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Vaisala Inc. CT12K Manual

1. SV RA 19 3910k CO 2 0 RDO 6 1 B 0 E 2 ej 2 S 0 L amp 10 2 2 u35 7 y PA 74 HC 283 5222 49 VAISALA PROCESSOR BOARD A CTM 12 P N 2681 CIRCUIT DIAGRAM 3 4 SEQ CONTROL Drag c CT3387 y NOLLdBHIOSHG IVNOLLON 1d ER 137 12 7 13 33742 NDA3 0 219 6 U43 13V RAO 3k32 R49 1467 ac 52 9 N2222A 4 a E C 05 GL gt 5082 2800 ell 19 1 D 3 RSO TO R6t Re TORGO R27 NOT ASSBLD 87 07 22 EEG CONTROL 8 112 2 O DA3 O x Sioun DA13 027 BLA 11 E 8 2 c 317 LZ 4 317 LZ lt L8R7 U24 R47 J16 10 _ 20VA 301R 220yH NIEM Iq 383R 714 z R 317 LZ ya GNDA 9 C 81 C60 R52 C86 64 57 14 7LHCT tL 2k74 con 3 10y 8258 100 2 8 f C23 0 C63 C77 10 e 100n 10 D7 7 asl c30 5 7 IN4 740 AY 00 10 100n Lr gm Pon T H 825R R56 L3 E 2204H VA ASSEMBLED 63 AW I A CONNECTED POINT ONLY ECO J9 3 1 7 V PROCESSOR BOARD 1 CTM 12 PIN 2681 CIRCUIT DIAGRAM 4 4 AMPLIFIER lt 2 AT ONE amp co gt T LL4VHO 5 VOT CPU 0 YCLE PHASES T1 This 2 CPU CLOCK ace 9 100 ul SEX o 6
2. A Rie LL R7 L Ris C RIS A 06 NX NY 16 wore L JE S 134205 134205 6 ISISSNH 20v oot v2 gt gt 40 RZOHRL R58 Reco 4 c77 c zie R23 C20 TED R24 R25 F U23 C33 Rais U25 gt g of AF ES pe gt C34 h2 R26 JF ui C37 U34 u35 Ji TEST 8 4 C42 R30 U36 R3 o d RAZI lt zz z C397R33 R29 mam AT4 7 R34 f z gt a5 TNE o TEST 6 RC Y 96 43 c 5 i LSE 42 Rn c s 2 E y INGLE Ues Ji4 i Dil r ied T 36 s v AE TF cas T x i RA22 Reg C50 jr 5 R65 C52 R38 ES n nia o 2 37 Y R40 d 2 u38 d 8 41 M ape 522 E c54 n des M 5 5 TEST s 42 C57 y PULSE Eso p VAI S mA 5 ed ER o JE Cel R47 c ES 5 i 013 2 30n3 416 41 9 o t4 TT OQ SCA 042 D U44 MEN 45 U46 21 C64 C65 C66 REO RAO R67 n SQI EE RSI WEN ul ces o 2 LTRG ces 4F ss L5 8 gt z 8 i LTON c U48 C67 2 5 N gt WSM O A 75 Ap lary d g e 013 T LTE aa et us Na EDS se CON wef ik 43 oT J20 SEV RSS 6v zac J gt YY ll F RSG GND A GND c 49 O zr L S2r OI HSL gt ZVY __ ZI z m 3 29 o 9811 S eo 3 GAIN 423 R60 2 N AD
3. o ln la CABLE CONNECTOR 2 GND FOR CT 12K UNIT RS 232C NTERFACE CABLE 3 ADA CONNECTOR J PART OF MAINTENANCE TERMINAL 2 RXD CONNECTOR E T 6 x 075 sqmm A W G 18 7 GND 8 8 FLAG P12M REFER DRAWING A CT 3306 FOR UNIT CONNECTORS 14 ELEME ine CEILOMETER CT 12K CONNECTION DIAGRAM 14 NOILILVTIVAISNI LC PROTRUDING INTERNAL HARDWARE PLACES AC LINE SUPPLY CONNECTOR J1 WINDOW CONDITIONER CONNECTOR Je CT 12K PEDESTAL ATTACHMENT NUTS 4 PLACES Oran 1985 08 20 ETA 1 Replaced by ARA GROUNDING SCREW MAINTENANCE TERMINAL CONNECTOR J4 A Ji OUTPUT INTERFACE CONNECTOR J3 EXT TEMPERATURE SENSOR lt TS 1 gt VENTILATION INLET CEICOMETER Cl tek EQUIPMENT BASE BOTTOM VIEW YILIVHO NOLLVTIVISNI 28 20 30 SECTION 3 1 3 2 CHAPTER 3 OPERATION TABLE OF CONTENTS GENERAL 3 1 1 INTRODUCTION NORMAL OPERATION 3 1 2 SWITCHES 3 1 3 INDICATORS 3 1 4 USE OF SERIAL DIGITAL INTERFACE 3 1 4 1 General 3 1 4 2 Frame Code and Speed 3 1 4 3 Notations and Abbreviations 3 1 4 4 Line Closed Line Open 3 1 4 5 Command Format and Editing Rules 3 1 4 6 Advanced Information 3 1 5 AUTOMATIC MODE MAINTENANCE MODE 3 1 6 FAST HEATER OFF STANDARD OUTPUTS 36 1 3 2 2 DIGITAL MESSAGE NO 2 A o General Format Status Line 1 Status Lin
4. e 3 25 YALIVHO e 2 AMPLIFIER SECTION E PAS ete VAISALA pes E CT3501 y O9T 15 X1 X 2 o oO 0 1 2 RA7 10k 3 52 6 8 5 ag gt 100n 2 1 11 8 1 2 2 9 2 3 3 10 4 1 4 11 S 17 S RESPECTIVEL Y IC s S ules OF THE IC S 5V a 7 3 7 UT AND U 20 P 16 18 SV 7 E s 10 ADS TP E 2 Qe a 3 0M Ju 1 DEI 7 Y A 5 5 3 4 5 26 iE 12 8 Y II RSS te E 00 2048 RTT dd 4096 8192 U19 THC 373 SED 6 7 19 C1 8 RA 2 pae 8510 02 ne 1 28 p 74 139 A A CIRCUIT DIAGRAM 1 4 CPU CT 3385 MONI TOR MONI TOR L7 2 8 g 2 5 3 3 2 3 d 5 Ui 7 p LE 7 MONI TOR MONI TOR ho L 247 PROCESSOR BOARD Al AC VAISALA YALAVHO NOLLJDNHOSHG TVNOLLON Ji GNDI al c2 i a2 1 207 c3 2 20VI ch LLAS 1 LSK c7 a7 GNDP 1 c8 12yM a8 PXHV c9 56 Rast MESE QW 5 6 5 ci0 f ai0 MRHV 4 3 RAS 25 att R5 k7 RA cal TL 131 ci4 TE als 15 TB 2015 0 c19 FLAG 5 at9 cD cA TRxD Sa WED c27 1 0 327 1 2281 028 S c29 LM a29 joNDO C26 T 12935 7j c30 1 23
5. gg E 3s 1 i e T 18 CI9 C20 Er Es J8 PART NO 2725 12 COMPONENT BOARD P N 2725 COMPONENTS LAYOUT 255 256 257 258 CHAPTER 5 PERIODIC MAINTENANCE TABLE OF CONTENTS SECTION ou MONTHLY CHECK OF MESSAGE ALARMS 5 2 90 DAY CHECK OF WINDOW CLEANLINESS AND CLEANING PROCEDURE 5 9 MONTHLY CHECK OF WINDOW CONDITIONER BLOWER 259 PAGE 261 261 202 260 5 1 52 CHAPTER 5 PERIODIC MAINTENANCE MONTHLY CHECK OF MESSAGE ALARMS Check that the data message contains no alarms see paragraph 6 1 1 If there are alarms proceed to troubleshoot following section 6 90 DAY CHECK OF WINDOW CLEANLINESS AND CLEANING PROCEDURE WARNING DO NOT LOOK INTO CEILOMETER OPTICS WTH MAGNIFYING GLASS BINOCULARS OR OTHER MAGNIFYING OPTICS DURING THE COURSE OF PERFORMING THE PROCEDURE BELOW Inspect the cleanliness of the ceilometer windows If they are definitely unclean e g film streaks or particles perform cleaning as detailed below Otherwise do not A Unplug Window Conditioner connector J2 loosen four 4 knurled screws holding Window Conditioner to Equipment Cover and remove Window Conditioner B Gently dust off all loose particles from the windows with dry cleaning cloth of Field Spares Kit or preferrably with soft brush Soak the window surfaces cleaning alcohol included in the Field spares Kit Let soak for a few minutes D G
6. 12 Ref PSI It can be measured between TP7 and GND The output current of the regulator is limited to 10 and the output voltage is monitored via J2 pin 8 signal PXHV The value of PXHV is determined by resistors R12 and R13 which divides the output voltage of the laser diode regulator The high voltage regulator consists of the following subcircuits Control Stage Error Amplifier 203 CHAPTER 4 FUNCTIONAL DESCRIPTION Control Stage The output is regulated with Darlington connected transistors Q8 and Q9 The base voltage of transistor Q8 controls the output current of the regulator through transistor Q8 and Q9 The output sink current of the error amplifier transistor Q7 determines the voltage drop over resistor R24 and therefore the base voltage of Q8 Zener diodes D8 and D9 limit its maximum value to 200V The regulator output current is limited to approximately 10mA It is measured as a voltage drop over resistor R25 When the voltage between the base of Q8 and the output exceeds the forward bias of diodes D12 and D13 these will conduct and limit the base drive of Q8 Error Amplifier The differential error amplifier formed by transistors Q6 and Q7 measures the output voltage then through resistors scales the feedback signal The output voltage is adjusted with trimpot R21 changing the scale ratio of the feedback resistors for the error amplifier The base of Q 1s connected to refe
7. 25 PCT 2 3 2 1 SOLAR SHUTTER Ki OP TION P N 2713 90 ENERGIZED OPEN gt 26 03 87 AEN Dwg no 0165697 IRCUIT DIAGRAM CT 3564 pe ce LIGHT MONITOR BOARD CTL 13 ebe VAISALA P N 10322 REF DESIGNATION 5 C t YALAVHO 5 T6T CTL 13 LIGHT MONITOR 5 c6t LIGHT MONITOR BOARD 27 m TP lt r CSN SOLAR SHUTTER FLAP TRANSMITTER OPTICS SOLAR SHUTTER SOLENOID Title CETILHEMETER CI Tek LIGHT MONITOR BOARD ASSEMBLY Oro E Note Drawn 1947 05 28 05 28 ETA Internal cables and harnesses CENAS are not included in this drawing t YALIVHO NOLLdTHOSHG IVNOLIONIH 4 3 5 4 3 5 1 CHAPTER 4 FUNCTIONAL DESCRIPTION RECEIVER BOARD CIR 13 Introduction The Receiver Board CTR 13 contains the photodiode that detects the reflections from any obstructions normally clouds in the path of the transmitted laser pulse The reflections are detected by the silicon avalanche photodiode located at the focal point of the receiver optics These focused reflections from the field of view of the receiver are converted to current in the reverse biased photodiode The change of current is sensed and amplified by the onboard circuits to provi
8. LEGEND 200 O of c 7c e NOTE 1 INTERPRET DRAWING PER Mil STO OO SC SLOTTED FLAT HEAD 90 SCREW DIN 96 AIS 304 LWsLOCK WASHER UN 127 AIL 04 NUT i a ABEL USE 230 LABEL 5 7230 CT 291 A PART 2 AND ALL METALL PARTS ON PART 13 SHALL BE CORROSION PROTECTED BY CRS SP350 SPRAYING AFTER ASSEMBLY Fran pr EMITE at VAISALA CTI2K HEATER SUBASS Y P N 210 USY Pin 220v y YALIAVHI 5 TYNOLIONNd TCC NOTE 3 TOLERANCES INTERPRET DHAWHIGO PER MIL STD 100 2 3 PAN HEAD SCREW DIN 84 AISI 304 Wa LOCK WASHER IN I NUT NGJA AISI AA 1 02 XXX rot ANGLES gt UNLESS OTHERWISE SPECIFIED 22 2 3PCS lw PCS 71 18 SW M3 NOTE PARTS 9 AND IO SHALL BE CORROSIONPROTECTEO BY CRS 56350 SPRAYING BEFORE ALIGNING 3 A NER PIO FW etw ADOEO SCREW LEGEND MOTE 1 B 04 5454 L ADOED Lw ma 46 04 11 HUA IAS 7 35 09 12 m m fr E PA A imum GR mi ae 0 15 00 1 0455451 Y 5 TVNOLDONNA CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 4 3 9 1 4 3 9 2 Maintenance Terminal CTH 12 Introduction Maintenance Terminal CTH 12 is designed for service and maintenance of Ceilometer CT 12K It
9. com C Cu lt U 2 y Y R5 R t 2 04 MOUNTING 100R 1k 00 1 4148 BLOCK V V V D5 D6 J2 1N4148 LD 7 LD 22 8S 1 10V X 10V X 011 012 013 ATP R28 3 x 1N4148 R24 Q 2 260V 215R I lt 1220 R20 Y AN DB Ny R21 1N985 e 10k 3 GND 66n os 100V NE R19 R22 R18 3 32 5k62 1N985 14759 100V NOTES L1 PRINTED CIRCUIT ETCHED V V U T1 EACH WINDING TWO TURNS ki qe ON COFELEC 10 TOROID TRANSMITTER BOARD A7 ote VAISALA Otago eU CTT 12 P N 2687 555 CIRCUIT DIAGRAM CT 3120 YALAVHO NOLLJDIWOSHG 91 05 01 6P CS OO LM355 33k etc mM35rt2 PCS w A3 2 2PCS NUT M3 PCS POLYAMID TIZ Qs imn CO BL Pasa C TT IP 50 M318 IPCS Lw 85 PCS NUT M3 PCS WIRE HABIA WST 3001 CUT LENGTH 2in STRIP LENGTH 0 2 79 VAISALA Ce y YALIVHO NOLLJTIOSHG TVNOLLONOA 212 4 3 7 4 3 7 1 2 2 CHAPTER 4 FUNCTIONAL DESCRIPTION High Voltage Power Supply CTP 12 REF PSI Introduction The High Voltage Power Supply CTP 12 is the 115V Line Input Voltage subunit of the Ceilometer CT 12K It performs the following main functions Transforms the line voltage to the low voltages needed by the electronics Transforms the line voltage and also rectifies filters and partly regulates the high voltages
10. 10279 OL 45410 6 SET MISCELLANEOUS OL 45410 7 ESE di TYPE PART DESIGMHATION FARTS LIST CEILOMETER 2 2680 NWS GENERATION BREAKDOWN CHART WMHLJVHO NOLLdDNMOSHG TVNOLIONNA CHAPTER 4 FUNCTIONAL DESCRIPTION ATMOSPHERIC BACKSCATTER NW TRANSMITTED LASER BEAM RECEIVER FIELD OF vi w WINDOW CONDITIONER BLOWER HEATER TEMPERATURE SENSOR pra 44 BLOWER CONTROL gt ME ATER CONTROL SHUTTER ON FIFTY UICHT MONITORO K SOLAR SHUTTER ORNES A POWER a LIN 7 I PL w 3 15 v d I cdm SOLAR SHUT ERICP IGNI gt L a ry e o c ee I I A Lou i INTERNAL TEMPERATURE CONTROL zm _ M lt F M M ON ASER INTERNAL TRANSMITTER TEMPERATURE OLTAGE REG LASER TEMPERATURE PROCESSOR 4 SOFT 8 292 TERMINA CUNE TC f Sk MGOEM BELL 0 YTERNA TEMPERATURE Sh LINE RECORDEA INTERFACE STAR SWEEP INTERNAL SUPPLY VOLTAGES INSCRIBE POWEP SUPPLY SECTION Ly HvHOYIO X2018 120 CAUTION oer WINDOW CONDITIONER EQUIPMENT COVER CT 12K SIDE VIEW CT 12K FRONT
11. Any fog precipitation or similar obstruct amp 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 15 proportional to the extinction coefficient at various heights and enables the use of fairly straightforward threshold criteria to determine what 1s cloud and what is not 100 CHAPTER 4 FUNCTIONAL DESCRIPTION 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 1s 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 1s constant with height The assumptions that have to be made are fairly truthful and in any case accurate enough for the purpose of cloud detection Likewise the inversion 15 also independent of several instrument
12. U38 12 determines which of the two 8 bit lines are carried through multiplexers to BDO 7 in the following way FD5 0 MUX outputs show the states of the input pins 2 5 ll and 14 This is FDO 5 and BDO 5 and BD6 BD7 0 FDS 1 MUX outputs show the states of the input pins 3 6 10 and 13 This 16 FD6 overflow on BDO 1 FDO 2 on DB2 4 as so multiplied by 4 and the function 4x FD 3 4 5 32 32 on BD5 7 As to the last mentioned function add 32 is performed by the EX OR gates U41 8 and 6 NAND gate U53 6 and inverter U45 4 which together make a full adder Multiplying by 4 is simply made by shifting up bit weights by two Subtract 32 is done by leaving FD3 out The MEN control from U44 6 via the inverter U45 8 enables the MUX outputs when RAS RAY are both low Bank 0 Otherwise outputs are all low GL high disables FD5 control The Samule RAM Read Control logics consist of the one JK Flip Flop 43 and the NAND gate U52 12 With P17 high and SQO going low triggers STOP high and P10 low Low state on SQI will set back the initial states ST goes low stopping the sequence only when STOP RSM and RL are all high 146 CHAPTER 4 FUNCTIONAL DESCRIPTION The Laser Trigger is composed of the two AND gates U46 6 and 8 the inputs and outputs of which are driven in parallel The outputs provide for low impedance drive for LTRG through resistor R60 and coaxial connector 526 The trigger line is raised high by SQO
13. 128 bytes of data memory in this application most 1s used for the stack and general purpose registers two 16 bit timers one of them is used as a Baud rate clock the other 1s used as a Real Time Clock RTC integral Universal Asynchronous Receiver Transmitter UAR T two general purpose I O ports Pl and P3 For instruction set and other details see REFERENCE The Processor s AD bus is pulled high by resistors in the array RAS This is to better meet the input level demands of the stan dard CMOS devices on the bus It also enables testing of the board with the EPROM removed In that case the Processor repeatedly fetches the code FFH from the bus which corresponds to a nonbranch internal operation instruction Thereby the Processor keeps running with its address outputs incrementing through the address space which is a convenient condition for isolating failures on the bus The Address Latch Ul3 15 a transparent type of latch When ALE pin 11 is high its input states show in the output When ALE goes low the current output states address are latched The Instruction Memorv U3 1s a 64 k byte CMOS EPROM type 2176512 mounted on socket The EPROM is continuously activated with its chip select pin 20 grounded Its output buffers are enabled when pin 22 is driven low by PSEN It should be noted that the EPROM is erased by UV light and thus the label on its window should not be removed EPROM with no shield on its window wi
14. 20V DIV 100us DIV 50ns DIV Drawn 86 04 23 SIS CTT12 TEST POINT ete VAISALA WAVEFORMS N CT 4535 Repiaced by CHAPTER 6 TROUBLESHOOTING AND REPAIR Replacement CAUTION Never look direct amp into laser beam coming from transmitter optics when laser is enabled Red LED on Light Monitor Board is lit when laser is enabled Remove all connectors Unscrew the three 3 spacer nuts holding board to optics assembly Pull board down clear of long screws Insert new board Tighten spacer nuts to approximately same tightness as with the removed board Plug connectors Place diffuser over transmitter lens such that the three notches in the diffuser ring are lined up with the three pairs of support screws located on the lens plate Diffuser ring must rest flat on lens plate Turn power to the ceilometer on using switch on front panel of power supply Now allow unit to warm up for at least 1 2 hour with the external covers replaced on unit Connect maintenance terminal to base of unit at connector J4 Using maintenance terminal command the following AUTO OFF Maintenance Mode FREQ 3 SEQ ON LASE ON AN LLAS Watch the values now displayed on the maintenance terminal If the average of these values is not equal to the value listed on the diffuser then terminate the output and do the following If Average is less than the diffuser value after 3 tolerance then command
15. 53 CHAPTER 3 OPERATION BMOD Settings Matrix OFF ON Syntaxes ST OFF None one or two bases recorded with long traces None or one base recorded with short trace RMOD ON CR MEASURED DATA RECORDING RMOD ON RMOD ON gt RMOD OFF CR DETECTED CLOUDS RECORDING RMOD OFF next input BMOD ON CR CLOUD BASE ONLY BMOD ON BMOD ON 54 ON None one or two bases recorded with long traces non cloud obscuration with short intermittent dots None or one base recorded with short trace non cloud obscuration with short intermittent dots gt CI3BOF gt RMOD OFF next input gt C29BIF 3 2 3 4 CHAPTER 3 OPERATION gt BMOD OFF CR gt C29BOF ALL CLOUD DATA BMOD OFF BMOD OFF next input next input settings are stored in non volatile memory Examples and Interpretations scaling The CT 12K 0t012000 ft range is linearly scaled for the Gifft RBC Recorder 0 to 90 degrees scale 1 e O ft 1000 ft 7 5 deg 12000 ft 90 deg Cloud Trace An instantaneous 12 sec cloud hit is recorded as a solid thin line starting at the detected cloud height and extending upwards a minimum of 240 ft 60 ms and a maximum equalling the penetration typ max 400 ft A time graph of cloud height 1s produced by several subsequent instantaneous traces In broken scattered or highly turbulent conditions in stantaneous hit traces may
16. 86 04 18 Or awn a VAISALA b t e 84 lt O co Qc O Un 2 Lu O O Qc OW e lt e Q O m LL CT 4532 amp Dwg no O a t Q C lt lt n gt o lt a Serial no NN E 158 ADDRESS LOBYTE Ej E Bi d 10 MHz z 5 z S lt AE 86 lt S O Os 8 H Y SEQ CNTRL COUNTER TP RA1 2 4 7 LTON SENA S MONITOR E 24 i SECTION r auc np iE cT gt REG O P CONTROL LATCH Q e 06 O P CONTROL LATCH 1 2ND 20 pa LEVEL DAMPING NETWORK x z lix HE 4 PRE MPXER ADC REF GAIN xil FROM SELECT SUPPLY RECEIVER CTR12 PROCESSOR BOARD A1 pA CIM 12 lso vb 5V EDS a y MI IC AEG 1 6NDD SYSTEM Tees ase aia SNO gem 1 1 MEATER BLOWER CNTRL REC CNTRL 1 mogen CNTR 2v d uve JET RE TXO gt p BNDA PART OF THE r AMPLIFIER SECTION BOARD EDGE 1 0 CONNECTOR PRINCIPAL BLOCK DIAGRAM SAMPLE DATA LATCH XMITTER CTT 12 tr ul c lt q z mol SUM WRITE RE eL a SEQ CONTROL SECTION RDO 7
17. C5 C6 C7 C8 C9 C10 value value value value value 87 CLOS Close line MES Data message display STA Status meesage display PAR Parameter message display CONF Configure unit M F 1 0 shutter CLIM Cloud limit parameter set display SCAL Output scale parameter set display NSCA Noise scale parameter Bet display DEV Device scale parameter set display SLIM Signal limit parameter set display CHAPTER 3 OPERATION C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 c22 C23 C24 C25 C26 C27 C28 C29 C30 lt 1 0 gt lt chan gt lt value gt 0 2 1 0 1 0 time date chan 1 0 value 88 AUTO EMOD RMOD AN LASE SEQ NOIS FREQ GAIN HEAT BLOW SHUT RECT TIME DATE ALIM RESET LNOR BMOD TOTA Automatic mode ON OFF Extinction normalization ON OFF Record Data 1 Clouds 0 Analog channel monitoring until aborted 2 Laser ON OFF 1 Sequence ON OFF 1 Noise value monitoring until aborted 2 Laser frequency set display Gain set display Window conditioner heater ON OFF Window conditioner blower ON OFF Solar shutter ON OFF Recorder ouput test until aborted 1 amp 2 Time Set Display HH MM SS Date Set Display YYYY MM DD Alarm limit set display CPU Reset Laser normal power
18. FREQ 4 SEQ ON LASE ON AN LLAS If Average is more than the diffuser value after 3 tolerance then command FREQ 2 SEQ ON LASE ON AN LLAS 294 CHAPTER 6 TROUBLESHOOTING AND REPAIR Again monitor the values displayed Repeat the previous step as many times as it takes incrementing or decrementing FREQ by 1 each time until the average LLAS value is equal to the diffuser value 3 Do not terminate the output when this average value 1s achieved Remove external covers from the unit Remove diffuser from lens plate being careful not to scratch lens or hit the light monitor board Notice the LLAS values now being displayed on the maintenance terminal Visually estimate the average of these values and then terminate the output Add 5 to this average which will be the value for LNOR Using the maintenance terminal command the following Example LNOR 150 NOTE The actual LNOR value inputted will be that calculated in the previous step Command The response seen the maintenance terminal should be LNOR XXX where XXX signifies the value inputted in the previous step If this 1s not the case repeat the previous step and check to make sure the information is transferred correctly Command AUTO ON Disconnect maintenance terminal from unit Replace transmitter optics assembly cover and unit cover Return used transmitter board to depot for repair 295 CHAPTER 6 TROU
19. Jumper Strappings are provided for the following signals J13 WEN Sum Write Buffer Enable J17 MEN Re Linearizer MUX Enable J20 STOP Stop Control J24 SQO Seq Phase Control 0 J25 CLD Delay Counter Load 147 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 4 4 Amplifier Section The First Amnlifier Stage U48 is a differential video op amp of type LM733 which features 125 MHz bandwidth and 250 kohm input resistance The signal RECO is brought in via J22 and applied to pin 2 The other of the differential inputs 1 is erounded R59 provides for approximately 50 ohm termination C78 does low pass filtering Total gain for the amplifier chain is adjusted by R55 The output pin 6 connects to the input of the Second Amplifier Stage as AC coupled via paralleled capacitors C66 C67 The other of the differential outputs 7 connects to eround via filter components C64 and R54 The static output level on the output pin 6 ATI is normally around 43V The device is powered from 6V lines consuming approximately I5mA It is normally packaged in a lo lead hermetic metal but the board also provides for 14 lead DIP The test pulse signal TP can be connected via jumper set J23 into the op amp input For proper operation the cable connector in J22 should be removed Since TP is brought in via two resistors R60 R61 three alternative pulse amplitudes can be selected by connecting the resistors separately or in parallel R59 attenuates TP sig
20. Space if S 0 B Bel character if S 1 Because bel is an invisible character the alarming line appears one character shorter than normal in a printout 267 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 1 1 1 Status Indicators Hardware Alarm Supply Voltage Alarm Laser Power Low Temperature Alarm Solar Shutter ON Blower ON Heater ON O Unit is Feet Unit is Meters Data of internal Table 2 is Height Square Normalized Only Data of internal Table 2 is Height Square and Extinction Normalized Sig Fast Heater Off is active A 9 2 UM NNNMNN M I li H H H H H I LO m Identify the alarm from the following alternatives and proceed to the Paragraph in question 6 1 1 1 if Status bit S is 1 signalling General Hardware Alarm 6 1 1 2 if Status bit 5 is I signalling Voltage Alarm 6 1 1 3 if Status bit S is 1 signalling Laser Power Low Alarm 6 1 1 4 if Status bit S is 1 signalling Temperature Alarm The fault in question may cause two or more bits to be 1 The order of troubleshooting is arbitrary After each single repair action operation shall be checked When all Status bits 5 to S are 0 proceed to observe operation as a whole Status Bit 5 is I signalling General Hardware Alarm Connect a terminal to the Ceilometer Open line for dialogue and request Status STA The Status will contain one or more of the fol
