is stuck Check if visible obstacles disable the blower operation VAISALA Blower is damaged Replace the blower 117 User s Guide Alarms Table 17 Problem Laser temperature shut off Alarms Reason Direct sunlight Instructions Direct sunlight can burn the laser diode Use Tropics window or turn the ceilometer away Environment temperature too high Do not operate the ceilometer Laser failure Laser is worn out or damaged Check the operation of laser transmitter CTT21 and its cable connections Laser does not get electrical power Check from the status message if there is an asterisk in front of any voltage value indicating malfunction in the DPS52 DC Converter board Outgoing laser power failure Check that the Optics Monitor CTL21 board is not misplaced or damaged INLASER setting does not function Check the operation of the Ceilometer Interface Board DCT51 Receiver failure Loose cable connection Check that the cables from the receiver CTR21 and from the Optics monitor CTL21 are undamaged and connected correctly Receiver test not operating Check that the Optics Monitor CTL21 board is not misplaced or damaged Voltage failure DC Converter board DPS52 is damaged Miscellaneous Table 18 Problem DPS52 Power OK LED D2
19. on page 122 1 Detach the connectors that are plugged into the board you want to remove 2 Detach the two screws at the upper and lower end of the board front panel Figure 36 above Because the board frame is tightly VAISALA 141 User s Guide 142 packed it is recommended to loosen the screws of the adjacent boards The adjacent board may be partly pulled out to help the removal Pull the board carefully out from the slot Replacing Boards l Plug the new board carefully into the corresponding slot Figure 36 on page 141 Attach the new board with the two screws Then plug in connectors Cable connections were described in section Cable Connections on page 28 When the Ceilometer Interface Board is replaced the parameters need to be restored refer to section Parameter Settings of Ceilometer Interface Board DCT52 below The other boards of the board frame DMFS51 do not need parameter settings If the DMCS0 Processor board has been replaced the software version of the new board can be checked with the command GET VERSION Parameter Settings of Ceilometer Interface Board DCT52 a The default baud rate for the maintenance line is 2400 Bd 7 data bits 1 Stop bit Even parity If some other baud rate was previously used with the removed DCT52 you may have to adjust your maintenance terminal to the default setting to be able to communicate with the ceilometer b Do the parameter settings for the Laser
20. 1 2 or 3 If detection status is 4 If detection status is O or 5 If detection status is 2 or 3 If detection status is 4 If detection status is 0 1 or 5 If detection status is 3 If detection status is 0 1 2 4 5 Alarm A Warning W and internal status information Each character is a hexadecimal representation of four bits 1 e values between 0 and 9 are presented with respective numbers and values 10 11 12 13 14 and 15 are presented with letters A B C D E and F respectively As each character represents the sum of four individual bits the total number of bits is 32 b00 b31 with the following breakdown and interpretation F b31 b30 b29 b28 E b27 b26 b25 b24 D b23 b22 b21 b20 C b19 8000 0000 4000 0000 2000 0000 1000 0000 0800 0000 0400 0000 0200 0000 0100 0000 0080 0000 0040 0000 0020 0000 0010 0000 0008 0000 Detection status as follows No significant backscatter One cloud base detected Two cloud bases detected Three cloud bases detected Full obscuration determined but no cloud base detected Some obscuration detected but determined to be transparent Raw data input to algorithm missing or suspect Warnings and Alarm information as follows Self check OK At least one Warning active no Alarms At least one Alarm active Lowest cloud base height Vertical Visibility as calculated III Second lowest cloud base height Highest si
21. 1 1 i 1 1 T 1 VOLTAGE i 20V SELECT 1 i i 1 1 i 1 1 lesse from DPS52 Ei P6 to INHEATER Lassi 22521 CONDITIONER ILINE FANLINE CONDIT M EN 115V ae HEATLINE i 230V i LLINE N rg NE i E 1 FLOWTA 1 1 asm a XC OSH E ms NI CSi from DMCS0_ MAINTENANCE LINE i 34 i REA 1 from modem or 50 L pg DATA LINE is 1 I bame 9806 004 Figure 24 CTP241 Wiring Line voltage selection 100 115 VAC or 220 240 VAC is carried out in the CTP241 by an internal switch the setting of which is written on the label on the subassembly This setting also accomplishes the series vs parallel connection of Internal Heater resistors NOTE For complete power disconnection both the main switch at CTP241 and the battery switch must be turned to position OFF Otherwise the unit is still supplied through the batteries and higher voltage levels inside the unit are possible although the line voltage is disconnected For normal operation both switches must be turned to position ON Some of the electronics subassemblies are provided with integral voltage regulators which internally regulate the actual voltage necessary for operation VAISALA 91 User s Guide 92 WARNING Internal Heaters Subassembly CT25039 e a te pe Pi at 115VAC d 2 115VNE L
22. 165 mm 0 5 x 6 5 in are drilled into the concrete The Wedge Bolt and Foundation Screw combinations are placed in the holes with Wedge Bolts down the protruding threads are alternately hammered and tightened a few times so that the Wedge Bolts attach to the hole walls In case the CT25K replaces a CT12K Ceilometer the existing foundation and screws can be used If the tilt feature will be used see section Using the Tilt Feature on page 27 observe this in the layout of the foundation screws and pedestal placement Assembling the Unit The CT25K Ceilometer is assembled in four stages Mount the pedestal on the foundation Attach the measurement unit to the pedestal Mount the shield on the measurement unit Connect the external cables 1 Place the Pedestal on the foundation or equivalent installation place so that the vertical leg of the pedestal faces East in the Northern hemisphere and West in the Southern hemisphere M210345en A Chapter 3 Installation L NORTH IN NORTHERN HEMISPHERE s SOUTH IN SOUTHERN HEMISPHERE PEDESTAL NUT M10 4 pcs FOUNDATION SCREW M10 4 pcs 9412 031 Figure 4 Mounting the Pedestal If the tilt feature will be used see section Using the Tilt Feature on page 27 observe this in the layout of the foundation screws and pedestal placement Place the flat washers on the foundation screws and fix the nuts see Figure 4 abo
23. Arrester Secondary VDRs Transient Zener Diodes or normal Diodes DMC50B as shown CENTRAL SITE Signal Termination Box CEILOMETER SITE CT3707 option T di 1 5 RxD Modem gt gt CT25K Measurement Unit ERU COMME NE GND EE 4 Se 1 6 RS 232 and 5 Modem rit Qe 1 Connection 7 V 8 2 Data Cable r 71 CT3838 xt E lt h M wte e ms g 12 1 14 E Lid 2 i iit 421 i GRY 3 i e I La a id mes NE 5 ia m lt i 1 20GND pd 11 T 51 amp 5 485 E 6 RED 111 6 2 wire bus tit Or i opn SiE 120 NOTE DMcsoB CASE ru MAKE SGND RS 232 422 485 connection to aL 1 i Modem connection P8 plugs into modem board or transition connector SD E 1 1 Modem Options DMX50 SD 1 342 2 1 DMX55 bg GND op i RD l E adu p C RC M 1 PEU RS 422 and ipa 7 RS 485 4 wire wood Os 2 i Connection Li T0000 2 9807 045 Figure 40 Data Line Connection Options 154 M210345en A Chapter 9 VAISALA Technical Data External Connector J4 Maintenance Line Maintenance line is intended for on site maintenance and can be used with Ceilometer Maintenance Terminal PC or other terminal Table 23 Maintenance Line Property Description Value Connector J3 Type Binder s
24. Palmtop Computer Setting up the Connection 1 Connect the RS cable to the ceilometer maintenance port connector J4 and the terminal computer 2 Setthe following settings for the terminal Baud rate 2400 Data bits 7 Stop bits 1 Parity Even Handshake None Operation Turn CT25K power on Press ENTER The prompt CT should appear on the screen If not check the cables and port settings 31 User s Guide Startup 32 The CT25K maintenance port has to be opened by command OPEN for giving commands The prompt CEILO gt should appear For more details see Chapter 4 Operation on page 39 Startup Procedure Open the unit door the key is included in the delivery Make a visual check of the internal connectors subassemblies etc Figure 3 1 describes the switches and LEDs needed to complete the start up procedure 1 the main circuit breaker to OFF position 2 Plugin the line supply cable to connector J2 after checking the voltage of the power supply cable connector 3 Tum the Main Circuit Breaker F1 and the Battery Switch to the ON position After initialization routines the following shall happen LED Light Emitting Diode DC Converter DPS52 LED D2 stable green LED DI blinking yellow In case the built in battery is deeply discharged it may take hours before LED D2 goes on 4 Processor Board DMC50B LED STATUS blinking at regular intervals 1 sec 5 Ceilometer Inter
25. SENS value which should be OK 8 Turm the power off Start the Ceilometer again and verify that it is operating properly Coaxial Cable Replacement In case Receiver Failure Alarm or Receiver Optical Crosstalk Compensation Poor Warning exist the reason may be a defective Coaxial Cable instead of a Receiver Hazardous voltage 500 V is present at the Receiver and at the Board Frame DMF51 Both the line and the battery switches must be turned off before removing the Coaxial Cable Removal To detach the Coaxial Cable you have to detach the receiver first as follows 1 Detach the Compensation Fiber from the receiver by loosening the screw See Figure 34 on page 133 with a 1 5 mm hexagon key and pulling the fiber end gently out Take care not to twist the compensation fiber 2 Detach the Ribbon Cable Connector of the Receiver from the connector J11 at the DMF51 Board Frame Refer to Figure 30 on page 123 Detach the Coaxial Cable from the DCT52 front panel 4 Loosen the CTR21 Receiver attachment ring See Figure 34 on page 133 using a 2 5 mm hexagon key as a lever there are holes in the attachment ring for that purpose If the Receiver begins to move along stop it from rotating by hand NOTE The photodiode has been centered at the factory do not apply force to the Receiver because this may disturb the centering 136 M210345en A Chapter 8 Repair 5 Take the receiver in your hand
26. Start up procedure and do as follows 1 Detach the ribbon cable connector of the transmitter from connector J10 at the DMF51 Board Frame by pressing the latches apart Refer to Figure 30 on page 123 2 Loosen the attachment ring Figure 31 on page 125 using a 2 5 mm Hexagon Key as a lever there are holes in the attachment ring for that purpose If the Transmitter begins to move along stop it by hand from rotating NOTE The laser diode has been centered at the factory do not apply force to the Transmitter because it may disturb the centering Take the Transmitter in your hand 3 Deliver the entire Transmitter to Vaisala 124 M210345en A Chapter 8 Repair 0208 070 Figure 31 Removing the Laser Transmitter The following numbers refer to Figure 31 above 1 Attachment ring 2 CTT21 Laser transmitter 3 Unscrew the attachment ring using 2 5 mm hex key as a lever no screw in the hole Replacement To replace a Laser Transmitter CTT21 See section Startup Procedure on page 32 1 Take the Transmitter CTT21 in your hand and set it in place Notice the right position the ribbon cable comes out from the back side Rotate the attachment ring Figure 31 above by hand and tighten it using a 2 5 mm hexagon key as a lever If the transmitter begins to move along carefully stop it by hand from rotating NOTE Do not apply force to the transmitter itself because it may disturb the centering VAISAL
27. and precipitation as well as cloud can be derived Since fog and precipitation attenuate the light pulse the cloud base signal will appear lower in magnitude in the return echo However the fog and precipitation information also provides data for estimating this attenuation and computing the necessary compensation up to a limit In its normal full range operation the CT25K ceilometer digitally samples the return signal every 100 ns from 0 to 50 us providing a spatial resolution of 50 feet from ground to 25 000 feet distance This resolution is adequate for measuring the atmosphere since visibility in the densest clouds is in the order of 50 feet Noise Cancellation For safety and economic reasons the laser power used is so low that the noise of the ambient light exceeds the backscattered signal To overcome this a large number of laser pulses are used and the return signals are summed The desired signal will be multiplied by the number of pulses whereas the noise being random will partially cancel itself The degree of cancellation for white Gaussian noise equals the square root of the number of samples thus the resulting signal to noise ratio improvement will be equal to the square root of the number of samples However this processing gain cannot be extended ad infinitum since the environment changes For example clouds move M210345en A Chapter 5 VAISALA Functional Description Return Signal Strength T
28. document Start of Header Start of Text End of Text Carriage Return and Line Feed are non printing characters in most practical terminal use VAISALA 45 User s Guide 46 Data Message No 1 This message is intended for cloud height vertical visibility measurement when no other measurement information is desired The message includes the most elementary status information which enables a host system or operator to see that no warnings or alarms are present An example of data message no 1 is presented below 1 8 CTA2010 9 l 1st line 11 char 30 01230 12340 23450 FEDCBA98 2nd line 31 char Od 3rd line 3 char total 44 characters Transmission time and size 0 18 s at 2400 baud 10 bit char 10 6 kbytes h 253 kbytes d 7 6 Mbytes mo at 4 msg min uncompressed Interpretation of the message is as follows IST LINE Example CTA2010 2 where Start of Heading character CT Ceilometers identification string always CT A Unit number 0 9 A Z 20 Software level id 00 99 1 Message number this message is always 1 0 Spare character for future subclasses of message Start of Text Character M210345en A Chapter 4 where 3 01230 12340 23450 FEDC BA98 VAISALA Operation 2ND LINE Example 30 01230 12340 23450 98 J OF irst digit of line Second digit of line 0 W A If detection status is
29. glasses binoculars telescopes etc When operating avoid looking at the ceilometer unit from the beam direction When tilting the unit make sure that it is not being viewed from the beam direction with magnifying optics Only trained personnel should perform maintenance functions Work area access by unauthorized persons during service operations must be prevented To minimize shock hazard the instrument chassis and cabinet must be connected to an electrical ground The instrument is equipped with a three conductor AC power connector The power cable must either be plugged into an approved three contact electrical outlet or the instrument must be carefully earthed to a low resistance safety ground Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment constitutes a definite safety hazard 13 User s Guide WARNING Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present WARNING Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to a Vaisala office or authorized Depot for service and repair to ensure that safety features are maintained WARNING Operating personnel must not remove instrument covers Component replacement and internal adjustments
30. is not lit Miscellaneous Reason Power is not connected Check the status message If there is an asterisk the voltage exceeds the limits Instructions Check that both the main and the battery switches are in ON position Check the presence and correctness of the line voltage Check also that the battery is OK Loose cable onnection Check the cable connections DCT52 LED D4 is not lit 118 DMC50B or DCT52 is damaged Check from the status message if the voltages are present and correct If yes suspect a damage in the DMC50B or DCT52 board M210345en A Chapter 7 Troubleshooting Problem The period of LED DA in the DCT52 board is much shorter than the normal 15 sec measurement interval Reason Self check not finished in 5 minutes Instructions Unit is unable to finish the compensation adjustment If the unit is operated indoors use the optical termination hood Other causes may be a dirty window or a broken compensation fiber Data message is missing Dialogue not operating Check the cable connections Open the terminal program and press the ENTER key a few times The ceilometer should respond with CT prompt Wrong communication parameters Check the communication parameters number of bits parity etc Wrong data port Open the terminal program and first give OPEN command and then GET MESSAGE command Check that t
31. make sure that nobody is watching it with binoculars or other magnifying optics Disable the automatic angle correction by giving commands CT gt OPEN d CEILO gt SET MESSAGE ANGLE COR OFF 2 CEILO CLOSE I Compare ceilometer s distance reading to a reference measurement Troubleshooting VAISALA The purpose of this troubleshooting is to locate the problem If a damage is suspected in a subassembly or a board replace it with a 115 User s Guide spare part and send the defective part to Vaisala for repair replacement NOTE Replacements have to be done according to instructions given in the Instructions for Replacement of Parts in section 8 and are allowed for trained personnel only As a principle customer made repairs are restricted to replacement of subassemblies only Warnings Table 16 Status Message Info Window contaminated warning Appears from time to time and lasts 5 min Warnings Reason Usually rain drops on the window Instructions The blower will clean the window If clouds are detected the height information is correct If no clouds are detected it is possible that high clouds are missed Window contaminated warning Continuous Bird droppings leaves dust etc have contaminated the window Clean the window Battery low warning The unit has been powered too long using the backup battery Connect the line voltage or replace the batter
32. must be made by qualified maintenance personnel Do not replace components with power cable connected Under certain conditions dangerous voltages may exist even with the power cable removed To avoid injuries always disconnect power and discharge circuits before touching them High voltage will be readily accessible when the transmitter CTT21 or receiver CTR21 covers are removed and they are connected to a powered unit High voltage is present in the Line and Power Interface Subassembly CTP241 the Internal Heaters subassembly the Frame DMF51 Mother Board and the Window Conditioners at the top of the Shield Transmitter CTT21 Receiver CTR21 and Line and Power Input Subassembly CTP241 have the following warning label WARNING HIGH VOLTAGE INSIDE THIS ENCLOSURE Internal Heaters Subassembly can be hot and has the following warning labels 14 M210345en A Chapter 1 General Information Warnings such as the example below precede potentially dangerous procedures throughout this manual Instructions contained in the warnings must be followed WARNING Dangerous voltages capable of causing death are present in this instrument Use extreme caution when handling testing and adjusting CAUTION The equipment contains parts and assemblies sensitive to damage by Electrostatic Discharge ESD Use ESD precautionary procedures when touching removing or inserting ESD Protection Electrostatic Discharge
33. of ceilometer data to calculate the cloud cover and the heights of different cloud layers The algorithm is based on so called Larsson algorithm developed by Swedish Air Force and Swedish Hydrological Institute SMHI but further modified at Vaisala The sky condition information is included in data messages 6 and 7 The algorithm updates sky condition information every five minutes based on data gathered during the last 30 minutes The algorithm reports up to four different cloud layers below 25000 feet Sky condition information can be displayed with the DD50 Digital Display NOTE The CTC21 Controller Unit DR21 Data Recorder and the CT VIEW software version 1 05 or earlier can NOT display the sky condition information Option code The sky condition algorithm is included in the 2 01 software The user activates the algorithm by giving an option code number to the ceilometer The option code number is based on the DMC50B Processor Board serial number If the CT25K ceilometer is purchased with the sky condition activated then this is done at the factory In case the sky condition option is purchased afterwards the user can find out the processor board serial number by giving the following commands CT open CEILO gt advanced PASSWORD ACCEPTED CEILO gt get dmc_sn DMC SERIAL NO 850509 example CEILO close The processor board serial number is also written on top of the microprocessor circuit with a letter as