21. supplies Diode DA1 8 9 protects against reverse voltages The Regulator is capable of producing 100 mA less than one third of which is used in the system The 12 V Regulator U7 is of adjustable type LM337LZ with the same characteristics and similar circuit realization as the 12 V Regulator The RS 232C Output TxD is driven by one of U14 op amps which inverts and level scales the TxD signal from the Processor 2 and RA2 1 2 provide for input signal threshold The output is protected by the series resistor RA14 7 8 and the clamp diodes in DA2 143 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 4 3 Test Points are provided for the following signals J5 10 12 V I F Positive Supply J5 9 12 V I F Negative Supply J6 10 Gl Amplifier Gain Control J6 7 V5 Mon ADC Ref Supply J6 6 MI Pre MUX Inverted O P Sequence Control Section The Time Base is obtained from the four unbuffered inverters in U33 One of them is the oscillator controlled by crystal Z1 RA23 7 8 and R34 provide for bias and by pass C38 and XI X2 U33 4 outputs the Seq Control Clock Xl applied to U38 9 and U43 13 in Freq Divider and Control block The Frea Divider and Control 1s composed of the JK Flip Flop U43 and the NOR gates U38 8 and 6 The clock is fed either through the F F its frequency divided by two LTE SQO applied to U38 10 11 and the J input of U43 SQO low or high results in 10 MHz or 5 MHz on U38 6 respectively S
22. the optical adjustments are carefully carried out to fulfill the requirements and specifications of the device Optical adjustments occur at factory or depot only There is no need to readjust any of these settings at the field site before installation If mishandling occurs during transit or installation the instrument should be returned to a VAISALA office or authorized Depot for inspection Do not touch the lens surfaces Maintain dust covers on the lenses during adjustments and during long periods of storage The optics and windows should always be kept clean of any dirt or particles especially during operation 11 22 Lifting and Carrying Do not attempt to carry the unit alone Do not lift the unit from Window Conditioner or Equipment Cover lift from Equipment Base only Use proper gloves for protection against sharp edges etc Disconnect Window Conditioner Cable from Equipment Base before placing unit on flat hard surface Remove cable from underneath Equipment Base edge 1 1 2 3 Exposed Connectors Maintain dust caps on all external connectors if stored unpacked for extended times in an unconditioned area When installed always maintain the integral protective caps on the unused interface connector 3 or J4 and the Maintenance Terminal CTHI2 connector CHAPTER 1 GENERAL INFORMATION 1 2 SPECIFICATIONS 1 2 1 MECHANICAL Height Total 52 8 in 1340 mm Excluding Pedestal 29 1 in 740 mm AOI o as Aaa 22 8
23. 0331 3191 154 383R 3k32 14k7 8k66 8k25 4k87 2k74 301R 20k0 0 1 1 4 W 25 ppM 00 0 1 1 4 W 15 ppM 322k 4k87 0 1 1 4 w 15 ppM 1 00 1k78 215R 10R0 A8k7 5 60 100R 825R A8R7 82k5 100R Trim pot 1 2 W 150 ppM 21k5 178R 4 7 8 Cl0 C12 C14 C15 C17 C24 C28 C33 C36 C37 C42 C45 C49 C5 1 653 C56 C58 C62 C63 C65 C68 C71 C73 C76 C78 C79 C86 C5 C6 C19 C23 C7 2 C7 4 C89 C9 C52 C78 C13 C35 C40 C47 C54 C57 C66 C16 C20 C22 C25 C27 C34 C48 C60 C75 C18 C64 C78 C26 C38 C50 C55 C88 C41 C46 C61 C67 C87 LI L2 L5 J3 J11 J13 J21 523 525 522 526 Capacitors 4507 100n 6020 10u 4782 220p 10008 lu 0610 22u 5705 92 3258 5726 22 4822 10n 5722 10p Inductors 1181 2321 Connectors 6800 5498 5158 155 CHAPTER 4 FUNCTIONAL DESCRIPTION 63V 35V 100V SOV 25V 63V 20V 63V 100V 63V 100uH min choke 220uH min choke 82 SMB 50 0 coax Cer tant polycarb polyest tant cer tant cer polycarb Cer 64 pin ac EURO connector Pin strip CHAPTER 4 FUNCTIONAL DESCRIPTION Switches SI 10019 107 SPDT on off mom Miscellaneous 0677 28 pole 5046 IC socket 40 pole 7439 IC socket 8 pole 1768 IC socket 18 pole 4684 IC socket 24 pole 5143 Female Shorting Plug 2 Pole 2997 Heat Sink THM 6107B 14 10014 PCB Ejector CBE 8 18 156 CHAPTER
24. 10 1390 11 1470 12 1600 13 1730 14 1870 15 2000 16 2130 17 2270 18 2400 19 2530 20 2670 21 2800 22 2930 23 3070 24 3200 20 3330 26 3470 27 3600 28 9130 20 3870 30 4000 ANGLE HEIGHT ANGLE HEIGHT degrees feet degrees feet 31 4130 61 8130 32 4270 62 8270 30 4400 63 8400 34 4530 64 8530 35 4670 65 8670 36 4800 66 8800 37 4930 67 8930 38 5070 68 9070 39 5200 69 9200 40 0990 70 9330 4 5470 11 9470 42 5600 12 9600 43 5730 13 9730 44 5870 74 9870 45 6000 75 10000 46 6130 76 10130 47 6270 10270 48 6400 78 10400 29 6530 19 10530 50 6670 80 10670 51 6800 81 10800 52 6930 82 10930 59 7070 83 11070 54 7200 84 11200 55 7330 85 11330 56 7470 86 11470 57 1600 87 11600 58 7730 88 11730 59 7870 89 11870 12 13 14 CHAPTER 2 INSTALLATION TABLE OF CONTENTS SECTION 2 1 GENERAL 2 1 1 PREFACE 2 16 TRANSPORTATION CONTAINER 2 1 3 ORIENTATION 2 1 4 REQUIREMENTS 2 2 SITE PREPARATION 2 2 1 FOUNDATION 222 CABLING 2 2 3 GROUNDING 2 3 START OF OPERATION 2 3 1 LINE POWER 2 3 2 INTERFACES 2 3 3 MAINTENANCE TERMINAL CTH 12 2 4 PERFORMANCE VERIFICATION 2 4 1 MESSAGE ALARMS 2 4 2 OPERATIONAL CHECK WITH TOTAL COMMAND 2 5 DRAWINGS CT 12K CEILOMETER U CT 3445 CT 12K INSTALLATION U CT 3282 CONNECTION DIAGRAM A CT 3105 EQUIPMENT BASE BOTTOM VIEW 3406 15 PAGE 16 16 2 1 GENERAL 2 1 1 2 1 4 CHAPTER 2 INSTALLATION PREFACE The installat
25. 580 228 WARNING IF INSTALLED BETWEEN LATITUDES 30 MAKE SURE THAT UNIT HAS SOLAR SHUTTER NOTE PREFERRED DIRECTION OF INSTALLATION RECEIVER SIDE NORTH ON NORTHERNHEMISPHERE SOUTH ON SOUTHERN HEMISPHERE RECEIVER SIDE LINE VOLTAGE INPUT SIDE DIRECT ION B B LL gt DEPTH DEPENDING t4 NDIN i NUT MIO PCS INCLUDED ON LOCAL FROST WASHER BIO 8PCS WITH CONDITIONS MINIMUM gua FOUNDATION SCREW MIO 4PCS DELIVERY 450 118 UE WEDGEBOLT MIOx40 4PCS 2 e a NOTE 123 DIMENSIONS ARE IN MM 123 DIMENSIONS ARE IN INCHES DIRECTON gt 45 0618 LS T 2 pw mer TRE ove VAISALA INSTALLATION A ue LEN 1 y H 1 NOLLVTIVISNI 9c JH CABLE CONNECTOR FOR CT 12K UNIT CONNECTOR A LINE AC SUPPLY CABLE LINE AC NEUTRAL CONNECTOR TYPE C 3 x 075 samm AWG 18 GND MS 316 1 35 I o PART OF WINDOW CONDITIONERS CABLE CONNECTOR 112277 WINDOW CONDITIONER CABLE NEUTRAL a E T E CONNECTOR TYPE TS un MS 8P E 6 x 075 sqmm AWG 18 TS bs re ee n CABLE CONNECTOR MOD 1 cee pres FOR CT 12K UNIT OUTPUT INTERFACE CABLE MOD 2 TUS CONNECTOR J3 s 3 RBCT 2 RBOI CONNECTOR TYPE 5 RBCE 1 MS 316 F12 8S 7 x 0 75 sq mm A W G 18 6 RBCE 2 Cloud Signa Twisted pars preferred 7 ND once rommoonmn o N
26. A5 AND SOLAR SHUTTER CTD 12 REF KD RECEIVER BOARD CTR 13 REF K2 TRANSMITPER BOARD CTT 12 REF A7 HIGH VOLTAGE POWER SUPPLY CTP 12 REF PSI TEMPERATURE CONTROL TRANSFORMER REF T1 TEMPERATURE CONTROL HEATERS R1 R2 TEMPERATURE SENSOR REF TS1 WINDOW CONDITIONER 115V REF BD MAINTENANCE TERMINAL CTH 12 REMOVAL OF CEILOMETER COVERS OFFSET CALIBRATION 265 PAGE 267 279 280 282 282 287 288 288 290 291 296 297 297 298 299 299 300 266 CHAPTER 6 TROUBLESHOOTING AND REPAIR THE TROUBLESHOOTING AND REPAIR SHOULD BE DONE AS FOLLOWS A Identify the symptoms of a fault from the alternatives of Chapter 6 1 Diagnosis listed in the manual s Table of Contents B Go to the Paragraph in question and determine the suspect LRU C Go to the Paragraph in Chapter 6 2 Verification and Replacement which covers the suspect LRU Verify that it is faulty and replace it 6 1 DIAGNOSIS 6 1 1 DATA MESSAGE CONTAINS AN ALARM The first line of the Data Message is Status Line 1 The general format is as follows NSB H H H H H T T T T T H H H H H T T T T T 5 5 5 5 5 5 5 5 5 5 0 For full interpretation turn to Section 3 2 The S bits and the indicator are the instrument status indicators of the unit Their interpretation is as follows S 0 No Status Bit 51 54 ON for more than 5 minutes S At least one Status Bit S1 54 ON for more than 5 minutes
27. Bell 103 or Gifft RBC Recorder interfaces All communication signals are isolated The board provides a trigger break to initiate the sweep of the stylus and a 120 Hz cloud signal to interface with the Gifft RBC Recorder The onboard integrated modem circuit provides a Bell 103 compatible modem output that is routed together with the Gifft RBC Recorder signals to output connector J3 located on the equipment base Onboard LED s provide for an easy way to monitor the board operation when necessary e g during maintenance SPECIFICATIONS Type CIT 12 Part Number 2683 Designation A3 Operational 5V 5 l7mA nominal Voltages 12V 20 8mA nominal 12V 20 IImA nominal 20 20 I5mA nominal 5V regulated onboard from 20V Dimensions W x D x H 4 X 69 x 1 2 inches 103 X 175 x 30 millimeters 175 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 3 3 Modem National Semiconductor Circuit MM 74HC942 300 Baud FSK Bell 103 Standard Ref Technical Note MM 74HC942 Interface All interface signals are electrically signals isolated and protected against line transients FSK 300 Baud Bell 103 Transmit level adjustable in 5 steps 12 9 6 3 O dBm Gifft Trigger Signal RBC Recorder Relay Contacts Normally Closed NC Ratings 2A at 150V max Data Signal 120 Hz Transmit level adjustable in 4 steps 2 0 2 5 dBm Functional Description The Output Interface board CTI 12 can be divid
28. C RELI HI REL2 80W heating ON below 5 C RELI HI REL2 LO OFF above 2 C RELI LO REL2 LO Two logic level signals zener protected CD modem carrier detect HI FLAG hand terminal detect LO CHAPTER 4 FUNCTIONAL DESCRIPTION Monitor I P Continuous monitoring of 19 parameters 11 unregulated operating voltages 25V 20VI 20VA 12VM l0VD l0VX IO0VR MRHV PXHV 4 temperature levels TI internal TE external TL laser TB heater blower 2 optically measured parameters LLAS Laser Power LSKY Ambient Light 2 systems parameters GND measured offset ADC internal reference Monitor 8 bits 5V corresponding to 2 C hit ADC Resolution for temperature and 20 150mV bit for operating voltages LED Indicators Two LED s Green and Red indicating CPU status Green Blinking OK Red Blinking or ON Not OK Both OFF Not OK 5V low Sequence Control Echo Signal Sampling Sequencer and Hardware Processor 134 General Features sample Convert and Store Feature Data Rates sample Add and Store Feature Data Rates Laser Frequency Control Software Alterable Delay Total Sequence Timing Sample Storage Laser Trigger O P LTRG Logic Level Drive Signal Amplifier General Features signal Input RECO 135 CHAPTER 4 FUNCTIONAL DESCRIPTION Sample Convert and Store sequencing by 10MHz clock rate Hard
29. D9 and DIO limit the output voltage to approximately 450V max while Zener D5 provides a collector voltage drop for Q4 and Q5 to within specifications of their breakdown voltage Resistors R17 and R18 provide protection for test points TP and TP2 Additional filtering 1s provided by C4 C5 and C6 and the final output voltage is from connector J7 to Receiver Board A6 The actual bias voltage for the Receiver Photodiode is adjusted by R13 The voltage to be achieved at room temperature 22 C or 72 F is found on a sticker mounted on the Receiver Board For other temperatures the adjustment value shall be corrected by applying the output voltage temperature coefficient 1 5V C or If the Ceilometer is equipped with Receiver board CLR L3 which has it s own bias voltage compensation circuit R15 has to be adjusted to it s maximum fully clockwise 216 4 3 7 4 Parts List Part Reference Number CBl 2956 CB2 2958 2 10021 32 2952 33 2954 FI F2 10179 10 10011 DSI 10231 RI 0956 R2 R3 10002 CHAPTER 4 FUNCTIONAL DESCRIPTION Description Circuit Breaker 2A Slow Airpax T21 2 2 0 01 00 Circuit Breaker 10A Slow Airpax T21 2 10 0 01 00 Relay 24VDC DPDT 16A Sigma 68R24 24DC SCO Fuseholder Littlefuse 345603 010 Fuse Knob 0 25 1 25 inch Littlefuse 345603 020 Fuse 62mA Slow 0 25 1 25 inch Terminal Weidmuller AKZ 4SS PA Indicator Lamp 125V 00 5 mch 1D1 1030 DI Metal Oxide Varistor 2
30. Data Recention The line signal through coupling transformer T2 produces a voltage across resistor R18 sensed by the input terminals RXAI and RXA2 of the modem circuit The demodulation is performed and the serial data is available at the output pin RXD of the modem circuit The 5V level data is converted to RS 232C levels and inverted by transistors Q4 Q5 and diodes D5 and D6 The LED Dll RXD indicates the presence of data after the demodulation by the modem circuit at transistor Q5 The data is available for the processor via connector Jl pin a25 signal IRXD The presence of the carrier frequency is indicated by LED D12 CD and sensed by the processor via connector Jl pin 18 signal CD 177 CHAPTER 4 FUNCTIONAL DESCRIPTION Control and Supply Circuits The Originate Answer mode can be selected by jumper J7 according to the jumper setting table in Circuit Diagram CT 2277 signal SQT of connector Jl pm a24 enables the processor to control the modulation of the modem circuit U2 The modulation is disabled when signal SQT is held high and it also prevents the data transmission to the modem circuit communication lines The function of the modem circuit U2 can be tested by the control signal ALB at connector Jl pin a24 The processor can test the operation of the modulation demodulation circuits with signal ALB in a high condition The data from the TXD input is then echoed back from t
31. and every time with Digital Message No 3 transmission start Signals TRIGGER BREAK Ref RBCT Normally Closed relay contact that opens for 80 milliseconds as an initiation for a new output Doubles as an Alarm Signal by extending the break duration to 200 ms when cause for Ceilorneter Fault Alarm exists This state is logically identical to that of bits S and B of Status Line 1 of Digital Messages CLOUD SIGNAL Ref RBCE Transformer Coupled 120 Hz signal twice Line Frequency on off controlled by Ceilometer for inscribing on Recorder paper OPERATION AND TIMING The Cloud Signal outputs cloud and obscuration heights as an analog delay with respect to the trailing edge of the Trigger Break O to 12 000 ft 1s covered in 3 seconds with a 20 ms resolution equalling 80 ft If the Trigger Break is 200 ms alarm then the reference starting point is 80 ms after the leading edge of the Break 232 0245227 CHAPTER 3 OPERATION Recording Modes and Set Up Commands Two on off parameters RMOD and BMOD condition the Cloud Signal output RMOD Recording MODe OFF Only Cloud bases are recorded ON In addition to Cloud bases also non cloud obscuration 1s recorded BMOD Base MODe OFF Up to two cloud bases may be output during one sweep each with a trace duration of mm 90 ms ON Only the lowest cloud base 1s output and with a fixed 60 ms trace duration RECOMMENDED STANDARD SETTINGS ARE RMOD ON BMOD OFF
32. c20 RELI 021 MRXD c21 RXD 022 RBCO c22 TXD a23 5S0 c23 RBC a24 ALB 24 SOT 025 BON c25 HON lt ac2 5V ac27 I0VD IPOD ac28 GNDO 2 00 _ _ NUBES 0c30 20V 20 5 o 311 20 M20A z gt BOR 32 GNDA cC ae 4 o amp amp t amp 5 x gt gt o o o gt e 5 88385352 xx G 9 9 Q 220 AMPIN 326 LIRIG zz gt ae A LTR I N Y e ar 889825255222 F Al elel Ed El E rf lol o ofS eta 9 mi L zd TA W7 W8 w9 W6 REC Xmit Hi V Hi v W3 T y u a a hy RSCT RBCE J3 2 1 2 2 TRIG INSCR FSK 6TT CEILOMETER OL 45450 0318 2679 FIELD SITE SPARES KIT OL 45462 1 1 U CT 6538 2676 2753 10319 CTH 12 2690 MAIN EQUIPMENT PACKAGE 2 MAINTENANC ASS Y PEDESTAL TERMINAL OL 65452 OL 45367 U C T4538 OL 45421 674 273 12 2713 SOLAR SHUTTER WINDOW SUBASS Y KI KIT CONDITIONER BI OL 45251 OL 45429 EQUIPMENT COVER OL 15395 TECHNICAL 2678 MANUAL NWS 2738 2677 COVER OPTICAL ELECTRONICS SUBAS
33. doubt Description of Parameters CLIM Cloud LIMit Sets the minimum increase in calculated extinction coefficient in Ceilometer specific units that must be present over a short range for cloud base condition See SLIM for additional conditions SLIM Signal LIMit Sets the minimum calculated extinction coefficient value in Ceilometer specific units that must be present in one range gate for cloud base condition DEV DEVice scale Multiplying scaling factor applied to all range gate values after normalization and prior to application of Cloud detection algorithms and output Does not affect heights Does affect CURRENT SIGNAL SUM see TOTA NSCA Noise SCAle Multiplying scaling factor which when multiplied with the RMS noise calculated from the 12 sec measurement scan sets the limit for discriminating between true signal and noise Decreasing NSCA will increase sensitivity but cause more noise hits SCAL SCALe Multiplying scaling factor to scale the value of PP LNOR Laser NORmal power Device specific parameter for 100 nominal laser power in units of Monitor A D converter increments Measured laser power LLAS is compared against this for laser power control and measurement normalization 62 CHAPTER 3 OPERATION TOTAI signal sum limit Limit for determining full partial or no obscuration For every 12 sec scan all range and equipment normalized range gate backscatter values are added to provide val
34. resist and component silk screen printed Dimensions 160mm x 233 mm height 21 mm max Temperature 40 70 operational 55 85 C storage Humidity Non Condensing Logic Supply IOV 6 12 VDC 330mA typical Analog Supply 20V 16 24 VDC typical 16 24 VDC 50mA typical Interface Supply 20V 15 25 VDC 15mA typical 15 25 VDC 30mA typical Logic Supply 5V 5 0 25 VDC 100mA maximum Interface Supply 12V 12 2 0 8 VDC 30mA maximum 12 2 0 8 VDC 20mA maximum On Board Reg ulated Voltages On Board Precision Reference Voltages CPU Processor Instruction Memory Data Memory Parameter Memory Watch Dog Timer CHAPTER 4 FUNCTIONAL DESCRIPTION Logic Supply 45V 5V 025V 300mA typical Interface Supply 4 12V 12 2 0 8V 10mA typical 12 2 0 8V 25mA typical Analog HI Supply 13V 12 7 0 8V 45mA typical 12 7 0 8V 45mA typical Analog LO Supply 46V 6 1 03V 15mA typical 6 1 0 3V 15mA typical Flash ADC Supply 9V 9 0 0 5V 40mA typical Basic Reference VR 10 0 0 03V 2 5mA typical Flash ADC Ref RP RC 8 30 01 typical 1 72 0 03V 7mA typical sink System Control and Data Processing Section 8031 single chip cor with Integral UAR T and RTC 128 Byte RAM Two I O Ports Operating Clock 10 MHz Cyc
35. 09 HHA OPEN LOPEN GROUNDED DEFINITION OF TERMS ete VAISALA a 2 x E AMS AMPLITUDE SELECT ON 123 SE PULSE DIAGRAM rnan 2 DCL s STATIC DC VOLTAGE LEVEL US IEST PULSE TIMING amp FORMS CT 3536 a AMPLITUDE 5 cas Ec rumen ME ee ee OUHHLdVHO NOLLATNOSHG TYNOLIONNA 4 3 2 4 3 2 1 4 3 2 2 CHAPTER 4 FUNCTIONAL DESCRIPTION UNREGULATED POWER SUPPLY BOARD CTS 12 REF A2 Introduction Unregulated Power Supply Board CTS 12 Ref A2 is a central support board of the CT 12K Ceilometer The CTS 12 performs the following rectifies and filters several low AC voltages from High Voltage Power Supply CTP 12 Ref PSI and Temperature Control Transformer Tl for supply to other parts relays and switches logic for operating internal Temperature Control Heaters RI and R2 with signals from Processor Board Al connects signals between the eleven 11 other input output connectors of the board interfaces RS 232C connector J7 with related over voltage protection and switches connection to FSK Modem for troubleshooting the remote data line SPECIFICATIONS Type CIS 12 Part Number 2682 Reference Designation A2 Dimensions W X D X H 5 0 X 8 86 x 1 77 Inches 150 x 225 x 45 Millimeters Environmental Temperature A0 F 140 F Inside 40 60 C Ceilometer Humidity Non Condensing 167 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 2 3 F
36. 1s sent from the Laser Control circuitry to the Transmitter board where it fires the thyristors of the Laser circuit The ultrafast thyristors force a current pulse through the Laser diode which thus emits a short high intensity pulse of invisible infrared single wavelength 904 nm radiation The pulse is emitted over a 30 angle so a lens is needed to collimate the radiation into a parallel beam The Laser Diode is thus located at the focal point of the lens 103 CHAPTER 4 FUNCTIONAL DESCRIPTION The Laser Power Monitor senses the Laser pulses and outputs a voltage signal proportional to the average laser power The laser pulse then traverses the atmosphere and small amounts of radiation are backscattered from any non gaseous particles in the atmosphere The optics are designed so that the Receiver field of view covers the transmitted beam completely at heights above approximately 1 000 ft Between 100 ft and 1 000 ft the coverage is partial ranging from 0 to 100 which aids in limiting the backscatter signal magnitude Below 100 ft no direct atmospheric coupling exists but due to the multiple scattering phenomenon signals can be measured A cloud produces so much multiple scattering that detection is certain Some of the backscattered radiation hits the Receiver Lens which focuses it onto a Silicon Avalanche photodiode operating as the radiation sensor since only the wavelength of the Laser source 904 nm is of interes
37. 2 pos AMP 5203152 Foil Receptacle Unused Jumper 2 pos 0 1 0 025 square Au Phillips F088 Cable Subassembly 2924 2946 100045 4014 Connector MS3 116F12 8P Connector Cap MIL C 26482 size 12 Cable Side Cable SxAWG 18 Alpha 45068 Terminal Bush AWG 18 Abiko 7575 Display Subassembly 2871 2718 2964 2965 231 LCD Display Module Densitron LM12BIC16CB H Heating Foil Connector 1 3 pos 0 1 Berg 76308 103 Connector 2x7 pos 0 1 Berg 76314 107 CHAPTER 4 FUNCTIONAL DESCRIPTION 2728 Keyboard Cable Subassembly Pl P2 6433 Connector 16 pos Ribbon Cable Header Yamaichi FAS 1601 2101 OAF 10044 Polarizing Pin Yamaichi No 2 FAS 0571 Ribbon Cable 16xAWG28 Spectrastrip 455 044 16 252 5V RS 232 c te ass as DRIVER U 9 ISPLAY LOGIC LIGHT CONTROL KEYBOARD ENCODER HEXADECIMAL FLAG 1 KEY BOARD gt TOW i 7 7 TXD 2 as R 7 I DISPLAY eise A 1 5 6 21 7 f CONTROL GND DISPLAY CIRCUITS 4 T T SUBASSY d sus que C RRC al L a GENERATOR HN HEATING b J L VDD L DR RESISTOR RESET Title CEILOMETER CT 12K mM VAISALA MAINTENANCE TERMINAL CTH 12 BLDCK DIAGRAM 1985 09 25 ETA Reploced by Y WA LdIVHD NOLIATIOSHG TW
38. 4 H H H H H second cloud height if not defined range of backscatter of second layer if not defined H H H H H calculated vertical visibility TTT T T signal range 1 e height of highest detected backscatter STATUS INDICATORS 2 n UN UN UN UN UN 1 n A 2 RP UN 510 Hardware alarm Supply Voltage alarm Laser power low Temperature alarm Solar shutter On Blower On Heater On Unit is feet 1 Unit 1s meters 0 Data in internal table 2 1s range and instrument normalized 1 Data in internal table 2 1s inverted 1 e extinc tion normalized Fast Heater Off 1s active Status Line 2 SUM LAS TLx OF F5 XX PP CR LF G 0 G 2 F 0 Pay Gain used is 250 Gain used is 930 Laser pulse frequency used is 620 Hz minimum Laser pulse frequency is 1120 Hz maximum 46 3 2 1 5 CHAPTER 3 OPERATION N NN Noise RMS voltage in units of ADC increments computed from the latest 12 s measurement period One digit two decimals SUM Sum of total backscattered power per unit solid angle 1 e range and instrument normalization applied Three digits no decimals Leading zeroes replaced by space characters IIN Algorithm related internal processing information 3 digits LASE Measured Laser Power in units of ADC increments LLAS 3 digits TL Internal variable indicating transmitter temperature 2 digits
39. 4 FUNCTIONAL DESCRIPTION E THIS J4 SETTING FOR 270512 SOFTWARE 23 AND HIGHER Ul 000600000 c GJ 00000000 D4 DS E 29 J9 8 fu 71 J15 4 3 3 J17 5 188 J16 e J20 1 n con Jee 24M Jee O se 1248 CEILOMETER CT 12K us VAISALA PROCESSOR BOARD CTM 12 JUMPERINGS AND CONNECTORS an B Serial 1 2 5 3 3 313 R 3 157 FUNCTIONAL DESCRIPTION CHAPTER 4 YSLLINX OL 4399181 83SV1 JOSINOO u3M018 831V3H TOYLNOD YILINHS TOYLNOD 8303800339 1OMINOO H3DOWN 130YV9 W300H 9V 13 H3831 ONVH 1 5 I ZEZ SY JOBLNOO SNI1V3H MOONIA Y3MOd 539 1 0 AlddNs Q31v1n93HNn P NIV9 A S O P CONTROL LATCHES MONITOR ADC 181 9 d O CENTRAL PROCESSING UNIT amp RELATED CONTROL LOGICS d 3WI 1 OOHO1VM SAMPLE SUM DATA 181 9 TOANON S A AMPL DDER r1 AS BANK BANKS 10 2 521001 IOYLNOD 32N3f1035 0383 9NITdWYS 8 kB DATA RAM ATi A6 AEL 5801 10938 39V110 0OYVO8 NO FLASH ADC papa 8 kB OPTION A9 32 kB TOYLNOD 3 SS3U8Q0QV ABUON3H 8 3 1YN9IS 8 181 2 NIYO 357108 1S31 pa z Uv O x 5 o 1 zi ul E E 91 2 m 2 x ei 00 AOS 8 AZl 53119405 39N383439 QM vO8 NO FROM RECEIVER y Title SIS
40. 4 3 9 3 1 6 During the first stop bit data 1s transferred from the Receiving register into the Receiver s buffer register RBR One clock cycle later the data ready signal DR goes HIGH After approximately 3us created by resistor 1 3 4 and capacitor C4 the state at pin 3 of circuit U5 goes LOW This 1s connected to the UART s input DRR which resets the output DR After another 3us the state at U5 pin 3 and the input signal DRR goes HIGH and the circuit 1s ready to receive a new character RS 232C Transmitter The RS 232C Transmitter 1s comprised of operational amplifier U3 LM 124 The serial data signal TRO coming from the UART Transmitter is brought to the inverting input of the op amplifier A ref voltage of approximately 1 7V is obtained by resistors RA3 1 2 and RA2 9 10 Here U3 has the function of an inverting comparator which at the same time converts the TTL level voltage into an RS 232C compatible voltage The operational amplifier is protected against overvoltages and short circuits by diode bridge DI and resistor R6 Outgoing RS 232C data is brought to terminal strip El pin 3 RS 232C Receiver Incoming RS 232C data is brought to terminal strip El pin 2 R5 and D3 protect the input against overvoltages beyond 15V RA3 3 4 provides a load resistance of 10 k ohm for the input and insures that the unconnected input is kept at state 0 RA3 5 6 and C7 form a low pass filter time constant 10 us preventing fu
41. A K1 A GRY K1 8 YEL K2 8 BLK K2 7 BRN K1 7 BLK K2 4 ORN T2 SEC F2 ORN T2 SEC J6 2 RED T2 SEC J6 4 RED T2 SEC F1 YEL F2 46 1 RED F1 46 3 es 3 lt 5 43 sc nie z EL 150 wie ld 134 ES M NO OO coco w ff LHAX 8 i Gf LHANWE 62 m a in HE NOTE ALL THE DIMENSION IN INCHES t4 134 64 E WZ S P2 v 85 10 22 Leitu Tee HI VOLTAGE POWER SUPPLY PSI uer ie awe 2 2688 EE AE AA N 1 IIA WIRING DIAGRAM U CT 1200 El c c Ag 221 FUNCTIONAL DESCRIPTION CHAPTER 4 19SILZ ON 1HVd yy qq L Hl 2 EQ yO WSIVAo H 90 r 6H oo LLL uu 28 a E x 918 Ep e siu Q E lt Q gt UJ O lt 1 gt TYPE CTP12 PA 2715CT 223 224 4 3 8 1 4 3 8 2 CHAPTER 4 FUNCTIONAL DESCRIPTION Window Conditioner Bl Introduction The Window Conditioner of the CT 12K Ceilometer serves for keeping the windows on top of the instrument free from precipitation and dust In addition it is used for regulating the temperature of the Ceilometer It is controlled by the processor of the Ceilometer via two power relays in the High Voltage Power Supply PS 1 Specifications Part Number 2736 Designation B
42. C5 6 68 10 11 0977 100 nF 63 V c4 6920 10 nF 35 V c7 10008 uF 50 v C9 C14 10006 10 nF 630 V C12 C13 4822 10 nF 100 v C15 10007 68 nF 630 V Inductors L1 L2 2321 220 pH Connectors Jl 2963 MIL C 83503 10 pos Male PCB 90 J2 2923 AMP Metrimate 3 pin PCB 90 J3 1692 SMP Submini coaxial PCB 90 Optics 1934 Infrared Interference Filter 904 25nm 198 661 t iw D Ku L7 P P1QR GNDR 30V MRHV 250 RA1 U1 m 1 317127 L2 Ad 220pH K 2 C3 C 2p 100n O C10 R7 1016 11 iL B25 22 00n 1998 m Cho d gt V J U3 11 93 0 A RUE NM SHIELD __ R9 3 02 p yw C7n1u C6n100n eee eee ss L THERMAL CONTACT m gt 1988 10 13 515 re 1SRB 0 T COL Pon tee ee ol RECEIVER BOARD A6 TYPE CTR 13 P N 20105 CIRCUIT DIAGRAM ets VAISALA TO nr 13593 UA LdVHO NOLLdJIY OSAA IVNOLLION 002 amp pcs U1 U4 01 02 p M2x10 2 pcs M2 2 pcs D2 U2 DETAIL SILICONE HEAT TRANSFER COMPOUND BETWEEN D2 AND U2 4 x e CUT THIS LEAD x e 0 2 INSULATING 02 U2 LOCATED LOCATEO ON UPSIDE DOWN SOLDER SIDE IN 0 195 HOLE SOLDERED ON IN PC BOARD COMPONENT SIDE AT BASE OF 02 WAMU WLM SOLOER 92 ON SOLDER SIDE SILICONE HEAT TRANSFER COMPOUND BETWEEN D2
43. CMOS CMOS CMOS CMOS CMOS Op amp x 4 CMOS Temp sensor CMOS ADC CMOS CMOS RAM CMOS Reg Ref CMOS CMOS CMOS CMOS CMOS CMOS CMOS CMOS CMOS CMOS Op amp video CMOS Transistors 01 04 06 5416 2N2222A QIO QII Q7 08 0285 2N2907A Q12 2975 2N4392 152 NPN PNP N JFET CHAPTER 4 FUNCTIONAL DESCRIPTION Diodes DAI DA3 2974 TND903 D1 D3 DII 4171 IN751A D4 5429 5082 4655 D5 1159 ESBG 5531 D6 D3 D10 D12 4685 5082 2008 D7 0024 IN4740 D9 4336 134005 Crystals Zl 10000 10 000 MHz Resistor Arrays all Single 1n Line SIL unless otherwise mentioned RALRA2 RA4 0965 5 12 RAIS 18 0942 6 14 4989 RAI7 RA21 RA23 RAT RAII 0057 RAS RAI9 4633 RAY 0967 RAIO RA16 10001 RAI3 RA22 2960 RA20 RA24 1199 RA22 2960 153 5 x 4k7 9 x 2k2 4 x 1k0 4 x 10k 9 x 10k 4 x 47k 4 x 100R 4 x 2k2 4 x 22k 4 x 2k2 Diode Array 8 x IN4148 Zener Diode 5 1V LED Red LED Green Schottky Diode Zener Diode IOV Diode CHAPTER 4 FUNCTIONAL DE SCRIPTION RLR3 R30 R47 R2 R4 R40 R42 R5 R24 R39 R49 R6 R7 R 19 R48 R8 R36 R41 R9 R 12 R28 R33 R10 RII R13 R14 R21 R15 R16 R22 R17 R18 R20 R35 R54 R25 R68 R26 R43 R53 R56 R27 R62 R31 R61 R65 R66 R34 R37 R44 R52 R57 R46 R58 R59 R63 R50 R67 R55 R60 R64 Resistors all 1 1 4 W 50 ppM metal foil unless otherwise mentioned 9167 5791 5126 0556 1677 1393 5156 7479 3532
44. Chapter 3 Operation In the maintenance mode most of the functions can be individually activated and therefore easily tested After monitoring the operation with the LEDs on Al and A3 the cables can be connected to the connectors J3 and J4 The operation should continue as described earlier If not then the cables operators terminals etc should be checked and possible mistakes corrected MAINTENANCE TERMINAL CTH 12 While operating at the installation site the Maintenance Terminal CIH 12 provides an easy way to monitor and control the operation of the Ceilometer Refer to Chapter 3 The Maintenance Terminal is connected to connector J4 of the equipment base 22 2 4 CHAPTER 2 INSTALLATION PERFORMANCE VERIFICATION 2 4 1 2 4 2 MESSAGE ALARMS Check that the Start Up Message Reference Paragraph 3 4 3 does not contain any messages of alarm error or suspicion and that none of the numerical values output in the message has an asterisk immediately after it After Start Up observe operation for a suitable time Check that no alarms are generated If cause for suspicion exists turn to Chapter 6 OPERATIONAL CHECK WITH TOTAL COMMAND The CT 12K Ceilometers are factory adjusted and aligned for optimum performance After installation the operation can be checked with a constant and solid cloud base within the height range of 1000 5000 ft with no fog haze or precipitation The TOTAL comman
45. ERROR ANALOG MONITOR ERROR EX XXXXX XX XX any hex number O F for x OFFSET ERROR AMPLIFIER ERROR NOISE ERROR SEQUENCE ERROR SEQUENCE RAM NOT CLEARED SEQUENCE PULSE COUNTER ERROR SEQUENCE HALT EEPROM ERROR If any one of these appears check that the jumpers on Al are installed according to the Technical Description If they are and if the source supply voltages are okay replace AI Supplv Voltage Alarm First check other units according to Paragraph 6 1 1 2 If all the voltages are correct replace Al Notice however that if cables W8 and W9 are disconnected or faulty PIOX PIOR PXHV and MRHYV are unmeasureable by Al thus causing an alarm Even after reconnecting W9 the PXHV reading may be invalid for some time Temnerature Alarm Check that the negative voltage levels MTE MTL MTB and MTI correspond to existing temperature for reference see Paragraph 6 1 1 4 If they do but the alarm persists replace Al If they don t check that sensor source voltage on D2 anode is inside 4 4V to 5 IV If not replace Al Otherwise suspect the sensor subassemblies and their cables and or connectors 283 CHAPTER 6 TROUBLESHOOTING AND REPAIR Other Alarms LASER POWER LOW with Automatic Mode ON check the Laser Trigger LTRG J21 9 This should be high for 60ns approximately every Ims To measure the pulse use SQO J21 3 trigger for oscilloscope LTRG pulse should appear right after the rising edge of SQO I
46. SMA OPTICS HOUSING TRANSFORMER 1 SERN RECEIVER OPTICS ADJUSTMENTS RECEIVER BOARD CTR 13 6 POWER SUPPLY 12 lt PS 1 Crown 1985 08 19 ETA 1 k CEILOMETER CT 12K Y VAISALA INTERNAL LAYOUT DWG no 64 y TYNOLIONNA LIGHT MONITOR BOARD CTL 13 5 SOLAR SHUTTER FLAP QUTPUT INTERFACE BOARD CTI 12 lt OPTICS HOUSING SUPPLY BOARD CTS 12 A2 gt TRANSMITTER OPTICS ALIGNMENT SCREW ALIGNMENT PLATE SCREWS FUCUSING ADJUSTMENT RING ox E POWER SUPPLY CTP 12 I dp M CIRCUIT BREAKERS A PUSES hl OND ER CB b AND LEE HIGH VOLTAGE POWER L 9 Casper a ue ER s SUPPLY HOUSING 0 81 0 TRANSMITTER BOARD FOCUSING ADJUSTMENT CTT ie lt A7 gt j SPACER LOCK NUTS ES En EQUIPMENT BASE Note 1995 08 20 ETA Mt Internal cables and harnesses CEILOMETER CT 12K not included this drawing INTERNAL LAYOUT RIGHT HAND VIEW NOLLJTHOSHG OPTICS HOUSING HIGH VDLTAGE POWER SUPPLY HOUSING RECEIVER OPTICS ALIGNMENT SCREW lt had POWER SUPPLY FUSES Fl AND Fe ALIGNMENT PLATE SCREWS FOCUSING ADJUSTMENT RING FOCUSING A
47. TI J3 and provide two 40 watt sources of power By turning switch SI to the OFF position the relay drivers release relays Kl and K2 This should be used only for temporary maintenance or service operations Control signals RELI and REL2 operate without the interaction of the processor or software RS 232C Interface The RS 232C signals come through connector J7 which 1s a D25 Male type There are two active signals which are the serial asynchronous data signals MTXD pin 2 Data Transmitted from Ceilometer and MRXD pin 3 Data Received by Ceilometer This corresponds with the Ceilometer appearing as Data Terminal Equipment DTE Signals MRXD and MTXD are over voltage protected by resistors RI and R2 and transient zeners D5 and D6 which are bi directional Data from the RS 232C Interface MRXD is OR ed with input data both on the Processor Board Al and the Output Interface Board A3 170 CHAPTER 4 FUNCTIONAL DESCRIPTION Data from Processor Board Al TXD is normally connected via switch 52 to the RS 232C interface as output data MTXD Switch S2 can also be set to connect the Ceilometer FSK line input data IRXD as output data MTXD of the RS 232C interface to enable communication from local RS 232C device via FSK line to the central site e g for maintenance and service purposes Further the RS 232C interface connector J7 carries a 12V supply to the maintenance terminal and a FLAG signal which W
48. The Main Equipment Assembly is protected by the Equipment Cover This has windows on top of it for the Optics and panels on its long sides to reflect sunshine The Window Conditioner mounts on top of the Equipment Cover and connects to connector J2 underneath the Equipment Base see Dwg ACT 3406 The main purpose of the Window Conditioner is to shelter the windows of the Equipment Cover from precipitation and dry the windows of water droplets with warm air flow over the windows In addition to this the Window Conditioner also prevents excessive dust contamination and curbs temperature extremes by warming the whole Ceilometer when external temperature is low and circulating the air when it is warmed by sunshine The Main Equipment Assembly consists of two major subassemblies The Optics Subassembly which contains the Optics Housing as a frame Transmitter Board Receiver Board associated optics adjustment hardware the Light Monitor Board Transmitter and Receiver lenses Temperature Control Transformer two Temperature Control Heaters and as an option the Solar Shutter The Optics Subassembly mounts on the Electronics Subassembly with six screws and connects to it with seven separate cables and four attached connectors The Electronics Subassembly which contains the Equipment Base High Voltage Power Supply Housing and Board Frame as its mechanical body High Voltge Power Supply Processor Board Unregulated Power Supply Bo
49. VIEW ee SEIEBMETER OT der pet dL GENERAL LAYOUT Related eG P YALAVHO NOLLJTHOSHG TYNOLIDNNA CCL LIGHT MONITOR BOARD CTL 13 lt 5 RECEIVER DPTICS TRANSMITTER DPTICS OUTPUT INTERFACE BOARD 12 SUPPLY BDARD PROCESSOR BOARD CTS 12 lt 2 CTM 12 Al BOARD FRAME RECEIVER OPTICS ADJUSTMENTS RECEIVER BOARD CTR 13 Ab gt TRANSMITTER OPTICS ADJUSTMENTS POWER SUPPLY CTP 12 PS 1 TRANSMITTER BOARD CTT 12 7 LIGHTNING PROTECTOR CIRCUIT PART OF W3 gt EXT TEMPERATURE SENSOR TS 1 EQUIPMENT BASE Note Internal cables ond hornesses ore not included in this drawing Tite CEILOMETER CT 12k VAISALA INTERNAL LAYOUT DWG na FRDNT VIEW ACT 3461 peni o o oe C AA Y NOLLJTWOSHG TVNOLIONNY ECT TRANSMITTER DPTICS SOLAR SHUTTER FLAP TEMPERATURE CONTROL P RESISTOR R2 i m SOLAR SHUTTER SOLENOID KI gt OPTION gt TRANSMITTER OPTICS E ADJUSTMENTS c AI E TRANSMITTER BOARD EA de CTT 12 A7 D FAY T LIGHTNING PROTECTOR eiteiis CIRCUIT lt PART OF w35 ES EXT TEMPERATURE SENSOR TS 1D Note Internal cables and harnesses gre not included in this drawing LIGHT MONITOR BOARD CTL 13 5 RECEIVER OPTICS TEMPERATURE CONTROL RESISTOR R1
50. Voltage Regulator The measurement circuits of the board are powered through an on board 3 lead voltage regulator U2 LM 317LZ Its supply is from the board s 24V and resistors R14 and R15 determine the level of the internal supply voltage 17V 1V Capacitors C4 and C5 provide filtering 188 4 3 4 4 Parts List UI u2 QI Q2 D1 D3 D2 D4 D5 D6 D7 CHAPTER 4 FUNCTIONAL DESCRIPTION Semiconductors 2456 LM124 1016 LM3 17LZ 5416 2N 2222A 1384 TIP 120 Quad Op Amplifier Voltage Regulator NPN Transistor NPN Darlington 2973 UDT PIN 3CD Photodiode 4685 HP 5082 2800 Schottky Diode 5429 HP 5082 4655 LED Red 4336 INA005 Diode Resistors all resistors Metal Film 1 50 ppm 0 25 W unless otherwise stated R15 R6 R 13 R8 R12 R2 R 14 R3 R10 RII R5 R4 RAI 2 4 5 J2 5156 2k74 6372 10k Potentiometer 5388 10k 6355 215R 6627 IMO 0791 68kl 5453 487R 5444 21k5 Resistor Array 2960 4 x 2k2 Capacitors 0977 100nF 63 V Polyester 0009 25 V Tantalum Connectors 2963 MIL C 83503 10 pos Male 90 2024 Amp Metrimate 207608 3 3 pos Header Female PCB 90 O6I i REELED 01 PIN3CD Es LASER POWER MONITOR C1 100 n MONITOR GAIN ADJ 17 SKY LiGHT MONITOR SOLAR SHUTTER DRIVER VOLTAGE REGULATOR LASER POWERILLAS SKY LIGHT LSK Y GNDP GN OP SSON 25V 25 25 P25V1 GNDS GNDS 5
51. W X D X H 4 0 X 4 0 X 1 6 inches 102 x 102 x 40 millimeters Photodiode RCA C 30817 Type Silicon Avalanche Photodiode APD Note For more specific information on photodiode see manufacturer s data sheet Filter Infrared interference filter 904 25nm Responsivity 40 A W at specific Bias Voltage and Temperature noted on board sticker 194 4 3 5 3 CHAPTER 4 FUNCTIONAL DESCRIPTION Functional Description Refer to Circuit Diagram CT 3593 The 10V DC supply voltage for the CIR 13 board is applied through connector Jl pins 1 and 2 A low pass filter formed by LI Cl and C2 blocks high frequency interference from the input of regulator UI The 45V output voltage of the regulator Ul is adjusted by resistors R7 and R and filtered by capacitors C3 and C4 The 5V output voltage for the board can be measured between test points TP3 and TPGND An unregulated high voltage bias supply is applied through connector J2 It is on board regulated by transistor Q3 which is driven by differential amplifier 1 4U3 output pin 7 The Avalanche Photodiode D2 which acts as the Ceilometer Receiver has a responsivity which is both highly temperature dependent and highly bias voltage dependent These are matched to maintain a constant responsivity by applying a linear bias voltage increase of 1 3 V for every 1 F temperature increase 2 3 VPC Temperature Sensor U2 is in close thermal contact with D2 Its output is a zener like
52. are then routed from PSI through harness W2 and Ceilometer connector J2 to the Window Conditioner Heating Resistor HRI foils are parallel connected for 115V operation Its heat is transferred to the Radiator part 7 upon which the Safety Thermostate SI and the temperature Sensor TS2 are mounted The Blower housing is designed to create an even efficient airflow over the radiator picking up approximately 13 F of heat before sweeping over the windows of the Ceilometer Operation is monitored with Temperature Sensor TS2 which 1s connected via PSI and A2 to Processor Board Al Monitor A D converter channel 1l software reference TB 226 CHAPTER 4 FUNCTIONAL DESCRIPTION Monitoring criteria are When both Heater and Blower are ON the temperature Shall be less than 72 F 40 C above ambient as measured with TSI Ref TE If Blower only is ON then the difference limit is 54 F 30 C If heater has been ON and subsequently the blower for more than 10 minutes then TB shall exceed TE by 3 C or more If temperature TB exceeds external temperature TE by 72 F 40 C more heating is cut off by software control and a hardware alarm is given The temperature measurement circuit is monitored against the alarm limit TB ALIM TB default value 176 F 80 C to insure proper operation Four 4 minutes time filtering is used As a final safeguard against overheating the Safety Thermostat Sl cuts off hea
53. as SQO and SQI are both low U44 8 15 high As also CBO is high the Fast Write signal from U52 6 will run through U53 8 WSM During SQPHI as SQO is high WSM is decoded from the combinatory state of CBO 01 generates low active Write During SQPH3 WSM is totally inhibited by SQO SQI 1 The Sum Write Buffer Enable signal WEN supplied by U52 8 acts simultaneously with WSM except during SQPHO as disabled by SQO low 145 CHAPTER 4 FUNCTIONAL DESCRIPTION The Sample Adding Logics consist of the full adders U34 U35 and one of the two D Flip Flops in U36 U34 forms the sum of BDO 3 RDO 3 and one bit carrying from U36 9 then applying the sum results to SDO 3 and carrying to U35 7 U35 forms the sum of BD4 7 RD4 7 and one bit carrying from U34 then applying the sum results to SD4 7 and carrying to the D input of U36 The F F stores the carry by rising edge of the clock RSM applied to its pin 11 Otherwise adding operation is asynchronous SQO applied to U36 10 sets the F F when low The Temporarv Store U28 contains eight D Flip Flops triggered by rising edge of common clock RSM applied to pin 11 Its reset pin is driven by the EX OR gate U41 11 which produces active low Reset either with SQO and both high SQPHO or both low STOP condition Re Linearizer is composed of the two quadruple 2 to 1 line multiplexers U39 U40 and the surrounding gates and inverters The Sample Data bit FDS 045 6
54. eee aon cand c d e PP Ns o r s 161 e U a e ee 1 s lt e r e aiie a 4569 CT RMOD ON BMOD OFF CT 4569 Fig 1 Cloud mass at 3500 to 4000 ft ing at 600 ft starting Showers some not reaching ground New cloud deck formi at time 1730 57 CHAPTER 3 OPERATION a prm PERE tei e e gu MA 0 A A a aa ns SUM 4 eh h 00 RMOD ON BMOD OFF CT 4570 Gradual increase of density with height distinct base indistinguishable at times Cloud mass at 3500 ft gradually lowering to 1500 ft e g 1900 Fig 2 58 CHAPTER 3 OPERATION T m tu m m m m a O a fj ij r r r r A d d d rr ul T m u N u fu n n t B f ti gg naa UiS q4 Y t 0 5 P RMOD ON BMOD OFF CT 4571 Fig 3 Blowing snow at 4000 to 5500 ft gradually lowering to ground during time 0
55. if necessary with alcohol and a clean lint free cloth according to Paragraph 5 2 Cover the Ceilometer by following steps 1 5 in a reverse order Be sure to remove temporary lens covers and to leave circuit breakers CBI and CB2 ON 299 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 4 OFFSET CALIBRATION The instrument offset has been factory calibrated and in normal conditions no need for field recalibration exists If however a part is replaced that has an influence on internal noise behavior a recalibration shall be performed after restoration of operation Parts influencing noise behavior are A Processor Board A2 Unregulated Power Supply Board A6 Receiver Board A7 Transmitter Board PS 1 High Voltage Power Supply W6 Receiver Low Voltage Cable W7 Transmitter Low Voltage Cable W8 Receiver Signal Cable W9 Transmitter Control Cable If for some reason noise hits are more frequent in some ranges than in others excluding the self evident higher probability for high range noise hits than for low range ones due to lower signal to noise ratio a recalibration is to be performed Procedure for Offset Calibration A Check that noise conditions are such that difference between two smallest numbers average and minimum seen with command NOIS are 8 or higher with GAIN 2 and 2 or higher with GAIN 0 Use artificial light pointed into Receiver if necessary B With equipment in normal operating configuration 1 e equipment co
56. key 1 decimal point E key 1 minus sign F key open line 1 2 line feed command line terminator return 3 message viewing FORWARD STEP key The operation of the CT 12K can be monitored controlled by giving commands from the Maintenance Terminal CTI I 12 The commands are identified by header key C and command numbers The correspondence of the number and commands 1s found in table 3 5 3 A label inside the cover of the CTH 12 Terminal includes operating instructions and a command list The use of commands and the command format is described in Sections 3 3 and 3 4 OPERATION Opening and Closing the Line F key Cl command The system indicates being ready to accept commands by outputting a prompt gt to the LCD display of the terminal After being connected to the CT 12K the terminal display is clear This indicates that the system is not ready for commands The communication line is opened by pressing the F key The system responds by displaying the prompt gt NOTE If the system is outputting the automatic message when the CTH 12 1s connected some characters may appear in the display and the line 1s not opened until the output 1s finished similarly the line should be closed when the command session is over so that the standard data message will be received 83 CHAPTER 3 OPERATION 29 22 The line is closed by the closing command CIF As with a standard terminal the line will
57. needed by the transmitter laser diode and the receiver avalanche photodiode Switches the line voltage by power relays to control the Ceilometer Window Conditioner Specifications Type Part Number Reference Designation Dimensions Weight Line Input CIP 12 2688 PSI W x x H 7 1 x 118 x 5 8 In 180 x 300 x 148 mm 10 1 Ibs 4 6 kgs 102V min 132V max 45Hz 65Hz 12 max continuous 213 CHAPTER 4 FUNCTIONAL DESCRIPTION outputs A1 J7 A1 J8 Electronics Primary Circuit Breaker Supply Rating 2A Slow Connector Voltage Current Note Pl SVAC Unregulated Pl 2 x 8VAC Unregulated Pl 20VAC 0 7A Unregulated P1 2 xISVAC 0 15A Unregulated 270VDC 30mA Unregulated 250VDC Regulated 425VCD ImA Adjustable Temperature Dependent 1 5VPC All of the above outputs are floating J3 Line Temperature Voltage Control Transformer Window Conditioner Circuit Breaker CB2 Control Rating 10A Slow Connector Voltage Note J2 Line Blower Supply Voltage J2 Line Heater Supply Voltage Environmental 40 F 140 F Temperature 40 60 C Inside Ceilometer Humidity Non Condensing 214 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 1 3 Functional Description Refer to Circuit Diagram CT 3289 4 3 7 3 General The Line Supply is brought in via connector J1 to Terminal Block J5 and further to Indicator Lamp DSI and Circuit Breakers and CB2 DSI is