34. or other light source If there are only fractures in the fiber the light is dim at the other end of the fiber 6 Tryto place the new fiber exactly in the same place as the original one was Tighten the two attachment screws mentioned 7 Perform steps 3 and 4a amp 4b under the title Replacement on page 125 8 Perform the Compensation adjustments all steps under the title Compensation Adjustments on page 128 9 Turn the power off Then start the Ceilometer again and verify that it is operating properly 138 M210345en A Chapter 8 Repair NOTE If you run into trouble performing step 8 above such that the adjustment is not finished because screw B has already traveled all the way out from the receiver you also have to adjust the other end of the fiber This can be quite laborious In this case follow these next steps 10 11 Turn the B screw back clockwise until it is several turns inside the threads Approximately in the original position Perform steps 1 3 of section Compensation Adjustments on page 128 adjustments again During step 3 however loosen slightly the M3 slotted head screw and make very small adjustments to the position of this fiber end The purpose of these adjustments is to increase the level of optical power that is coupled into the fiber This effect is seen in the terminal display so that the amount of stars increases the empty hole is filled and finally a c
35. ribbon and coaxial cables come out from the back side Rotate the attachment ring see Figure 34 on page 133 first by hand and then tighten it using a 2 5 mm hexagon key as a lever If the receiver begins to move along carefully stop that by hand NOTE Do not apply force to the receiver itself because it may disturb the centering 134 Check that the receiver is now in the correct position that is the long edges of the receiver case are approx horizontal If this is not the case loosen the attachment ring first then correct the receiver position and fasten as described above 3 Plug the Compensation Fiber into the receiver and tighten the screw marked Fibre attachment with a 1 5 mm hexagon key 4 Attach the Coaxial Cable to the J1 connector at the front panel of DCTS2 5 Attach the ribbon cable connector to DMF51 Board Frame connector J11 Refer to Figure 30 on page 123 6 Connect the Power Cable and the Maintenance Terminal Turn the power on 7 Ifthe receiver has been replaced by a new one do the following parameter settings a the command set by first typing OPEN d at the command prompt and then typing the password ADVANCED JI b Adjust the internal crosstalk compensation according to section Compensation Adjustments on page 128 c Turn the power off and start the Ceilometer again in order to run the automatic receiver self check M210345en A Chapter 8 VAISALA Repair
36. samples then get added into the First In First Out FIFO register of the DCT52 This FIFO is cleared to all zeroes before start its data content is rotated so that a sample from a specific distance specific delay time after the laser pulse launch always gets summed into the same rotating and accumulating register location Thus the sequential summing of new samples gradually creates a high resolution digital image of the backscatter profile Noise being random increases only in proportion to the square root of the number of samples whilst the effective signal increases in direct proportion to the number of samples Thus the final digital profile will reveal properties of the atmosphere that couldn t be seen from an instantaneous signal At the end of the set number of pulses the DCT52 issues an interrupt to the DMCSOB upon which the software fetches the digital profile to its RAM for the algorithmic processing After processing the measurement result is ready for message transmission through the data link to the equipment it connects to In conjunction with the backscatter measurement the laser pulse energy is also measured by the Optics Monitor CTL21 photodiodes The measured value is used by the algorithm for normalizing the profile into the right magnitude for adjusting the laser voltage by the Digital to Analog Converter DAC placed on the DCT52 and ultimately for warning or alarming of loss of laser power During the exit of th
37. table with the door upwards 2 Remove the protective cap of the External Connector J4 Maintenance Line if the cap is attached All cables must be disconnected from the External Connectors J1 J4 3 There are 6 screws at the bottom of the CT25K that are situated around the rectangular opening of external connectors J1 J4 See Figure 37 on page 144 Loosen these screws so that they come out approx 1 cm do not remove them completely releasing the flange of the CTP241 4 the ceilometer to a vertical position again 5 Detach the Internal Heater Cable by pressing the right and left clips of the mating connector at J5 on the CTP241 6 Disconnect the AC Power Interface Connector P6 from the Board Frame DMF51 J15 Refer to Figure 30 on page 123 7 Disconnect the plug in Connectors P7 and P8 from the DMC50 Processor Board and modem if installed VAISALA 143 User s Guide 8 Open and remove the screw and spacer that connects the CTP241 to the battery holder see Figure 37 below 9 left front corner of the CTP241 approx 1 cm and pull it out o o 8 8 BOTTOM VIEW FRONT VIEW REMOVE THE SCREW WARNING HIGH VOLTAGE INSIDE THIS ENCLOSURE LOOSEN THE 6 SCREWS LINE amp POWER SUBASSEMBLY CTP241 9605 023 Figure 37 Removing Line and Power Interface Subassembly CT
38. the tilt angle SET MESSAGE HGTH OFFSET 1000 1000 ft or 304 304 Height offset Cloud and vertical visibility values are corrected by this offset value Positive values add to negative values subtract from measured height Unit is m or ft as set by UNITS command SET MESSAGE MODE AUTOSEND Measurement messages are transmitted automatically set by command INTERVAL SET MESSAGE MODE POLLING Measurement messages are transmitted according given polling string SET MESSAGE PORT DATA Message is directed to the Data port default non volatile SET MESSAGE PORT MAINTENANCE Message is directed to the Maintenance port non volatile SET MESSAGE PROFILE SCALE 0 999 Factor for scaling the range gate data items of Message No 2 Normal value 100 96 SET MESSAGE PROFILE NOISE H2 OFF Range gates data is range normalized only if backscatter is contained SET MESSAGE PROFILE NOISE H2 ON Range gates data is always range normalized even noise SET MESSAGE TYPE MSG1 Message No 1 is transmitted SET MESSAGE TYPE MSG2 Message No 2 is transmitted SET MESSAGE TYPE MSG3 Message No 3 is transmitted SET MESSAGE TYPE MSG6 Message No 6 is transmitted SET MESSAGE TYPE MSG7 Message No 7 is transmitted SET MESSAGE TYPE STATUS Status message is transmitted SET MESSAGE UNITS FEET Reported heights unit is feet SET MESSAGE UN
39. truthful and in any case accurate enough for the purpose of cloud detection Likewise the inversion is also independent of several instrumental uncertainties including transmitted power and receiver sensitivity An estimate of Vertical Visibility can easily be calculated from the extinction coefficient profile because of the straightforward extinction coefficient to visibility relationship provided that a constant contrast threshold is assumed Visibility will simply be that height where the integral of the extinction coefficient profile starting from ground equals the natural logarithm of the contrast threshold sign disregarded Tests and research have however shown that the 5 contrast threshold widely used for horizontal measurement is unsuitable for vertical measurement if values close to those estimated by a ground based observer are to be obtained The CT25K uses a contrast threshold value which through many tests has been found to give Vertical Visibility values closest to those reported by ground based human observers A wide safety margin is 67 User s Guide obtained with regard to pilots looking down in the same conditions since the contrast objects especially runway lights are much more distinct on the ground Technical Description General Figure 12 below shows the internal layout of the Measurement Unit and the following Figure 13 on page 69 the subassembly interconnections Summary of part numbers
40. value for p p 0 0006 0 006 m srad 0 6 6 km srad M210345en A Chapter 5 VAISALA Functional Description Extinction Normalization and Vertical Visibility Any fog precipitation or similar obstruction to vision between ground and cloud base may attenuate the cloud base signal and produce backscatter peaks that far exceed that from the cloud Virtually any backscatter height profile is possible up to some physical limits To distinguish a significant cloud return signal the attenuation of fog precipitation etc has to be taken into account by normalizing with regard to extinction The profile thus obtained is proportional to the extinction coefficient at various heights and enables the use of fairly straightforward threshold criteria to determine what is cloud and what is not By assuming a linear relationship between backscatter and extinction coefficient according to the previous formula and that the ratio k is constant over the range observed it is possible to obtain an extinction coefficient profile through a mathematical computation This is also called inverting the backscatter profile to obtain the extinction coefficient profile and answers the question What kind of extinction coefficient profile would produce the backscatter profile measured No assumption as to the absolute value of the ratio k needs to be made if k is constant with height The assumptions that have to be made are fairly
41. 0 100 Sky Condition Algorithm eee 102 4 M210345en A VAISALA General uiii Inm eui 102 Option code eee ec iet ied eode de 102 Activation iii ederet se deed ead eu dan edt euo d ded 103 Algorithm Overview sssssseseeeeeemenn 103 CHAPTER 6 L A gdz pilum 107 Periodic Maintenance ccccceseesseeneeeeeeeeeeeeeeneneeeenees 107 Alarms and Warnings ssse enn 107 Window Cleaning eme 108 Battery Check uei eie RR a eerte 108 Storage xil eI LU Pe Gcr fos 109 CHAPTER 7 TROUBLESHOOTING here 111 Normal Operation 111 Equipment aaa ehem 111 InStrictlODs iioii ero dE UIS 111 Troubleshooting eere 115 WaitilligS eme nU OI III RS 116 Alas codo m 118 Miscellaneous i a a ae aa aaa 118 Failure Diagnosis inttr ret teen denen 119 CHAPTER 8 PRE PAU dE 121 Genera luier aaen 121 Writing Conventions Used eene 121 Start Up Procedure for Replacement All Parts 122 Transmitter CTT21 onere 124 oet MU DR 124 125 Compensation Adjustments
42. 0 Figure 8 CT25K Switches and LEDS 33 Figure 9 Operation Modes eene eene 39 Figure 10 Open and Closed Port sssssssseee 41 Figure 11 Typical Measurement 64 Figure 12 Measurement Unit 68 Figure 13 Subassembly Interconnections esee 69 Figure 14 Block Diagram of Operational Units 71 Figure 15 Optical Subassembly CTB22 with Optics Monitor Transmitter and Receiver 74 Figure 16 CTT21 Block Diagram seem 76 Figure 17 21 Block Diagram sse 77 Figure 18 CTL21 Block Diagram 78 Figure 19 DMF51 eene nter tnnt nennt 80 Figure 20 DMC50B Block Diagram seem 82 Figure 21 DIP Switch Settings of the 50 85 Figure 22 DPS52 Block Diagram seem 86 Figure 23 DCT52 Block Diagram sese 89 Figure 24 241 Wiring 2i icit dece eee cce e ence 91 Figure 25 CT25039 Wiring Diagram sse 92 6 M210345en A Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figur
43. 0 W 230 VAC CT2614 AND CT2688 CABLE LENGTH 1300 mm BINDER 99 4225 70 07 FAN LINE 1 1 lt FANNE 2 HEAT LINE N C Ts 100C FLOWTA FLOWTB WHT SGND YEUGRN TO BE CONNECTED TO HEATER Figure 27 96 WEAN AND CASE EARTH 9412 086 Window Conditioner CT2614 CT2688 M210345en A Chapter 5 Functional Description CAUTION WARNING VAISALA The Window Conditioner consists of a blower motor heating element and an NTC temperature sensor inside an enclosure The air stream from the blower is directed across the measurement unit window for clearing it from water drops condensed humidity snow and particles The blower is automatically switched on when contamination or precipitation is detected on the window surface or when the atmospheric measurement indicates that a high risk of precipitation exists The temperature sensor is used for determining whether the heater should be turned on or not All of this is done under software control via DPS52 and CTP241 Because the window of the measuring unit is declined and the blower air is directed from up to down on its surface water drops and snow are effectively removed There are two different window conditioners for the two supply voltages 230 V and 115 V The plug for the correct connection cable has a markin
44. 000 300 ft 3 000 4 000 400 ft 4 000 5 000 500 ft 5 000 15 000 1 000 ft 15 000 25 000 5 000 ft Overcast 8 oktas 1s reported 1f all the measurements during the last 30 minutes have a hit Overcast height is assigned according to the bin where 14 15 of the total count value is exceeded However overcast is not reported if there are weak hits during the latest 15 minutes period A weak hit is defined as a backscatter signal which is less than 80 of the reference The reference value depends on the previous measurements i e it s a kind of sliding average value of signal strength M210345en A Chapter 5 VAISALA Functional Description Vertical visibility VV hits are considered as cloud hits if higher than 1500 feet The cloud height is defined as VV signal range 2 Lower VV hits are assigned to a VV register If the percentage of VV hits in the register during the last 10 minute period exceeds the VLIM parameter value see Table 7 on page 42 the sky condition algorithm reports VV The VV height is the average height of VV hits Otherwise the lower hits are also considered as normal cloud hits 1 e VV hits are assigned to cloud height categories bins 105 User s Guide This page intentionally left blank 106 M210345en A Chapter 6 CHAPTER 6 Maintenance MAINTENANCE This chapter provides information that is needed in basic maintenance of the product Period
45. 0000000000FFFCO000FFFFFFFEFFFF 1120000000000000001FFFCFFFF00000002FFFE00000000FFFFFFFF00010000FFFE l 128000000000000000000010000FFFFFFFF00000000FFFE00000000000300000001 l 144000200010000FFFFFFFFFFFEFFFEFFFFFFFF00000000FFFE0001FFFFFFFF0000 l 160FFFE0000FFFE0015004300B200B300E300540022000C0030FFFF000000000001 l 176FFFF000000000001FFFC00000000000000000001FFFF0000000100000001FFFD l 192000000000000FFFE00000000000100010001000000000001FFFFFFFFFFFFFFFE 2080000FFFE0000FFFE00000001FFFF000000020000000000010000FFFFFFFF0001 l 22400000000FFFE000000020001FFFEFFFFFFFEFFFF000000000001000100010001 l 240FFFE0000FFFEO000FFFFFFFD0000000400000001FFFF00000000000000000000 l 1028 5 135 0 OJ T Transmission size and time for Msg7 is total 1223 characters gt 5 1 s at 2400 baud 10 bit char gt 147 kBytes h 3 52 MBytes d 106 MBytes mo at 2 msg min uncompressed NOTE Not enough data i e detection status 99 1s reported after a start up until the unit has operated for 25 minutes Data missing i e detection status 1 is reported if more than 25 of gathered data is considered invalid due to a hardware failure 54 M210345en A Chapter 4 Operation Status Message S The Status Message displays internal monitoring of the whole unit including prevailing parameter values for voltages receiver and transmitter temperatures environmental factors and internal heating
46. 0345en A Chapter 5 VAISALA Functional Description contamination A Blink Timer controls an LED indicator which indicates when the laser is switched on i e sends laser pulses For testing of the complete receiver subsystem a short pulse is sent from a test LED in the direction of the receiver The control signal for triggering the test LED is given from the ceilometer interface board DTC52 The optics is heated in order to protect it against condensed humidity A temperature sensor delivers a control signal for the heating via an amplifier processor board A to D Converter and software Board Frame DMF51 The frame DMF51 is a subassembly into which the Processor Board DMCSOB Ceilometer Interface Board DCT52 DC Converter DPS52 and the optional modem are plugged Its mechanical construction suits well for housing printed circuit boards Being fully metallic it protects the electronics against electromagnetic disturbances see Figure 19 on page 80 79 11 User s Guide M210345en A 0208 068 DMFS51 Frame J10 Figure 19 80 Chapter 5 VAISALA Functional Description The following numbers refer to Figure 19 on page 80 J3 Optics monitor J4 Local display DMCSOB Processor board DPS52 DC converter board J14 12V local battery J15 AC power interface 11 Receiver J10 Tran
47. 1 9 Z if polling or message logging from several units requires separating identifiers 37 User s Guide This page intentionally left blank 38 M210345en A Chapter 4 Operation CHAPTER 4 OPERATION This chapter contains information that is needed to operate this product Operation Modes There are two operation modes continuous i e normal and standby Commands OPER MODE STANDBY and OPER MODE CONTINUOUS are used to switch between the modes In NORMAL mode continuous measurement and message transmission occurs according to chosen parameters In STANDBY mode the wearing parts are turned off and it can be used e g during periods when measurement is not needed It allows single cycle measurement by command START OPER MODE STANDBY f STANDBY Power on NORMAL Continuous measurement and message transmission ref INTERVAL Single cycle measurement MESSAGE MODE by command START OPER MODE CONTINUOUS No continuous measurement 9806 001 Figure 9 Operation Modes Serial Lines Open and Closed Port Two serial lines are provided termed MAINTENANCE external connector J4 Line Port A at Processor Board and DATA external connector J3 Line Port B at Processor Board Line B is intended to be used for measurement data communication and can be operated through modem or baseband Line A is intended for on site VAISALA 39 User s Guide maintenance access and is used
48. 400 Blower heater is ON 0000 0200 Internal heater is ON 0000 0100 Units are METERS if ON else FEET 9 0000 0080 Polling mode is ON 0000 0040 Working from battery 0000 0020 Single sequence mode is ON 0000 0010 Manual settings are effective 8 0000 0008 Tilt angle is gt 45 degrees 0000 0004 High backround radiance 0000 0002 Manual blower control 0000 0001 spare M210345en A Chapter 7 Troubleshooting For example if the battery voltage is too low a warning is given and the second line appears as ow 00400200 In this example the internal heater is also on Check the operation of the window conditioner 8 Waituntil the 15 minutes start up blowing has passed Place a piece of white paper on the ceilometer window Within one minute the blower should start Remove the paper Within one minute the blower should stop 9 fthere are clouds present compare the ceilometer measurement with the qualified weather observer s height approximation 10 In case there are no clouds present and if the site is suitable do a hard target test Turn the measurement unit 90 degrees and aim on a fixed target wall forest front etc NOTE The minimum distance to a hard target should be 300 meters 1 000 ft The backscatter signal from a hard target is very strong compared to the signal from a cloud The receiver may saturate if the distance is too short CAUTION When tilting the unit
49. 52 2 Enable watchdog timer 52 3 OFF Disable download of operating system 52 4 Enable SRAM battery back up DC Converter DPS52 The DPS52 DC Converter is an efficient and self monitoring power distributor board specially designed for the CT25K Having five independent switch mode voltage converters the board is capable of delivering up to 20W Figure 22 on page 86 shows the block diagram of DC Converter DPS52 VAISALA 85 User s Guide POWER 2 18VAC INPUT I POWER 2 10VAC INPUT II 86 18V 12V 12V TOA D 65V CONVERTER DISBAT DMC50 BOARD V2 13VR 13VR 5VR 5VR 400VR BAT i AMBTA FLOWTA DISBAT i CHARGE ENABLE Internal 5VEN Pc Control DVEN RVEN V2 BLOWER OUTHEATER I O INHEATER Control LASERHEAT POWER OK ACCESS 9807 050 Figure 22 DPS52 Block Diagram Totally 13 voltages are generated within five switching circuits One step down switcher is reserved for both 5V and 5V outputs One flyback switcher produces 18V for CPU 12V 12V for optics monitor and 65V for transmitter Another isolated flyback switcher generates five receiver voltages 13VR 13VR 5VR 5VR and 400VR All these voltages are normally supplied by two 18VAC windings The second supply rectified from two 10VAC windings is reserved for internal battery charger heating power for transmitter and inheater and outheater control relays
50. 6 Measured internal voltages in units of 0 1V as follows BAT Battery voltage e g 098 CHA Battery charge voltage e g 144 VCA Internal raw voltage e g 225 PHV Receiver high voltage e g 2306 PFB Rec switcher feedback voltage e g 17 P65 Transmitter high voltage e g 674 P18 General internal supply voltage e g 178 P13 Receiver supply voltage e g 128 P12 General internal supply voltage e g 125 P5G General internal supply voltage e g 54 P5R Receiver supply voltage e g 50 M13 Receiver supply voltage e g 124 M12 General internal supply voltage e g 126 M5R Receiver supply voltage e g 50 M5G General internal supply voltage e g 54 LINES 8 13 Prevailing Receiver and Transmitter settings and variables as follows RECEIVER TRANSMITTER GAIN BAND SAMP SENS COMP PLEN POTY OUT SENS IN H or L N or W 10MHz OK 13 125 Lor S 64K 1416mV 101 190 Gain is High or Low Bandwidth is Narrow or Wide Sampling rate is 10 MHz Receiver sensitivity OK compared to factory setting Internal crosstalk compensation setting codes coarse 013 and fine 125 Pulse length is Long or Short Pulse quantity is 64x1024 Laser pulse energy measured by Optics Monitor is 1416 mV at Monitoring A to D Converter input Measured pulse energy is 101 of nominal value Pulse energy control input code is 190 M210345en A Chapter 4 Operation LINES 15 20 Temperature and environment var