58. of CT 12K shuts down operation and gives an alarm Laser Diode Triggering Circuitry The Laser Triggering signal LTRG from the Processor Board controls the laser diode pulsing The signal is active high and trailing edge sensitive and 1s applied through connector Jl Signal LTRG can be monitored at The operating voltage of the circuitry is 10V and is applied via connector J2 pins 1 and 2 It can be measured at TP4 The Trigger Pulse is generated by a single shot formed by transistors Q2 and Q3 This in turn is triggered through QI Transistors Q2 and Q3 are normally off 1 e no current 15 flowing LTRG when high turns QI off and allows R4 to charge Cl The trailing edge then pulls the emitter of Q2 down and current passes through Q2 to the base of Q3 causing its collector to rise high and keep Q2 conducting via C2 and R8 while at the same time driving current through transformer TI primary After approximately 20ns capacitor C2 1s charged and prevents Q2 from getting base current which leads to Q2 turning off and consequently to turning off D4 limits the kick back of Tl secondaries turn the laser pulse thyristors Q4 and Q5 on in less than 20ns 207 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 6 4 Parts List Semiconductors Q1 Q3 0285 1832LM335H Ul 2N2907 Q2 5416 2N2222 24 05 2369 GA201 Q6 Q9 2970 TIP50 DI D5 3384 INA148 DI0 D13 D6 1960 LD224 8S D7 4011 IN759 D
59. parameter set display Base only output ON OFF Total parameter set display current signal sum display CHAPTER 3 OPERATION Col value 7 SEND Digital message no select display C32 value vv RAT Gain Ratio Set Display G33 value 7775 5 SERN Serial Number Set Display C34 value 7755 5 HOF F Height Offset Set Display C40 value 777775 CAL Offset calibration secl Notes 1 can be used only in maintenance mode 2 abort display with A key 89 06 Monitored parameters Typical values emperotreHW A D bits 5 Official signal when loaded dependence scaling respectivel designations 20VI I F pos supply unreg 21 0 3 5 V 018 1195 52 P20 1 20VA Analog pos supply unreg 19 545 9 V 0 18 1179432 P20A 2 25V Shutter amp heoting supply unreg 26 014 V DTS 9224227 P25V 3 410VD Logic supply unreg 8 0 2 V 023241327509 100 4 410 Receiver LOV supply unreg 9 5 2 V 0 52 loo oo P10R 5 10VX Xmitter LOV supply unreg 9 5 x2 V 52 1199459 10 6 412VM Maint term supply unreg 12 0 2 5 V 0 52 196 41 P12M 7 XHIV Xmitter HIV supply unreg 4160 40 V a 0 3 C 0 01 82420 0 3x 0 PXHV 8 LLAS Laser peak power 1 5 45 V 1 00 773 230 LLAS 9 LSKY Ambient light level FOO V 1 00 299 LSKY 10 MTE External temperature 2 98t 0 06V 0 01V C 1 00 152 3 0 51 C TE 11 MTB Blower temperature 2 98 0 06V 0 01V C 1 00 152 5 0 51 0 TB 12
60. presented are those of the last complete 12 s scan The cloud heights etc presented in Status Line 1 ref paragraph 3 2 1 3 may have been determined from the two last 12 s scans and minor inconsistencies may therefore appear in rapidly changing situations Key First digit of field XX of Status Line 2 ref paragraph 3 2 1 4 indicates number of scans used for Status Line 1 cloud information 48 3 2 1 6 CHAPTER 3 OPERATION Data Item to Backscatter Power Relationship Let S RAWDATA MINV Noise where Noise is the remaining noise induced offset of the data table Then instantaneous received backscatter power P 16 P S 0 188 GAIN u W where GAIN is 250 at No 0 or 930 at No 2 Message Example STXCRLF 10 04200 00150 0000011010 CR LF 2 3 0 08 56 12 168 23 9 4 56 20 10 CR LF DD CR LF 1 CR LF 2 CR LF 3 CR LF 4 CR LF 5 CR LF 6 DATA VALUES CR LF 7 CR LF 8 CR LF 9 CR LF CR LF CR LF 12DD DD CR LF ETX CR LF Space Character 49 CHAPTER 3 OPERATION 2202 32 2 2 2252 DIGITAL MESSAGE NO 3 General This message contains Status Line 1 identical to Message No 2 see 3 2 1 3 and one single range gate data line indicating the presence or absence of backscatter in each range gate Message is output automatically every 12 seconds simultaneously with the Gifft RBC Recorder Output 3 3 in Automatic Mode when Line is Closed Ac
61. range gate With EMOD ON range gate bit is 1 if Ceilometer determined extinction coefficient at that range gate exceeds a value corresponding to a horizontal visibility of approx 10 km 6 miles except for three lowest range gates which have higher thresholds D represents the four lowest 50 ft range gates 1 e Oft 500 100ft 150ft D represents the four next ones i e 200 ft 250ft 300ft 350ft etc O indicates no detectable backscatter in four adjacent range gates F indicates backscatter in all four range gates 8 indicates backscatter in the lowest range gate only 1 indicates backscatter in the highest range gate only All other characters indicate a gate by gate combination of backscatter according to the binary nibble converted to hexadecimal Message Example SIX CR LF 10 04200 00150 0000011010 CR LF 0001 FFF80000000000007A000 000 CR LF ETXCRLF 51 CHAPTER 3 OPERATION 222221 209 GIFFT RBC RECORDER OUTPUT Introduction The CT 12K Ceilometer provides two floating non polar output signal circuits for producing graphical sky condition records on a Gifft RBC Recorder operating according to the facsimile principle A new output is generated once every 12 seconds when the Ceilometer is in Automatic Mode regardless of the state of the Digital Interface Open or Closed In normal operation Line Closed output coincides once per minute with Digital Message No 2 transmission start
62. the Monitor ADC channel 10 The 13V Regulator 018 is of adjustable type LM317LZ Its output voltage is determined by the adjust resistors as follows Uout 1 R9 RIO x 1 25V RIO x SOuA 12 7V The input voltage is filtered by L2 C23 Diode in DA13 protects against reverse voltages C81 performs bypassing in the adjust terminal C20 in the output The system consumes about 45mA from the regulator The 13V Regulator U17 is of the type LM337LZ with the same characteristics and similar circuit realization as the 13 Regulator The 6V Regulator U47 U49 is of a similar type with about similar circuit realization as the Regulators The system consumes ca 20mA from both supplies The 9V Regulator U24 is of type LM317LZ Its input voltage level is attentuated by R63 and R20 as it would otherwise cause overheating in extreme conditions The other of the adjust resistors is composed of two paralleled resistors in RA18 D7 the 10V zener diode in the output protects the ADC against over voltages The system consumes ca 45mA from the regulator 150 CHAPTER 4 FUNCI IONAL DESCRIPTION lest Points are provided for the following signals J9 7 J9 5 J9 4 J9 3 19 2 19 1 3 J11 l J14 3 J14 2 J14 1 J16 10 J16 9 J16 8 J19 7 J19 6 J19 5 J19 4 J19 3 J19 1 GNDA Analog Ground 9V RP RC IN VR RDO 7 GND AT4 13v AT3 7 1V 1 9V SCA AT2 13V ATI 6V 6V Flash A
63. the line If correct now suspect the unplugged LRU Otherwise check for shorts on A2 and data cables connectors If no shorts found replace AI 284 CHAPTER 6 TROUBLESHOOTING AND REPAIR For data input check that IRXD Alc21 and MRXD Ala21 swing from below zero to above 5V when commands are transmitted to the Ceilometer IRXD is supplied by A3 and MRXD by Maintenance Terminal or equivalent Note that the lines cannot be used simultaneously one must be low when the other is active If the levels are not good suspect A3 or Maintenance Terminal Otherwise proceed to check for levels from below 1V to above 43V at RXD A3 6 If incorrect replace Al Modem Control Check that both ALB and SQT on Al are logic low 1 5 Volts thus enabling the Modem If not unplug A3 If still not replace Al otherwise suspect A3 Gifft RBC Recorder Control Activate Recorder Test according to Paragraph 6 1 7 RBCT should now be activated high for 80 ms every 12 seconds and RBCE alternate for 3 seconds thereafter Check that levels are from below IV to above 4V If not unplug and repeat the test If still not replace Al otherwise suspect A3 Signal Amnlifier With cloud detection missing or repeated mis hits or high offset data base first check that parameter values are intact and perform Offset Calibration Section 6 4 If the problem still exists do the Amplifier test as follows for reference see Dwg CT 3536
64. therefore needed for controlling the most significant bit DB7 of the display data bus 243 CHAPTER 4 FUNCTIONAL DESCRIPTION DB7 is controlled by the register circuit U7 output The register can be set or reset by setting the least significant data bit coming from the UART at 1 or 0 The register 1s clocked by circuits US and U6 which decode incoming control commands so that U7 will receive a clock pulse only when a control command of the following format is issued to the display D7 6 5 4 3 2 0 0 01 DL N F 0 0 DB7 Reset 0 01 DLN 0 1 DB Set 4 3 9 3 1 8 5 Display Illumination To enable display reading in conditions of insufficient lighting an electroluminescent light set beneath the display module provides a greenish illumination for the display The electroluminscent light requires a high voltage AC supply The 600 Hz rectangular wave from the baud generator is used for this purpose Because of lifetime limitations a light dependent resistor LDR 15 used in the El supply circuit This turns OFF the illumination when there is sufficient light for reading Transistor Q5 forms a level converter 5V to 12V and the power stage consisting of transistors Q3 and Q4 feeds a 12Vpp rectangular wave to the transformer via capacitor Transformer raises the voltage to approximately 160Vpp for the El light 4 3 9 3 1 8 6 Display Heating Because the lowest operating temperature of the LCD display is 20 C a d
65. 00 gt COF gt DEV 1 2000 gt C9B1F gt DEV 1 0000 gt C8F gt NSCA 2 5000 gt C8B3F gt NSCA 3 0000 gt 7 gt SCAL 20 0000 gt C7B10F gt SCAL 10 0000 gt C28F gt LNOR 162 gt C28B164F gt LNOR 164 gt C30F gt TOT 6 0 25 6 gt 30B5F gt zOT 5 0 25 6 gt C32F gt RATIO 3 7012 C34F gt HOFF 0 t 12F gt EMOD ON gt C1ZBOF gt EMOD OFF CHAPTER 3 OPERATION gt RMOD CR DETECTED CLOUDS RECORDING RMOD OFF gt RMOD ON CR MEASURED DATA RECORDING RMOD ON gt BMOD CR CLOUD BASE ONLY BMOD ON gt BMOD OFFE CR ALL CLOUD DATA BMOD OFF gt CONF CR SELECT UNIT M F F SHUTTER OPTION Y N N END OF CONFIGURATION gt SEND CR AUTOMATIC MESSAGE 3 SEND 2 CR AUTOMATIC MESSAGE 2 gt AUTO CR MAINTENANCE MODE gt AUTO ON CR AUTOMATIC MODE SERN VAISALA CT 12K VERSION 2 42 SN O gt SERN 87023 NEW CR VAISALA CT 12K VERSION 2 42 SN 87023 gt CLOS CR LINE CLOSED 66 gt C13B1F gt RMOD ON gt C29F gt BMOD ON gt C29BOF gt BMOD OFF gt C5F UNIT M F 1 0 0 SHUTTER Y N 1 0 9 gt END OF CONF gt C31F gt AUTO MES 3 gt C31B2F gt AUTO MES 2 gt C11F gt MAINT MODE gt C11B1F gt AUTOMATIC MODE gt C33F gt 2 42 C33F87023BB123F gt V2 42 87023 gt LINE CLOSED CHAPTER 3 OPERATION 3 4 PERFORMANCE MONITORING AND ALARMS 3 4 1
66. 01 1 20 100m 631 ad 1 20 c32 GNDA EE GNDA V 20VAL 20 VA EURO 64 AMPLIFIER 15x100n C1 2101214 C36 37 43 49 51 C 58 62 68 7176 Common for each arcut block AMPLIFIER gt 45 10 02 SY 6 2 511 RA1 2x4 k7 R8 4x97 gt 2 RA 2 407 10 4 9 4 1 LM124 PROCESSOR BOARD CTM 12 E 4 13 SED CON TROL L TON 12V CIRCUIT DIAGRAM 2 4 k k AkO DA2 8 RAIS 1kO DA2 TND903 12 PIN 2681 MONITOR 2x 2N2222A TXD a 24 cx 23 022 y acLLavr1J x lt x 1 WA m c9 X2 216 3 x1 a CPU 933 74HCUO 10 13 CCK 955 21 10MHz 2 8 5V AND GND CONNECT TO PINS 14 AND 7 RESPECTIVELY OF THE IC S U33 U36 U38 041 083 46 AND 050 53 JZ m PNE A RE 1 5 he WS 9 uH 13 nen nuc eh P ian TEST PULSE R6S 500 77 RAT 415 R66 5 036 gt SINGLE 2 Be a 5 z DE s 30 NS RA1 230 NS C52 P13 220 E 500 y 500 TP 17 A AMPLIFIER 12116 RD SC 0 7 AMPLIFIER 2 U38 74HC27 8 12 5V V GL 1P 22118 7 16 8 2 045 2 7 amp 157 4 800 T PM J la m oj Q E Y o lt 2
67. 0V 600 Hz see Section 4 3 9 3 1 8 5 The oscillator circuit consists of crystal Zl capacitors C17 and C18 resistors R24 and RA4 1 2 as well as HCMOS circuit US 74HC4060 The latter contains an inverting oscillator circuit which can be used to form a crystal oscillator of the parallel resonance type Capacitors C17 and C18 provide the load capacitance for the crystal Resistor R24 biases the inverter into the active range Circuit U8 contains an asynchronous counter dividing the fundamental frequency down by 214 In order to obtain the transfer rate frequencies from these division results frequencies divided by 64 128 and 512 have been used 239 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 8 Display 4 3 9 3 1 8 1 Operation of the Display Module The display of the CTH 12 is a 16 character alphanumeric LCD module The module is comprised of the display control circuits a processor and the required storage devices There are three 3 types of memory 80 Character RAM to Hold Display Data 8 Character Characters Memory to retain eight 8 characters of the User s Choice 192 Character ROM for a permanent retention of the following See Table 3 96 Alphanumeric Characters 64 Katakana Characters 32 Symbols The characters are formed by means of a 5 x 7 dot matrix Display control is via the eight bit bus An electro luminescent light behind the display provides lighting as required 4 3 9 3 1 8 2 Operat
68. 1 Dimensions W D H 22 8 16 5 x 13 4 inches 580 x 420 x 340 millimeters Weight 2 Ibs 9 5 kg Blower Fan Single Phase 1 ISVAC 75W Capacitor Coupled Air Volume 410m h 14450ft3 h Ball Bearings Maintenance Free Life Expectancy 4 5 Years at 20 C 68 F in Continuous Operation Heater Silicon Insulated Foil Power 600W Nominal Resistance 44 ohm 44 ohm Parallel Connected at 115V Safety Open at 256 F 124 C Increasing Thermostat Close at 202 F 94 C Decreasing Rating 100 000 Cycles at IISVAC 15A Temperature Semiconductor Type Sensor Voltage Drop 10mV x T K Air Speed Over Window Pane 33 ft s 10m s Air Temperature Rise 13 F 7 C Typical 225 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 8 3 Functional Description Reference Circuit Diagram Window Conditioner Bl CT 4290 Processor Board Al CT 3386 2 4 Unregulated Power Supply Board 2 CT 3196 High Voltage Power Supply PSI CT 3289 Ceilometer Wiring Diagram CT 1104 The Processor Board Al outputs HON and BON are routed via Unregulated Power Supply Board A2 to its connector where they connect to High Voltage Power Supply PSI and drive relays Kl and K2 Line power is supplied via a dedicated circuit breaker CB2 in PSI to relays KI and K2 contacts These are connected so that heating is not possible unless the blower is on The Line Supply signals LB Blower and LH Heater
69. 10 3 AO 7 Address LO byte J7 10 3 ADO 7 AD bus J5 3 X2 CPU clock J5 4 PRES CPU reset J5 5 TXD Serial Line Xmitted Data J5 6 RXD Serial Line Received Data J5 7 ALE Address Latch Enable J5 8 PSEN Program Store Enable J6 3 RS System Reset J6 4 WR I O Write Strobe J6 5 RD I O Read Strobe J6 8 5 V Logic Supply J6 9 RL Sample Latch Enable J3 J5 J6 and J7 1 GND Logic Ground Monitor Section The Monitored Signals are brought into the board via the edge connector Jl The resistor arrays RA4 RAS 9x2k2 4x4k7 4x4k7 4xl0k and resistor R5 14k7 perform scaling of the signals The signals LLAS LSKY and MRHV are not attenuated but carried through series resistors LLAS and LSKY lines are protected by diodes DAI clamping to 5 V as they originate in the A5 op amps powered from 17 V Ref AS Negative bias for the Temperature Sensors is applied through 2k2 resistors RA13 to the TL TE and TB lines on Jl The bias supply is regulated by D2 5 1 V zener diode giving but output of only 4 8 V due to restricted zener current The negative level signals from the Temperature Sensors TL TE TB are brought in through 4k7 resistors The positive level signals connect to channel input pins 1 9 11 of the Monitor ADC U8 The negative level signals connect to U15 the Pre MUX This also includes the on board Temperature Sensor U16 output carried through the re
70. 140 to 0210 ng to 2200 ft 59 Vertical Visibility ceiling at 5500 ft to time 0140 then loweri Cloud deck forming at 2200 ft starting at time 0255 OPERATION CHAPTER 3 a T m 8 y wt la y E uuu m m m m m datu SU hit gu CT 5572 Example of RMOD ON BMOD ON recording CT 4572 Fig 4 k r rN 3 gt T m T m ci r l r rYn o 8 uu F y m IH I CT 4573 Example of RMOD OFF BMOD OFF recording CT 4573 Fig 5 Y T m fu T T T 4 1B m m r TT UY WA DW W N n h iw m V Lac 1 m amp 57 amp Example of RMOD OFF BMOD ON recording 45774 Fig 6 60 3 3 PARAMETERS AND OPERATION MODES 3 3 1 CHAPTER 3 OPERATION STANDARD PARAMETER SETTINGS Existing parameter settings are checked with commands PAR SHUT SEND AUTO SERN Below is a dialogue session showing the syntaxes and standard factory settings If deviations exist please check also instrument specific configuration documen
71. 2 otherwise replace Bl If the temperature TB is not correct check the supply circuit as with TSI Section 6 2 11 and replace Bl if this is correct Otherwise suspect PSI Al or A2 Replacement Disconnect at J2 Loosen four 4 knurled screws holding Window Conditioner to Equipment Cover Lift off Remove cable from guiding clamp at inside Unscrew four 4 screws holding Heater Blower to the housing Pull down Heater Blower Replace in reverse order 208 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 2 12 MAINTENANCE TERMINAL CTH 12 A self test can be performed on the Maintenance Terminal to verify operation See Section 4 3 9 3 4 6 3 REMOVAL OF CEILOMETER COVERS WARNING WHENEVER WORKING CLOSE TOA CEILOMETER DO NOT UNDER ANY CIRCUMSTANCES LOOK INTO IT S OPTICS WITH MAGNIFYING GLASSES BINOCULARS OR OTHER MAGNIFYING OPTICS NOR ALLOW ANYBODY ELSE TO DO SO IT MAY BE HARMFUL TO THE EYES 1 Disconnect Window Conditioner Connector J2 2 Loosen four 4 Window Conditioner knurled screws on wide sides of Ceilometer 3 Raise Window Conditioner and place on ground 4 Open latches of Equipment Cover at lower edge of wide sides of Ceilometer 5 Carefully raise the Equipment Cover over the equipment and place on ground IN ALL MAINTENANCE OPERATIONS PREVENT DUST PRECIPITATION ETC FROM COLLECTING ON THE LENSES Use temporary covers if necessary Especially avoid touching the lenses with bare hands Clean lenses
72. 3 value of 8 2 ohms heating current is 205mA and power is 2 5 W 4 3 9 3 1 8 7 Initial Reset Circuit The initial reset circuit is comprised of D register U7 resistor 2 and capacitor C14 When power is turned ON and the SV supply goes up Cl4 is charged via resistor RAI I 2 The clock input of the D register is connected to ground likewise input R When input 5 is also zero the register is set into state 1 As voltage at Cl4 goes up input W is turned into state 1 whereupon the register 16 reset by input R The duration of the reset pulse is determined by the RC time constant of approximately 50ms The reset pulse functions are Reset DB7 Bit Inhibit Key In Display Inhibit DB7 Bit Setting Reset UART Circuit Reset Baud Clock Counter The voltage of the initial reset circuit is also brought to test connector J10 pin 10 4 3 9 3 1 8 8 5V Supply The supply voltage of the terminal is 12V From this voltage the logic supply voltage is produced by an adjustable linear regulator U2 The voltage is determined by resistors R12 and R13 which also perform the function of minimum load for the circuit Capacitors Cl C2 C3 C12 C13 C15 and C16 are filter capacitors for the logic circuits The 5V operating voltage is brought to test connector J10 pin 3 245 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 8 9 9V Supply 4393 2 A negative voltage is generated for display biasing and the RS 232C
73. 3163 5118 6375 3191 1297 5388 6372 5434 0057 0965 4989 6920 0977 4802 1287 10008 5726 250 Resistor Metal Film 3k32 1 50ppm 0 25W Resistor Light Dependent LDR Silonex NSL493 1 Resistor Wirewound 882 5 SW Unused Resistor Metal Film IOR 1 50ppM 0 25W Resistor Metal Film 332R 1 50ppM 0 25W Unused Resistor Metal Film Ik 1 50ppM 0 25W Unused Resistor Metal Film 332k 1 50ppM 0 25W Resistor Metal Film 3k83 1 50ppM 0 25W Unused Resistor Metal Film 10k 1 50ppM 0 25W Trimpot 10k 0 5W l turn CE Beckman 72P Resistor Metal Film 5M6 1 50ppM 0 25W Resistor Array 4xl0k 2 Separ SIL 8 pin Bourns 4608X 102 103 Resistor Array 5x4k7 2 Separ SIL 10 pin Bourns 4610X 102 472 Resistor Array 4xlk 2 Separ SIL 8 pin Bourns 4608X 102 102 Capacitor Tantalum 10u 20 35V ITT TAG Capacitor Polyest 100n 10 63V EVOX 05 Capacitor Polycarb In 10 100V EVOX CMK5 Capacitor Al El 100u 25V Siemens B41326 A5707 V Capacitor Polyest lu 10 SOV EVOX 5 Capacitor Ceramic 22p 2 NPO 63V Phillips 2222 681 10229 TI El Jl J2 and J5 J10 J3 JA P5 P6 and P7A P7B 2726 2727 10013 6377 5498 1399 5143 CHAPTER 4 FUNCTIONAL DESCRIPTION Transformer 220V 8V 0 2VA Spitznagel SPK 2202 Terminal Block 3 pole Lumberg KRE 3 Connector Pin Strip 0 1 0 025 square Au Phillips F095 32 pin stock Connector
74. 34 2 GENERAL The primary indicator of performance failure 15 the second bit S of Digital Message Status Line which operates concurrent with the third character B which equals ASCII BEL when S 1 this sounding the beeper of a std terminal Concurrent with this the Trigger Break of the Gifft RBC Recorder Output extends from 80 ms to 200 ms The S indicator is an ORed sum of bits SI S2 S3 S4 of Status Line 1 The S setting is delayed 5 minutes 51 54 have no delay The optical path of the Ceilometer can be monitored by observing the SUM value of Digital Message No 2 Status Line 2 or the CURRENT SIGNAL SUM output when requesting the TOTA parameter In conditions of no precipitation nor fog with a solid and stable cloud base at 1000 5000 ft DEV I and no temperature extremes SUM should be in range 20 40 Detailed performance data 1s obtained with commands described below STATUS MESSAGE Internal status is requested and reported as in the example that follows Alarms are reported as plain language messages added to this message or in case of numerical data as asterisks immediately after the numerical value In case of alarms Section 6 is to be consulted ST MT STA CR gt C3F CT12K STATUS CT12K STATUS F 00 0000000000 00 POWER STATUS 1g E P10D 8 5 P201 21 5 M201 20 7 P25V 27 9 0000000000 E 20 20 9 P20A 19 3 P12M 13 1 P10X 9 9 output
75. 75V 15A GE V275 LA 15 Metal Oxide Varistor 150V 10A GE V150 LA 10 10274 Main Transformer Subassembly TI 2722 1 2931 2936 Transformer Vaisala CT 31123 Header 18 pos AMP 207442 1 Socket AMP 163k084 2 10275 Line Input Harness Subassembly JI 2929 2934 Receptacle 6 pos 207153 1 163082 2 CHAPTER 4 FUNCTIONAL DESCRIPTION 10276 Blower Control Harness Subassembly P2 2029 J2 2928 2934 2936 Receptacle 6 pos 207153 1 Header 6 pos 207152 1 163082 2 Socket AMP 163084 2 10277 Temperature Control Transformer Harness Subassembly J3 2928 2936 2934 T2 2123 218 Header 6 pos AMP 207152 1 Socket AMP 163084 2 Pin AMP 163082 2 Transformer Vaisala CT 3114 CHAPTER 4 FUNCTIONAL DESCRIPTION Al 2715 High Voltage Power Supply Board Ul 1832 01 05 2970 DLD2 1336 DII D14 D3 D4 D6 3884 D7 D5 2912 D8 D9 DIO 2971 R4 R5 4080 R6 R9 4248 RIO 5791 RILR15 7481 R12 R14 4247 R13 0012 R16 5153 R17 R18 5388 CLC2 C7 10003 c3 4507 C4 C6 C8 10007 J7 J8 2924 Temperature Sensor NS LM335 Transistor NPN 400V TI TIP50 Diode 600V 1A IN4005 Diode 75V 0 2A IN4148 Zener 100V 0 4W IN985 Zener 150V 0 4W IN989 Resistor Carbon Film 220k 5 0 5W Resistor Carbon Film 330k 5 0 5W Resistor Metal Film 3k32 1 0 25W Resistor Metal Film IkA7 1 0 25W Resistor Carbon Film 150k 5 0 5W Trimpot 2k 0 75W 15 Turn