51. 9 Parts List Part no Description Notes CT15035 ENCLOSURE CT35042 STANDARD WINDOW CT35043 TROPICS WINDOW Specified at order CTP241 LINE amp PWR INTERFACE SUBASSEMBLY AC 4592 BATTERY CT25039 INTERNAL HEATERS SUBASSEMBLY CT3675 TILT ANGLE SENSOR 69 User s Guide 70 Part no Description Notes CTB22 OPTICAL SUBASSEMBLY CTT21 LASER TRANSMITTER CTR21 RECEIVER CTL21 OPTICS MONITOR CT25015 COMPENSATION FIBER DMF51 BOARD FRAME DMC50B PROCESSOR BOARD DPS52 DC CONVERTER BOARD DCT52 CEILOMETER INTERFACE BOARD DMX55 MODEM BOARD Specified at order DMX50 MODEM BOARD Specified at order DM35945 DMX50 CONNECTION ADAPTER CT3681 BATTERY SWITCH SUBASSEMBLY CT3696 COAXIAL CABLE CT4697 OPTICS MONITOR CABLE CT1679 SHIELD CT2614 BLOWER 230 VAC Specified at order CT2688 BLOWER 115 VAC Specified at order CT25106 PEDESTAL metal Specified at order CT2665 PEDESTAL fiberglass Specified at order CT3839 POWER LINE CABLE CT3838 DATA CABLE CT3709 POWER TERMINATION BOX Specified at order CT3707 SIGNAL TERMINATION BOX Specified at order TERMBOX TERMINATION BOX Specified at order 1200 POWER amp SIGNAL PSION MAINTENANCE TERMINAL Specified at order CT35198 PC TERMINAL CABLE Specified at order 17430 DOOR KEY SOUTHCO E3 3 CT45155 ALLEN KEY 6mm CT25KWBK WEDGE BOLT KIT CT25184 OPTICAL TERMINATION HOOD Specified a
52. A Check that the transmitter is now in the correct position that is the sides of the transmitter case are approx parallel with the edges of the lower part of the Optical Subassembly If this is not the case loosen the attachment ring first then correct the transmitter position and fasten as described above 125 User s Guide 126 Attach the ribbon cable connector to the DMF51 Board Frame to connector J10 Refer to Figure 30 on page 123 Connect the Power Cable and the Maintenance Terminal Turn the power on If the transmitter has been replaced by a new one do the following a Then Open the command set by first typing at the command prompt and then typing the password ADVANCED I Interrupt autoadjustments with the command STOP give the following commands SET DATA AUTOADJ OFF J Sets the autoadjustments off SET PORT TIMEOUT 20 1 Sets the timeout of the dialog to 20 minutes SET DATA INTERVAL 154 Sets interval for measurement and message sending to 15 seconds First check the prevailing settings with the command GET FACTORY J The value of INLASER tells the prevailing factory setting of the Transmitter Calibration Factor Note the Calibration Factor of the transmitter written on the subassembly If the transmitter has been replaced and the Calibration Factor differs from the prevailing factory setting give the new Calibration Factor value 7 new factory setting
53. Check the data messages by using the maintenance terminal see section Data Messages on page 45 7 Check the adjustment of the unit see section Prevailing Parameter Settings on page 59 8 Check the status message see section Data Messages on page 45 The diagnosis is made on the basis of the information given in the status message see section Troubleshooting on page 115 NOTE Service has to be done according to instructions given in this manual and are allowed for trained personnel only As a principle customer made repairs are restricted to replacement of subassemblies only 120 M210345en A Chapter 8 Repair CHAPTER 8 REPAIR General Replacing a subassembly comes into question when there is reason to suspect that malfunction of the Ceilometer CT25K is caused by a fault in that subassembly CAUTION Servicing the equipment must be performed by qualified personnel Writing Conventions Used Replacement of a subassembly may require parameter settings that are specified in the description of that subassembly The commands are expressed in this manual as follows COMMAND where COMMAND Command given by the user can consist of several command words and parameters e g GET STATUS J lt l Symbolizes pressing the ENTER key VAISALA 121 User s Guide NOTE All words of the commands shall be separated from each other by a space character i e by pressing the space bar Every
54. EFERENCE ad ZL au a z ge Ea 8 EO 2 ES ad AN 3u Om z ro Alo z 20 Ele i zlin SENSOR ANALOG MEASUREMENTS 9412 083 The DMC50B Processor Board is the central processing unit of the CT25K It performs the following functions A to D conversion of signals from various internal sensors Data processing under a powerful real time operating system Serial communication with external devices M210345en A Chapter 5 VAISALA Functional Description Internal subassembly control Built in tests of the whole system Processor The DMCSOB has a fully static 16 bit CMOS processor type 80C188EB This processor is especially designed for very low power applications and it can be switched by software to its low power idle mode between tasks FLASH EEPROM memory is used as storage for the real time operating system and application specific code files The SRAM memory stores the variables and serves as an intermediate database A Watchdog timer is employed to assure a complete system reset in the event of system malfunction A to D Converter Analog data is digitized by a fast 12 bit A to D Converter located on the DMCSOB Board The converted data is analyzed by the processor and used for various purposes e g internal monitoring Serial Communication Ports A UART Universal Asynchronous Receiver Transmitter controls the serial com
55. EFFOFOF2FOEFFOEFEFFO 160F2F2EFFI1FAFl1F2F2F1F3F2F2EFFIEFFOFOEFFIEFFOFIEFFOFOF2FOEFFOEFEFFO l76EEFIEFEDEFEEEFEEEEFOEDFOF2EFEDEFEFEFFOEFECECECEEEAFOEDEDECEAEAEA 192bEFIEFEDEFEEEFEEEEFOEDFOF2EFEDEFEFEFFOEFECECECEEEAFOEDEDECEAEAEA 208EEFIEFEDEFEEEFEEEEFOEDFOF2EFEDEFEFEFFOEFECECECEEEAFOEDEDECEAEAEA 224FOECEFEDFOECEBEEEDEEEO9EAEFFOEEECEAEDECEBEAEEE7EDEAEAEAEBECEAEAEA 240FOECEFEDFOECEBEEEDEEEO9EAEFFOEEECEAEDECEBEAEEE7EDO00000000000000004 4 19 line 16 692 1104 char 12th line 3 char total 1193 char Transmission time and size 5 0 s at 2400 baud 10 bit char 143 kbytes h 3 44 Mbytes d 103 Mbytes mo at 2 msg min uncompressed Interpretation of the message is as follows IST LINE Identical to that of message no 1 except that the two last digits identifying the message are always 23 2ND LINE Identical to that of message no 1 3RD LINE Example 100 N 53 34 204 146 2 621 LF7HN1 139d 49 User s Guide 50 Measurement parameters are mostly in engineering units Plus and minus signs are possible Out of Range is indicated by slashes Contents 100 Parameter SCALE 100 is normal 0 999 possible N Measurement mode N Normal C Close range not available in CT25K 53 Laser pulse energy of nominal factory setting 0 999 34 Laser temperature degrees C 50 99 204 receiver sensitivity of nominal factory setting 0
56. ITS METERS Reported heights unit is meters SET MESSAGE WARN DELAY OFF Warning character W is set in message immediately SET MESSAGE WARN DELAY ON Warning character W is set in message after 5 minutes delay SET OPER MODE CONTINUOUS Operation mode Continuous measurement mode SET OPER MODE STANDBY Standby mode no measurement unless commanded by START initiates one cycle SET PORT TIMEOUT 2 60 Timeout for automatic CLOSE of dialog mode Value is minutes Default 2 minutes SET PORT MAINTENANCE BAUD B300 Set maintenance port bit rate to 300 bits s SET PORT MAINTENANCE BAUD B2400 42 Set maintenance port bit rate to 2400 bits s M210345en A Chapter 4 Operation Command SET PORT MAINTENANCE BAUD B4800 Description Set maintenance port bit rate to 4800 bits s SET PORT MAINTENANCE BAUD B9600 Set maintenance port bit rate to 9600 bits s SET PORT DATA MODEM BELL 103 300 bits s modem mode Note Requires DMX50 modem SET PORT DATA MODEM V21 300 bits s modem mode SET PORT DATA MODEM BELL 212A 1200 bits s modem mode SET PORT DATA MODEM V22 1200 bits s modem mode SET PORT DATA MODEM V23 FDX 1200 bits s 4 wire full duplex Note Requires hardware configuration SET PORT DATA MODEM V42 NORMAL 1200 2400 bits s modem mode with error correction V 22bis V 42bis SET PORT DATA MODEM V42 BIS 1200
57. Ki A A A AU 3 115 230 X 5 K2 4 115 230 5 SGND 2d Ji 9807 051 Figure 25 CT25039 Wiring Diagram The Internal Heaters subassembly CT25039 increases the temperature in the area of the optical subassembly to prevent the lens and the measurement unit window from becoming wet or misty At the same time it also keeps the whole interior above condensation temperature The heating subassembly consists of two power resistors with radiation elements made of aluminium This provides a good thermal contact with the base plate and transmission of heat to the ambient air Thermal switches protect the system against overheating At 230 V supply voltage the resistors are connected in series by the line voltage selection switch in the subassembly CTP241 and at 115 V supply voltage they are connected in parallel A relay in the CTP241 switches power on off under software control via DPS52 The heating resistors can be very hot even after the heating has been switched off Be cautious when working in the vicinity of the heating Specifications Maximum power 180W 115VAC 15 230VAC 71595 Max surface temperature 130 C Heating resistors R1 R2 resistance 2209 power 100W M210345en A Chapter 5 Functional Description Thermal switches K1 K2 switch temperature 95 2 105 C nominal current 2 5 operating voltage 250 VAC VAISALA 93 User s Guide Tilt Angle
58. LINE DATA IN RxD RD AN1HI MODEM LINE B DATA OUT TxD SD AN1LO NEUTRAL L2 IN POWER EARTH LINE 115 230VAC IN not connected HEATER POWER OUT NEUTRAL L2 OUT BLOWER POWER OUT POWER EARTH TEMPERATURE SENSOR B IN TEMPERATURE SENSORA IN not connected 9807 046 External Connectors bottom view The Window Conditioner warm air blower mounted in the Shield is connected to J1 Line Power input is connected to J2 Remote communication is normally connected to J3 A local maintenance terminal for example a laptop or a palmtop is intended to be connected to J4 A protective cap is included for covering J4 when not in use External mating connectors with 2 m 7 ft cable are included for J2 and for J3 The power plug of the J2 cable can be cut when the unit is permanently installed at the final site The cables for J2 and J3 are intended to be drawn through the hole of the pedestal to the connectors Provide sufficient slack for permitting the unit to be tilted later 29 User s Guide NOTE Before connecting power check the voltage setting of the CTP241 Line and Power Interface voltage setting shown between the switches F1 and F2 see Figure 8 on page 33 Figure 7 below shows the connecting signal leads with optional Power and Signal Termination Boxes POWER TERMINATION BOX SIGNAL TERMINATION BOX r 9 2 2 x o R R gt a a
59. MPERATURES BLOWER CPU LASER LENS OUTSIDE INHEATER OFF TRANSMITTER PLEN L POTY 64K OUT 1270mV SENS 100 IN 190 ENVIRONMENT 20C WINDOW 200mV 100 32C RADIANCE 69mV 28C ANGLE 5DEG M 32C HUMIDITY NONE 20C OUTHEATER OFF BLOWER OFF M after the angle value indicates the use of a manual value M210345en A Chapter 5 Functional Description CHAPTER 5 FUNCTIONAL DESCRIPTION Theory of Operation Basic Principle of Operation The operating principle of the CT25K Ceilometer is based on measurement of the time needed for a short pulse of light to traverse the atmosphere from the Transmitter of the Ceilometer to a backscattering cloud base and back to the Receiver of the Ceilometer With the speed of light being c 2 99 x 10 m s 186 000 miles per second A reflection from 25 000 ft will be seen by the receiver after 50 9 us where c is the speed of light Practical Measurement Signal Generally particles at all heights backscatter light and so the actual return signal may look like that shown in Figure 11 on page 64 VAISALA 63 User s Guide 64 BACKSCATTER SIGNAL PRECIPITATION CLOUD BASE VISION BLOCKED BY CLOUD HEIGHT 9807 047 Figure 11 Typical Measurement Signal The instantaneous magnitude of the return signal will provide information on the backscatter properties of the atmosphere at a certain height From the return signal information about fog
60. OARSE COMP FINE COMP RECEIVER TEST VALUE CLEAN WINDOW CEILO gt GET MESSAGE MESSAGE ANGLE CORRECTION HEIGHT OFFSET NOISE H2 COMPENSATION PROFILE SCALE PORT TYPE UNITS MODE ON 15 SEC 10 MHz 188 64K 12 109 96 185 1200 13 125 350 200mV ON 0 OFF 100 DATA MSG1 FEET AUTOSEND 210345 Chapter 4 Operation cEILO gt GET OPER MODE OPERATION MODE CONTINUOUS CEILO gt GET PORT MAINTENANCE PORT BAUDS 2400 E71 DATA PORT BAUDS 300 E71 MODEM CCITT 300 MODEM STATUS ON YOU ARE USING MAINTENANCE PORT CEILO GET UNIT ID UNIT ID 0 NOTE ndividual values are automatically adjusted by the software ndividual original factory settings or updated original settings in conjunction with subassembly replacement Manual Angle Setting VAISALA The automatic tilt angle measurement can be disabled and replaced with a manual value To set the manual angle value type CEILO SADV ANCED PASSWORD ACCEPTED CEILOSSET MESSAGE ANGLE MEAS MANUAL 5 MANUAL ANGLE 5 To check the current state of tilt angle setting get the status message CEILO gt GET STATUS VOLTAGES UNIT 0 1V P12 130 M12 122 P5G 53 M5G 54 VCA 220 P13 126 M13 121 P5R 49 M5R 48 BAT 121 P18 176 PHV 2755 PFB 20 P65 769 CHA 121 61 User s Guide 62 RECEIVER GAIN H BAND N SAMP 10MHz SENS OK COMP 013 125 TE
61. P241 Replacement WARNING The Line amp Power Subassembly contains dangerous voltage of 115 VAC 230 VAC even when the Power Switch F1 is turned off Do not connect the Power Cable to an unmounted Line amp Power Subassembly 144 M210345en A Chapter 8 Repair NOTE Before connecting power check the voltage setting of the CTP241 Line and Power Interface voltage setting shown between the switches F1 and F2 see Figure 8 on page 33 1 the CTP241 in your hand Turn cables P6 P8 so that they stay on the cover of the subassembly Set the CTP241 in its place 2 Setthe screw and spacer that connects the CTP241 to the battery holder in places Tighten the screw slightly by fingers see Figure 37 on page 144 3 Connect the plug in Connectors P7 and P8 to the DMC50 Processor Board and modem if installed See the drawing on the front panel for the correct positions 4 Connect the AC Power Interface Connector to the Board Frame DMF51 J15 Refer to Figure 30 on page 123 Plug Internal Heater cable into connector J5 on the CTP241 6 the Ceilometer to horizontal position Turn the 6 screws at the bottom of the CT25K clockwise Figure 37 on page 144 and push then slightly until they go through the holes in the gasket of the connector flange Then tighten the screws normally 8 Tighten the screw that connects the CTP241 to the battery holder Figure 37 on page 144 to normal tightness
62. Return Line Feed Polling command examples lt Enq gt CT11 lt Enter gt Message 1 from ceilometer nr 1 lt Enq gt CT12 lt Enter gt Message 2 from ceilometer nr 1 lt Enq gt CT1S lt Enter gt Status message from ceilometer nr 1 NOTE If the id character in a polling string is replaced with a blank space all ceilometers on the line will respond Accordingly if No is a blank space CT25K sends the default message Prevailing Parameter Settings The prevailing control and parameter settings that chiefly determine operation can be seen by the following GET commands Shown parameter values are equal to standard factory settings but may vary depending on installation in question Operator input is marked in CAPITAL Times letters after the command prompt CEILO gt and the Ceilometer response under the operator input as COURIER font In case you want to change parameter values see section Factory Settings of User Programmable Parameters on page 35 for settings of user programmable parameters CEILO gt GET ALGORITHM NOISE SCALE 1 7 MINIMUM SUM 30 MINIMUM EXTCO 6 0 VAISALA 59 User s Guide 60 CEILO gt GET DATA AUTOADJUSTMENTS DATA ACO INTERVAL RECEIVER GAIN BANDWIDTH SAMPLING RATE TRANSMITTER LENGTH OF PULSE POWER OF PULSE QUANTITY OF PULSES COMPENSATION COARSE COMPENSATION FINE COMPENSATION CEILO gt GET FACTORY FACTORY BEAMSPLITTER IN LASER OUT LASER C
63. Sensor CT3675 The built in tilt angle sensor CT3675 enables accurate cloud base measurements in a tilted direction See section Using the Tilt Feature on page 27 for information about alternatives on how to use the tilt feature Mounting position in vertically pointed CT25K WHT P1 SIGNALS ji 1L 10 GND id 2L 0 12V 1 10 Uout i YEL RED 0208 069 Figure 26 CT3675 Tilt Angle Sensor 94 M210345en A Chapter 5 VAISALA Functional Description The tilt angle sensor CT3675 contains a silicon micromechanical acceleration sensor It measures the Earth s gravitational force as projected on the ceilometer axis Every change in its position from vertical results in a measurement signal dependent on the angle which ranges from 15 to 90 degrees from vertical Internal temperature compensation and linearization circuits provide high stability The output voltage of the angle sensor is digitized through the processor board A to D converter and used for automatic correction calculation which enables accurate function in a tilted direction Automatic correction can be disabled with command SET MESSAGE ANGLE COR OFF Tilt angle can also be set manually as described in section Manual Angle Setting on page 61 95 User s Guide Window Conditioner CT2614 CT2688 CT2614 Mo VAISALA TYPE NO CT2614 230 VAC 50 Hz 250 W CT2688 VAISALA TYPE NO CT2688 115 VAC 60 Hz 25
64. Specifications eene Seren n EP ra 151 Mechanical 2 ie haee 151 External Connector J1 Window conditioner 152 External Connector J2 Power 152 tee eM 152 External Connector J3 Data line 153 External Connector J4 Maintenance Line 155 Modem Options nei Ie dede erts 155 Modem Board 55 155 Modem Board 50 156 T anSmitter oodd torneo mtcr otc cd om ecce tt sae 156 R6G6lVOE 2 tute tetera hs Ale otis teal 157 Optical System 157 s ra dett eI 157 Environmental Conditions eese 157 INDEX c 159 List of Figures Figure 1 CT25K Ceilometer a tenens 18 Figure 2 Measurement Unit Handle sse 22 Figure 3 Foundation Construction sssessseee 23 Figure 4 Mounting the 25 Figure 5 Attaching the Measurement Unit and the Shield 26 Figure 6 External Connectors bottom view 29 Figure 7 Termination Box Wire 3
65. Transmitter CTT21 as described in section Replacement on page 125 Step 4 The internal Cross talk Compensation does not need adjusting in this case Instead give the command SET ALGORITHM DEFAULTS l c parameter settings for the Receiver CTR21 as described in section Replacement on page 134 Step 7 The internal Cross talk Compensation does not need adjusting Instead give the command SET DATA ACQ AUTOADJ ON 4l d Restore the maintenance and data line communication speed message type interval units etc as required if defaults are not to be used M210345en A Chapter 8 Repair Line amp Power Subassembly CTP241 Removal When there is reason to suspect malfunction in the Line amp Power Subassembly CTP241 do as follows WARNING The Line amp Power Subassembly contains dangerous voltage of 115 VAC 230 VAC Turn the power off according to section Start Up Procedure for Replacement AIl Parts on page 122 before you continue NOTE If the Ceilometer is installed outdoors and a replacement unit is not immediately available it is advisable either to bring the unit indoors or cover the exposed opening with tape to protect the interior against water insects etc 1 Ifthe Ceilometer is mounted on a pedestal loosen the two attachment screws and tilt the Ceilometer to a horizontal position If the Ceilometer is already demounted from the pedestal and brought indoors place the unit on a
66. Use extreme caution when handling testing and adjusting VAISALA Laser Safety To guarantee the eye safety of the laser equipment the cable connecting the subassembly is short permitting operation only when the installation is complete For removing the laser transmitter subassembly the cable between the transmitter and the laser interface board must be disconnected first Receiver CTR21 Y 4 X CX N er a LL vigeo oyt 300k 15MHz 7 29 3 MHz 3 28 30k Gain select Bandwidth 6 56 select Gain control Bandwidth control _ _ 9807 049 Figure 17 CTR21 Block Diagram The Receiver subassembly CTR21 consists of two identical avalanche photo diodes APDs The second APD compensates most of the optical cross talk appearing in the lens system through signal reflection by means of a half bridge connection The first APD receives the actual measuring signal and sends the pulse current through a transimpedance amplifier with selectable gain At the output of this amplifier the signal is a voltage signal transferred further through a filter with a frequency limit of 15 MHz to a second signal amplifier According to the operating mode the signal goes further to a new amplifier stage or to a combined additional filter with a frequency limit of 3 MHz and an amplifier The amplifier gain is selected by the system automatically so that the smallest noise signal appearing in the measurem
67. Vvoltages ON ON 5V voltages OFF 1 4 OFF Receiver voltages OFF ON Receiver voltages ON 87 User s Guide 88 Specifications Input voltages Power inputs Voltage ranges AC 10 22VAC DC 11 5 30VDC Il AC 9 12VAC Il DC 9 16VDC Output voltages Signal name Acceptable range V Nominal current A 5V 5 0 5 8 5V 5 8 5 0 5VDISC 5 0 5 8 18V 16 0 18 5 12V 12 0 13 5 12V 13 5 11 5 65V 60 90 13VR 12 0 14 0 13VR 14 0 12 0 5VR 4 8 5 2 5VR 5 8 4 5 400VR 360 425 VBAT 11 5 16 5 M210345en A Chapter 5 VAISALA Functional Description Ceilometer Interface Board DCT52 LASER TEMPERATURE TO FROM VOLTAGE CONTROL E TRANSMITTER PULSE LENGTH SELECT TESTPULSE MONITOR CTT21 TRIGGER PULSE ENERGY CTL21 WINDOW CONTAMINATION RADIANCE OPTICS TEMPERATURE VOLTAGE CONTROL GAIN SELECT BANDWIDTH SELECT TILTANGLE ANGLE TO FROM TUNI 2 x SENSOR RECEIVER DCT52 BACKSCATTER CTR21 TIMING amp EN 1 OUT VIDEO SIGNAL i DATABUS TO FROM FIRST IN PROCESSOR FIRST OUT DMC50B ADDER C 9412 082 Figure 23 DCT52 Block Diagram The Ceilometer Interface Board DCT52 together with the Processor Board DMC50B are the main components
68. allation grounding periodically to minimize shock hazard CAUTION Do not modify the unit Improper modification can damage the product or lead to malfunction Safety Summary The following safety precautions must be observed during all phases of operation service and repair of this instrument WARNING Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Vaisala Oyj assumes no liability for the customer s failure to comply with these requirements Laser Safety The CT25K is classified as a Class 1M laser device in accordance with International Standard IEC EN 60 825 1 It is also classified in accordance with U S regulation 21 CFR 1040 as a Class 1 laser device This means that a CT25K Ceilometer installed in a field environment with instrument covers on and pointed vertically or near vertically poses no established biological hazard to humans 12 M210345en A Chapter 1 General Information WARNING WARNING WARNING VAISALA The device is equipped with the following label The instrument is intended for operation in an area restricted from public access and to be pointed vertically or near vertically up The following precautions are to be noted and followed during service and maintenance of the instrument Never look directly into the Laser Transmitter with magnifying optics
69. and detach the Coaxial Cable from the receiver 6 Ifthe Coaxial Cable is found defective replace with a new one refer to section Replacement below Replacement To replace the Coaxial Cable see section Start Up Procedure for Replacement All Parts on page 122 for replacement l Attach the new Coaxial Cable to connector J2 of the receiver Note the marked ends of the cable Take the Receiver CTR21 in your hand and set it in place The ribbon and coaxial cables come out from the back side Rotate the attachment ring see Figure 34 on page 133 first by hand and then tighten it using a 2 5 mm hexagon key as a lever If the receiver begins to move along carefully stop it by hand from rotating NOTE Do not apply force to the receiver itself because it may disturb the centering VAISALA Check the receiver correct position that is the long edges of the receiver case are approx horizontal If this is not the case loosen the attachment ring first then correct the receiver position and fasten as described above Plug the Compensation Fiber into the receiver and tighten the screw marked Fibre attachment with a 1 5 mm hexagon key Attach the Coaxial Cable to the connector J1 at the front panel of DCT52 Attach the ribbon cable connector to DMF51 Card Cage to connector J11 Refer to Figure 30 on page 123 Connect the Power Cable and the Maintenance Terminal Turn the power on No parameter settings a
70. and subassemblies is listed in Table 9 on page 69 The technical description is split into subparagraphs according to Unit Block Diagram illustrated in Figure 14 on page 71 For more detailed block diagrams and descriptions see section Module Descriptions on page 74 CT35042 STANDARD WINDOW ASSEMBLY CTL21 OPTICS MONITOR CT25039 INTERNAL HEATERS SUBASSEMBLY CT3675 DMF51 FRAME TILT ANGLE SENSOR DPS52 DC CONVERTER BOARD DMC50B PROCESSOR BOARD MODEM BOARD OPTIONAL DCT52 CEILOMETER INTERFACE BOARD CTB22 OPTICAL SUBASSEMBLY CTR21 RECEIVER CTT21 LASER TRANSMITTER BATTERY 4592 AND CT3681 BATTERY SWITCH SUBASSEMBLY of CTP241 LINE amp POWER NTERFACE SUBASSEMBLY AC 9412 035 Figure 12 Measurement Unit Components 68 M210345en A Chapter 5 VAISALA WINDOW CONDITIONER CT2614 CT2688 CTL21 CT3675 RECEIVER TILT SENSOR Y OPTICAL 1 SUBASS Y LASER TRANSMITTER 21 Monor Functional Description INTERNAL HEATER CT25039 FRAME DMF51 Board CTP241 LINE amp PWR INTERFACE SUBASS Y 5 DMX50 MODEM BOARD WITH DM35945 CONNECTION ADAPTER J6 49 9806 002 Figure 13 Subassembly Interconnections Table
71. ansmitter ninar Let tate A te Ede beet e eere est 156 RecelVer iet e ern doe e ie ins 157 Optical System cicero dd ni n ane 157 Performance ied ete tette e eame eus 157 Environmental Conditions esee 157 User s Guide This page intentionally left blank 8 M210345en A Chapter 1 General Information CHAPTER 1 GENERAL INFORMATION About This Manual This manual provides information for installing operating and maintaining the CT25K Ceilometer Contents of This Manual This manual consists of the following chapters VAISALA Chapter 1 General Information provides important safety revision history and warranty information for the product Chapter 2 Product Overview introduces the CT25K Ceilometer features advantages and the product nomenclature Chapter 3 Installation provides you with information that is intended to help you install this product Chapter 4 Operation contains information that is needed to operate this product Chapter 5 Functional Description gives a functional description on the product Chapter 6 Maintenance provides information that is needed in basic maintenance of the product Chapter 7 Troubleshooting describes common problems their probable causes and remedies and contact information Chapter 8 Repair explains how to repair the product User s Guide 10 Chapter 9 Technical Data provides the technical data
72. as been detected i e the limits have been exceeded the software sends warning and alarm messages which can be seen by the STATUS message see section Status Message S on page 55 73 User s Guide Module Descriptions Optical Subassembly CTB22 0208 067 Figure 15 Optical Subassembly CTB22 with Optics Monitor Transmitter and Receiver Subassemblies 74 M210345en A Chapter 5 VAISALA Functional Description The following numbers refer to Figure 15 on page 74 1 Lens 2 CIL21 Optics monitor 3 CT3656 Compensation fiber 4 CTT21 Laser transmitter 5 CTR21 Receiver 6 CTB22 Optical subassembly Description The optical subassembly consists of the following major units the conical optical tube with fixture for the lens a precise beam integrator block at the lower end including a beamsplitter and a narrow band filter and a connection flange for the laser transmitter and receiver subassemblies The receiver and transmitter subassemblies are factory aligned and focused to the optimum They can be replaced any time by new assemblies without need for readjustment The adjustment necessary for the compensation of the optical crosstalk after replacement of the receiver or transmitter subassembly can be made by means of a graphical presentation on a maintenance terminal At the upper end of the optical tube is the Optics Monitor for control of the laser performance window contamina
73. ase at the bottom left or upper middle in Figure 33 on page 131 is reached When this is achieved tighten the M3 slotted screw well again and make the fine adjustment with the B screw Secure the M3 screw with red paint Continue to finish the replacement operation as in steps 8 and 9 above NOTE The adjustments at the Center Block end must be very small 0 2 mm or so and you have to wait a couple of seconds before the effect is seen on the terminal Optics Monitor CTL21 VAISALA Removal When there is reason to suspect malfunction of the Optics Monitor do as follows See section Start Up Procedure for Replacement Parts on page 122 1 Detach the ribbon cable connector from the Optics Monitor CTL21 Mark with pencil the position of the CTL21 in order to replace it correctly 139 User s Guide 140 Loosen the two screws Figure 35 below with a screwdriver The optics monitor ribbon cable remains attached to section Optical Subassembly CTB22 on page 74 Send the defective Optics Monitor to Vaisala CTL21 OPTICS MONITOR FACTOR LOOSEN THE SCREWS NOTE THE POSITION OF THE CTL21 TO REPLACE IT RIGHT 9511 025 Figure 35 Removing the Optics Monitor Replacement To replace Optics Monitor CTL21 l Fasten the Optics Monitor CTL21 to the Ceilometer with two screws Figure 35 above The previous horizontal position of the CTL21 is a good estimate of
74. at the factory for operation and safety The following safety precautions however must be taken into account WARNING Open data lines can have a static charge Handle the connection wires especially carefully do not touch them during a thunderstorm The existing voltages can be dangerous 100 M210345en A Chapter 5 Functional Description LED Indicators The DMX50 Modem features the following front panel LED indicators STATUS Modem operation status blinking when the processor is active RI Ring Indicator LINE Indicates that the modem is online off hook CD Carrier Detection is ON when the carrier signal is received TXD Transmitted Data RXD Received Data SPEED Indicates that modem line speed is 2400 bits sec blank when 300 to 1200 bits sec MR Modem Ready blinking once per sec when Test Mode is active Connector layout DSR Data Set Ready DTR Data Terminal Ready CD Carrier Detection RTS Request to Send CTS Clear to Send TXD Transmitted Data RXD Received Data GND Ground 4 pin connector This connector carries telephone line audio signals for special applications and SHALL NOT BE CONNECTED when the DMX50 is to be used over public telephone lines 6 pin connector For line connection The attached modular telephone cable connector shall be connected to this jack VAISALA 101 User s Guide Sky Condition Algorithm General The CT25K sky condition algorithm uses a time series
75. ced indoors or outdoors with fog or clouds below 1 000 ft present then an Optical Termination Hood CT25184 must be used to prevent the receiver from saturating from the backscatter signal Optical termination hoods can be purchased from Vaisala 122 M210345en A Chapter 8 VAISALA Repair Refer to Figure 30 below for cable connections of the subassemblies 0208 068 Figure 30 Board Connectors of the DMF51 Board Frame The following numbers refer to Figure 30 above 1 2 3 4 J3 Optics monitor J4 Local display DMCSOB Processor board DPS52 DC converter board 123 User s Guide The following numbers refer to Figure 30 above J14 12V local battery J15 AC power interface J11 Receiver J10 Transmitter DCT52 Ceilometr interface board Modem board optional Jl Tilt angle sensor CT3675 OOo tA ll ll Il Transmitter CTT21 WARNING Removal The laser diode at Laser Transmitter CTT21 emits invisible laser power which is harmful to the eye if viewed at short distance Never remove the transmitter from its normal position without first switching both the line and the battery power off and detaching the ribbon cable of Laser Transmitter CTT21 from the Board Frame DMFS5I When there is reason to suspect malfunction of the Transmitter turn the power off Note Paragraph 8 3
76. dically randomly How many failed only one defect other same or similar defects several failures in one unit What was connected to the product and to which connectors Input power source type voltage and list of other items lighting heaters motors etc that were connected to the same power output What was done when the failure was noticed Include a detailed return address with your preferred shipping method on the Problem Report Pack the faulty product using an ESD protection bag of good quality with proper cushioning material in a strong box of adequate size Please include the Problem Report in the same box Send the box to Vaisala Oyj SWD Service Vanha Nurmij rventie 21 FIN 01670 Vantaa Finland 149 User s Guide This page intentionally left blank 150 M210345en A Chapter 9 Technical Data CHAPTER 9 TECHNICAL DATA This chapter provides the technical data of the CT25K Ceilometer Specifications VAISALA Mechanical Table 19 Property Dimensions Measurement unit Height with shield and pedestal CT25K Ceilometr Mechanical Specifications Description Value 760 x 280 x 245 mm 30 x 11 x 10 in 1320 mm 52 in Weight Measurement unit Shield Metal pedestal Fiberglass pedestal option Cardboard transport container size Cardboard transport container weight Plywood transport container size Plywood transport container weight
77. direction with magnifying optics Maintenance Bytilting the unit back 15 degrees better access is gained to the interior during maintenance Inthe tropics Between the latitudes of 25 degrees where the sun can be straight above the unit a slight tilting prevents the laser from direct sun radiation which would otherwise destroy the laser The other alternative is to use a tropics window on the measurement unit instead of a standard window As these advantages are partly contradictory and cannot or need not all be realized the user must decide the final installation direction In doing so the following must be observed NOTE Unless a tropics window is used the unit must never be directed so that the sun shines directly into the optics because the lens will focus all radiation into a very hot spot 28 Cable Connections All external connectors to the Measurement Unit are located at the bottom left edge as seen from the door direction Figure 6 on page 29 shows the external connectors J1 J2 J3 and J4 M210345en A Chapter 3 Installation J4 MAINTENANCE LINE J3 DATA LINE J2 POWER INPUT J1 WINDOW CONDITIONER VAISALA O female male Figure 6 12V OUT DATA OUT DATA IN SIGNAL amp EQUIPMENT GND SIGNAL GND spare i o SD AN2HI EQUIPMENT GND 12V OUT spare i o RD AN2LO MODEM
78. e Set internal crosstalk compensation setting fine code value SET DATA ACQ TRANSMIT POWER OF P value Set pulse energy input code value SET FACTORY INLASER value Set pulse energy input code value at startup SET FACTORY OUTLASER value Set pulse energy target value for software adjustment SET FACTORY RECVALUE value Set receiver test reference value SET FACTORY WIN CLEAN value Set clean window reference value SET MESSAGE ANGLE MEAS AUTO Automatic angle measurement for angle correction SET MESSAGE ANGLE MEAS MANUAL 0 89 Manual angle value degrees for angle correction SET MESSAGE MANUAL MSG 30 01000 02000 03000 12345678 Set test message example SET MESSAGE MANUAL MSG Cancels manual message SET MESSAGE VLIM 1 100 Set vertical visibility reporting limit 96 for sky condition SET OPER MODE COMP MONIT 44 Run internal crosstalk compensation monitor until M210345en A Chapter 4 Operation Command Description ESC SET OPTION SKY COND ON code Activate sky condition option with CPU board specific code number SET OPTION SKY COND OFF Deactivate sky condition option SET OPTION HUMITTER ON Enable humitter option SET OPTION HUMITTER OFF Disable humitter option SET OPTION BLOWER ON Enable blower related status and warning information needs reset SET OPTION BLOWER OFF Di
79. e 29 Table 30 Manual Revisloris mE 10 Revision ae 10 Hardware 11 Related Man als teta 11 CT25K Ceilometer Main Parts Nomenclature 19 Factory Parameter 5 36 User Level Commands 5 e enne 42 Advanced Level Commands 44 Parts EISE eco e ooa eese 69 Technical Information 84 DIP Switch Settings of the DMC50 85 Weight Factors ete rte eb eti 103 Bin ciens 103 Minimum Number of Counts Hits for Each Layer 104 Minimum Distance Between Different Cloud Layers 104 Warnings oeste aito tede t RR dde 116 eg RR hae aon ne An as ela 118 Miscellaneous cedro eere 118 CT25K Ceilometr Mechanical Specifications 151 Window Conditioner 152 Power Input 1 even eda eda eiu a 152 Data Line eb ited eatin lee 153 Maintenance Line 155 Modem Board 55 155 Modem Board 5 156 Tr
80. e 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 CT3675 Tilt Angle Sensor sse 94 Window Conditioner CT2614 CT2688 96 DMX55 Block Diagram eene 98 DMX50 Block Diagram enm 100 Board Connectors of the DMF51 Board Frame 123 Removing the Laser 125 Adjusting the Compensation esee 129 Compensation Graph 131 Removing the 133 Removing the Optics 140 Boards of the DMF51 Board Frame 141 Removing Line and Power Interface Subassembly CTP241 144 Internal Heater Replacement 147 Battery 148 Data Line Connection Options 154 List of Tables VAISALA Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Table 17 Table 18 Table 19 Table 20 Table 21 Table 22 Table 23 Table 24 Table 25 Table 26 Table 27 Table 28 Tabl
81. e laser and 89 User s Guide WARNING for angle measurement of the tilt angle Controlled by the processor it connects the analog signals to the A to D converter of the processor board The timing and control circuit takes care of the triggering and length of the laser pulse and simultaneously for the selection of receiver gain and bandwidth The system parameters as they are defined in the configuration and factory settings are stored in a special EEPROM on the DCT52 board The data transmission to and from the EEPROM is carried out through an I C Bus which is independent of the actual Data Bus Line and Power Interface Subassembly CTP241 Line AC power is connected to the Line Power and Interface Subassembly CTP241 where it gets transformed down to low voltage AC for supplying the DC Converter DPS52 Further the CTP241 contains relays for controlling the Internal Heater CT25039 and the external Window Conditioner blower motor and airflow heater Internal heating and window conditioning are under software control via DC Converter DPS52 Line Power and Interface Subassembly CTP241 Internal Heaters Subassembly CT25039 and Window Conditioner CT2614 or CT2688 contain Line AC voltage which may be lethal 90 M210345en A Chapter 5 Functional Description M to DPS52 y LINE LS a P6 1 l 1 l 1 1 2 18V i 1 1 I 1 l 1 1 1 1 1 1 1 1 1 1 1 1 l 1 1 I 1
82. e laser pulse a small fraction of energy is also reflected back into the receiver by the optics surfaces of the unit Due to the tremendous sensitivity of the receiver this optical cross talk could seriously distort the profile and therefore it needs to be neutralized This is done by a secondary APD which gets its input from an optical fiber light guide placed so that it only sees the M210345en A Chapter 5 VAISALA Functional Description outgoing laser pulse but not the backscatter The two APD s are connected in a half bridge configuration whereby most of the optics cross talk signal is substracted from the measurement signal For best possible balancing of the bridge the compensating APD gain is under software control through the DAC of the DCT52 The backscatter measurement sampling actually starts before the launch of the laser pulse and thus the resulting distortion is visible to the software in the raw measurement profile and this is iteratively kept within limits Internal Monitoring and Control All essential subassembly functions are monitored continuously to ensure measurement accuracy and reliability Temperature laser performance etc is measured by sensors and transferred to Processor Board DMC50B converted from analog to digital by its Monitor A to D Converter and further analyzed by the processor software Warning and Alarm limits are defined in software through parameter settings In case a malfunction h
83. e measurement unit handle for lifting and carrying See Figure 2 on page 22 VAISALA 21 User s Guide 9412 033 Figure 2 Measurement Unit Handle If mishandling occurs during transit or installation the instrument should be returned to a Vaisala office or authorized Depot for inspection Foundation The standard foundation for the CT25K ground installation is a concrete foundation The minimum dimensions suggested are presented in Figure 3 on page 23 Mounting hardware is included with the delivery 22 M210345en A Chapter 3 Installation GROUND LEVEL SLOPE 1 50 HORIZONTAL TO 3 SLOPE 1 50 R 2 x 4 Ss S N J So E DEPTH DEPENDING ON LOCAL FROST CONDITIONS SUGGESTED MINIMUM 450 500 FOUNDATION SCREW M10 4 pcs HORIZONTAL TO 3 P SLOPE 1 50 4 WEDGEBOLT M10x40 4 pcs 9412 027 Figure 3 Foundation Construction There are two alternative ways to make a foundation to cast a new or to use an existing foundation Ifanew foundation is laid the M10x40 Wedge Bolts and Foundation Screws 4 each are suggested to be cast into the concrete so that approx 30 mm 1 25 in of the foundation screw threads stand above the surface VAISALA 23 User s Guide 24 Ifan existing foundation is used four holes of diameter 12 mm and depth