76. 8 D9 2972 IN985 Resistors all metal film resistors 1 0 25W unless otherwise stated R1 R2 R6 6355 R8 R28 R3 5116 R4 3453 R5 6373 R7 6375 R9 3163 RIO RII R13 1188 RI2 R22 3176 R4 R15 R24 4080 R16 R23 5467 7 2490 R18 5444 RI9 5791 R20 4247 R21 7464 R25 5699 R26 4242 R27 R29 5388 215R 48R7 487 100R IORO 562k 5k62 220k 33k2 33k 21k5 3k32 150k 10k 38R3 1k0 10k0 Temperature Sensor Transistor PNP Transistor NPN Thyristor Transistor NPN Diode Laser Diode Zener Diode 12V Zener Diode 100V Carbon Film 5 0 5W NTC Carbon Film 5 0 5W Trimpot 15 turns 3 4W Carbon Film 5 0 5W CI C2 C9 C12 C14 C4 C5 C8 C6 C7 LI J2 J3 Capacitors 4782 220pF 5734 100pF 4802 4507 100nF 22 10007 68nF 10008 1uF Inductors Miscellaneous 1863 Connectors 1692 2963 2923 209 CHAPTER 4 FUNCTIONAL DESCRIPTION 100V 63V 100V 400V 630V 50V Part of PC Board Layout FACTORY ASSEMBLED From P N 1863 Toriod dia 10mm Ref Tl Assembly SMB Submini Coaxial PCB 90 MILC 83503 10 pos Male PCB 90 AMP 207541 3 3 pos Male PCB 90 OT 2 R27 10k0 L1 Dt R9 V 184148 10R a 28 55 02 i p R10 31 3 48 487R Y 2 GA201 N R 26 LTRG XD 03 Q3T2N2907 T C 05W i C1 1N 4148 01 220p 2N2907 pe im 002222 RB Que M n 22n 400 SS 2158
77. A ac30 27 1 V 108 mV P25V acll 2 X 38 4 v 150 mV PIOD ac27 3 X 15 6 V 61 mV PIOR c9 4 X t15 6 V 61 mV PIOX a9 5 X 15 6 V 61 mV 2 c8 6 X 15 6 V 63 mV PXHV as 7 X 5 0 v 20 mV 4 LLAS c6 8 X 5 0 v 20 mV LSKY a6 9 X 5 0 v 20 mV MTE cl 4 10 0 4 8 V 2 20 mV 3 MTB cl 5 10 4 8 V gt 20mV 3 MTI 10 2 p 20 mV 3 MTL cl3 10 3 4 8 V gt 20 mV 3 M201 ac 3 10 4 26 6 V 108 mV MRHV acl0 10 5 48 V gt 20 mV 4 20 aclO 10 6 26 6 V gt 108 mV GND 10 7 20 mV INT SELF TEST 11 X CHAPTER 4 FUNCTIONAL DESCRIPTION Table 3 Monitored Signals with Channel I P Full Scale Level and Conversion Resolution Shown Note 1 On Board Connected Note 2 Limited by the Pre Mux Negative Bias Note 3 Corresponds to Temperature Resolution 2 C Bit Code 149 Decimal Corresponds to 25 C Note 4 Corresponds to Resolution of 2 V Bit for original high voltages Notice that if Xmitter or Receiver coaxial cables are disconnected both HIV and LOV values for the respective units are unmeasurable by the Monitor After reconnecting the Xmitter cable PXHV reading may be invalid for some time The EEPROM US is a 64x16 bit CMOS device of type NMC 9346 mounted on socket It is an Electrically Erasable and Programmable Read Only Memory preserving its storage during power outages This provides for handling of the EEPROM US like the EPROM e g removing it from socket and placing into another CTM 12 so as to transfer the syst
78. AL DESCRIPTION Parts List Semiconductors Ul 1056 74 HC 132 Nand Quad U2 2968 74 HC 942 300 Baud Modem U3 2989 337 LZ Voltage Reg amp 04 0285 2N 2907 A Transistor PNP 020305 5416 2N 222 A Transistor NPN D1 D2 4011 IN 759 A 12 Zener Diode D3 D4 D5 D6 3884 IN 4148 Diode D7 4336 IN 4005 Diode D8 D9 2969 BZW 06 94 Transient Zener D10 D11 D13 1431 ESAY 5531 LED Yellow D14 D12 1159 ESBG 5531 LED Green D15 D16 4171 IN 751 A 5 1 V Zener Diode 71 2967 3 579545 MHz Crystal Resistors All Metal Film 1 0 25 W 50 ppm unless otherwise stated RI 6375 00 R2 7480 21 R3 R16 0955 825R R4 R18 R21 6358 562R R5 5453 487 R6 R7 R8 7393 4k87 R9 R10 R22 2534 10 23 RII 3167 383R R12 R15 5156 2k74 R13 R14 1920 47R 1732 274R R19 7026 1k78 R20 3176 5k62 Resistors Arrays All Single in line SIL unless otherwise stated RALRA3 0057 4 x 10K RA2 0965 5 x 4K7 RA4 10070 4 x 680R 181 CHAPTER 4 FUNCFIONAL DESCRIPTION Capacitors CI C5 C14 6920 35 V C15 C17 C18 C6 CI0 C12 4507 100nF 63V C16 C19 C20 C7 4802 InF 100V 8 9 5726 22pF 63 4822 10nF 100V Inductors LLL2 232 220uH TLT2 10012 600 600 Connectors 6800 2x32C J2 2592 10 pin J3 J5 J8 5498 19 0 0172 P3 P7 P8 5143 Miscellaneous Kl 0988 12 Relay 182 Tantalum Ceramic Polycarbonate Ceramic Polycarbonate Miniature Choke Coupling Transformer Connector Ribbon Cable Connector Connector
79. AND REPAIR Diagnosis Verification and Replacement Removal of Ceilometer Covers Offset Calibration Vl DRAWING NO OR ILLUSTRATION NO U CT 3445 U CT 3282 C CT 3105 A CT 3406 FIG 1 CT 4569 FIG 2 CT 4570 FIG 3 CT 4571 FIG 4 CT 4572 FIG 5 CT 4573 FIG 6 CT 4574 CT 4413 CT 4411 CT 4412 U CT 1104 U CT 2101 CT 2295 A CT 3400 A CT 340 A CT 3402 A CT 3403 A CT 3404 A CT 3405 ACT 3406 A CT 4407 CT 4532 CT 3501 CT 3385 CT 3386 CT 3387 CT 3388 CT 3544 C CT 2492 CT 3536 CT 3196 C CT 2294 CT 2271 LIST OF DRAWINGS AND ILLUSTRATIONS REV DESCRIPTION C C B UY UE gt gt gt gt CT 12K Ceilometer CT 12K Installation CT 12K Connection Diagram CT 12K Equipment Base Bottom View RMOD On BMOD Off RMOD On BMOD Off RMOD On BMOD Off RMOD On BMOD On RMOD Off BMOD Off RMOD Off BMOD On Actual Return Signal Diagram of Internal Cycles Diagram of Recorder Outputs CT 12K Wiring Diagram CT 12K Generation Breakdown Chart CT 12K Block Diagram CT 12K General Layout CT 12K Internal Layout Front View CT 12K Internal Layout Rear View CT I2K Internal Layout Right Hand View CT 12K Internal Layout Left Hand View CT 12K Internal Layout Top View CT 12K Equipment Base Bottom View CT 12K Processor Board CTM 12 Jumpers amp Connectors CTM 12 Main Functions and Primary Data Control Flow CTM 12 Processor Board Principle Block Diag
80. AND U2 ve 1288 11 04 AEN E emen Per RECEIVER BOARD A6 pore TYPE CTRI3 P N 20105 lt ta VAISALA t NOLLdTHOSHG TYNOLLONNA CHAPTER 4 FUNCTIONAL DESCRIPTION MRHV V MRHV VALUE ADJUSTED 250 STICKER READING ON CTR 13 400 300 200 50 40 30 20 10 10 20 30 0 5 TIC TYPICAL TEMPERATURE DEPENDENCE OF AS A FUNCTION OF MRHV ADJUST VALUE 25 C CT4594 201 ete VAISALA Dai th CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 6 4 3 6 1 4 3 6 2 Laser Transmitter Board CTT 12 REF A7 Introduction The Ceilometer CT 12K uses laser light pulses to obtain reflections from any particles in the path of the collimated laser light beam The Gallium Arsenide laser diode on the Transmitter board emits the laser light pulses under control of the processor board s Laser Trigger signal The operating voltage for the laser diode is supplied by the on board high voltage regulator and is switched to the laser diode through the laser diode supply circuits by the triggering circuitry The laser diode operating voltage and temperature monitoring signals are available for the processor and referred to as TL TL Laser Temperature and PXHV Positive Transmitter High Voltage The board requires two voltage supplies 10V DC for the triggering circuitry and 260V DC for the high voltage regulator The Laser Trigger si
81. BLESHOOTING AND REPAIR 6 2 7 Perform offset calibration according to Section 6 4 Set unit into Automatic Mode AUTO ON CLOS Observe operation with real clouds Observe value of CURRENT SIGNAL SUM with command TOTAL If cloud detection shows clear signs of uncertainty and value of above SUM is out of range 20 40 See Section 3 3 Total in specified conditions return unit to Depot or Manufacturer for thorough performance check HIGH VOLTAGE POWER SUPPLY CTP 12 REFERENCE PSI WARNING HIGH VOLTAGES Verification Check that the line input voltage is within specified limits Indicator lamp DSI should be lit regardless of circuit breakers CBI or CB2 positions With CBI or CB2 ON check that all output voltages are present and within specifications Check Window Conditioner Controls Blower ON Line voltage PSIJ2 1 signal LB and Heater ON PSIJ2 2 signal LH with commands AUTO OFF BLOW ON HEAT ON If not okay check PSI relays and K2 drives BON and HON active Low and supply 25V at A2JIl Suspect Al or A2 if not okay otherwise replace PSI Replacement Unplug all connectors of PSI Unscrew four 4 screws at front and two 2 at rear using the Allen hex key found in the Field Spares Kit Slide entire power supply out from the front Replace in reverse order If the Ceilometer is equipped with receiver CTR 13 R13 has to be adjusted to it s maximum fully clockwise If the old receiver 12 is bein
82. Connector Jumper est 017 a du E E jin Vv Y 3 A V J 29074 de tn eny i t Ady YELLOW YA xO b ie M e 3 194158 i j gare Di inc 113 lt A r V V YELLOW L 3 REC x L3 0 a ar Ba tes 5 x ES k RB NE p on i 2 e 548 ye co LS al E I bin gt m R Hi Ji T Won e RM i SAOR 02 12 OA E A a ib y U y 9 Sy 0 11 cn A 1N1222A I NDO Cis 2 m l m ny mee ES 825 grog p eium 1 i 4647 v v v v 8 TRANSMIT LEVEL SELECT J ABC LEVEL SELECT dam TYPE CT 12 P N 2683 CIRCUIT DIAGRAM 95 06 07 ul Jt HCI 5Y f aye y GND Fw ment OUTPUT INTERFACE BOARD VAISALA NOLLJPMOSHG TYWNOLIDNNA vst M 7 M2x12 LW M2 5 2pcs NUT M2 2pcs FACTORY SETTING OF JUMPERS VAISALA Cty m 2 1 KS G C D DET LG Cl 3 12 PAL 2683 COMPONENTS LAYOUT C CT3278 a OUTPUT INTERFACE BOARD e VAISALA tr C YULLIVHO NOLLdTIAOSICO TVNOLIONOA 4 3 4 4 3 4 1 4 3 4 2 CHAPTER 4 FUNCTIONAL DESC
83. DC Supply Flash ADC High Ref 8 3V Flash ADC Low Ref 1 7V Flash ADC Input Basic System Ref 10 0V Sample Data Bus Logic Ground Amplifier Test Point 4 Analog HI Supply positive Amplifier Test Point 3 Level Shifter Source Supply Level Shifter Return Supply Flash ADC Clock level shifted Amplifier Test Point 2 Analog HI Supply negative Amplifier Test Point 1 Analog LO Supply negative Analog LO Supply positive GNDA Analog Ground Notice that Analog Ground is connected to Digital Ground only in one point near U25 otherwise they are completely separated 151 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 1 5 Parts List Integrated Circuits U2 2993 TC5564P 1 U3 12850 27C5 12 25 UA 2996 TD 031 U5 10341 NMC9346EN U6 U18 U24 1016 LM3 I7LZ U47 U7 017 049 2989 _ LM337LZ U8 2087 TLC534 IIN U9 1047 139 Ul0 U21 1048 74 259 UI LU20 1056 132 UI2 2977 74HC4060 UI3 UI9 1049 74HC373 U 14 022 2456 LMI24J UI5 2076 4051 U16 1832 LM335H U23 299 CA3300CE U25 U27 2080 74 244 U26 2992 HMI 63161 9 U28 2979 273 U29 2998 LM2935T U30 2988 LH0070 1 U3I 1833 7AHCTOS U32 U37 U42 2330 74 161 U33 045 2086 74HCUO4 U34 U35 2978 7AHC283 U36 1910 74HC74 U38 044 2083 74HC27 039 040 2981 74 157 UAI 1046 74HC 86 U43 U5 1 2082 74HC113 046 050 2984 7AHCII U48 2990 LM733H U52 U53 2085 74 10 CMOS RAM CMOS EPROM NMOS uPROC CMOS EEPROM Reg Reg CMOS ADC
84. DJUSTMENT SPACER LOCK NUTS Note internal cables and hornesses are not included in this drawing APA A PF 4UWWU DO Dc BOARD FRAME PROCESSOR BOARD CTM 12 Al D CIRCUIT BREAKERS CB1 AND RECEIVER BOARD CTR 13 6 EQUIPMENT BASE woe 1985 08 20 ETA Sa CEILOMETER CT 12K amp VAIS ALA INTERNAL LAYOUT DWG ne LEFT HAND VIEW A CT 3404 y YALAVHI NOLLdI3OSHG TVNOLIONOA 9 ZT LIGHT MONITOR POWER SUPPLY CTP 12 BOARD CTL 13 lt FUSES Fl AND Fe HIGH VOLTAGE POWER m SUPPLY HOUSING IPTICS FRAME B SOLAR SHUTTER FLAP OPTIONAL 2 RECEIVER TRANSMITTER OPTICS OPTICS BOARD FRAME EQUIPMENT BASE Uis WINDOW CONDITIONER LINE VOLTAGE O SSG E CIRCUIT BREAKER OFF i INDICATOR MEASUREMENT EQUIPMENT CIRCUIT BREAKER 1985 08 19 is Ge CEILDMETER CT 12K be INTERNAL LAYOUT naet aise TOP VIEW A CT 3405 Raced by RE NOLLARIDSAC IVNOLLON Y Let PROTRUDING INTERNAL HARDWARE 6 PLACES AC LINE SUPPLY CONNECTOR Jl WINDOW CONDITIONER CONNECTOR Je CT 12K PEDESTAL ATTACHMENT NUTS 4 PLACES GROUNDING SCREW MAINTENANCE TERMINAL CONNECTOR J4 OUTPUT INTERFACE CONNECTOR J3 EXT TEMPERATURE SENSOR X TS 1 OVE U SAPOS avs 47
85. FUNCTIONAL DESCRIPTION Window Conditioner The Window Conditioner is controlled by two outputs from the Processor Board These are routed through the Unregulated Power Supply Board A2 connector to High Voltage Power supply PSI to drive two relays These switch Line Power to the blower and the heater of the Window Conditioner via connector J2 The relays are connected so that the heater can never get power without the blower being on Window Conditioner line power has its own circuit breaker CB2 in PSI The Window Conditioner is monitored with a temperature sensor software reference TB which 15 placed in the warm air stream This senses both the effect of the heater and a potential blower motor failure that would cause a rapid increase in TB when the heater is ON safety reasons the heater also has thermostat which breaks its current at about 250 F 120 C 115 116 FUNCTIONAL DESCRIPTIO CHAPTER 4 2 e t 1 U CT II04 A5 x 5 o nt lt im ajal gt i gt z Yi wl gt lz Six O 215 1 s O Sz 273 22 ala ur UIT 97797 Su WAR I ER 7 20VAC r NO E AAA E NET EA E 117 12 MODI 7 Y h N RBCEI 5 QE 2 6 e Us RACTALIO SS h PHM ai9 CD Ta ox a20
86. GOGE VENTILATION 1 INLET Prom 1985 08 20 ETA ie poe CEILUMETER CT 12K oein EQUIPMENT BASE DWG na a BOTTOM VIEW ACT 3406 Repioced by VAISALA NOLLIdTIWNOSHG TVNOLLONOH t AALIVHI CHAPTER 4 4 3 FUNCTIONAL DESCRIPTION MODULE DESCRIPTIONS 4 3 4 3 1 1 PROCESSOR BOARD CI M 12 REF Al General The CTM 12 is the main signal conditioning and processing unit for the CT 12K Ceilometer On a single size PC board it contains all the electronics to control laser pulse triggering at software determined intervals buffer and amplify by software controlled gain the backscattered echo signal from the Receiver Board sample convert and store the amplified echo signal digitally integrate the stored series of samples throughout the detecting range process the echo signal data and calculate the cloud base levels and other relevant data according to software rules transfer data and commands through the on board serial RS 232C port monitor the unregulated power supply voltages Transmitter and Receiver operating voltages laser power ambient light level and temperatures measured at four points of the system control the Window Conditioner and optional Solar Shutter according to monitored parameter values and software rules automatically control internal heating of the Ceilometer The Principal Data and Control Flow of the CTM 12 is illustrated in Dra
87. H for active signal If the latter toggles at about 3Hz but one or both of the others deviate then replace A3 otherwise proceed to check the external circuits Suspect Al and or A2 Replacement Unplug W3 at J2 Unplug A3 from A2 Replace with spare board in reverse order Check that jumper settings are according to specifications in Technical Description LIGHT MONITOR BOARD CTL 13 REFERENCE A5 AND SOLAR SHUTTER CTD 12 REFERENCE KI Verification Check that nothing obstructs monitor photodiodes and D3 from seeing their respective light sources Check supply voltage between TP3 17V IV and 5 GND If not in range check 25V at cathode of D7 If not present suspect W5 A2 or 288 CHAPTER 6 TROUBLESHOOTING AND REPAIR Laser Power Monitor If an out of range Laser Power Monitor signal LLAS has been observed but positive cloud or hard target detection has verified laser operation check linearity with OV equalling LLAS 0 and 5V equalling LLAS 255 max If this is not the case suspect W5 2 or Al If V TP1 is less than 1 5V or greater than 4V with laser ON and positive cloud or hard target detection replace A5 Skv Light Monitor Check the voltage at TP2 to be close to OV when no strong light source is right above Ceilometer and photodiode D3 1s pointed upward and check with high intensity focused light brought right above D3 that the voltage increases to a value exceeding 2V If this is
88. I Receiver Register Input to UART 10 Reset Signal from Reset Logic Table 6 Test Connector J10 Signals 248 4 3 9 4 Parts List CHAPTER 4 FUNCTIONAL DESCRIPTION Reference Number Description 10022 2129 2130 5612 2125 Component Ul 1832 U2 1016 U3 2456 U4 3216 US 1056 U6 2983 U7 1910 U8 2977 U9 541 Ql 1384 Q3 05 Q7 5416 Q4 0285 Q2 DI 0555 D2 D9 D11 3884 D5 1237 DI2 47 D3 D4 D6 D8 Zl 3846 249 Box Vero 75 3019J Hole Dwg CT 4269 Front Panel Instructions Label Keyboard Grayhill 88BB2 062 Board Subassembly Integrated Circuit NS LM335H Integrated Circuit NS LM317LZ Integrated Circuit NS LM124 Integrated Circuit Intersil IM64021PL Integrated Circuit 74HC132 Integrated Circuit 74HC27 Integrated Circuit 74HC74 Integrated Circuit 74HC4060 Integrated Circuit NS 74C922N Transistor TIP120 Darl NPN 60V 5A Transistor 2N2222A NPN 40V 800mA Transistor 2N2907A PNP 40V 500mA Unused Diode Bridge Varo VM28 140V IA Diode IN4148 75V 200mA Transient Zener Thomson BZW 06 15 15V 0 6 Ws Zener Diode IN751A 5 1V 5 0 4W Unused Unused crystal 2 4576 MHz HC 6 U CHAPTER 4 FUNCTIONAL DESCRIPTION R15 R23 R2 R3 R4 R5 R9 R21 R6 R13 R7 R8 R10 R12 R19 RII R14 R16 R17 RIS R20 R22 R24 RAI RA3 RA2 RA4 C1 C8 C10 and C2 C3 C12 C15 C16 and 9 C4 C5 and C7 C6 C9 C20 C17 CIS 5791 3853 1902
89. ISPLAY THE NORMALIZED SIGNAL SUM LIMIT SET DISPLAY NOISE SCALE SET DISPLAY OUTPUT SCALE SET DISPLAY THE LASER POWER NORM ON OFF EXTINCTION NORMALIZATION ON OFF DATA RECORDING MODE ON OFF BASE OUTPUT ONLY ON OFF ON OFF AUTOMATIC MODE ON OFF LASER ENABLE DISABLE ON OFF SEQUENCE START STOP lt HIGH LOWGAIN gt SET DISPLAY THE GAIN RATIO FOR NORMALIZATION lt TIME S gt LASER MEASUREMENT lt HEIGHT gt SET DISPLAY OFFSET VALUE FOR THE MEASURED HEIGHTS 0 7 SET DISPLAY LASER PULSE FREQUENCY SAMPLE NOISE DISPLAY 0 17 ANALOG TEST SELECT GAIN 0 2 ON OFF BLOWER HEATER CONTROL ON OFF BLOWER CONTROL ON OFF SOLAR SHUTTER MANUAL CONTROL lt ID gt lt VALUE gt SET DISPLAY ALARM LIMITS RECORDER TEST OUTPUT UNTIL ESC 78 3 4 5 16 3 4 5 17 CHAPTER 3 OPERATION MEAS time Performs a measurement using the specified time for sampling If no time 15 specified 1 second is used The command can only be used in Maintenance Mode After measurement completion the raw range gate data values are available in Table 0 see TAB No further processing is performed Syntax example ST MT gt MEAS 12 no equivalent BACK SCATTERED POWER 12 sec terminal inactivity INPUT DATA AVE 15 9488 gt next input TAB n si ci Output of internal data tables where n 1s table number as follows 0 1s raw receiver data in Flash AD converter units 1 is intermediate calculation table 2 is final range and instrument norm
90. J R39 FROM RECEIVER TEST PULSE R6 Ee epo ee COMP SIDE SILK P CTOI 165 99 rus 2 3 5 6 7 8 q 10 n o 340 3857 RO RO 720 590 M oae nc 54 0 SEQUENCE PHASE 0 SQ O0 SQ1 201 i SAMPLE CONVERT amp STORE sQ 0 cMMETLIIIIICCARMUUIITLTICCILLIOMMNUIIIIIIITTWUUUL a RA2 RA 6 j RA6 J SINGLE EA a 00204 x TYPICAL RE LINEARIZED SAMPLE 530 5 PULSE READINGS SHOWN J RA7 y u 230ns 200 El TP RESPONSE IN SAMPLE RAM U36 5 TP CLOUD BASE LEVEL ALTERNATIVE 230ns gt FORM DOUBLE uY TYPICALLY HERE SELECTS a Em m 430 La ATI AT 2 AT 3 SINGLE PULSE AS FLASH ADC IN 230 gt FOR SCALES DOUBLE PULSE A __ FORMS SEE BELOW 1 4 AT2 3199 5387 AMS GAIN 2 TP SIGNAL GAIN O amp 2 RESPONSES SHOWN ON THE RIGHT CLAMPEO 10V 07 NOTE PULSE FORMS AND MEASURE DCL OCL READINGS ARE 3QV ATI 49V AT3 USHT 2 EM 23 ALL TYPICAL 43 AT 2 15 V AT4 15 VI ATA 15 4 CLAMPED J23 AMPLITUDE SELECT so 0 9 1000 440 31 TP ATTENUATION FACTOR DURING TEST amp ADJUST PROCESSOR BOARD 1 CTM 12 b 86 05
91. MTI Internal ambient temperaturej 2 98 0 06 V9 0 01V C 1 00 152 3 0 51 C 13 MTL Loser diode temperature 2 98 0 06V 0 01V C 1 00 152 5 0 51 C TL 14 20M I F neg supply unreg 20 0 3 5 V 0 18 184 32 M 201 15 RHIV Receiver HIV supply unreg 310 80 Vet 7 0 01 158 t 41 4 1 MRHV 16 20VA Analog neg supply unreg 20 055 5 V 0 18 1184 352 20 17 GND Offset GND for 10 17 TO0O 00T0 02 V 1 00 0 1 GND TOS 2 adjusted depending on laser or photodiode parameters 3 may be higher value during the adjustment procedure up to 425 V 4 approximately 5 max scale 255 refers to A D ref voltage VS 5 0 L XiaNaddv VALIVHO NOLLVYJIdO sJyojeureJed palioyiuoW ZL NLO GIveClO 91 02 SECTION 4 1 4 2 CHAPTER 4 TABLE OF CONTENTS OPERATION PRINCIPLES TECHNICAL DESCRIPTION 4 2 1 4 2 2 4 6 3 GENERAL OUTLINE OPERATIONAL OUTLINE 4 2 2 1 Measurement Circuit 4 2 2 2 Output Interfaces 42 2 3 Internal Temperature Control 4 2 2 4 Internal Monitoring 4 2 2 5 Power Supply Section 4 2 2 6 Solar Shutter Option A221 Window Conditioner DRAWINGS Wiring Diagram CT 1104 Generation Breakdown Chart CT 2101 Block Diagram CT 2295 General Layout A CT 3400 Internal Layout Front View A CT 3401 Internal Layout Rear View A CT 3402 Internal Layout Right Hand View A CT 3403 Internal Layout Left Hand View A CT 3404 Internal Layou
92. ND 10V 1 5V Low Voltage Supply TP7 GND 260V 40V High Voltage Supply TP3 GNDDC voltage marked on sticker on board measured with laser off Maintenance Mode and correcting for ambient temperature deviation from 70 F temperature coefficient approximately 1V F 1 8V C TP6 GND 2 94VDC at 70 F temperature coefficient 5 5mV F 10 2 laser temperature sensor Command AUTO ON and observe the following waveforms with oscilloscope Note that these are typical forms measured with 60MHz or faster Oscilloscope Lower bandwidth will round off steep changes Dwg No CT 4535 If the Trigger pulse input at is missing or severely deformed suspect Al or W9 If the input voltage at TP7 15 too low suspect PSI or W7 If the temperature sensor voltage TP6 TP5 1s too low suspect Al A2 or W7 If the low voltage supply at TP4 is too low suspect A2 or W7 If voltage at TP7 is okay but TP3 is close to zero turn Ceilometer power OFF then ON and check again If operation is restored observe it for a period if the situation is repeated replace A7 In all other cases and in cases mentioned above in which a check of the suspect part has yielded no fault replace A7 292 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6V TP 1 2V DIV SOns DIY TP 2 INP 50ns DIV 10V 4V DIV SOns DIV 4 lA mi AA miss TP 3 roov
93. NOLIDNNA VGC M mmr ee n DISPLAY SURASSY n Wasa 0 BLL AMP 05 12v 1011 412 3 5 e u LM124 V i x 77916 A NUM LCO DISPLAY 4 i i q E x NI 1 i 2 HAD SS DAY KEYBOARO cpa 1122 0I ma h 1122 Db It 085 117 2 DAS at fas r pak T1 r i t t a x En a LOCAL 00PgAcK TEST 47 291 18 SETINO EXT TxOI 27 ON 2 3 4 5 KET F Y OPERATE 17 ON 1 2 5 6 KEY DATA BAUD RATE SELECT 1 61 300 Bd J OM 4 5 STANDARD 120084 36 ON 2 3 OR 3 4 110089 2 Q7 indice B uv 1522224 My 18751 Ua 4 n C406 imeem 94719 A o MAINTENANCE TERMINAL ove VAISALA 2 P N 2690 GHD 7 CIRCUIT DIAGRAH CT2284 wen 10 YUALIVHO NOILJDNIOSHG TVNOLLONO CHAPTER 4 FUNCTIONAL DESCRIPTION J9 D2 A R4 D3 R5 RE R7 D4 R8 R9 OS I4 13 RI JI R12 E 42 M U2 Ria Loop 2 1 RIS u u s RI6 jJ RI7 CI J4 T cy 5 D eo 3 D6 8 de 9 D7 08 04 RIS on 2p VERLA JE icc ee QS CIO CI M O 4 4F l zl T e E DIO DI2 D9 R22 D Q6 U7 6 R23 97 xx E
94. P N 2682 7 CIRCUIT DIAGRAM CT 3196 o Replace by NOLLdIIOSHG IVNOLLON 4 t IH LdVHO PLI a t e ms s td sat sa IB 1 10 9 6r w 3 EVAISAL A TYPE CTSI2 PART NO 2682 Ju Es vd SJ 2 4 3 8 E O 63 69 7 bul 6 i 8a E 2 010 CX X 912 612 vid CX El d 51 XAO gt o 1 Bdi 1 vau ZE 52 E 4 o At m os 4 o uro mz ge ro E o e lt v cid 2s JNI 17 I WWHYON NO 2 I Edl C A02 0 10 20 13 1 02 32 3831 1 nazie j di H 212 ay H a __ so Oi O pu Tni ETT eem seen cen Teast Joni T ZA zr vf Ii c N N gt UPREGULATED POWER SLPFLY CTS Q COPO ENTS LAYOUT VAISALA wen o es tonne pew be teed ty y NOLLdRIDSAC TVNOLIONNA 4 3 3 4 3 3 2 CHAPTER 4 FUNCTIONAL DESCRIPTION OUTPUT INTERFACE BOARD CTI 12 REF A3 Introduction The Output Interface board CIT 12 is the communication module of the CT 12K It provides for simple connection with devices that have 300 Baud FSK