84. e receiver Instructions To check the normal operation of the CT25K do the following steps 1 Clean the window carefully with a soft lint free cloth moistened with mild detergent Be careful not to scratch the window surface VAISALA 111 User s Guide 112 If you are indoors put the Optical termination hood black hat on the ceilometer window From the ceilometers point of view this corresponds to a clear nighttime sky Connect the maintenance terminal to the maintenance port at the bottom of the CT25K Turn on both the CT25K and the maintenance terminal If you are using the palmtop or the CT VIEW program for the first time do the necessary installation according to the corresponding User s Guide instructions Check that the operation of the ceilometer starts normally as follows After power up routines the MEAS LED D4 LED Light Emitting Diode on the DCT52 board periodically lights 12 seconds and the cycle is repeated according to the programmed data acquisition interval In the DC Converter DPS52 Board LED D1 should be blinking yellow and LED D2 should be stable green Also in the Processor board LED STATUS should be blinking at a 1 second interval 5 Get the status message as follows Press ENTER on the maintenance terminal PC keyboard and a CT prompt should appear Give the command OPEN and press enter CT OPEN 4 A gt prompt should appear Give command GET STATUS and press enter
85. ection OFF gives less noisy appearance PROFILE SCALE 100 Scales backscatter values of message No 2 and corresponding SUM value PORT DATA Optional selection MAINTENANCE TYPE MSGI Message No 1 Options MSG2 MSG3 MSG6 MSG7 and Status S UNITS FEET Option METERS Note also HEIGHT OFFSET M210345en A Chapter 3 VAISALA Installation Responce to User s Menu Commands Standard Factory Settings of User s Menu Parameters Notes WARNING DELAY OFF Option ON Sets a 5 minutes delay for warning oper mode OPERATION MODE CONTINUOUS Option STANDBY requires command START for carrying out each cycle Options MODEM NAME INSTALLED Modem name is DMX55 or DMX50 SKY CONDITION INACTIVE ACTIVE HUMITTER INACTIVE ACTIVE BLOWER ACTIVE INACTIVE port MAINTENANCE PORT 2400 E71 Optional baud rates 300 2400 BAUDS 4800 9600 DATA PORT BAUDS 300 E71 Optional baud rates 300 1200 2400 4800 9600 NOTE Reverts to 300 if standard modem DMXSS is plugged in 2400 is factory setting if this modem is not present MODEM CCITT 300 If modem DMX55 installed Options ITU T V 21 and V23 4 wire DMX50 V42 BIS If modem DMX50 is installed MODE 1200 9600 Options Bell 103 Bell 212A ITU T V 21 ITU T V 22 V42 MODE V42 BIS MODE MODEM STATUS ON OFF YOU ARE USING DATA PORT Option MAINTENANCE PORT unit id UNIT ID 0 Insert
86. ees from vertical GET VALUE OTHERS POWER OF P Print measured value of laser pulse power units mV at A to D converter input GET VALUE OTHERS RADIANCE Print measured value of background radiance units mV at A to D converter input GET VALUE OTHERS WINDOW Print measured value of window contamination monitor units mV at A to D converter input GET VALUE TEMPERATURE BLOWER Print value of measured blower temperature units C GET VALUE TEMPERATURE CPU Print value of measured CPU board temperature units C GET VALUE TEMPERATURE LASER Print value of measured laser temperature units C GET VALUE TEMPERATURE LENS Print value of measured temperature adjacent to lens units C GET VALUE TEMPERATURE OUTSIDE VAISALA Print value of measured outside temperature units C 43 User s Guide Command GET VALUE VOLTAGE BCIRCUIT Description Print status of battery circuit connected disconnected 1 0 GET VALUE VOLTAGE BATTERY Print value of battery voltage approx 13 V GET VALUE VOLTAGE CHARGE Print value of battery charge voltage approx 13 V GET VALUE VOLTAGE VCA Print value of internal raw voltage approx 25 V GET VALUE VOLTAGE PHV Print receiver high voltage approx 25 V GET VALUE VOLTAGE PFB Print value of receiver switcher internal feedback voltage approx 2 V GET VALUE VOLTAGE P65 P
87. els become 0 and 5 V External Connector J3 Data line The data line is intended to be used for measurement data communication but it can also be used with Ceilometer Maintenance Terminal PC or other terminals Table 22 Data Line Property Description Value Connector J3 Type Binder series 693 09 4227 00 07 7 pin male Mating connector type Type Binder series 693 99 4226 70 07 female elbow Baud Rate 2400 baud standard with RS 232 300 4800 and 9600 baud available 300 bit s with modem DMX55 2400 bit s standard with modem DMX50 300 1200 2400 bit s available Data compression allows up to 9600 bit s throughput Max Distance to Operate 300m 1000 ft with RS 232 1 2 km 4000 ft with RS 422 and RS 485 all at 2400 baud with typical communication cables 16 km 10 mi with Modem 16 km 10 mi with Modem Standard Character Frame 1 Start Bit 7 Data Bits Even Parity 1 Stop Bit Standard Character Code USASCII Pin Connections 1 RD AN2Lo 2 Modem Lead A RxD RD AN1Hi 3 Modem Lead B TxD SD AN1Lo 4 Signal Ground 5 SD AN2Hi 6 12 V DC supply 200 mA max for 1 hour 100 mA continuous for external equipment VAISALA 153 User s Guide Modem circuits are non polar and symmetrical All modem circuits are electrically floating to overvoltage protection rating 300V 500 V Overvoltage Protection in each circuit Primary Noble Gas Surge
88. ent signal is bigger than the resolution of the flash AD converter of the Ceilometer User s Guide Interface Board DCT52 The biggest measurement signal must not exceed the full measurement range of the flash AD converter The gain control as well as the bandwidth selection are automatic and controlled by the processor software and the DCT52 WARNING Dangerous voltages are present in this instrument Use extreme caution when handling testing and adjusting Optics Monitor CTL21 Laser em On LED 9 gt Window Il L gt Contamination Signal Out T3 Bud Blink Timer 14 Sample ER Timer 2 Hold Laser Pulse Energy Signal Out PAM I Laser ts Test LED Trigger In Test Optics lens LED ot Temperature Out Pulse Optics Temperature Sensor 9807 048 Figure 18 CTL21 Block Diagram The laser pulse train sent from the laser transmitter CTT21 is monitored by two PIN photodiodes After a corresponding amplification and AD conversion on the processor board the signal is used as a control signal for the laser output power The pulses also give a start signal for a sample amp hold circuit which through a further photodiode measures the light reflected back from the window due to contamination This signal is also transferred further to the processor board A to D Converter and software to give an indication of window 78 M21
89. eries 693 09 4224 06 04 4 pin male Mating connector type Type Binder series 693 99 4221 70 04 female elbow Baud Rate 2400 baud standard and default 300 4800 9600 baud available Distance to Operate 300 m 1000 ft at 2400 baud with typical communication cables Standard Character Frame 1 Start Bit 7 Data Bits Even Parity 1 Stop Bit Standard Character Code USASCII Pin Connections 1 RxD RD 0 5 V 2 TxD SD 0 5 V 3 12 V DC supply from internal battery 100 mA continuous 200 mA max 4 Signal Ground Equipment Ground Overvoltage Protection in each Primary Noble Gas Surge circuit Arrester Secondary Transient Zener Diodes or normal Diodes Modem Options Modem Board DMX55 ITU T V 21 V 23 4 wire full duplex modem interface for serial asynchronous data interchange Table 24 Modem Board DMX55 Property Description Value Data Rate 300 bit s 1200 bits s V23 Modulation method FSK Signal Level 10 dBm 0 3 V into 600 Ohm standard Jumper selectable Max Distance to Operate 0 16 km 0 10 miles with 22 AWG 0 35 mm unshielded twisted pair 155 User s Guide 156 The signal circuit is electrically floating to overvoltage protection rating 300V 500V Modem Board DMX50 Table 25 Modem Board DMX50 Property Description Value Processor Intel 80C32 custom version Modem Signal Processor Chip Silicon Systems SSI 73K224L Modem standa
90. ers 1 000 ft Unexpected behavior is not totally excluded if e g a strong reflector saturates the receiver When tilting the unit make sure that nobody is watching it with binoculars or other magnifying optics M210345en A Chapter 3 VAISALA Installation Settings for Normal Operation Switch settings for normal operation are as follows Main circuit breaker F1 ON Window conditioner circuit breaker ON Battery switch ON Data message and interface configuration and the configuration of measuring interval and transmission speed are standard factory settings When required the settings can be changed by giving commands with the terminal During the factory alignment procedure the optical adjustments are carefully carried out to fulfill the requirements and specifications of the device Optical adjustments have been made at factory or depot thus there is no need to readjust in the field Factory Settings of User Programmable Parameters Table 6 on page 36 shows the standard factory settings of user programmable parameters The prevailing parameter settings can be seen by the command GET parameter group Parameter groups are displayed as bold text in Table 6 on page 36 As response to the command a list of parameters with prevailing parameter values is shown The standard factory set parameter values which may be changed by the user are collected in the second column in Table 6 on page 36 The values d
91. etach the Receiver Ribbon Cable Connector from the connector J11 at the DMF51 Board Frame by pressing the connector latches apart Refer to Figure 30 on page 123 Detach the Coaxial Cable from the DCT52 front panel 4 Loosen the attachment ring See Figure 34 below using a 2 5 mm hexagon key as a lever there are holes in the attachment ring for that purpose If the Receiver begins to move along stop it by hand The photo diode has been centered at the factory do not apply force to the Receiver because that may disturb the centering Take the receiver into your hand and detach the Coaxial Cable from it 5 Send the defective receiver to Vaisala VIEWED FROM THE RECEIVER CIRCUIT BOARD SIDE LIGHT LEVEL ADJUSTMENT DETACH THE COMPENSATION FIBER A Y USING 1 5 MM HEX KEY A T CTR21 RECEIVER CT25015 COMPENSATION FIBER COMPENSATION FIBRE ATTACHMENT UNSCREW THE ATTACHMENT RING CTR21 RECEIVER Figure 34 USING 2 5 mm HEX KEY ATTACHMENT RING 9511 023 Removing the Receiver 133 User s Guide Replacement To replace Receiver CTR21 Refer to section Start Up Procedure for Replacement All Parts on page 122 1 Attach the Coaxial Cable to connector J2 at the receiver Note the marked ends of the cable 2 Take the Receiver into your hand and set it in place Note the right position the
92. face Board DCT52 green LED D4 goes on during the laser pulse train for about 12 seconds and is repeated according to the configuration in question After power up it may take a couple of minutes before the unit starts normal operation If LEDs operate in a different way than described above the unit may need service or maintenance Refer to Chapter 7 Troubleshooting on page 111 M210345en A Chapter 3 VAISALA Installation D4 MEAS D2 PWR OK D3 ACCESS D1 ACCESS DPS52 DC CONVERTER BOARD DCT52 CEILOMETER INTERFACE BOARD RESET LED STATUS LED MODEM BOARD RESET PUSH BUTTON OPTIONAL DMC50B OPTION PROCESSOR BOARD O DMF51 FRAME FRONT VIEW Jeoooococo BATTERY ON OFF TOP VIEW PART NO CTP241 SERIAL NO F1 MAIN CIRCUIT ON F2 BREAKER WINDOW CONDITIONER POWER ON OFF OFF HSV OFF NS CIRCUIT BREAKER 115V F1 2ASLo F2 3AsLO EQUIPMENT WINDOW POWER CONDITIONER 9412 036 Figure 8 CT25K Switches and LEDs Mobile Operation Aspects The small and lightweight CT25K Ceilometer is suitable also for mobile operation It has a built in 12V battery which enables 33 User s Guide operation without external power supply for about an hour in normal room temperature NOTE For switching power to the CT25K fully OFF turn also the Battery
93. g indicating its nominal voltage The heating resistors can be very hot even after the heating has been switched off Be cautious when handling in the vicinity of the heating Maintenance Terminal Option A palmtop computer is offered as an optional light weight maintenance terminal It is a pocket size terminal with high resolution display and it includes RAM and FLASHRAM for data storage Two standard Mignon AA batteries enable operation for abot 40 hours The palmtop is connected to the CT25K s maintenance line connector J4 with the PC Terminal Cable CT35198 Standard port settings are the following Baud rate 2400 Data bits 7 Stop bits 1 Parity Even Ignore parity Yes 97 User s Guide For further information about the terminal see manuals included in the delivery Modem DMX55 Option PICOBUS int t 1 X5 B interrupt IN e 5k11 123 1 OPTO ISOLATION COUT continuously on CIN LED VB NC RELAY LOOPON 20 TED dle 4 Ru _ _ RELAY gt a lt RX level 1 adjust 1 22V 470 33k2 EURO CONNECTOR SIGNALS DIN 41612 ID EEPROM P2 RECEIVERS DRIVERS 5V 3 LOOP ON p POWER VB SUPPLY SUPPLY OK SECTION LED Figure 28 DMXSS Block Diagram 1 eos LOOP 9412 084 Modem DMX55 is a universal modem primarily for fixed point to p
94. g lines should appear example Msg 1 CTA20100 2 oo 00000200 Od Reading instructions for the second line identical in all messages Message O O MM HHL Ill FEDCBA98 Position 1 2 3 4 5 6 113 User s Guide 114 Position 1 Position 2 Position 3 Position 6 0 indicates that no cloud layers are detected 0 indicates that there are no warnings or alarms W indicates a warning and A indicates an alarm indicates no cloud heights Alarm A Warning W and internal status information Each character is a hexadecimal representation of four bits altogether 32 bits with the following breakdown Interpretation as follows F 8000 0000 Laser temperature shut off A 4000 0000 Laser failure A 2000 0000 Receiver failure A 1000 0000 Voltage failure A E 0800 0000 spare A 0400 0000 spare A 0200 0000 spare A 0100 0000 spare A D 0080 0000 Window contaminated W 0040 0000 Battery low W 0020 0000 Laser power low W 0010 0000 Laser temperature high or low W C 0008 0000 Internal temperature high or low W 0004 0000 Voltage high or low W 0002 0000 Relative Humidity is gt 85 96 option W 0001 0000 Receiver cross talk compensation poor W B 0000 8000 Blower suspect 0000 4000 spare W 0000 2000 spare W 0000 1000 spare W A 0000 0800 Blower is ON 0000 0
95. gnal detected IMIII Highest cloud base height Laser temperature shut off A Laser failure A Receiver failure A Voltage failure A spare A spare A spare A spare A Window contaminated W Battery low W Laser power low W Laser temperature high or low W Internal temperature high or low W 47 User s Guide b18 0004 0000 Voltage high or low W b17 0002 0000 Relative Humidity is gt 85 96 option W b16 0001 0000 Receiver optical cross talk compensation poor W B b15 0000 8000 Blower suspect b14 0000 4000 spare W b13 0000 2000 spare W b12 0000 1000 spare W A bll 0000 0800 Blower is ON b10 0000 0400 Blower heater is ON b09 00000200 Internal heater is ON b08 00000100 Units are METERS if ON else FEET 9 607 0000 0080 Polling mode is ON b06 0000 0040 Working from battery b05 0000 0020 Single sequence mode is ON b04 0000 0010 Manual settings are effective 8 b03 0000 0008 Tilt angle is gt 45 degrees b02 0000 0004 High background radiance b01 0000 0002 Manual blower control b00 00000001 spare For example if the window is contaminated the battery voltage is too low the internal heater is on and units are meters a warning is given and the second line appears as OW 00C00300 3RD LINE Od End of Text and CRLF Data Message No 2 Data message no 2 contains the range and sensitivity normalized backscatter profile w
96. h number of line Height of the 2nd cloud layer 17 000 ft or 1 700 m depending on feet or meter selection 0 The fifth number of line Cloud amount of the 3rd layer in oktas The sixth number of line Height of the 3rd cloud layer 0 The seventh number of line Cloud amount of the 4th layer in oktas The eighth number of line Height of the 4th cloud layer 53 User s Guide The reporting resolution is 100 ft or 10 m depending on feet or meter selection If the cloud amount is zero the corresponding layer height is Data Message No 7 Message number 7 is similar to message number 2 but extended with a sky condition see section Sky Condition Algorithm on page 102 line The sky condition line is identical to that of message number 6 For interpretation see section Data Message No 2 on page 48 and section Data Message No 6 on page 52 Below is an example of message number 7 13 CTA2073Q l 50 000002004 100 N 101 19 90 200 6 21 LF7HN1 27d 0000003000400030003000300020003000300030001000100010000000000000000 l 0160000000000000000000000000000FFFF00010000000200000001FFFFFFFE0000 l 032FFFCOO000FFFE00000001FFFF000000010000FFFE000000020000000000000004 l 0480000FFFE00030007FFFE0000FFFEFFFE000100050011FFFF000000000000FFFE l 0640001FFFEFFFF0000000000020000000100000000FFFF00010003FFFEFFFE0000 l 08000010000FFFF0002FFFEFFFEFFFEFFFD000000020001FFFEFFFD000000000001 l 0960002000300000000000000010000FFFF00
97. he PORT is set to DATA Operation mode standby Open the terminal program and first give OPEN command and then GET OPER MODE command Check that the OPERATION MODE is CONTINUOUS Cloud detection missing Alarm or warning in the data message Open the terminal program and first give OPEN command and then GET STATUS command Check that the there are no alarms or warnings CT25K parameters are not correct Compare parameters with the parameters of the delivery documents Reduced capacity to see high clouds Broken or misplaced compensation fiber Failure Diagnosis When sky is clear but GAIN is low and PLEN is short the fiber is most likely broken Remove the optical fiber carefully Place the other end near a light source If the light is dim at the other end of the fiber the fiber is damaged Replace it In case of malfunction do the following f VAISALA Check the cable connections see section see section Cable Connections on page 28 Check the presence and correctness of the line voltage Check the operation states of the LEDs in the unit see section Startup Procedure on page 32 119 User s Guide 4 data line check that the connection and the configuration is correct see sections Output Interface on page 152 and Cable Connections on page 28 5 Switch on the unit see section Startup Procedure on page 32 all switches to position ON 6
98. he instantaneous return signal strength is in general form the Lidar equation 2 0 2 2 2 Eo S S B e 2 2 where P z Is the instantaneous power received from distance z W Watt Eo Is the effective pulse energy taking all optics attenuation into account J Joule Ws Watt second s the speed of light m s meters per second A Is the receiver aperture m 7 s the distance in question m B z Is the volume backscatter coefficient at distance z m srad srad steradian 2 0 Is two way atmospheric transmittance and accounts for the attenuation of transmitted and backscattered power by extinction at various distances z between transceiver and distance in question z The expression equals 1 in a clear atmosphere 1 no attenuation Height Normalization Assuming a clear atmosphere it can be seen that the power is inversely proportional to the square of the distance or height i e the strength of a signal from 10 000 ft is generally one hundredth of that from 1 000 ft The height square dependence is eliminated by multiplying the value measured with the square of the height height normalization However noise being height independent from a measurement point of view will then be correspondingly accentuated with increasing height 65 User s Guide 66 The Backscatter Coefficient The volume backscatter coefficie
99. iables as follows TEMPERATURE BLOWER 20C Temperatue measured at the Window Conditioner blower airfow exit e g 20 deg C CPU 34C Temperature on the microprocessor CPU Board e g 34 deg C LASER 29C Temperature measured at the laser diode e g 29 deg C LENS 34C Temperature measured adjacent to the lens e g 34 deg C OUTSIDE 23C Temperature measured by the external sensor at connectors e g 23 deg C ENVIRONMENT WINDOW 210mV Value of window contamination 102 measurement e g 210 mV and ratio in per cent compared to factory setting e g 102 RADIANCE 60mV Value of background radiance measurement e g 60 mV ANGLE 3DEG Value of tilt angle relative to vertical e g 3 degrees Positive value means that door of the unit tilts towards ground HUMIDITYNONE Relative Humidity in per cent inside the ceilometer if sensor is furnished LINE 21 Status of Internal Heater INHEATER ON OFF Window Conditioner Heater OUTHEATER ON OFF Window Conditioner Blower BLOWER ON OFF LINE 22 Od End of Text and CRLF VAISALA 57 User s Guide Manual Message The ceilometer can be set to transmit user defined cloud heights and status information The user can set a cloud message in the format of line 2 of any real cloud message e g Msg 1 The message must be between quotation marks see example This message is volatile The manual message command is behind the password adva
100. ic Maintenance VAISALA Periodic maintenance is normally limited to window cleaning In addition Warnings and Alarms should be checked regularly with the maintenance terminal or another terminal or PC with serial connection See section Status Message S on page 55 Proper function of the Window Conditioner air blower the only mechanically moving part should also be checked Alarms and Warnings The data message has to be checked for alarms and warnings at regular intervals At the second character of line two there is Warning and Alarm information indicating the present status of the device as follows 0 Self check OK W At least one Warning active no Alarms A At least one Alarm active In case there is an active alarm or warning more information is given at the end of the second line as a binary code indicating the cause The status message gives detailed information about the failure see section Data Messages on page 45 107 User s Guide Repair and service must be done according to instructions in Chapter 7 Troubleshooting on page 111 and Chapter 8 Repair on page 121 Window Cleaning The lens and window should always be clean of any dirt or particles during operation Data messages include a warning if the window is contaminated After the system has detected the contamination it starts the blower which removes contamination caused by precipitation etc Ifthe Window Contaminated warning does not disa
101. ifs VAISALA USER S GUIDE Vaisala Laser Ceilometer CT25K M210345en A PUBLISHED BY Vaisala Oyj Phone int 358 9 8949 1 P O Box 26 Fax 358 9 8949 2227 FIN 00421 Helsinki Finland Visit our Internet pages at http www vaisala com Vaisala 2006 No part of this manual may be reproduced in any form or by any means electronic or mechanical including photocopying nor may its contents be communicated to a third party without prior written permission of the copyright holder The contents are subject to change without prior notice 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 Table of Contents CHAPTER 1 GENERAL nnne n nette nnn nn ennt 9 About This Manual eese enne 9 Contents of This Manual sss 9 Version Information sssssssssssssseeeeeee 10 Related Manuals sss 11 Safety nne agone He etre 11 General Safety Considerations 11 Product Related Safety 12 Safety Summary eene 12 Easeroafety esi ioo eerie De dove 12 ESD Pr
102. in obtaining the LIDAR backscatter signal controlling the laser transmitter as well as in real time processing of the backscatter signal from the receiver as described in section LIDAR Measurement on page 70 Additionally the ceilometer interface board DCT52 contains special circuitry for the timing of all activities and a very fast flash A to D Converter The backscatter signal detected by the photodiode in the receiver is sampled in real time in this subassembly at the speed equal to that of the light beam in the atmosphere sent from the laser transmitter All Range Gates are sampled at each laser pulse and digitized by means of the 8 bit flash A to D converter They are stored in a First In First Out FIFO memory according to the height profile see Figure 23 above For improving the Signal to Noise Ratio a large number of laser pulses is utilized and the samples are added to the FIFO memory in digital format This way a complete backscatter profile is then available at the end of a complete measurement cycle The raw values are sent via a data bus directly to the Random Access Memory on the processor board to be algorithmically evaluated A Digital to Analog converter outputs control signals to the laser transmitter and receiver The D to A converter is also controlled through the data bus of the processor board A multiplexer contributes to the monitoring of different analog signals from the optics monitor for temperature measurement of th
103. ing 117 Voltage high or low warning 117 Window contamined warning 116 Wavelength 156 Wedge bolts 23 Window cleaning 108 Window conditioner CT2614 CT2688 96 Writing conventions 121 X xxx values 113 161 www vaisala com
104. is executed when ENTERed This way one needs to know only approximately what one wants to do and the system provides the necessary aid In addition to the user s menu and command set there is a second in depth maintenance and service level menu and command set which is intended for more profound system changes and diagnostics Password for this level is advanced Commands on this level should be used only according to instructions described in this manual 41 User s Guide Table 7 User Level Commands Command Description CLOSE Release port for message transmission i e abort command dialog SET CONTROL BLOWER ON Turn window conditioner blower on SET CONTROL BLOWER OFF Turn window conditioner blower off SET CONTROL BLOWER MANUAL Set window conditioner blower to manual control SET CONTROL BLOWER AUTO Set window conditioner blower to automatic control SET CONTROL INHEATER ON Turn internal heater on SET CONTROL INHEATER OFF Turn internal heater off SET CONTROL OUTHEATER ON Turn window conditioner heater on SET CONTROL OUTHEATER OFF Turn window conditioner heater off SET DATA ACQ INTERVAL 15 120 Set interval for measurement and message sending SET MESSAGE ANGLE COR ON Cloud and vertical visibility heights distances in messages ARE corrected for the tilt angle SET MESSAGE ANGLE COR OFF Cloud and vertical visibility heights distances in messages are NOT corrected for
105. isplayed in the first column are factory settings that the user cannot change For changing a value to the desired content and function depending on the particular installation the corresponding command is SET parameter group parameter 35 User s Guide 36 Table 6 Responce to User s Menu Commands Standard Factory Settings of User s Menu Parameters Factory Parameter Settings Notes CEILO gt get data acq AUTOADJUSTMENTS ON DATA ACQ 15 SEC 15 120 seconds available INTERVAL RECEIVER GAIN H BANDWIDTH N SAMPLING RATE 10 MHz Constant TRANSMITTER LENGTH OF PULSE L POWER OF PULSE 188 Varies with unit temperature and age QUANTITY OF 64K Constant PULSES COMPENSATION COARSE 13 Varies with unit and COMPENSATION contamination FINE COMPENSATION 125 Varies with unit and contamination Inessage MESSAGE ANGLE CORRECTION ON Shall be ON if unit is operated tilted May be ON even if unit is operated vertical Option OFF will turn detected values into distances rather than heights HEIGHT OFFSET 0 Insert installation height 1f signifi cantly different from reference zero height in reporting units MODE AUTOSEND Option POLLING Transmits date message only when polled NOISE H2 OFF Option ON Affects the visual COMPENSATION appearance of message No 2 graphical presentation Sel
106. istory Description CT25K model A First Release CT25K model B Enclosure CT1669 replaced with CT15035 Model A pedestal CT2665 Fiberglass is option New Metal Pedestal CT25106 is standard Line and Power Interface Subassembly CTP21 changed to CTP241 Internal Heaters Subassembly CT2690 replaced with CT25039 CTB22 Replaces CTB21 since 97 05 26 DMC50B Replaces DMC50A since 97 11 05 DPS52 Replaces DPS51 since 99 03 03 DCT52 Replaces DCT51 since 00 08 08 DMX55 No longer support for Bell 103 since 02 09 25 Related Manuals Table 4 Related Manuals Manual Code Manual Name U067en CT VIEW User s Guide M210310en Termination Box User s Guide General Safety Considerations Throughout the manual important safety considerations are highlighted as follows Warning alerts you to a serious hazard If you do not read and follow instructions very carefully at this point there is a risk of injury or even death Caution warns you of a potential hazard If you do not read and follow instructions carefully at this point the product could be damaged or important data could be lost 11 User s Guide NOTE Note highlights important information on using the product Product Related Safety Precautions The CT25K Ceilometer delivered to you has been tested for safety and approved as shipped from the factory Note the following precautions WARNING Ground the product and verify outdoor inst
107. ithin a range of 0 25000 ft which makes it suitable for e g graphical plotting of the atmosphere Data resolution is 100ft 30 m with distance and 16 bits four hex ASCII characters with signal magnitude NOTE Message no 2 should not be used with slow baud rate and short data acquisition interval this may lead to overflow of the transmit buffer E g 300 baud rate requires 45 sec data acquisition interval with message 2 In case the buffer is filling up the response time to user command may extend to minutes 48 M210345en A Chapter 4 VAISALA Operation An example of data message no 2 is presented below CTA2023 1st line 11 char 30 01230 12340 23450 FEDCBA 98 l 2nd line 31 char 100 53 34 204 146 2 621 LF7HN1 1394 3rd line 44 char 00047F200000000000000000000000000000000000000050D010000000000000000 01600FFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFEFEFEFEFEFEFEFEFEFEFDFDFDFDFDFD 03200FFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFEFEFEFEFEFEFEFEFEFEFDFDFDFDFDFD 048FDFDFDFDFDFCFCFCFCFCFCFCFCFBFBFBFBFBFBFBFAFBFAFBFBFAFAFBFAF9FAF9 064FDFDFDFDFDFCFCFCFCFCFCFCFCFBFBFBFBFBFBFBFAFBFAFBFBFAFAFBFAF9FAF9 080F9FAF9F9F9F9F9F9F9F8F7F8F7F9F8F7F7F8F6F7F7F7F6F6F7F6F7F6F6F6F6F6 096F9FAF9F9F9F9F9F9F9F8F7F8F7F9F8F7F7F8F6F7F7F7F6F6F7F6F7F6F6F6F6F6 l12F5F5F5F6F5F2FAF5F6F5F5FAFAFAFAF3FAF3FAF5F3F5FAFAF2F3F3F3F3FAFAF3 128F5F5F5F6F5F2FAF5F6F5F5FAFAFAFAF3FAF3FAF5F3F5FAFAF2F3F3F3F3FAFAF3 144F2F2EFFl1FAFl1F2F2F1F3F2F2EFFIEFFOFOEFFIEFFOFI
108. kkkkkkkkkkkxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxkkxkxk kkkkkkkkkkkkkxk ke ee ee ee ec e e v AG x kx x e ee e e ce eee e ce ecce ec ec ck ce ck e x e A k e x kx e kx kx kx kx kkkkkkkkkkkkkxk kkkkkkkkkkkkkkkkkkxk xe oe e e e eee ce ee cec ce eee e e e e e e e e e e e e e e e e ke e ke kx AX kkkkkkkkkkkkkxkxk kkkkkkkkkkkkkkkkkkkxk ee e e eee eee ce e e e e e ke e e e e e e e e e e e ke ck e e ee Ae e he He He de ee ce e ee e e e He ee He e ee ke ke ke ke k e e e k k e e kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk e e e e eee eee e e e e ee e e e e e e e e e e e e ce e e e e e e kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk CN IF THE PEAK IS UPWARDS TURN THE SCREW B CLOCKWISE KKKKKKKKKKKKKKK kkk k k k k k k k k k k k k kkkkkkkkkkkk kkk kkk k k kk k k k k k k kk kkkkkkkkkkkkkkk ke e e e e e e e e e e e kkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkk kkk kkk kkk kkk kkk kk kkkkkkkkkkkkkkkkkkkkk IF THE PEAK IS DOWNWARDS TURN THE SCREW B ANTICLOCKWISE Figure 33 Compensation Graph VAISALA 9512 010 131 Use r s Guide 5 Set the autoadjustments on with the following command SET DATA AUTOADJ ONJ 6 Wait for some minutes Give the command GET STATUS J Check from the status message under the title Receiver that the COMP values which are fine adjusted by the software are close to the original 13 Coarse and 125 Fine In case either of these values has changed more than 3 steps ca
109. lculate the following sum 17 x Coarse Fine If this value remains in the range 300 400 it is acceptable 7 Wait again for at least one measurement cycle 15 seconds and give the GET STATUS command Check once more from the status message the Receiver COMP values These should be the same as before indicating that the automatic adjustment has stabilized 8 Turn the power off and start the Ceilometer again in order to verify that the unit is operating properly Receiver CTR21 132 WARNING Removal Hazardous voltage 500 V is present at the Receiver and at the Board Frame DMFS51 Both the line and the battery switches must be turned off before removing the Receiver When there is reason to suspect malfunction of the Receiver i e Receiver Failure Alarm or Receiver Optical Crosstalk Compensation Poor Warning exist follow the instructions below First note section Start Up Procedure for Replacement All Parts on page 122 In case there is reason to suspect failure in the Coaxial Cable instead of the Receiver refer to section Coaxial Cable Replacement on page 136 In case the compensation fiber is suspected refer to section Compensation Fiber on page 138 M210345en A Chapter 8 VAISALA Repair 1 Detach the Compensation Fiber from the receiver by loosening the screw See Figure 34 below with a 1 5 mm hexagon key and pulling the fiber end gently out Do not twist the compensation fiber 2 D
110. m a lt a tr 22 2 lt 50 o oO 2202 d Q x a 230 115V 2 2 gt e S lt 0 10 O g I 5 BLU WHITE o gt gt a o 7 NEUTRAL L2 252 LINE 115 230VAC L1 L BRN BLACK Y a YIG GREEN 2 POWER EARTH PE t z a z O 1 c nc m z e X oO a T TEC 9412 037 Figure 7 Termination Box Wire Connections Suggested wire dimensions for the external cabling are Line Power Supply 3 x 1 5 mm AWG 16 Remote Communication Remote Communication NOTE When permanent line power installation is made the maximum size of the fuse protecting the power line is 10 A 30 M210345en A Chapter 3 VAISALA Installation Grounding The power supply connector J2 provides a standard protective ground for the instrument chassis The CT25K is equipped with a separate grounding screw on the measurement unit flange for external earthing see Figure 5 on page 26 Connection to a solid earth ground at the installation site is mandatory for adequate lighting and transient protection Connection of Maintenance Terminal Any terminal or PC with serial interface and terminal emulation program can be used for operation and maintenance of the CT25K Ceilometer A standard Maintenance Terminal option is offered including the following components PSION Palmtop Computer RS 232 cable CT35198 Technical Manuals for the
111. mizes recording sensitivity to a backscatter value of 100 10 000 km srad 4TH LINE Identical to the 3rd line of message no 3 Data Message No 4 Data message no 4 is not in use Data Message No 5 Data message no 5 is not in use Data Message No 6 Message number 6 is similar to message number 1 but extended with a sky condition line see section Sky Condition Algorithm on page 102 For interpretation see section Data Message No 1 on page 46 M210345en A Chapter 4 VAISALA Operation Message number 6 format example 2 CTA2060Q l 1st line 11 char 30 01230 12340 23450 FEDCBA98 2nd line 31 char 3 055 5 170 0 O 4 3rd line 30 char Od 4rd line 3 char total 75 characters Transmission time and size total 75 characters gt 0 31 s at 2400 baud 10 bit char gt 18 0 kBytes h 432 kBytes d 12 7 MBytes mo at 4 msg min uncompressed Message interpretation LINES 1 and 2 are indentical to that of Message number 1 LINE 3 Example 3 055 5 170 0 0 where 3 The first number of line detection status as follows 0 8 Cloud amount of the first layer in oktas 9 Vertical visibility 1 Data missing or the ceilometer is in standby mode 99 Not enough data after start up 055 The second number of line Height of the 1st cloud layer 5 500 ft or 550 m depending on feet or meter selection 5 The third number of line Cloud amount of the 2nd layer in oktas 170 The fourt
112. munication of the system The CT25K provides two serial communication ports MAINTENANCE external connector J4 Line Port A at Processor Board and DATA external connector J3 Line Port B at Processor Board Port B is intended to be used for measurement data communication and Port A for on site maintenance When desired port settings can be changed by corresponding software commands see section Factory Settings of User Programmable Parameters on page 35 and section User Commands on page 41 for more information The communication to the DC Converter DPS52 is carried out by Bus and to the Interface Board 52 by Bus and by address and data busses The DMCSOB Processor Board is built using surface mount technology on both sides and has no jumpers or IC sockets The DMCSOB is conformal coated for harsh conditions its temperature range extends from 50 C to 70 C 83 User s Guide 84 The DMC50B external communication connectors are located on the front edge of the processor board The cables can be disconnected for maintenance Technical Information Table 10 Technical Information Property Description Value Processor 16 Bit 80C188EB Intel Clock Speed 24 MHz 12 MHz Bus Memory FLASH EEPROM 640 kB STATIC RAM 256 kB 1 MB continuous memory addressing A to D Converter 12 Bit Accuracy 0 05 96 of FSR Speed 200 us Conversion Gain control Automatic and programmable Full scale ranges 2 5 V
113. nced Below is an example of a manual message CETLO gt advanced PASSWORD ACCEPTED CEILO gt set message manual_msg 30 00200 01000 05000 00000000 MANUAL MESSAGE 30 00200 01000 05000 00000000 If the given message does not have the correct format it is not accepted and an error message will follow To return to the normal measurement mode give an empty string CEILO gt set message manual_msg MANUAL MESSAGE NOT ACCEPTED USE FORMAT 30 00100 02000 15000 00000000 MESSAGE MODE IS NORMAL MEASUREMENT MODE The manual message is intended for testing purposes After reset the normal cloud detection mode takes effect Polling Mode 58 A port can be set to transmit a message only when polled by a predetermined polling string of characters The polling string can contain the message identification The CT25K unit can be assigned an identification of one character digit or letter The factory setting is 0 zero The polling mode is activated with the command CEILOSSET MESSAGE MODE POLLING and return to normal autosend mode is done with command CEILO gt SET MESSAGE MODE AUTOSEND M210345en A Chapter 4 Operation The polling string format is lt Enq gt CT dNo 4l where Is character ENQUIRE ASCII 05H control E CT Is fixed ceilometer identifier Id Is identification character 7 bit printable ASCII character No Is optional message identifier 1 2 3 6 7 S ENTER Carriage
114. nt B z of the Lidar Equation represents the portion of light which is reflected back towards the Ceilometer from a distance z e g by water droplets It is obvious that the denser a cloud is the stronger the reflection will be The relationship can be expressed as R z k o z where k sa constant of proportionality Il Is the extinction coefficient 1 e the attenuation factor in a forward direction o z The extinction coefficient relates to visibility in a straightforward manner If visibility is defined according to a 5 contrast threshold World Meteorological Organization definition for Meteorological Optical Range MOR equals daylight horizontal visibility then o 3 V where o the extinction coefficient V Is MOR visibility 5 contrast The constant of proportionality k also called the Lidar Ratio has been subjected to a lot of research Although the Lidar Equation can be solved without knowing its value it must remain constant with height if accurate estimates of the extinction or visibility profile are to be made It has been found that in many cases k can be assumed to equal 0 03 tending to be lower in high humidities to 0 02 and higher in low humidities to 0 05 However in e g precipitation of various kinds k will have a wider range of values Assuming a value 0 03 srad for k and visibility in clouds being in the range 15 150 m 50 500 ft gives the range of
115. of the CT25K Ceilometer INDEX Version Information Table 1 Manual Revisions Manual Code U059en 1 1 CT25K Ceilometer User s Guide M210345en A CT25K Ceilometer User s Guide this manual This manual covers ceilometer CT25K in all its configurations as defined by the parts and options listed in section Chapter 2 Product Overview on page 17 running under software revision CT25K 2 12 Table 2 below lists the revision history that may apply in comparison to other units in use Table 2 Revision History Software Revision Description CT25K 1 01 First Release CT25K 1 02 Intermediate release not in use CT25K 1 03 Intermediate release not in use CT25K 1 04 Production rev 95 05 15 97 02 03 CT25K 1 04h Special rev with Qualimetrics and DR21 messages CT25K 1 05 Production rev 97 02 03 CT25K 2 00 Production rev 97 11 01 CT25K 2 01 Production rev 98 03 17 CT25K 2 01a Production rev 99 02 09 CT25K 2 02 Special rev with higher reporting resolution CT25K 2 02a Special rev with higher reporting resolution CT25K 2 10 Special rev with Cibus interface CT25K 2 11 Production rev 00 08 08 CT25K 2 12 Production rev 02 09 19 Table 3 on page 11 lists the hardware history that may apply in comparison to other units in use M210345en A Chapter 1 General Information Safety WARNING CAUTION VAISALA Table 3 Hardware History Hardware H
116. oint connections The operation mode of the modem is set at the factory In CT25K the supported modes are V 21 and 4 wire V 23 Safety precautions Before delivery the DM X55 modem is tested at the factory for operation and safety The following safety precautions however must be taken into account WARNING Open data lines can have a static charge Handle the connection wires especially carefully do not touch them during a thunderstorm The existing voltages can be dangerous 98 M210345en A Chapter 5 VAISALA Functional Description LED Indicators STATUS Modem operation status blinking when the processor is active INT RI Interrupt Ring indicator COUT Transmitting data CIN Receiving data TXD Transmitted data data onto modem line RXD Received data data from modem line SUPPLY Power supply RELAY Indicator relay closed MR Modem Ready Connector layout The internal signal routing of the CT25K connects the modem outputs to connector J3 For further details refer to the wiring diagrams The front panel is provided with the following connections 6 pin RS 232 Connector P2 1 2 3 4 5 6 CD Carrier Detection RTS Request To Send CTS Clear To Send TXD Transmitted Data RXD Received Data GND Ground 11 pin Connector P1 8 amp 9 11 INT Interrupt INT Interrupt N C Normal Closed COM Relay Common N O Normal Open LINEIN Line In when sepa