95. RIPTION LIGHT MONITOR BOARD CTL 13 REF A5 Introduction The Light Monitor Board of Ceilometer CT 12K is placed between the laser transmitter lens and the instrument cover window in a position which minimizes attenuation of transmitted laser power refer to CTL 13 Assembly A CT 3410 It contains the following circuits Ref Circuit Diagram CT 3564 Laser Power Monitor Its silicon PIN photodiode is pointed down toward the collimated laser beam at a position which best represents the average power of the non uniform beam Skv Light Monitor Its silicon PIN photodiode is pointed upward and its field of view is limited to a detection angle of approximately 5 7 from vertical Its signal is used both by the Solar Shutter circuitry and by the processor for monitoring purposes Solar Shutter Driver This circuit drives the optional external Solar Shutter and shuts its flap for protection of the laser diode from focused sunlight if the signal from the Sky Light Monitor should exceed the voltage set by a trimpot It is fail safe in operation 1 when no power is supplied the is shut The operation is also self contained so that no processor activity is required for shutting Voltage Regulator for providing an internal regulated 17 V supply for the measurement circuits Specifications Type CTL 13 Light Monitor Board Part Number 10322 Designation A5 Supply 22V 30V 20mA typ without shutter 650mA typ wi
96. SEMBLY SUBASSEMBLY OL 45394 OL 45453 OL 45455 2720 OPTICS HOUSING ETT 12 2687 TRANSMITTER A7 OL 45408 2695 LIGHT MONITOR CABLE WS OL 5375 2740 HEATER SUBASS Y MAIN CHASSIS OL 5 00 2 OL 45456 OL 25456 OL 45410 OL 25400 1 CTR 13 20105 CTL 13 1032 CTS 12 2682 CTM 12 2681 10274 RECEIVER LIGHT MONITOR UNREG POWER PROCESSOR MAIN BOARD A6 BOARD AS SUPPLY BOARD A2 BOARD AI TRANSFORMER OL 5 00 OL 45400 6 OL 45824 OL 65689 OL 45411 OL 45415 OL 45410 1 10251 2745 2714 2712 CTA 12 2689 CT 2 2683 0274 CAPACITOR TurnunsrAT TEMP CONTROL TEMP CONTROL TEMPERATURE OUTPUT INTERFAG LINE INPUT i TRANSFORMER T1 HEATER RI R2 SENSOR 51 BOARD A3 HARNESS OL 45400 5 OL 45400 7 OL 45384 OL 5383 OL 45382 Ot 45413 OL 45410 2 2716 10248 2691 TEMPERATURE GROUNDING MAIN HARNESS Wt SENSOR CABLE w8 WIRE W12 HARNESS OL 5 00 3 OL 45378 OL 45457 OL 0537 OL 45410 3 269 10249 2692 0 TRANSMITTER GROUNDING WINDOW CONDITIO TEMPERATURE CONTROL CABLE WIRE W13 NER HARNESS W2 HARNESS OL 45458 OL 45372 OL 45410 2 W OL 49379 2694 2693 MAINT TERMIN OUTPUT HARNESS Wt HARNESS W3 TRANSFORMER OL 25374 OL 45373 OL 45410 5 TRANSMITTER Ht VOLT CABLE wit Ov 69381
97. STANDBY MODE for minimizing wearout of laser and moving parts The Window Conditioner is operated automatically only the first 5 minutes every hour of the internal clock The following are the commands for setting the mode of operation along with Ceilometer response Omitting the parameter part OFF ON or results response according to the prevailing mode ST MT gt AUTO OFF CR gt CIIBOF WAIT FOR SEQUENCE STOP WAIT SEQ STOP_ MAINTENANCE MODE gt MAINT MODE gt next input next input gt AUTO ON CR gt CIIBIF AUTOMATIC MODE gt AUTOMATIC MODE gt next input next input The current 12 second measurement sequence is completed before switching to Maintenance Mode The Mode selection will remain in effect over a Restart or Powerdown 42 CHAPTER 3 OPERATION FAST HEATER OFF The 600W Window Conditioner Heater can be forced OFF at any tme e g to decrease the loading of an Uninterruptible Power Supply System The OFF state is set via the FSK or KS 232C serial line by sending two subsequent BELL characters Control G 07 Hex to the Ceilometer After reception of the last bit of the two incoming characters the Heater will be disconnected within a maximum of 20 milliseconds The state is stored in EEPROM and will thus be preserved over a power outage or Reset Status Bit S10 of the Digital Messages see 3 2 1s set to to indicate the forced OFF state No other acknowledgement will be out
98. T low applied to the set input of U43 entirely inhibits the clock feed through and sets U38 6 low The Write Pulse Shaper is formed by the NAND gate U52 6 and the delay generating circuits U38 6 and U45 2 its input capacitance driven through paralleled resistors During SQPHO the NAND gate outputs a 10 MHz pulse freq with ca 1 3 duty cycle suitable for Write accessing the Sample RAM The Sea Control Counter consists of the three similar 4 bit synchronous counter circuits U42 U37 and U32 which feature synchronous operation Load Control pin9 is used in two of the counters in U42 to inhibit the first counter stage by loading in all ones and U32 for loading in PII through 13 to the third counter stage RS applied to pin 1 resets the counters at PWR ON or Manual Reset The Sea Control Register consists of the JK Flip Flops of U51 and the AND gates of U50 and the NAND gate U53 12 The circuitry by most of its action behaves like a two bit shift register operating synchronously witb the Seq Control counter It is driven by the clock from U33 10 applied to F F clock inputs US1 1 13 The operation is described below 144 CHAPTER 4 FUNCTIONAL DESCRIPTION During SQPHO the Register outputs SQO SQI U51 5 9 are both low As the Seq Control Counter overflows the carry pins 15 of U42 U37 U32 are all high which achieves high state on U50 12 As it connects to the J input pin 3 the next falling edge of the clock ra
99. age by adjusting R2 1 Ceilometer in Maintenance Mode Frequency 3 Laser on Sequence on Increase voltage towards a maximum of 160V until the LLAS value in status message equals LNOR 5 A typical procedure would be as follows 1 Increase voltage with R21 2 Open line command AUTO ON close line 3 Allow time to stabilize 4 Check LLAS LNOR 5 5 Repeat if necessary 274 6 1 1 4 CHAPTER 6 TROUBLESHOOTING AND REPAIR Temperature Alarm Temperatures are expressed in degrees Centigrade Celsius Equivalent degrees Fahrenheit is TCF 1 8 x TCC 32 or inversely 32 1 8 A Temperature Alarm occurs if the reading EXCEEDS the preset alarm limit An open circuit will cause a HIGH temperature reading approximately 200 C equalling a voltage of 5V The output of an operational temperature sensor will be V x l mV where TCK 273 equalling V z ICE 32 273 x 10mV 1 8 Typical values are T F TC Sensor Voltage V 140 60 3 33 104 40 3 13 68 20 292 52 2 19 4 20 2 53 40 2 99 275 CHAFER 6 TROUBLESHOOTING AND REPAIR 6 1 1 4 1 Troubleshooting Connect a terminal to the Ceilometer open the line for dialogue by requesting status STA This will contain one or more temperatures above the alarm limit see ALIM command pinpointed by an asterisk 4 after the temperature value e g too large a difference between ambient temperature and
100. ages listed are unregulated 1 e line input and load fluctuations cause variations All DC voltages are further connected to the Analog Monitoring section of the Processor Board Al connector Jl and have reference codes for software messages etc The Maintenance Terminal 12V supply Ref P12M has a series diode D7 for isolating the full wave rectified 120Hz signal from the filter capacitors and thus provides the signal required for the Gifft RBC Recorder output signal 120Hz to the Interface Board A3 connector j6 A28 Diode prevents the optional Solar Shutter Supply via Light Monitor Board A5 connector J5 from discharging capacitor C3 and thus creates two separate 25VDC sources 169 CHAPTER 4 FUNCTIONAL DESCRIPTION 49 2 92 2220222 Temperature Control The RELI and REL2 signals are derived from an internal temperature sensor through comparators and drivers all located on the Processor Board Al At temperatures above approx 20 C neither relay is activated and the Temperature Control Heaters and R2 connectors J2 and J4 are OFF At temperatures between approx O C and 20 C signal RELI activates relay Kl This will connect and R2 in series across the 20 VAC source from TI J3 and provide two lo watt sources of power At temperatures below approx O C signal REL2 activates relay K2 while signal RELI opens relay Kl This will connect RI and R2 in parallell across the 20 VAC from
101. al 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 1f values close to those estimated by a ground based observer are to be obtained The CT 12K 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 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 101 CHAPTER 4 4 2 FUNCTIONAL DESCRIPTION TECHNICAL DESCRIPTION 2 1 GENERAL OUTLINE Refer to mechanical drawings A CT 3400 A CT 3406 Drawing A CT 3400 shows the Ceilometer in its normal operating configuration It is mounted on the pedestal at a height which allows for convenient installation and maintenance and raises it above snow and dust etc
102. alized data values if EMOD is OFF Or final extinction normalized inverted data values if EMOD is ON 3 1s static offset data table 4 1s instrument only normalized data table si Is Start Index 0 253 equalling the 50 ft range gate number from which output starts If not specified O is used 0 ft 79 CHAPTER 3 OPERATION 3 4 5 18 ci Is Cycling Index 1 254 equalling the number of range gates desired for cyclic continuous output If not specified output will be once only from Start Index to end of table If specified then Start Index must also be specified and output cycles continuously until aborted with ESC Output and recycle of table starts with latest cloud heights and penetration in the form in Digital Message Status Line 1 Non cloud obstruction heights are not indicated Output line contains height of first sample in line followed by five samples Syntax example ST MT STAB no equivalent LASER PULSE COUNT 10907 850 16 0043 16 0070 25 9978 15 9945 15 9913 IO 1543585801 Los OJO 15 9049 50829702 1599150 ISO doo o 21585 740 19549739 650 16 0045 TOOT 2539975 1549945 15 9913 1109 1549900 5 9949 Dae Gols 5297165 1949799 1950 19 9745 15 9714 15 9735 850 16 0043 16 0010 15 9978 15 9945 15 9913 ESC next input GRAP n SC si 1C Command for semigraphic output of internal measurement
103. and 7 Two of the gates are unused and two provide for level shifting one for SCK SCA as level shifted the other for SQO ADC Enable as level shifted SQO as applied to pin 4 also performs disabling SCA when low SQPHI and 3 Resistors in RA22 and RA21 do primary level shifting The Sample Write Buffer U25 is a CMOS buffer enabled by SQO low applied to pins 1 19 Its inputs are fed by the ADC via resistors dividers 17 2 1 18 which attenuate the output levels to meet the 5V logic input level demands 149 CHAPTER 4 FUNCTIONAL DESCRIPTION The Flash ADC Reference Supply consists of two op amps in U22 which is a quad op amp type LM124 The 10 0V reference VR is divided by R15 R17 precision resistors to nominally 8 30V Op amp U22 7 and transistor Q3 make a unity gain buffer this applies RP to the ADC pin 9 RP is further divided by R21 22 18 to nominally 1 72V U22 l as a unity gain buffer applies RC to the ADC pin 16 The GLL control high applies ca 45W to U22 3 via D6 The op amp so aims to drive 4 5 V into RC but because of the diode in its feedback loop it cannot do so and RC level is set to ca 4 2V by the ADC internal resistor ladder The Monitor ADC Reference divides VR by R14 R13 precision resistors and buffers the result by U22 8 which so supplies 5 0V reference V5 to the Monitor ADC The one op amp still left in U22 inverts the Pre MUX buffered output signal MB and applies the result MI to
104. and control of Window Conditioner Blower status In Automatic Mode an OFF command will cancel the automatic operation algorithm an ON command has a 3 minute timeout whereupon automatic control commences An OFF control will also shut the Heater OFF see HEAT Syntax example ST MT gt BLOW CR gt 21 BLOWER OFF gt BLOWER OFF gt BLOW ON CR gt C21B1F BLOWER ON gt BLOWER ON gt next input next input SHUT on off Interrogation and control of Solar Shutter status provided one 1s installed and configured see CONF In Automatic Mode a control command will be cancelled within 15 seconds by the automatic operation algorithm An OFF command cannot cancel an ON state controlled by the Light Monitor Board AS 74 3 4510 3 4 5 11 CHAPTER 3 OPERATION Syntax example ST MT SHUT CR gt C22F SHUTTER IS OFF gt SHUTTER IS OFF gt SHUT ON CR gt C22B1F SHUTTER IS ON gt SHUTTER IS ON gt next input next input RECT Gifft RBC Recorder Output test continuous until aborted with ESC character Operates only in Maintenance Mode Outputs a pattern of alternating on off cloud signals each half period 160 milliseconds 4 8 degrees long starting with on at O degrees Trigger Break interval is 12 seconds Syntax example ST MT gt RECT CR gt C23F TEST RECORDING UNTIL ESC RECTEST ON ESC A gt next input next input TIME HH MM SS Interrogation and setting of the inter
105. andard Character Code USASCII Sth unused data bit MARK 1 1 2 3 1 2 Gifft RBC Recorder Interface Trigger Break Relay Contact N C Ratings 150 VDC max 2 Amax 107 cycles at 24 VDC 1A Resistive Break Duration 80 ms normally 200 ms for Fault Indication Inscription Cloud Signal Transformer Coupled 600 ohms standard Signal level ON 2 dBm standard Jumper selectable 2 0 2 5 dBm Frequency 2 x Line Frequency normally 2 x 60 Hz 120 Hz 123 2 CHAPTER 1 GENERAL INFORMATION Signals Interrelationship End of Trigger Break starts timing of delay to Cloud Signal 3 seconds max delay equals 12 000 ft linear delay to height relationship Distance to Operate 0 10 miles 16 km with AWG 22 0 35 mm2 unshielded twisted pair terminated by recorder Field Junction Box Output Interface for Local Equipment J4 RS 232C standard serial asynchronous full duplex input output interface internally parallelled with FSK interface Used also with Ceilometer Maintenance Terminal Ceilometer configured as Data Terminal Equipment DTE Baud Rate 300 Baud standard and default 1200 Baud available on command Note FSK interface operates at 300 Baud only Distance to Operate 1000 ft 300 m at 300 Baud 300 ft 100 m at 1200 Baud typical values with standard communication cables Overvoltage Protection Series resistors and Transient Zeners Connector 54 MILC 26482 type MS3110E12 8S female Mating
106. ard Output Interface Board the last three mounted in the Board Frame The External Temperature Sensor and four connectors are mounted to the Equipment Base and connect to various subassemblies with cables 102 4 2 2 2 CHAPTER 4 FUNCTIONAL DESCRIPTION The four external connectors placed underneath the Equipment Base for best protection are see drawing ACT 3406 Jl Line Input J2 Window Conditioner Control and Monitoring J3 Output Interface FSK Recorder J4 Maintenance Terminal OPERATIONAL OUTLINE The operation of the Ceilometer is described by way of the following separate functions refer to Block Diagram CT 2295 4 2 2 1 Measurement Circuit 4 2 2 2 Output Interfaces 22 219 Internal Temperature Control 4 2 2 4 Internal Monitoring 4 2 2 5 Power Supply Section 4 2 2 6 Solar Shutter Option 4 2 2 7 Window Conditioner These will be described in conceptual terms Where reference is made to modules or subassemblies with module descriptions of their own or to the Software detailed descriptions of the operation are found in the corresponding sections The Measurement Circuit This 1s the main operational part of the instrument that which measures the atmosphere It is controlled by the processor and its software A measurement cycle is started by the processor by signaling the Laser Control Circuitry to issue Laser Trigger pulses at a selected frequency for a predetermined time A Laser Trigger pulse
107. ard voltage regulators some of which also feed the Output Interface Board CTI 12 Ref A3 Several on board precision reference supplies for measurement needs are also provided The board was designed and realized to be easily maintainable Seventy eight 78 test points provide for easy access to the most important signals Jumper strappings on selected feed back signal paths facilitate testing on component level The board includes a test pulse generator from which several different echo signal combinations are attainable for simulating cloud base conditions without the need of an optical path Parameter monitoring capability further provides for easy isolation of failures both on component and board level The CTM 12 Processor Board was specified and designed for low power operation in a wide temperature range The total power consumption of the board is typically 6 Watts about 40 of which is dissipated by the on board voltage regulators 129 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 1 2 Specifications Type Part Number Reference Designation Functions Mechanical Environmental Power Input Power Output regulated DC Voltages 130 CTM 12 Processor Board 2681 A Central Processing Unit for CT 12K Ceilometer with the following Main Functional Blocks CPU Monitor Sequence Control Signal Amplifier Size E2 plug in board 64 pin two part connector PCB 1 6 mm glass fiber solder
108. are which also monitors and checks other functions The summary of the use of the Monitor A to D channels is presented in the Appendix of Chapter 3 Power Supply Section This consists of the High Voltge Power Supply PSI the Unregulated Power Supply Board A2 and the Temperature Control Transformer TI This section supplies unregulated power to all subassemblies where the actual voltage regulators are located solar Shutter Option The option must be furnished if the geographical location is such that the sun may be right above the instrument 1 between the tropics of Capricorn and Cancer plus some safety margin The solar shutter consists of a solenoid and a flap placed above the transmitter lens The receiver 1s adequately protected by its filter The sunlight sensor and solar shutter driver electronics are situated on the Light Monitor Board A5 The shutter design is fail safe 1 e when no power is applied it is closed The solenoid has to be energized to open This is done by the electronics circuits without the need of processor control The processor is able to read the Sky Light sensor The processor can also drive the shutter ON for testing purposes but cannot force it to be OFF when the shutter circuit detects excessive light Note that in all documentation Shutter ON corresponds to solenoid current being OFF and vice versa due to the fail safe design 114 4 2 2 7 CHAPTER 4
109. atch dog reset strobe WOR generates no data RD 71 COMMON READ STROBE i RD 5 CPU loads the data u9 12 RO 24 l VEL 6 Read strobe HI releases the 149 RL gt ADORESS SPECIFIC READ STROBES 600 RRO RL WOR bus and anew cycle begins u9 9_ WORJ 1 i T1 eee eee T12 TI 72 T3 T 15 T6 T Te T9 T12 INSTRUCTION FETCH 1 0 WRITE 1 0 WRITE CYCLE AS ABOVE 9 e ALE SEEN GG As qbove ROIS HI 4 CPU emits the data to be i F ADOR LOBYTE 1 0 DATA OUT p oto ADO i Write strobe RWO LENO or I USKO ADDRE 55 LOBYTE AQ 7 9 loads the dala into i the 1 0 device ADORESS HIBYTE 8 15 P2 6 Write strobe raised HI mue ends the cycle WR COMMON WRITE STROBE Y 600 WR RWG l NOE 1 ADDRESS SPECIFIC WRITE STROBES 2 0 RWO LENO LENI LENI CT 3544 CHAPTER 4 FUNCTIONAL DESCRIPTION 2X 8x C2 C3 RI R2 Ca U2 J2 UI J3 i AO 83 gt A3 7 ui e j z 852 Q A E J4 m dist lt o Uu P i 2H 2 o c gt c 5 Svy L 22 peg 253 a P pe al 5 3 T L c Sd e f uUi 4 O N Q a sq 2 o c x ne 3 J 13
110. ates its execution One or more spaces must separate identifier and parameters ID PARI PAR2 CR With input commands new data values or states of operation are defined by the parameter one only If the parameter 15 omitted the current value or state will he output with certain output com mands a default set of parameters will be used With standard ASCII communication ST the identifier part con sists of 2 to 4 letters Additional letters will be ignored The pararneters are numbers or letter combinations The DEL RUBOUT key can be used for editing the command With Maintenance Terminal Communication MT the identifier part consists of letter C and a number code these need not be separated by space The parameters are numbers ON and YES is 1 OFF and NO is 0 No DEL RUBOUT equivalent 15 available Numeric parameters may be input as they are written 1 e zeroes and decimal point are used as in writing All input characters are echoed 40 3 1 4 6 CHAPTER 3 OPERATION Advanced Information Internally Ceilometer CT 12K is equipped with one serial digital interface This is used both for FSK and RS 232C electrical inter face ports Outputs are identical inputs are ORed Input devices may be simultaneously connected to RS 232C and FSK ports but may not input characters simultaneously No handshake signals are used The RS 232C port J4 doubles as a port for Maintenance Terminal CTH 12 The presen
111. ayout C CT 3278 REFERENCES Technical Note MM 74HC942 300 Baud Modem LIGHT MONITOR BOARD CTL 13 REF AS 4 3 4 4 3 4 2 4 3 4 3 4 3 4 4 4 3 4 5 Introduction Specifications Functional Description Parts List Drawings Circuit Diagram CT 3564 Component Layout CT 3560 CTL 13 Assembly 1 3410 RECEIVER BOARD CTR 13 REF A6 4 3 5 1 4 3 5 2 4 3 5 3 4 3 5 4 4 3 5 5 Introduction Specifications Functional Description Parts Lists Drawings Circuit Diagram CT 3593 Components Layout CT 3596 Temperature Dependence CT 4594 TRANSMITTER BOARD CTT 12 REF A7 4 3 6 1 4 3 6 2 4 3 6 3 4 3 6 4 4 3 6 5 Introduction Specifications Functional Description Parts List Drawings Laser Diode Temperature Curve TP3 Voltage Curve CT 4417 Circuit Diagram CT 3120 Components Layout CT 2210 95 175 175 176 181 183 184 185 185 186 189 190 191 192 193 194 195 197 199 200 201 202 202 203 208 206 210 241 4 3 7 4 3 8 4 3 9 HIGH VOLTAGE POWER SUPPLY CTP 12 REF PSI 4 3 7 1 Introduction 4 3 7 2 Specifications 4 3 7 3 Functional Description 4 3 7 4 Parts Last 4 3 7 5 Drawings Circuit Diagram CT 3289 Wiring Drawing UCT 1200 Al Components Layout CT 3207 WINDOW CONDITIONER 2736 REF Bl 8 1 Introduction 8 2 Specification 8 3 Functional Description 8 4 Parts List 8 5 Drawings Circuit Diagram CT 4290 Heater Subassembly Drawing U CT 1300 Blower Subas
112. backscatter signal of one laser pulse from 254 discrete heights at 50 ft intervals resulting in a backscatter profile ranging from O to 12 650 ft For reasons of convenience the speed of light 1s assumed to be 1 ft ns Because the laser pulse transmitted is not infinitely short but of a duration of typically 150 ns corresponding to an instantaneous ray length of 150 ft the instantaneous backscatter signal will not represent the atmospheric conditions at the actual sampling height only but will be an average value representing a height range Based on the fact that both the laser ray and the backscatter signal propagate at the speed of light it can be shown that this height range is half of the ray length 1 75 ft with a 150 ns pulse The digitized backscatter signal will thus represent averages over approximately 75 ft of height range at 50 ft height intervals As was described Operation Principles Section 4 1 the amount of backscatter power within the field of view of the Receiver decreases by the square of the height and is further attenuated by any backscattering matter The signal received from more than about 1000 ft is completely buried in noise both light noise and electrical noise As described the noise partially cancels itself relative to the number of samples summed or averaged from the same height Hence the laser 1s pulsed several times Before the second pulse is transmitted the data values of the first
113. be spread over a wide range or group into several distinct cloud mass images Visual grouping and averaging of a longer period of the record will then provide a better result for reporting purposes than instantaneous hits Non Cloud Obscuration Height ranges where backscatter has been detected and the obstruction calculated to have a point extinction coefficient exceeding a value corresponding to a horizontal visibility of approx 6 miles 10 km but not exceeding the cloud criteria are marked with a greyish cloud signal in the RMOD ON recording mode The greyish appearance is accomplished by semi randomly on off switching the cloud signal during the sweep and disabling the non cloud obscuration signal altogether every second sweep 55 CHAPTER 3 OPERATION In totally obscured conditions where no cloud base is detected the non cloud obscuration signal will be output up to the calculated Vertical Visibility ceiling height this can then be seen in the record as the upper higher edge of the greyish area In cases of rapid changes in cloud heights and or posi tion backscatter from a cloud base may be blurred over a wide range and momentarily fail to produce a reliable cloud backscatter signature These instants will however at least provide a non cloud obscuration detection to enhance the record image of the situation 56 OPERATION CHAPTER 3 cr aa Pr
114. blower temperatures TE TB see Section 3 5 2 2 If temperature is within the limits of Table below check Alarm Limits ALIM If these are okay suspect an intermittent connector fault Normal Range Alarm Temperature After Limit Reference Stabilization High TE Ambient 0 C 5 C 100 C 32 F 41 F 212 F TI Ambient 5 C 15 C above 0 C 100 C 41 F 59 F 212 F Ambient 10 C 30 C below 09 50 F 86 F TL TI 5 C 5 C 70 C 23 F 41 F 158 F TB TE 0 20 C in sunshine 80 C 32 F 68 F 176 F with Blower off Heater off TE 0 C 5 C 32 F 41 F with Blower on Heater off TE 5 C 10 C 41 F 50 F with Blower on Heater on Stabilization times are in the order of minutes for TE and TB and in the order of hours for TI and TL 2 6 CHAPTER 6 TROUBLESHOOTING AND REPAIR If after sufficient stabilization the temperature 1s out of range identify the type of error from the following alternatives and proceed to the Paragraph in question 6 1 1 4 2 Temperature Close to 200 C 392 F Indicating Open Circuit 6 1 1 4 3 Temperature Alarm with Credible Values 6 1 1 4 2 Temperature Close to 200 392 F Indicating Open Circuit CHECK TL 7 TP6 TP5 A2 13 Al Ul5 12 Connectors A7J2 A2J8 A2J1 AIJI Cable W7 TE TSI UI A2 J9 1 2 A2 Jl a14 cl4 A Ul5 13 Connectors TSIPI 20 AIJI TI A U16 A
115. ce of this special 16 key 16 character terminal is sensed by an input signal FLAG whereupon an opening of the line will convert data interchange to be in the Maintenance Terminal mode Output from Ceilometer may be stopped by issuing an XOFF Control S 13 hexadecimal Output will commence upon reception of any character except XOFF The BEL character is output in addition to that shown in this chapter when Line is Opened or Closed when a Syntax Error is encountered All input parameters and operation modes are stored in non volatile memory EEPROM except when specifically mentioned AUTOMATIC MODE MAINTENANCE MODE The Automatic Mode is the normal mode of operation the Maintenance Mode is available for e g maintenance checking etc The following is a summary of their operations AUTOMATIC Normal mode of operation A measurement MODE cycle is completed every 12 seconds Outputs according to 3 2 are active The Digital message is withheld if the line is opened for operator dialog Internal monitoring and controls are updated every 15 seconds 41 CHAPTER 3 OPERATION MAINTENANCE Used temporarily for checking operation etc MODE Measurement cycle is halted but may be operated by command Measurement calcu lations are not performed Internal settings and controls may be operated by commands No automatic time out for closing an open communication line is applied The Maintenance Mode doubles as a
116. cedure found with the kit Remove faulty shutter in reverse order RECEIVER BOARD CTR 13 REFERENCE A6 WARNING HIGH VOLTAGE IS ACCESSIBLE WHEN THE RECEIVER BOARD COVER IS REMOVED Check Ceilometer Receiver noise behavior according to Paragraph 6 1 4 Check voltages V TP3 GND should be 5V 0 5V provided V Ll either lead GND 15 10V 42V otherwise replace If V L1 is out of limits suspect 2 or Voltage at TP2 should be at value found on sticker on the board at 25 C 77 F with a temperature dependency of 1 3V F 2 3V C for other temperatures If not suspect PSI or WIO Check photodiode current by measuring voltage across R4 10k0 at TPI TP2 When the receiver lens is covered this should be less than ImV In bright daylight with bright clouds above this may be as much as but not significantly more Artificial light may be used as a substitute Check preamplifier QI and Q2 operation by placing concave shield above Ceilometer and measuring the resulting pulse with laser on either by connecting an oscilloscope directly to A6J3 after unplugging W8 or at the corresponding Al test point Oscilloscope bandwidth shall be 10MHz minimum Observe positive pulses in the order of 100mV length 135ns repetition rate 620Hz 1100Hz If above conditions are not met replace A6 otherwise suspect Al or W8 290 6 2 6 CHAPTER 6 TROUBLESHOOTING AND REPAIR Replacement Disconnect all conn
117. close automatically 1 minute after the last keyboard entry Command format After the system displays the prompt gt commands may be given using the following command format C n B par B par2 F where C n B parl par2 where NOTE is command header C key is command number 1 40 see Sections 3 3 and 3 4 for the command descriptions is blank B key equals space are optional command parameter values in the ormat is minus sign E key is integer portion of the parameter decimal number is decimal point D Key is decimals decimal number E D d are omitted if not needed is command line terminator F key 84 22 CHAPTER 3 OPERATION When entering a command the alphabetic key characters are displayed as follows A not used inside a command line B blank space character C C command header D decimal point E minus sign F command line terminator Examples The user entered characters are underlined Standard data message display command gt C2F entered gt displayed Cloud limit parameter setting gt C6B0D15 67 F entered gt C6 0 1567 displayed Alarm limit setting C2060BIIBIOOFE entered gt 26 11 160 displayed Viewing Messages The LCD display of the Maintenance Terminal is capable of displaying only one line of 16 characters at a time The commands MES C2 STA C3 PAR C4 and ALIM C26 generate response
118. connector MS 3116F12 8P or equivalent Circuits B TXD Transmitted Data from Ceilometer C RXD Received Data from external equipment F Signal Ground A Equipment Ground 12 V DC supply for Maintenance Terminal CTH 12 G Flag from Maintenance Terminal CTH 12 GENERAL INFORMATION Laser Source Wavelength Operating Mode Initial Transmitted Pulse Energy Peak Pulse Power Pulse Width 50 Repetition Rate Average Power Max b radiance Laser Classification Laser Source Dimensions Transmitter Optics System Focal Length Transmitter Effective Lens Diameter Transmitter Beam Divergence Lens Transmittance Window Transmittance 1 2 4 LASER TRANSMITTER Gallium Arsenide GaAs Semiconductor Diode 904 nm nominal Pulsed 6 6 uWs 5 factory adjustment 40 W typical 135 ns typical 620 Hz 1120 Hz processor controlled for constant average power 5 mW 50 uW cm measured with Dia 7 mm aperture Class 1 in compliance with FDA CFR 1040 10 Subsection e 3 50 mil square 1 3 mm x 1 3 mm 14 45 inches 367 mm 4 65 inches 118 mm 2 5 mrad maximum 90 typical 97 typical clean 1 2 5 RECEIVER Detector surface Diameter Interference Filter 50 Pass Band Transmissivity at 904 nm Focal Length Receiver Lens Effective Diameter Field of View Divergence Lens Transmittance Window Transmittance CHAPTER 1 GENERAL INFORMATION Silicon A
119. d at the 5V level to the microprocessor internal Universal Asynchronous Receiver Transmitter UART This is operated by software Its Baud rate is determined by software through one of the microprocessor s internal counters The Baud rate of the RS 232C interface of the CTS 12 board is 300 Baud as standard and default but may be commanded to operate at 1 200 Baud The RS 232C interface 15 normally connected to the processor but may be manually switched to the FSK modem equipment side for FSK line troubleshooting purposes Beside RxD TxD and Grrd signals the RS 232C connection of Unregulated Power Supply board A2 also contains a 12V DC power supply and a Flag signal These are used for the Ceilometer Maintenance Terminal CTH 12 This is powered from the Ceilometer and since its keyboard is 16 key hexadecimal the Flag is needed to signal the processor to interpret inputs from the terminal according to its special protocol 109 CHAPTER 4 FUNCTIONAL DESCRIPTION CTH 12 Maintenance Terminal interfaces directly to the Equipment Base connector J4 to where Unregulated Power Supply RS 232C interface of Board A2 is routed by internal cablings Internally the RS 232C interface of Board A2 is connected via a standard male 25 pm D subminiature connector which thus enables connections with standard cables for in depth maintenance and service operations The standard asynchronous character frame 1s start bit 8 data bits whereof 7 u
120. d of the CT 12K software is used for this purpose To use the TOTAL command proceed as follows 0 Open the communication line giving a CR symbol CR Carriage Return from the Operator s Terminal 0 Give TOTAL command and CR The CT 12K software responds to this by giving the parameter value TOTAL SIGNAL LIMIT and the measured total value CURRENT SIGNAL SUM The SUM values reported in above conditions should be in range 20 40 If out of limits then turn to Chapter 6 For exact command syntaxes and additional information see Section 3 4 23 CHAPTER 2 INSTALLATION AINO S3SOdM d INISALIVIANVA 3YV 5 1 SHJ WNAN 3IN343338 ISIV 441 H3HSVM A907 M7 9I ISIV ZIBNIO MIYIS 139205 001 Q1S TIW Yad ONIMVYO L138d831N 5347 QW 1 5397 9Ix9NW oW y H 2 LA A 2 A M 46 t 1 m gt M odd LU 3 en smal Ya gt 15 CEILOMETER P N 2680 CT 12K tm CEILOMETER ASSY DWG BEER ERU NEN AAA a6 06 0 SIS LS x gt wagumcec UPPDATED DW De see pes gt senal Pu ST 1340 52 8 740 29 1 Y t 600 L20 165
121. data 1 e same as with TAB where n is table number see TAB SC 15 Scaling Factor for specifying how many horizontal character positions shall equal a value of 1 0000 in the table in question If not specified 200 is used si is Start Index 0 253 1 e first range gate number of output If not specified then 10 is used 2500 feet 80 3 4 5 19 CHAPTER 3 OPERATION ic 15 Index Count 0 254 1 e how many 50 foot range gates shall be output If not specified then output will be to end of range Output is once only no cycling is available Comrnand parameters may be omitted from the end of the line but not in between Output may be aborted with an ESC character Range gate data is output one gate per line starting from the Start Index each line contains the height points one per character position and an asterisk as a mark for the data value of that range gate Syntax example ST MT gt GRAP 0 100 0 12 CR no equivalent a de next input MES For output of Digital Message No 2 in the Dialog Mode LINE OPEN In AUTOMATIC MODE the message will be that of the last completed measurement this operates continuously in the background in spite of automatic message transmission being inhibited In MAINTENANCE MODE a correctly formatted message will be output but only internal monitoring data will be updated Additionally if a MEAS command 3 4516 is carried out the raw range gate data tabl
122. de a suitable output for the Processor Board CTM 12 Ref AI The bias voltage of the photodiode is supplied from the High Voltage Power Supply Ref PSI regulated and temperature compensated on the Receiver Board and monitored by circuitry on the Processor Board The photodiode sensitivity Is temperature dependent This Is compensated for by a temperature dependent control of the bias voltage The value of the bias voltage should be checked at maintenance or service of the Receiver It 1s factory adjusted to a value found on a sticker on the board at room temperature giving the Receiver a nominal responsivity of 40 A W The actual bias voltage then varies by a factor of 1 3 VPE 2 3 V C depending on the actual temperature giving it a constant responsivity The positioning of the photodiode and its mounting hardware on the receiver board is extremely critical and is held to tight manufacturing tolerances This assumes field interchangeability of all receiver boards without the requirement of optical realignments 193 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 5 2 Specifications Type Receiver Board CTR 13 Part Number 20105 Designation A6 Photodiode Bias Voltage 250 VDC 425 VDC Note The bias voltage is individually adjusted for specified responsivity at room temperature and marked on a sticker on the board Temperature dependency is 1 3V F 2 3 VP C Preamplifier Supply Voltage 10 VDC 15 Dimensions
123. e 2 Data Line Format Message Example DIGITAL MESSAGE NO 3 3 22 221 000 255 3 2 29 General Format Status Line 1 Backscatter Data Line Message Example 31 PAGE 33 35 36 27 37 38 39 40 4 4 43 44 44 45 46 47 49 50 50 5 51 51 3 3 3 4 3 23 GIFFT RBC RECORDER OUTPUT Introduction 32 9 2 Signals 22359 Recording Modes and Set Up Commands 3 2 3 4 Examples and Interpretation PARAMATERS AND OPERATION MODES 5 35 1 3 3 2 STANDARD PARAMETER SETTINGS DESCRIPTION OF PARAMETERS PERFORMANCE MONITORING AND ALARMS 3 4 1 3 42 3 4 3 3 4 4 3 4 5 GENERAL STATUS MESSAGE START UP ALARM LIMITS COMMANDS FOR DETAILED CHECKING 3 45 1 AN 3 4 5 2 LASE 3 4 5 3 SEQ 3 4 5 4 NOIS 3 4 5 5 FREQ 3 4 5 6 GAIN 3 4 5 7 HEAT 3 4 5 8 BLOW 3 4 5 9 SHUT 3 4 5 10 RECT 3 4 5 11 3 4 5 19 DATE 3 4 5 13 RESE 3 4 5 14 CAL 3 4 5 15 HELP 3 4 5 16 MEAS 3 4 5 17 TAB 3 4 5 18 GRAP 3 4 5 19 MES 22 32 53 55 61 62 3 5 OPERATION WITH MAINTENANCE TERMINAL CTH 12 3 5 1 GENERAL 3 52 OPERATION 3532 1 Opening and Closing the Line 2222 Command Format 35 2 3 Viewing Messages 3 5 24 Operating Session 3 5 3 COMMANDS TABLE APPENDIX 1 CTM 12 MONITORED PARAMETERS CT 3415 33 82 83 84 85 86 87 90 34 3 1 GENERAL 3 1 1 CHAPTER 3 OPERATION INTRODUCTION NORMAL OPERATION The normal operation of Ceilometer CT 12K is f
124. e of signal DA in the keyboard controller goes HIGH state at test point J10 5 Signal TBRL state then falls LOW if it was HIGH and data is loaded to the buffer register of the Transmitter When the key is released DA state goes LOW and TBRL state goes HIGH The states of the data lines TBRI TBR4 from the keyboard circuit and hardwired data lines TBR5 TRRS are then locked in the Transmitter buffer register signal TBRE is reset by the rising edge of the I3 TBRL pulse which prevents keying in of further data until the contents of the buffer register 0 1 baud clock cycle later is transferred to the Transmitter buffer register transmission has started and signal TBRE has returned back to HIGH state If the previous data transmission was still unfinished signal TBRE does not return to state 1 until the previous data transmission has been concluded Only after this 1s data transferred from the Transmitter buffer register to the Transmitter register and TBRE state returned 4 3 9 3 1 4 2 UART Receiver Incoming data is received at input RI test connector J10 pin 9 When data is not sent input RI is normally HIGH Incoming data is clocked by the RRC clock obtained from the baud generator RRC frequency is 16 times the baud frequency The receiver timing 1s shown in Figure 2 below RRI data data DDR DR Figure 2 UART Receiver Timing Diagram 237 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 5
125. e will be updated 81 CHAPTER 3 3 5 OPERATION With Maintenance Terminal CIH 12 the output of Status Lines and 2 will be in groups of max 16 characters and range gate contents will be output one gate at a time preceded by the range height in feet or meters Message viewing is controlled by Forward F Backward B Continuous C stepping and Abort A keys Syntax example ST MT gt 5 CR gt 2 10 04200 00150 3000011010 10 04200 00150 2 3 0 08 36 12 168 23 9 4 56 20 11111 11111 F 0000011010 F ash ois asian ptas DD 23 0 08 3 6 F 1 12 168 F 2 23 9 4 56 20 F 3 4 0 Data Value F 50 Data Value F 6 DATA VALUES 7 etc to 8 9 12450 Data Value A 10 11 LADD as DD gt next input gt next input OPERATION WITH MAINTENANCE TERMINAL CTH 12 3 5 1 GENERAL The Maintenance Terminal CTH 12 is connected to the CT 12K Ceilometer through the Maintenance Terminal connector J4 at the Equipment base bottom The Terminal is controlled with the hexadecimal keyboard incorporated in the terminal The decimal number keyis 0 9 are used in entering number data the alphabetic keys A F have special functions 82 3 5 2 3 5 2 1 CHAPTER 3 OPERATION A key l message viewing ABORT DISPLAY key B key 1 blank character space 2 message viewing BACK STEP key C key 1 command header 2 message viewing CONTINUOUS DISPLAY key D
126. eate a hysteresis of 1 volt at comparator input pin 12 corresponding to a light power of approximately 16 W m2 Thus the trip point must always exceed the I volt value The output of the comparator Ul pin 14 is high 15V when sky light power is low 1 e below the trip point and the output is low when sky light power is high This output drives the Solar Shutter Darlington transistor Q2 the design being such that the Solar Shutter Solenoid has to be energized to be open collector of Q2 low and de energized to be closed voltage of collector Q2 close to 24 V supply This fail safe mode of operation provides for high reliability protection in all cases of power failure and most cases of equipment component failure Resistor R12 provides for safety should the wiper of trimpot R13 fail The processor can close the solar shutter with signal SSON pin 5 by raising it high thereby switching transistor QI on which will short the base of Q2 and prevent it from keeping shutter Kl energized The processor cannot force the shutter to stay open should the light power detected by D3 cause a voltage exceeding the set point at TP4 The shutter driver circuitry has a separate current return ground GNDS in order not to disturb the measurements These have a low current return ground GNDP which is routed separately to the common ground Diodes D5 and D6 protect the components in case of failure of any ground lead
127. ector 6 pos Female PCB AMP 172 207524 3 J1 c 5 at gt J6 c 2 REL e ml el ALE lt 24 m q A O AS 20V RIS oe z 5071517 gt Seb a e gt 9 gt lo CD 218 923 005 z la 2V1 0653 lt z ac 7 GNDP DE D eee 10A 2 1 10 30 saci 25V SV loc 2 4C TB K2 1 DE 125VAC SA GNDD 16 TE D 32 25 BON 3 1226 N Dy sc D2 FL 629 A Y poo VM28 MRXD 1 19 A RD la25 S c24 SQT enu LL AES 2011 c c 15 sel CD GNOI c c 16 12VI 20VI Tm acs 12VI RBCE F 22 AAN SC 0525 RBCT 1027 22 TA 120Hz 1 25 x a2 MRXD c2 IRXD ac 20VI D R2 Ol gt 05W N c MRXD 3 Ea WIXD 12 Ud Y AE s2 cek Ri 0 222 RBCT E Ei Y SV 122 q 27 10vD 0 pb Zips 25 oc28 GNDD Of af 12VM BZW06 fSB BZW06 5B Y hn Sac C7 C6 lc 100 10 4 ae 2 630 20VA L6 L3 38 231 20VA t TEs i GNDX 3 Seu TE 2 x1NZ005 L 13 Ths D1Z 1D15 TP gt Sa y 10VX gt n UU tl gt 98 PXHV TL ls ES 12 VM TL 6 2 gt pP lt 9 J9 1 p ii d NREGULATED POWER suPPLY VAISALA gt me 512
128. ectors Unscrew hex spacer nuts holding board to optics assembly Pull board down to clear long screws Place into bag or box immediately to protect mirror like infrared interference filter ESPECIALLY AVOID TOUCHING FILTER WITH FINGERS Replace with new Receiver Board Observe the same filter protection precautions Tighten spacer nuts to approximately same tightness felt when loosening them Connect cables turn Ceilometer ON Replace all covers and perform offset calibration as per Section 6 4 Observe performance with real clouds and no fog or precipitation Check current signal sum by TOTAL command Check several and note average If cloud detection reliability appears significantly reduced and the CURRENT SIGNAL SUM obtained is out of range 20 40 See Section 3 3 Total in specified conditions then return Ceilometer to Depot or Manufacturer for thorough performance check TRANSMITTER BOARD CIT 12 REFERENCE A7 Verification The absence of laser power can be verified by cloud hits missing monitored laser power reference LLAS being very low which should give a Laser Power Low alarm status bit S 1 and by using an external infrared detecting device WARNING DO NOTATTEMPT TO LOOK AT TRANSMITTER OPTICS WITH MAGNIFYING GLASSES BINOCULARS ETC WARNING HIGH VOLTAGES ARE ACCESSIBLE WHEN THE TRANSMITTER BOARD IS REMOVED 291 CHAPTER 6 TROUBLESHOOTING AND REPAIR Measure the DC voltages TP4 G
129. ed aC 2 STRUCT TF EDGR STR ros s Jen LOWEST E MED SARL ADDRESS AQ 7 S UD ADDRESS LOBYTE EDO ADDRESS ar suo ADORESS LOBYTE MAU ADDRESS mes 0D NI EE 5 CPU loads the instruction in NOTE 1 PULSE WIDTHS AND DELAYS SHOWN ARE ALL TYPICAL VALUES NOTE 2 THE TERM 1 0 DEVICE INCLUDES DATA RAM LOCATIONS AS WELL AS OTHER 1 0 FUNCTIONS ADDRESSEO BY THE CPU NOTE 3 F is 90 BUS FLOATING DATA INSIGNIFICANT DATA UNDEFINED Checa Eoo US wen 86 06 13 SIS PROCESSOR BOARD 1 CTM 12 CPU CYCLE TIMING INSTRUCTION FETCH CYCLE Two consequent cycles shown 1 ALE enables intormation trans lec from ADO 7 to 0 7 2 EPROM HI oddress is pushed onto P2 by the CPU 3 Fallinq ALE latches EPROM LO address on AQ 7 4 PSEN enables the instruction from the EPROM onto ADO 7 y 4 NOLLAPDHOSHG IVNOLLONOM 6 EPROM releases ADO 7 floating ue 1 21 28 A8 151P 2 ADORESS HIBYTE ADDRESS HIBYTE CD ADDRESS HIBYTE ADORESS TERIS BUS Fetching a new byte begins I I Tt ees ene INSTRUCTION FETCH Rs T 1 0 READ CYCLE As above WR is HI i dn 2 1 0 device s address is ADO 7 pusned onto P2 i ADSO 7 3 Fallinq ALE latches 1 0 4 devices LO address on AO 7 E ADORESS A0 7 X Read strode RRO or enable data from 1 0 device onto e ADDRESS A8 15 P 2 ADO 7 W
130. ed into the following functional circuits Modem Circuit Control and Supply Circuits Gifft RBC Recorder Interface Modem Circuit The integrated modem circuit U2 provides all functions and signals needed to create a Bell 103 compatible modem Data Transmission The RS 232C level data for transmission is applied through connector Jl pin a26 signal TXD data from the processor board or pin al9 signal MRXD data from the maintenance terminal connector The two input data lines for the Interface board are OR ed together with diodes D3 and D4 176 CHAPTER 4 FUNCTIONAL DESCRIPTION The signal is limited to 5V levels by the resistors of resistor array RA3 pins 3 4 and 7 8 The signal is inverted by UI and applied to the input pin TXD of the modem circuit U2 The monitoring LED D10 TXD indicates the presence of data at the TXD input of the modem circuit U2 The modem circuit U2 modulates internally the input serial data of 300 Baud and outputs the modulated data via pin TXA The modulated data is transmitted through the coupling transformer T2 600 ohms and output via connector J2 pins 1 and 2 signals MODI and MOD2 The zener diodes D15 and D16 protect the modem circuit U2 from line transients The transmit level of the modem output can be adjusted in the range of 12 dBm 0dBm by jumper J8 For the adjustment of the line transmit level refer to jumper setting table in the Circuit Diagram CT 2277