117. oltage high or low warning Line voltage is not OK Check that the line voltage is present and correct DC Converter board DPS52 is damaged Check the status message If there is an asterisk the voltage exceeds the limits Relative humidity gt 85 warning option Water has been condensed inside the ceilometer Leakage in the enclosure or leakage in the door Take the ceilometer inside open the maintenance door and let it dry in a warm air conditioned place Condensed water on optical surface may disturb the measurement There is a danger for short circuits Receiver optical cross talk compensation poor warning Obstacle or dirt on the lens or on the window Check the optical surfaces Clean if contaminated The compensation fiber is damaged When sky is clear but the GAIN is low and the PLEN is short the fiber is most likely broken Remove the optical fiber carefully Place the other end near a light source If the light is dim at the other end of the fiber the fiber is damaged Replace it The compensation fiber is misplaced Do compensation adjustment following the replacement instructions see Chapter 8 Repair on page 121 Blower suspect warning Cable is not connected Check that the blower cable is connected Window conditioner circuit braker F2 is not ON Check that the window conditioner circuit braker F2 is ON Line voltage level is not
118. ompleted and the new value has been updated in the status message Give the command GET STATUS J Check from the status message that the WINDOW value percentage is in the range 97 103 This tells you the 127 User s Guide 128 present measured WINDOW contamination value compared to the factory setting j Then adjust the Internal Crosstalk Compensation according to section Compensation Adjustments below Turn the power off Then start the Ceilometer again and verify that it is operating properly Compensation Adjustments Internal crosstalk compensation must be adjusted after a transmitter a receiver or an optics monitor has been replaced or if the compensation fiber has been replaced Adjustment should be done in clear weather conditions or indoors using the Optical termination hood CT25184 After the command set has been opened using the password ADVANCED give the following commands l To interrupt autoadjustments give the command STOP J Then give the following commands SET DATA AUTOADJ OFF SET PORT TIMEOUT 204 which set the autoadjustments off and the timeout of the dialog to 20 minutes Give values for fine and coarse compensation as follows SET DATA ACQ COMP COARSE 13d SET DATA ACQ COMP FINE 125d Wait until a few measurement cycles have been completed To monitor the quality of the compensation give the command SET OPER MODE COMP MONIT I which gives you a graphical output a
119. only baseband However functionally the operation of the lines is identical the same commands operations and messages operate through any of the lines and the following description applies to both of them Factory default setting is 7 data bits Even parity 1 Stop bit and for baseband lines 2400 baud Baud rate is selectable in the user menu 7 bit USASCII character format is used Letter case UPPER lower can both be used response will use the upper case Standard operation of the serial lines requires no handshake signals A communication port i e serial line has two internal states Figure 10 on page 41 CLOSED Measurement data message transmitting state In this state messages are transmitted automatically at predetermined intervals or as a response to a polling input string depending on the corresponding settings User commands are not accepted except command OPEN which turns the line into the OPEN state No input is echoed but ENTER inputs are responded to by character string CT OPEN User dialog state In this state the user commands are responded to Command input is echoed A command prompt CEILO gt is displayed as an indication of readiness for command input from the user Command line termination and command execution is by key and character ENTER RETURN CARRIAGE RETURN No automatic measurement data message transmission is executed in the OPEN state The port reverts into the CLOSED state by command CLOSE Au
120. ontrol and parameter settings 59 Principle of operation 63 Processor 83 Processor board DMC50B 82 A to D converter 83 DIP switch settings 84 Processor 83 Serial communication ports 83 Technical information 84 Pulse properties 156 R Receiver 157 Receiver CTR21 77 Coaxial cable replacement 136 Removal 132 Replacement 134 Specifications 157 Technical description 77 Repetition rate 156 Resolution 64 157 Return Instructions 149 Return signal strength 65 Revision history 10 S SCALE 50 Secondary APD 72 Serial lines 39 CLOSED 40 DATA 39 MAINTENANCE 39 OPEN 40 Service connection 111 SET command 35 Shock absorber 20 Sky condition 52 54 102 Activation 103 Option code 102 Start up procedure for replacement 122 Storage 109 VAISALA SUM 34 50 Switch settings for normal operation 35 T Temperature 57 Termination boxes 19 Theory of operation 63 Thermal switches 92 Tilt angle 61 Tilt angle sensor CT3675 94 Tilt feature Hard target 28 In the tropics 28 Transimpedance amplifier 77 Transmitter 156 Transmitter CTT21 76 Calibration factor 126 Removal 124 Replacement 125 Transportation 21 Tropics window 20 28 Troubleshooting Alarms 118 Warnings 116 U User commands 41 V Vertical visibility 67 Volume backscatter coefficient 65 Warning check 107 Warnings 116 Laser power low warning 116 Laser temperature high or low warning 116 Receiver optical cross talk compensation poor warning 117 Relative humidity 28596 warn
121. orders such as Vaisala DR23 DD50 with printer etc The message is derived from Message no 2 by setting a threshold for the range and sensitivity normalized backscatter profile and reporting signal exceeding this threshold as a 1 and otherwise as a 0 The bit line gets split into groups of four successive range gates which are then transmitted as a string of 64 hexadecimal characters 0 F Message format example CTA20330Q l 1st line 11 char 30 01230 12340 23450 FEDCBA98 2nd line 31 char 00002204FFEFFF8C00000000627EEFFF310000000335A0BFFFFF100000000000 3rd line 66 char Od 4th line 3 char total 111 characters Transmission time and size 0 46 s at 2400 baud 10 bit char 26 64 kbytes h 639 kbytes d 19 18 Mbytes mo at 4 msg min uncompressed 51 User s Guide 52 Message interpretation IST LINE Identical to that of Message No 1 except that the second to last digit which identifies the message number is always 3 2ND LINE Identical to that of Message No 1 3RD LINE Example 00002204FFEFFF8C00000000627EEFFF310000000335AOBFFFFF100000000000 l 64 hexadecimal characters 0 F each bit in its binary format representing one of four subsequent range gates at 100 ft 30 m resolution Bit is set to 1 if its internal unscaled value in units of 10 000 km srad ref message no 2 exceeds 1 000 DID i e maximizing the value of parameter SCALE to 999 minimizes the threshold and thus maxi
122. otections an 15 Ecl PE 16 CHAPTER 2 PRODUCT OVERVIEW cca cecseseaetteecescsvadsntetheeccuctunncnsengecerenensaunceedev 17 Introduction to CT25K Ceilometer 17 Product Nomenclature esses 19 CHAPTER 3 INSTALLATION reote een 21 Installation Procedure esee 21 Unloading and Unpacking Instructions 21 Fo ndatlon eee aee d Ces e e pub rede dus 22 Assembling the Unit esee 24 Using the Tilt 27 Cable Connections ssssssssseeeen 28 Groufndirig i 5 amm thee toi deni 31 Connection of Maintenance Terminal 31 Setting up the 31 ODefatiOn eite ment dels 31 MD 32 Startup Procedure sese 32 Mobile Operation 33 Verification of Proper 34 Settings for Normal 35 Factory Settings of User Programmable Parameters 35 CHAPTER 4 OPERATION IT 39 Operation Modes 5 ore een eite erinnern 39 Serial Lines Open and Closed Port
123. power subassembly CTP241 90 Battery 4592 replacement instructions 147 Removal 143 Replacement 144 160 M Maintenance Alarms and warnings 107 Battery check 108 Manual angle setting 61 Manual message 58 Max irradiance 156 Measurement mode 50 Measurement parameters 50 Measurement range 157 Measurement signal 63 Measurement unit 68 Meteorological Optical Range MOR 66 Modem board DMX50 156 Modem board DMX55 155 Modem DMX50 100 Connector layout 101 LED indicators 101 Safety precautions 100 Switched point to point connections 100 Technical description 100 Modem DMX55 98 Connector layout 99 Fixed point to point connections 98 LED indicators 99 Safety precautions 98 Technical description 98 MOR 66 Motherboard 82 N Narrow band filter 75 No break power supply 152 Noise cancellation 64 40 Operating principle 63 Operation modes CONTINUOUS 39 STANDBY 39 Optical cross talk 72 TT Optical filter 157 Optical subassembly CTB22 74 Optical system 157 Optical termination hood 20 111 122 Optics monitor CTL21 78 Removal 139 Replacement 140 Output interface 152 Overvoltage protection 152 154 155 P Parts list 69 Password 41 M210345en A INDEX PC terminal cable 20 Performance 157 Pin connections 155 PIN photodiodes 78 Polling mode 58 Polling string 59 Polling string format 45 Power and signal termination boxes 30 Wire dimensions 30 Power consumption 152 Power disconnection 91 Prevailing c
124. ppear after a while the window has to be cleaned Toclean the window first flush it with clean water to remove coarse grains During this operation the enclosure door should be closed Clean the window with a soft lint free cloth moistened with a mild detergent Be careful not to scratch the window surface The condition of the Window Conditioner air blower can be checked with the maintenance terminal connected Give the commands SET CONTROL BLOWER ON SET CONTROL BLOWER OFF In case of malfunction the Window Conditioner has to be replaced The door of the measurement unit utilizes an electrically conductive rubber gasket to suppress electromagnetic radiation When the door is opened check that the gasket and the opposite contact surface are clean Use wet cloth for cleaning if necessary Battery Check Check the battery condition annually If any signs of aging is observed like bulging battery case white powder or residue near the battery vent leaking electrolyte corroded terminals etc replace the battery Lead acid batteries may age in 3 to 5 years time and result in a rupture and loss of electrolyte NOTE When disposing of old batteries be sure to do so in accordance with local environmental regulations 108 M210345en A Chapter 6 Maintenance NOTE In freezing temperatures there is a danger of battery rupture if the battery is completely discharged Do not store empty batteries in free
125. rate transmission and reception lines are used 4 wire connection LINE OUT Line In Out when standard 2 wire connection is used or only Line Out at separate wire for transmission and reception LOOP Power supply not used in CT25K LOOP Power supply not used in CT25K 99 User s Guide Modem DMX50 Option BASE DMX50 BOARD DAA501 ADD ON BOARD 1 26 VB HOOK IN X1 12 CONNECTOR RELAY JACK MODEM CHIP 2uF ll A 22MHz Bx SURGE AR pu RESTER N 1 6 8kB 128 kB 8kB Resse frit SRAM 256 kB EPROM ptr SURGE DRIVERS DETECTOR ARRESTERS RECEIVER 5 ID EPROM FC E i 25 M 1 5 L o4 ol_ ly 114 TxD RxD LED LED OPTO MISI TT ISOLATION p2 RESET rA 5 T oh Ho gt f Dil RING s i m AUDIO UT LOW DC AND AUDIO IN WATCHDOG CIRCUIT ID EPROM 10V 12V 5V 5V 10V SECTION AUDIO AMPLIFIERS EURO CONNECTORS AND SWITCHES SIGNALS CONTROLS 5 5V FC BUS oy AUDIO BUS lt gt 9707 011 Figure 29 DMX50 Block Diagram Modem DMX50 is a universal modem for fixed or switched point to point connections The operation mode of the modem is set at the factory The modem supports standards V 21 V 22 V22 bis and Bell 103 amp 212 Safety precautions Before delivery the DM X50 modem is tested
126. rds supported V 21 V 22 V 22bis and Bell 103 Bell 212 Modulation method 300 FSK 1200 DPSK 2400 QAM Compression amp error correction V 42 V 42bis and MNP 2 5 Adaptive equalization for optimum performance over all lines Transmitter Table 26 Transmitter Property Laser Source Description Value Indium Gallium Arsenide InGaAs Diode Laser Center Wavelength 905 5 nm at 25 77 F Operating Mode Pulsed Nominal Pulse Properties at Full Range Measurement Energy 1 6 uWs 20 factory adjustment Peak Power 16 W typical Width 50 100 ns typical Repetition Rate 5 57 kHz Average Power 8 9 mW full range measurement Max Irradiance 170 uW cm measured with 7 mm aperture Laser Classification Classified as Class 1M laser device in accordance with IEC EN 60 825 1 Class 1 in compliance with FDA CFR 1040 10 Subsection e 3 Beam Divergence 0 53 mrad edge 0 75 mrad diagonal M210345en A Chapter 9 Technical Data Receiver Table 27 Receiver Property Description Value Detector Silicon Avalanche Photodiode APD Responsivity at 905 nm 65 AW factory adjustment Surface Diameter 0 5 mm 0 02 in Interference Filter Center wavelength 908 nm typical 50 Pass Band 35 nm at 890 925 nm typical Transmissivity at 905 nm 80 typical 70 minimum Field of View Di
127. re needed Verify that the Ceilometer is operating properly 137 User s Guide Compensation Fiber Compensation Fiber Replacement The Compensation fiber is made from optical fiber Handle the fiber with care Don t twist Do not allow the ends of the fiber to be contaminated by grease or dust When there is reason to suspect malfunction of the Compensation fiber CT25015 do as follows See section Startup Procedure on page 32 1 Identify the black compensation fiber which leads from the CTR21 Receiver to the Center Block of the optics tube See Figure 32 on page 129 2 Check with care the position and alignment of the fiber at the Center Block end The fiber is attached with a flat metal part which is also supplied with the new fiber Mark the position of the edges of this part in respect to the Center Block with a pencil 3 the fiber attachment screw at the receiver bottom shown in Figure 32 on page 129 with a 1 5 mm hex key Take this fiber end gently out from the receiver 4 the MG slotted head screw sealed with red paint that fixes the fiber to the Center block Look at the replacement fiber and carefully note the shape of the end of the fiber Take the hooked fiber end carefully out from the center block 5 You can visually compare the old and new fibers now If the old fiber is totally broken no light is seen transmitted through it when one end of the fiber is pointed towards a lamp
128. rint value of transmitter high voltage approx 65 V GET VALUE VOLTAGE P18 Print value of general internal supply voltage 18 V GET VALUE VOLTAGE P13 Print value of receiver supply voltage 13 V GET VALUE VOLTAGE P12 Print value of general internal supply voltage 12 5 V GET VALUE VOLTAGE P5G Print value of general internal supply voltage 5 V GET VALUE VOLTAGE P5R Print value of receiver supply voltage 5 V GET VALUE VOLTAGE M13 Print value of receiver supply voltage 13 V GET VALUE VOLTAGE M12 Print value of general internal supply voltag 12 5 V GET VALUE VOLTAGE M5R Print value of receiver supply voltage 5 V GET VALUE VOLTAGE M5G Print value of general internal supply voltag 5 V GET VERSION Print identifier for software version START Start single cycle measurement in operation mode STANBY Refer to command SET OPER MODE STANDBY Table 8 Advanced Level Commands Command Description BACK Back to normal user command set RESET NO Do not reset RESET YES Make full reset SET ALGORITHM DAFAULTS Set default algorithm parameter settings SET DATA ACQ AUTOADJ ON Data acquisition parameters are software controlled SET DATA ACQ AUTOADJ OFF Data acquisition parameters are manual controlled SET DATA ACQ COMP COARSE value Set internal crosstalk compensation setting coarse code value SET DATA ACQ COMP FINE valu
129. ry CTP241 12V T 9806 003 Figure 14 Block Diagram of Operational Units In addition there is another mode for carrying out a simulated measurement without laser with the Light Emitting Diode LED of the Optics Monitor CTL21 acting as the simulated backscatter This mode serves for testing the whole receiver section When the measurement starts the Timing and Control logic of the DCT52 starts issuing trigger pulses to the Laser Transmitter CTT21 at 71 User s Guide 72 the specified repetition rate At each trigger pulse the transmitter sends out one laser pulse This laser pulse gets collimated by the lens into a near parallel beam of light As this short laser beam traverses the atmosphere particles cause scatter in the backward direction a part of which hits the lens and gets focussed by it The beamsplitter reflects a fixed fraction of it through the Infrared Interference Filter onto the Avalanche Photodiode APD of the Receiver CTR21 The Infrared Interference Filter eliminates all background light noise outside the laser wavelength band The APD transforms the backscatter photons into electrical current at a fixed ratio This current gets amplified in the transimpedance type Receiver Amplifier to a voltage which is fed into the Flash Analog to Digital Converter ADC of the Ceilometer Interface Board DCT52 This ADC converts the analog voltage to 8 bit digital bytes at the specified sampling rate These digital
130. s shown in Figure 33 on page 131 In case the graph differs from the graph shown in Figure 33 on page 131 you have to adjust the Compensation light level manually This is done via Screw B Compensation light level M210345en A Chapter 8 VAISALA Repair adjustment on the receiver CTR21 using a 1 5 mm hexagon key See Figure 32 below Later revisions of the receiver have a 5 5 mm locking nut on screw B if so loosen it first Turn the screw either clockwise or anticlockwise to optimize the form of the graph If the peak of the graph broadens change the direction VIEWED FROM THE RECEIVER CIRCUIT BOARD SIDE COMPENSATION LIGHT LEVEL ADJUSTMENT TO ADJUST COMPENSATION TURN SCREW B WITH 1 5 MM HEX KEY CTR21 RECEIVER 9512 014 Figure 32 Adjusting the Compensation Adjusting should not require more than a couple of turns The screw should not move too easily after the adjustment has been completed If a locking nut is in place tighten it In case the graph does not get optimized the following faults are possible The window or the lens of the ceilometer is extremely dirty The Optical termination hood required during the indoor adjustment is dirty or missing Other possible faults are the following Compensation Fiber itself is defective Receiver is damaged 129 User s Guide Beamsplitter at the lower end of the Optical Subassembly is broken etc In the latter case cons
131. sable blower related status and warning information SET PORT MAINTENANCE PARAMS E71 Set maintenance port character frame to even parity 7 data bits 1 stop bit SET PORT MAINTENANCE PARAMS N81 Set maintenance port character frame to no parity 8 data bits 1 stop bit SET PORT DATA PARAMS E71 Set data port character frame to even parity 7 data bits 1 stop bit SET PORT DATA PARAMS N81 Set data port character frame to no parity 8 data bits 1 stop bit SET PORT DATA MODEM OFF Switch modem off and use serial line communication SET SW STATUS OK Set report algorithm conflict status bit ok GET DMC SN Print DMC50 board serial number GET SW STATUS Print report algorithm conflict status bit GET VALUE OTHERS RECVALUE Print measured receiver test values GET VLIM Print sky condition vertical visibility reporting limit 96 STOP Data Messages Stop internal compensation routine The following standard messages are provided Data message No 1 2 3 6 and 7 Status message S Each port can be set to transmit a specified message automatically Alternatively the port can be set to transmit the set message only when polled by a predetermined polling string of characters or the polling string can contain the message identification NOTE All characters are 7 bit USASCII lt symbolizes Carriage Return Line Feed 2 characters throughout this
132. smitter DCT52 Ceilometr interface board Modem board optional Jl Tilt angle sensor CT3675 Il _ Il The printed circuit boards are of size 100 x 144 mm Each board is provided with a front panel that is securely fastened with two screws to the frame simultaneously providing a good electrical ground connection The connections between the separate plug in boards are realized by means of a motherboard and multiple board connectors 81 User s Guide 82 Processor Board DMC50B RS 232C ATXD RXD L ARTS CTS 1 CTS TXD SD w RXD RD L 2RTS SD CTS RD L 24TXD SD RD RTS SD w CTS RD S 232C DRIVERS FLASH EEPROM BOOT FLASH RECEIVERS 7 RECEIVERS RS 232C DRIVERS DRIVERS RECEIVERS DRIVERS RECEIVERS y EEPROM a FLASH 9 EEPROM o ES 25 FLASH EEPROM INTERRUPT CONTROLLER 82C59A FLASH EEPROM STATIC RAM 18V 5V 5V Figure 20 DMCS50B Block Diagram T POWER SUPPLY PICOBUS DRIVERS PICOBUS s PIO 82C55 12BIT FASTA DC BOARD SELECT 16 I C BUS RS 232C RS 422 RS 423 RS 485 MIL STD 188 144 ID EEPROM R
133. t order CT35022 SHOCK ABSORBER Specified at order CT25338 BIRD COLLAR Specified at order LIDAR Measurement Refer to block diagram in Figure 14 on page 71 Top level control resides in the software of Processor Board DMCSOB This determines what settings are to be used for the measurement The settings are written by the software into Ceilometer Interface Board DCT52 which then carries out the actual measurement autonomously When the measurement is complete an interrupt is issued from the DCT52 to the DMCSOB upon which the accumulated measurement backscatter raw data profile is fetched by the DMCSOB into its RAM for the algorithmic processing M210345en A Chapter 5 VAISALA Functional Description Laser pulse 100 ns Energy 1 6 uJ Repetition rate 5 57 kHz Number of pulses 65 536 Measurement time 11 7 s Receiver on High Gain Bandwidth 3 MHz Sampling at 100 ns 500 useful samples per laser pulse Measurement range 0 25 000 ft 0 7 5 km ATMOSPHERE Optics Monitor Internal Window CTL21 Heater Conditioner CT25039 Backscatter signal Receiver dp 2 Power CTR21 afi Laser power Trigger Irans Window contamination mitter 21 Receiver test Maintenance Control CPU Board gt meter DMC50B Interface i i Data Board Data ES t pota DETS2 Modem option Monitoring amp Control Line AC Supply Power supply voltages Subass y Line Power Batte
134. t protection for power and signal Termbox 1200 Tropics Window CT35043 on Measurement Unit instead of Standard Window to protect the laser from direct sun radiation Optical Termination Hood CT25184 for indoor service use Shock Absorber CT35022 for ship installations PC Terminal cable CT35198 to connect the connector of the RS 232 port of the PC to the maintenance port Bird Collar CT25338 to reduce the disturbing effect of birds sitting on the ceilometer at sites with a large amount of birds M210345en A Chapter 3 Installation CHAPTER 3 INSTALLATION This chapter provides you with information that is intended to help you install this product Installation Procedure Unloading and Unpacking Instructions The CT25K is shipped in one container containing the Measurement Unit Shield and Pedestal and all equipment accessories and documentation needed for carrying out the installation Store the original packaging for possible later transport need For opening the package is to be placed on a flat surface with the indicated top side up The container is opened from the top side and the ceilometer including all other parts are carefully removed Use proper gloves for protection against sharp edges etc Avoid touching the window or lens surfaces unless cleaning according to instructions Maintain the integral protective caps on the unused external connectors J3 Data line or J4 Maintenance line Use th
135. the correct position The Sensor Arm of the Optics Monitor should be about in the middle of the lens Attach the ribbon cable connector to the CTL21 Connect the Power Cable and the Maintenance Terminal Turn the power on If the Optics Monitor has been replaced or the horizontal position of it has been changed do the following a the parameter settings for the Laser Transmitter CTT21 as described in section Replacement on page 125 Steps 4 a j finishing with the Internal Crosstalk Compensation section Compensation Adjustments on page 128 b Do the parameter settings for the Receiver CTR21 as described in section Replacement on page 134 Steps 7 c h It is not necessary to adjust the Internal Crosstalk Compensation again M210345en A Chapter 8 Repair Boards of Board Frame DMF51 The boards of Board Frame DMF51 are shown in Figure 36 below Replacement of boards does not require parameter settings except the Ceilometer Interface Board DCT52 the adjustments of which are described in section Parameter Settings of Ceilometer Interface Board DCT52 on page 142 0208 071 Figure 36 Boards of the DMFS1 Board Frame The following numbers refer to Figure 36above 1 DPS52 DC Converter board 2 DMCS0B Processor board 3 Modem board optional 4 DCT52 Ceilometer interface board Removing Boards Before removing boards note section Start Up Procedure for Replacement All Parts
136. the year code Forward the DMCSOB serial number to Vaisala In response Vaisala will send the option code needed for the example below 48612 102 M210345en A Chapter 5 Functional Description Activation CT open CEILO gt advanced PASSWORD ACCEPTED CEILO set option sky cond on 48612 example Code OK Sky Condition option activated Then select the sky condition message type msg6 or msg7 to be reported CEILO gt set message type msg6 MESSAGE TYPE 6 CEILO close NOTE It is recommended to use a 15 or 30 seconds data acquisition interval with the sky condition option VAISALA Algorithm Overview The sky condition algorithm collects data for 30 minutes All cloud heights are rounded to the nearest 50 ft or 10 m and a weight factor is assigned Each measurement has a total weight of five which is divided between different cloud layers according to Table 12 below Table 12 Weight Factors 1st layer 2st layer 3rd layer 1 layer detected 5 2 layers detected 3 2 3 layers detected 3 1 1 In addition a weight factor of 2 is applied to the data collected during the last 10 minutes to make the algorithm more responsive to variations in cloudiness The weighted cloud hits counts are assigned to the cloud height categories or bins i e 0 100 ft 100 ft 200 ft etc The bin width increases with the distance according to Table 13 below Table 13 Bin Widths
137. tion and temperature 75 User s Guide TRIGGER MAX REP RATE 25yus INH RECHARGE Ic LASER TRIG 76 Laser Transmitter CTT21 HIGH VOLTAGE SUPPLY VOLTAGE CONTROL gt 0 4V TRIGGER gt gt P HEATER SUPPLY Tm DIODE HEATER sO k INHIBIT LONG PULSE LIMIT GAIN SELECT INHIBIT amu ic ERE cpu RECHARGE LONG PULSE SHORT PULSE MAX REP INHIBIT CHARGE CHARGE RATE RECHARGE STORE STORE THERMAL CONTACT 50ys gt gt LASER TEMP OUT Figure 16 CTT21 Block Diagram 9412 058 Description An unregulated supply voltage P65 is brought to the Laser Transmitter CTT21 and adjusted to a suitable level by means of an internal voltage regulator The laser diode of the subassembly is supplied with this regulated high voltage A trigger pulse is routed through a transformer to the trigger electrode of the switching thyristor for driving a current pulse through the laser diode A special pulse forming network makes this current pulse near rectangular A small control circuit with a temperature sensor and a heating element ensures the correct laser temperature The laser temperature is also routed to the Ceilometer Interface Board DCT52 and Processor Board DMC50B for internal monitoring M210345en A Chapter 5 Functional Description WARNING Dangerous voltages are present in this instrument
138. tomatic 2 minute time out after last character input is applied A 2 60 minute time out may be set by command SET PORT TIME OUT NOTE Only one of the ports can be OPEN for commands at a time Only one of the ports transmits measurement messages at a time Additionally in RS 485 mode a unit ID must be given with the command OPEN 40 M210345en A Chapter 4 Operation OPEN ru Port CLOSED Data messages transmitted Port OPEN User s command set available Prompt CEILO gt Top level commands CLOSE SET GET START password PASSWORD port OPEN BACK Extended maintenance and factory command set available 9804 065 Figure 10 Open and Closed Port User Commands VAISALA User commands command hierarchy and description are described in Table 7 on page 42 User commands are accessible after opening the line by command OPEN no password needed The command line interpreter provides interactive help support so that the exact format of commands doesn t have to be remembered At each level of the menu keying ENTER first provides an output of the menu available the second ENTER provides an eventual HELP text Keying in a letter followed by ENTER outputs all commands with the same first letter keying in two letters followed by ENTER outputs all commands with the same first two letters etc when only the one desired command is left then it
139. ttery switch subassembly front panel shown in Figure 39 on page 148 and remove the panel 2 Pull the battery out by the plastic stripe attached around the battery Do not pull by the battery switch connector wires 3 Detach the red and black wires from the battery and move them to the new battery Transfer the plastic pull out stripe to the new battery VAISALA 147 User s Guide 4 battery back in its original position and close the front panel with the attachment screw REMOVE THE SCREW dh H WARNING HIGH VOLTAGE INSIDE THIS ENCLOSURE LINE amp POWER SUBASSEMBLY CTP241 9805 012 Figure 39 Battery Replacement Getting Help For technical questions or for comments on the manuals contact the Vaisala technical support E mail helpdesk vaisala com Telephone 358 9 8949 2789 Fax 358 9 8949 2790 148 M210345en A Chapter 8 Repair Return Instructions If the product needs repair please follow the instructions below to speed up the process and avoid extra costs 1 2 VAISALA Read the warranty information Write a Problem Report with the name and contact information of a technically competent person who can provide further information on the problem On the Problem Report please explain What failed what worked did not work Where did it fail location and environment When did it fail date immediately after a while perio
140. uct Overview Table 5 CT25K Ceilometer Main Parts Nomenclature Code Common Name Description Measurement Unit CTB22 Optical Subassembly CTT21 Laser Transmitter CTR21 Receiver CTL21 Optics Monitor Frame DMF51 DMC50B Processor Board DPS52 DC Converter DCT52 Ceilometer Interface Board DMX55 DMX50 Modem Optional CTP241 Line and Power Interface Subassembly No break Battery CT25039 Internal Heaters Subassembly CT3675 Tilt Angle Sensor Internal Cables etc Shield CT2614 Built in Window Conditioner 220 240 VAC warm air blower option CT2688 Built in Window Conditioner 100 115 VAC warm air blower option Pedestal CT25106 Metal Pedestal standard For off shore applications it is recommended to use fiberglass pedestal CT2665 The complete delivery also includes mating cables with connectors for power and communication installation hardware an Allen key a triangle key for the Measurement Unit door and this CT25K User s Guide In addition the following options may be included in the delivery Maintenance Terminal PSION Palmtop computer Connected to Measurement Unit at the external connector J4 via RS 232 interface Termination Boxes 2 for Line Power CT3709 external connector J2 and Communication Cable CT3707 external connector J3 connections 19 User s Guide 20 Termination box with heavy duty transien
141. ult Vaisala 4 Press the Esc key one or two times to stop the compensation monitoring 130 M210345en A Chapter 8 Repair 1 I 2 T 3 I 4 I 5 I 6 I 7 I 8 I 9 I 0 I 1 kkk I 2 kkk I kkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkk oe ce eee ce e e e e e e c e e c e f f A Mk e Mk e e n ke kx kx x AX kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkxkk e e e e ce e e ce de ce e oe ce deck cfe fece ce ce e ck de cce ee e e kx e kx kx x kx kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkx kxx k kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxkxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxk e e e de ee e ce de cede e ce de ce cfe dece ee che e ce dece ce ee kx AX kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxk I M THE COMPENSATION IS GOOD WHEN THE DIFFERENCE FROM PEAK TO PEAK IS MAX 5 LINES 1 I 1 I 2 I 2 I 3 xk I 3 I 4 doe I 4 I 5 ek I 5 I 6 1 6 I 7 doe I 7 1 8 waa I 8 I 9 kkkkxk I 9 I 0 okckckc kk I 0 I 1 okckckc kk I 1 I 2 kkekkkk I 2 T kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk oe oec e ce e e e AG x x x ke oe e e e ce e ce e e v eG x x kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkxk eee ee ecce e c e e x x kx kx x kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kxk oe ke ce ec e e x kx x x kkkkkkk
142. ure The Measurement Unit and Pedestal of Ceilometer CT25K are designed so that the unit can operate in a tilted direction The built in tilt angle sensor CT3675 detects the tilt angle i e deviation from the vertical The tilt angle ranges from 15 to 90 degrees from vertical the angle is positive when the measurement unit door turns towards the ground The cosine of the tilt angle is used for automatic correction of the detected cloud base height which enables accurate cloud base measurements also in a tilted direction Several advantages can be realized with the aid of this feature Heavy weather conditions Usinga slight tilt angle for instance 15 degrees the measurement unit window is kept better protected from precipitation thus enhancing the performance in heavy weather conditions Aircraft approaches 27 User s Guide WARNING The beam can be directed towards a direction which better represents the approach of an aircraft than the straight vertical Useful e g for helicopter approaches and sites where the ceilometer cannot be located exactly at the desired spot Hard target and testing purposes Tilting the unit down by 90 degrees permits verification of operation against a hard target at a known distance Useful in connection with installation and maintenance Enables real backscatter signal detection when there are no clouds in the sky Make sure that nobody is viewing the unit from the beam
143. user command must be ended by pressing the ENTER key illustrated in this manual by Start Up Procedure for Replacement All Parts Replacement can be done outdoors even in the presence of light precipitation but in this case take care that the removed subassembly remains dry and no water gets into the interior of the Ceilometer CT25K However if adjustment is needed after replacement then that must be done in clear weather conditions or indoors using the Optical termination hood CT25184 Before you start to remove or replace parts do as follows 1 Open the enclosure door of the Ceilometer 2 the Circuit Breakers and F2 to OFF position 3 Turn the Battery Switch OFF 4 Detach all cables from the external connectors J2 J4 Tilting the Ceilometer unit slightly backwards gives better access to the interior To tilt the unit loosen the two screws of the pedestal first Tilting backwards must not be done in rainy weather Clean the window by flushing it with water to remove coarse grains During this operation the enclosure door should be closed Use a soft lint free cloth moistened with mild detergent Be careful not to scratch the window surfaces Check also the condition of the shield and clean it if necessary NOTE Outdoor adjustments should be done in clear weather conditions no precipitation no fog present and no clouds below 1 000ft Also the window must be clean If the ceilometer is servi
144. ve 2 Start mounting the measurement unit by rotating the friction ring of the flange to the position shown in Figure 5 on page 26 the screw holes horizontally Remove the Allen head screws 2 pes and flat washers Place the measurement unit on the pedestal flange Attach the pedestal flange to the measurement unit by the two Allen head screws with flat washers An Allen key is included in the delivery VAISALA 25 User s Guide 0208 066 Figure 5 Attaching the Measurement Unit and the Shield 26 M210345en A Chapter 3 VAISALA Installation The following numbers refer to Figure 5 on page 26 Shield Knob Friction ring Flat washer Earth connection Flange on measurement unit Measurement unit Pedestal flange Pedestal 0 External connector J1 3 Before placing the shield pull knobs pidgeon blue on shield outwards Place the shield carefully on the Measurement Unit be careful with the Window Conditioner cable Tighten the two attachment knobs see Figure 5 on page 26 Before connecting the Window Conditioner cable check that the voltage rating of the Window Conditioner written at its connector is correct Connect the Window Conditioner cable plug of the shield to the measurement unit external connector J1 4 Connect external cables according to section Cable Connections on page 28 Using the Tilt Feat
145. vergence 0 66 mrad Optical System Table 28 Optical System Property Description Value Optics System Focal Length 377 mm 14 8 in Effective Lens Diameter 145 mm 5 7 in Lens Transmittance 96 typical Window Transmittance 98 typical clean Performance Table 29 Performance Property Description Value Measurement Range 0 25 000 ft 0 7 5 km Resolution 50 ft 25 000 ft Acquisition Time min 15 s max 120s Receiver Bandwidth 3 MHz 3db Environmental Conditions Table 30 Environmental Conditions Property Description Value Ambient Temperature 50 60 60 140 F Humidity to 100 RH Wind to 100 kt 50 m s Vibration 0 5g 5 500 Hz VAISALA 157 User s Guide This page intentionally left blank 158 M210345en A INDEX A Alarm check Alarms Laser failure Laser temperature shut off Receiver failure Voltage failure Angle correction Angle measurement Parameter settings APD Atmospheric transmittance Avalanche photodiode APD Average laser power B Background light Backscatter Backscatter coefficient Battery charger Bulk charge Float charge Over charge Trickle charge Beam divergence Beamsplitter Bird collar Bird droppings Blink timer Board frame DMF51 Removing boards Replacing boards C Ceilometer interface board DCT52 124 125 134 Changing a prevailing parameter value Centering VAISALA 142 89
146. with the command SET FACTORY INLASER I and type the new Calibration Factor value l Set the laser power into effect with the command SET DATA TRANSMIT POWER OF PJ M210345en A Chapter 8 VAISALA Repair and type the new value Calibration Factor l The same Calibration Factor value as in step d Wait until a few measurement cycles have been completed and the new value has been updated in the status message Give the command GET STATUS J Check from the status message under the title Transmitter that the IN value of the transmitter in question equals the Calibration Factor Check from the status message under the title Transmitter the OUT value which tells you the measured optical power and write it down Give the command SET FACTORY OUTLASER and type the recent OUT value Jl Wait again until a few measurement cycles have been completed and the new value has been updated in the status message Give the command GET STATUS J Check from the status message that the Transmitter SENS percentage is in the range 99 101 This tells you the present measured OUT value compared to the factory setting Check further from the status message under the title Environment the WINDOW value and write it down Set this value as a reference value of a clean window with the command SET FACTORY WIN _CLEAN and enter the recent WINDOW valued Wait again until a few measurement cycles have been c
147. y Recharging of the battery fails If the battery is old replace it If the battery is OK check the operation of the DPS52 DC Converter Laser power low warning Laser diode too old Replace Transmitter CTT21 Optics monitor CTL21 failure If you have replaced the Transmitter CTT21 and the warning did not disappear replace the CTL21 Optics Monitor Laser temperature high or low warning 116 Environment temperature too high If the environment temperature is above 60 C do not operate the ceilometer Direct sunlight can burn the laser diode Use Tropics window or turn the ceilometer away Environment temperature too low If the environment temperature is below 50 C the heating capacity is not sufficient Do not operate the ceilometer Ceilometer is battery operated If the ceilometer is battery operated all the heating functions are disabled and the unit can be operated only in temperatures above 10 C Connect the line voltage and wait for a while M210345en A Chapter 7 Troubleshooting Status Message Info Reason Heating fails Instructions Check the Transmitter Board CTT21 where the heating circuitry is located Check that the DC Converter DPS52 supplies the current for the heating Internal temperature high or low warning Environment temperature above 60 C or below 50 C Do not operate the ceilometer V
148. zing temperatures Replace the battery if signs of mechanical rupture are observed VAISALA Storage Have caps on all external connectors if stored unpacked for extended times in an unconditioned area Also maintain a dust cover on the window during long periods of storage The container is suggested to be saved for future transport use When replacing the equipment shall be placed and padded in the same way as when initially received 109 User s Guide This page intentionally left blank 110 M210345en A Chapter 7 Troubleshooting CHAPTER 7 TROUBLESHOOTING This chapter describes common problems their probable causes and remedies and contact information Normal Operation Equipment To establish a service connection to the CT25K you need to have a maintenance terminal which can be a palmtop computer with an RS 232 Interface or a PC with serial interface PC Terminal Cable CT35198 and any terminal program CT VIEW software can be used for this purpose Instead of maintenance connector J4 the service connection can also be made directly to the front panel of DMC50B processor board for example with RS cable 16385ZZ On the DMCSOB front panel the data port is marked as P8 and maintenance port as P7 Also if you perform the operation check indoors you need to have an Optical Termination Hood CT25184 which absorbs the laser light that otherwise would reflect from the ceiling and possibly saturate th

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