131. ed through bushing from hole in Optics Frame wall Unscrew two 2 screws holding resistor to wall Transfer as much as possible of heat conducting silicon compound from replaced resistor to new resistor Assemble in reverse order 297 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 2 10 6 2 11 TEMPERATURE SENSOR REFERENCE TSI Check circuit voltage at A2 to be approximately 2 94V at 70 F 21 C temperature coefficient 5 5mV F 10mV C If not disconnect TSI at A2J9 and measure an open circuit voltage of approximately 5V at A2J9 pins 1 and 2 Short it and measure a current of approximately 2mA If the latter measurements are not okay suspect Al or A2 Otherwise replace TSI Replacement Disconnect from A2J9 Cut bundle ties Remove air filter from vent Lift TSI from vent Replace in reverse order Replace cut bundle ties with new ones WINDOW CONDITIONER 115V REFERENCE Bl WARNING HIGH VOLTAGES Verification Using maintenance commands check temperature sensor TB to give credible values Command BLOW ON HEAT ON Maintenance Mode AUTO OFF and observe TB to rise approximately 12 F 7 C above ambient TE in a few minutes If temperature rises considerably more suspect blower operation if not at all suspect heater operation Disconnect the Window Conditioner at J2 and measure resistivities Blower circuit approximately 60 ohms Heater Circuit 22 ohms If these are okay suspect PSI Al or A
132. efer to Drawing 4412 If faults are detected they are signalled by activating the trigger break for 200 ms which causes the projector lamp on the Gifft RBC Recorder to blink 111 Trigger brea signal resolution m 5 Height ft Gifft scale degrees E 0 1bit 50 1 67 bit 1 4 i e cs 0 20ms 1 0 33 3 ms i 0 80tt 000 133 3 ft 0 6 deg 30 ideg FIG 2 DIAGRAM OF RECORDER OUTPUTS 100 20 8000 60 CT 4412 150 157 3 0 12000 90 NOLLdDNOSHG TWNOLDDNNA 4 2 2 3 CHAPTER 4 FUNCTIONAL DESCRIPTION The FSK and Recorder outputs are connected by Output Harness W3 to Output Interface Connector J3 at the Equipment Base Primary surge protectors in the form of noble gas filled spark gaps are placed at the J3 connector Secondary surge protectors in the form of series resistors and transient zener diodes are placed on the Output Interface Board The internal RS 232C interface 1s connected via male 25 pin D subminiature connector J7 on the Unregulated Power Supply Board A2 with Maintenance Terminal Harness W4 to Maintenance Terminal Connector J4 at the Equipment Base The signals are protected by series resistors and transient zeners Internal Temperature Control Internal temperature is controlled by switching the two Temperature Control Heater resistors R1 and R2 OFF in series o
133. elow check Alarm Limits ALIM If these are okay suspect e g temporary Line Voltage dip or intermittent connector fault Alarm Acceptable Voltage Nominal Limit High Reference Value Low Value P20I 20V 15 V 24V PIOX 10V 75V 12V M20A 20V 15 V 24V PIOR 10V 7 V 13V MRHV 300V 1 150 V 450V P12M 12V 8 V 15V PIOD 10V 6 5 12V P25V 25 20 30V 130V 1 52 200V 20 20 15 V 24 201 20V 15 V 24V Note 1 These voltages are individually adjusted at 72 F 22 C to values found on the respective boards 270 CHAPTER 6 TROUBLESHOOTING AND REPAIR If voltage 1s out of limits proceed to check the following Voltage CHECK VOLTAGE AC INPUT AT A2 LOADING BY low FUSE S AT TEST POINT P10D A2 F3 A2TP4 D8 3 4 8 UAC Al P20I A2 A2TP3 Dll 3 4 30 VAC Al or A3 or F7 201 A2 A2TP2 Dll 3 4 30 UAC Al or A3 F6 or F7 P25V A2 Fl A2TP1 D2 3 4 20 VAC R1 R2 Al A5 or PSI SUPPLY Tl M20A A2 A2TP5 D10 3 4 30 VAC Al F4 or F5 P20A A2 A2TP6 D10 3 4 8 VAC Al FA or F5 P12M A2 F8 A2TP7 D12 3 4 10 VAC Al or A3 MAINTENANCE TERMINAL PlOX A2 F9 A2TP9 D13 3 4 8 VAC Al or A7 PXHV PS1 Fl PS1A1J8 1 3 7 P1OR A2 F2 A2TP8 D 8 3 4 8 VAC Al or A6 MRHV PS1 F2 A6 TPI TPGND and 4 6 51 1 2 271 CHAPTER 6 TROUBLESHOOTING AND REPAIR General Troubleshooting Guide i 2 10 Re
134. em parameters Read and Write access are carried out serially Transfer clock is applied to pin 2 SK and code address data to pin 3 DI Data is brought out to pin 4 DO Pin 1 1s the active high chip select input The O P Control Latches 10 and 021 8 bit addressable CMOS latches Access to the latch registers is carried out by pulling pin 14 LENO LENI low which accomplishes transferring the pin 13 input state to the output register determined by the address on pins 1 through 3 Returning pin 14 high will latch the output The Latch 1 output pins 11 12 are buffered by transistors QI and Q2 which drive the coils of Heater and Blower Relays in the HIV PWR Supply Ref PSI The HON and BON lines are protected against inductive transients by diodes on the Unregulated Power supply Board Ref A2 The Latch 0 output pins 11 12 drive the Green and Red LED indicators through the RAO resistors The LED s provide for high brightness with only 6mA current sunk by the Latch outputs 142 CHAPTER 4 FUNCTIONAL DESCRIPTION The Internal Heating Control is composed of two op amps of U14 resistor arrays RA9 RAIO 4x47k 4xl00R and diode DA2 9 8 and furthermore the resistor dividers 7 8 and R6 RA12 1 2 which supply the temperature controlled voltages to the inv inputs of the op amps 13 2 Ul4 1s a quad op amp LM 124 also providing for the Pre MUX and TxD buffers on the board The op amps capable of sinking 10mA min pro
135. en sweep start and synchronization signal 0 D14 yellow RBCE RBC recorder Enable Cloud Signal Gifft RBC Recorder cloud data signal 21 CHAPTER 2 INSTALLATION 2509 These LEDs provide an easy means to check and monitor the operation of the communication After POWER UP the following sequence is performed automatically by the CT 12K software 0 Data transmission starts with the data memory and modem test messages and TXD will blink according to the character stream 0 The modem circuitry and communication lines if used are tested and the communication 1s established CD will be turned on for 2 3 seconds while the testing is performed then remains OFF except when an active counter modem with carrier ON is connected to J3 0 Modem test program memory tests and internal status messages are transmitted and TXD will indicate the presence of transmission In the normal operation mode Automatic mode the cloud data collection and the calculations take maximum of 30 seconds to provide the first message table When the message 16 sent TXD will indicate the character stream of transmission for serial communications RS 232C or Modem The Gifft RBC Recorder output LEDs D13 and D14 shall start operating according to the interface specifications in 12 seconds However the automatic measurements of the Ceilometer may be terminated for maintenance purposes by using the AUTO OFF command Refer to
136. ently wipe off liquid with cleaning cloth Do not rub Avoid scratching the surface Turn cloth and gently wipe until dry E Replace Window Conditioner Be sure to tighten all four 4 knurled screws well Reconnect connector to J2 B Wash cleaning cloth 261 CHAPTER 5 PERIODIC MAINTENANCE 5 3 MONTHLY CHECK OF WINDOW CONDITIONER BLOWER In connection with Window cleanliness check observe the performance of the Window Conditioner Blower by listening to 1ts sound and feeling the air flow to detect signs of wear If necessary use the following commands AUTO OFF BLOW ON AUTO ON CLOS to control the blower If heating is ON observe that the temperature difference between Blower TB and Ambient TE is approximately 7 C OK A significantly higher difference is a sign of reduced blower efficiency 262 263 264 SECTION 6 1 6 2 6 3 6 4 CHAPTER 6 TROUBLESHOOTING AND REPAIR TABLE OF CONTENTS DIAGNOSIS 6 1 1 6 1 2 6 1 3 6 1 4 6 1 5 DATA MESSAGE CONTAINS AN ALARM FSK INTERFACE OPERATION IMPROPER OR MISSING LOCAL RS 232C INTERFACE OPERATION IMPROPER OR MISSING CLOUD DETECTION MISSING SUPERFLUOUS DETECTION VERIFICATION AND REPLACEMENT 62 1 6 2 2 6 2 3 6 2 4 6 2 5 6 2 6 6 2 7 6 2 8 6 2 9 6 2 10 6 2 11 6 2 12 PROCESSOR BOARD CTM 12 REF Al UNREGULATED POWER SUPPLY BOARD CTS 12 REF A2 OUTPUT INTERFACE BOARD CTI 12 REF A3 LIGHT MONITOR BOARD CTL 13 REF
137. er Sub Assembly CT 12K Blower Sub Assembly CTH 12 Maintenance Terminal Block Diagram CTH 12 Maintenance Terminal Circuit Diagram CTH 12 Maintenance Terminal Component Layout viii PAGE 184 190 191 192 199 200 201 206 210 211 220 221 223 229 230 231 253 255 LIST OF TABLES NUMBER DESCRIPTION PAGE CT 3415 Monitored Parameters 00 CT 4577 Contents of Character ROM 242 CHAPTER 1 GENERAL INFORMATION TABLE OF CONTENTS SECTION PAGE 1 1 SAFETY AND HANDLING 1 1 1 SAFETY PRECAUTIONS 1 1 1 1 Laser Safety 3 1 1 1 2 High Voltage 3 1 1 2 HANDLING 1 1 2 1 Handling of the Optics Assembly 4 E122 Lifting and Carrying 4 51 22 Exposed Connectors 4 1 2 SPECIFICATIONS 1 2 1 MECHANICAL 5 1 2 2 POWER 5 1 2 3 OUTPUT INTERFACES 5 1 2 3 1 Output Interface Connector J3 5 1 2 3 1 1 Bell 103 FSK Interface 6 12 3412 Gifft RBC Recorder Interface 6 1 2 3 2 Output Interface for Local Equipment 54 7 1 2 4 LASER TRANSMITTER 6 1 2 5 RECEIVER 9 1 2 6 OPTICAL SYSTEM 10 1 2 7 PERFORMANCE 10 1 2 8 ENVIRONMENTAL CONDITIONS 10 1 3 RBC ANGLE HEIGHT TABLE CHAPTER 1 GENERAL INFORMATION 1 1 SAFETY AND HANDLING 1 1 1 SAFETY PRECAUTIONS 1 1 1 1 Laser Safety The CT 12K laser ceilometer is classified as a Class 1 laser device when used within its normal operational conditions This means that a CT 12K Laser Ceilometer installed in a field environment with instrument covers on poses no established biological hazard to humans Howeve
138. er fuses One secondary supplies the Avalanche Photodiode Receiver bias voltage regulating circuit while the other secondary is fullwave rectified and filtered at J8 and connected to the Transmitter Board A7 for onboard regulating 215 CHAPTER 4 FUNCTIONAL DESCRIPTION The operation of the receiver bias voltage regulating circuit 1s as follows The 200VAC from T2 1s rectified filtered and doubled in circuit 2 2 to 550VDC This biases l mV K temperature sensor Ul which together with diode D3 creates a reference voltage of approximately 2 5V at room temperature with a temperature coefficient of 12mV K 22mV F between diodes D3 and D4 D4 serves for temperature compensation of the transistor Q5 base emitter voltage drop The output voltage is sensed with adjustable voltage divider R14 R12 R13 R15 and connected via Q5 to a difference amplifier Q3 A4 where the difference between reference and output controls the base of series pass transistor Q2 The drive is supplied by R8 R9 Transistor QI takes half of the regulation voltage drop which in case of output short circuit may exceed that of a single series pass transistor Current limiting is achieved when the voltage over R16 exceeds that of a diode junction 1 approximately 0 6V The maximum output current with full voltage is approximately ImA When this occurs diodes D6 and D7 will conduct excess Q2 base drive current to the output Zeners D
139. erently the unit needs service or maintenance Refer to Chapter 6 Troubleshooting 20 CHAPTER 2 INSTALLATION INTERFACES The CT 12K provides three 3 different interfaces for remote devices 0 RS 232C Maintenance Terminal Interface 0 Bell 103 Modem Interface 0 Gifft RBC Recorder Interface Depending on the distance between the Ceilometer and the observer site the data communication can be arranged either with the RS 232C level direct connection up to 1000 feet or with the Bell 103 modem connection for distances exceeding 1000 feet The RS 232C Maintenance Terminal connection signals are available at CT 12K equipment base connector J4 The Gifft RBC Recorder interface consists of two 2 signal pairs 0 Recorder sweep synchronization trigger break 0 Cloud Data signal The modem signals and Gifft RBC Recorder signals are available through connector J3 Reference Connection Diagram CCT 3105 The CTI 12 Interface Board Reference A3 provides five LEDs for monitoring the communication 0 D10 yellow TXD Transmitted Data Indicates a presence of data being transmitted from the processor board Al either via the modem circuitry or via the RS 232C 0 Dil yellow RXD Received Data Data received via the modem line 0 DI2 green CD Carrier Detect Indicates the presence of a carrier in the receive channel of the modem communication 0 D13 yellow RBCT RBC recorder Trigger Break Gifft RBC Recorder p
140. es LINE CLOSED Normal operation Measurement data messages are transmitted automatically if in AUTOMATIC MODE of operation see 3 1 5 Commands are ignored except for OPEN and FAST HEATER OFF This is also Restart and Power Up default state LINE OPEN Dialog mode Commands are accepted and responded to Command Prompt arrowhead bracket gt signifies readiness State is not maintained through a Restart or Power Down The state of operation is changed by the OPEN and CLOSE commands OPEN 15 accomplished with a Carriage Return CR only Command syntaxes and Ceilometer responses are ST MT CR F LINE OPENED FOR OPERATOR COMMANDS LINE OPEN ready for command input ready for input gt CLOS CR gt CIF LINE CLOSED LINE CLOSED message output continues output continues The LINE OPEN state is automatically terminated in the Automatic Mode by a one minute time out after the last character input The Line may be commanded OPEN in the middle of a message transmission Message is not interrupted but response to command is delayed until the end of message transmission In the LINE OPEN mode the last Digital Message No 2 can be requested with command MES see Section 3 4 39 CHAPTER 3 OPERATION 3 1 4 5 Command Format and Editing Rules The command consists of a command identifier ID and none one two three or four groups of parameters PARn It is terminated by a Carriage Return CR which also actu
141. es pass capacitor C8 to common emitter preamplifier stage QI and emitter follower stage Q2 QI Q2 drive feedback resistor RII and a voltage is produced 12 Ik times QI base input current Output is through capacitors C6 and C7 which block the DC component The output signal from connector J3 is connected to the amplifier of Processor Board AI Resistors RI R2 and R3 divide the bias voltage by one hundred which is then brought to connector Jl This is further routed to the analog monitoring section of the Processor Board Software reference is MRHV WARNING Bias Voltage may reach 425V 196 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 5 4 Parts List Semiconductors U1 1016 LM 317 LZ Voltage Regulator U2 1832 LM 335 AH Temperature Sensor u3 2456 LM 124 Quad Op Amp U4 20106 236 5 0 Voltage Shunt 5 0 V Q1 Q2 359 2N918 Transistor NPN Q3 2970 TIP50 Transistor NPN DI 4336 IN4005 Diode D2 1987 c30817 Avalanche Photodiode D3 not used D4 D5 3884 IN4 148 Diode Resistors all metal film resistors 1 1 4W unless otherwise noted Rl R2 R3 R21 R22 R4 R16 R5 R20 R R7 RS RIO R9 RII R12 R13 R14 R15 R17 R18 R19 RAI 5169 20k5 6627 IM 5388 10k 3191 332k not used 0955 825R 1732 274R 1297 3k83 0165 12k 5444 21k5 5118 332R 3186 48k7 5156 2k74 6375 Ik 0012 2k 0057 4 x 10k 197 Trimpot SIL Resistor Array CHAPTER 4 FUNCTIONAL DESCRIPTION Capacitors Cl Cl6 0610 22 uF 25 v C2 C3
142. essage with default values and a specific example 69 CHAPTER3 OPERATION 3 4 5 3 4 5 1 ST MT gt ALIM CR gt C26F ALARM LIMITS POWER LIMITS Output one data item at a time P20I 15 0 P10X 7 5 M20A 15 0 P10R 7 0 MRHV 150 P12M 8 0 P10D 6 0 P25V 20 0 Channel numbers PXHV 52 P20A 15 0 M20I 15 0 instead of SIGNAL LIMITS alphanumeric references LLAS 155 LSKY 256 GND 4 TEMPERATURE LIMITS TI 100 TE 100 TL 70 TB 80 gt ALIM PXHV 54 CR gt 26 7 54 NEW LIMIT 54 0 gt NEW LIMIT 54 0 gt next input next input COMMANDS FOR DETAILED CHECKING The following commands are intended for use in conjunction with troubleshooting Section 6 or other special situations Some of the commands can be used in Maintenance Mode only Misuse will produce comment AUTOMATIC MODE AN channel Continuous output of ANalog monitoring channel in units of Monitor A to D converter increments range 0 255 Output is aborted with ESC character Channel is specified either with the reference designations or code numbers of Appendix I CTM 12 Monitored Parameters with the Maintenance Terminal only numbers work If no channel is specified the AD Converter internal self test channel value will be output value 125 131 70 3 4 5 2 3 4 5 3 CHAPTER 3 OPERATION Syntax example ST MT gt 8 CR or AN LLAS CR gt C14B8F 195 195 195 195 195 195 ESC A next input gt n
143. ext input LASE on off Control of Laser Enable Interrogation without ON OFF produces no response Control possible only in Maintenance Mode Requires SEQ setting for Laser trigger pukes output The setting is automatically cleared after each measurement scan either in Automatic Mode or a commanded one in Maintenance Mode MEAS CAL Syntax example ST MT gt LASE _ON CR gt C15B1F LASER IS ENABLED gt LASER ENABLED gt next input next input SEQ on off Control of Measurement Sequence Enable Interrogation without ON OFF produces no response Control possible only in Maintenance Mode Requires LASE setting for Laser trigger pulses output The setting is automatically cleared after each measurement scan either iin Automatic Mode or a commanded one in Maintenance Mode MEAS CAL 71 CHAPTER 3 OPERATION 3 4 5 4 3 4 5 5 Syntax example ST MT gt SEQ ON CR gt C16B1F SEQ ON gt SEQ ON gt next input next input NOIS Continuous output of Highest Average and Lowest Receiver data measurement sample recorded after last laser pulse of last 12 seconds scan completed Aborted with ESC character input Output in units of Flash AD Converter increments Updating is instantaneous in Maintenance Mode once every 12 seconds in Automatic Mode Syntax example ST MT gt NOIS CR C17F NOISE MEASUREMENT NOISE 19 16 13 19 16 13 19 16 13 19 16 13 19 16 13 19 16 13 ESC A gt n
144. ext input gt 19 16 13 next input FREQ number Interrogation and setting of Laser Pulse Frequency number Setting 1s possible only in Maintenance Mode 12 3 4 5 6 CHAPTER 3 OPERATION Nominal Frequencies are Frequency Number in Hz 0 620 1 660 2 710 3 710 4 830 5 910 6 1000 7 1120 Minor deviations may be measured due to breaks between scans in Automatic Mode Syntax example ST MT gt CR gt C18F LASER FREQ COUNT 2 gt LASER FREQ 2 gt FREQ 5 CR gt C18B5EF LASER FREQ COUNT 5 gt LASER FREQ 5 gt next input next input GAIN 0 or 2 Interrogation and setting of Receiver Measurement Amplifier Gain Setting is possible in Maintenance Mode only Gain 0 is 250 Gain 2 1s 930 nominal values Syntax example ST MT gt GAIN CR gt C19F GAIN SELECT gt GAIN 0 0 gt GAIN 2 CR gt C19B2F GAIN SELECT gt GAIN 2 2 gt next input next input 73 CHAPTER 3 OPERATION 3 4 5 7 3 4 5 8 3 4 5 9 HEAT on off Interrogation and control of Window Conditioner Heater status In Automatic Mode a control command will be cancelled within 15 seconds by the automatic operation algorithm An ON control will not be responded to unless the Blower is ON see BLOW Syntax example ST MT gt HEAT CR gt C20F HEATER OFF gt HEATER OFF gt HEAT ON CR gt C20B1F HEATER ON gt HEATER ON gt next input next input BLOW on off Interrogation
145. f no pulse seen unplug W9 from 526 If still not replace Al otherwise suspect W9 or A7 If LTRG is okay proceed to check LLAS input level If it is not in conformance with the Laser Power reading suspect other subassemblies Otherwise replace Al SKY MONITOR SUSPECTED check for LSKY input level that it 15 in conformance with its corresponding Status reading If not replace Al Otherwise suspect A5 or interconnections SHUTTER CONTROL SUSPECTED check that signal SSON is low If not even after Reset unplug A5 as it may overload SSON If still high replace Al otherwise suspect A5 and or KI BLOWER HEATER ERROR enter Maintenance Mode by commanding AUTO OFF Set Blower ON and OFF by respective commands and check that signal BON is low while ON and open circuit while OFF Similar check can be used for Heater control signal HON but it should be noted that Heater shall not be activated by the Processor if the Blower is OFF When the signals are inactive open circuit 25V should be present at control lines supplied through the relay coils in PSI Communication Lines Actuate the RESET switch The Processor should start sending Status Data onto serial line Check that voltage level at TXD A3 5 swings from below IV to above 43V If no data or incorrect levels replace Al If okay proceed to check TXD Alc22 The level should swing from below 5V to above 5V If not unplug A3 and or Maintenance Terminal as they overload
146. g used adjust Receiver High Voltage at 2 with R13 to initial value found on sticker on Receiver Board 6 and Quality Assurance documents Observe temperature co efficient 0 83V F 1 4V C at temperatures outside 60 F 80 F range 15 C 27 C Perform offset calibration as per Section 6 4 296 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 2 8 TEMPERATURE CONTROL TRANSFORMER REFERENCE WARNING HIGH VOLTAGES Verification Check output voltage of transformer 20VAC 3V found on A2 e g at diode bridge D2 pins 3 4 Cool down Ul6 of Al with cold spray to obtain maximum loading Check voltage with TI disconnected from A2 J3 Check line supply voltage outputs at PSIJ3 Replace faulty part Renlacement Disconnect connectors from A2J3 PSIJ3 Open up cable clamp holding secondary wires to top of Optics Frame Remove Receiver Cover Cut bundle ties holding primary wires to Optics Frame lower part Lift plastic feed through bushing guiding secondary wires through Optics Frame top Remove wires through slot Unscrew two 2 screws holding Tl to Optics Frame top Remove Tl Replace in reverse order Replace cut bundle ties with new ones 6 2 9 TEMPERATURE CONTROL HEATERS REFERENCES RI AND R2 Verification Disconnect from A2 connector J2 or J4 respectively and measure resistance to be 10 ohms 5 Replace if not within limits otherwise suspect A2 Al or TI Renlacement Disconnect from A2 Pull out fe
147. gnal activates triggering circuits to switch on the laser emission providing one laser light pulse to traverse upward via the transmitter optics to the atmosphere The Laser Trigger signal 1s an active high and trailing edge sensitive pulse referred to as LTRG Laser Trigger The positioning of the laser diode and its mounting hardware on the transmitter board is extremely critical and is held to tight manufacturing tolerances This assures interchangeability of all transmitter boards without the requirement of optical realignments Specifications Type Transmitter board 12 Part Number 2687 Designation A7 Supply Voltage 260V DC 15 25mA 10V DC 15 20mA Dimension x D x H 5 1 x S 1 8 inches 130 x 130 x 45 millimeters 202 4 3 6 3 4 3 6 3 1 Laser Diode Monitored Signals CHAPTER 4 FUNCTIONAL DESCRIPTION LDL LD 224 85 PXHV 1 of Laser Supply Voltage TL Laser Temperature Trigger Pulse 50 ns LTRG Laser Pulse Peak Power 40 W Duration 50 level 135 ns typical Energy Dia 118nm 6 6 uWs Max repetition rate 1120 Hz Functional Description Refer to Circuit Diagram CT 3120 The CIT 12 Transmitter Board consists of the following circuits High Voltage Regulator Laser Diode Pulse Circuitry Laser Diode Laser Diode Triggering Circuitry High Voltage Regulator The supply voltage of 260V DC is applied via connector J3 pin 1 from Power Supply
148. going high at the beginning of SQPHO About 60 ns later LTE from U43 9 goes low dropping the trigger low again LTON low will disable triggering The Test Pulse Generator is composed of the D Flip Flop U36 5 EX OR gate U41 3 and Jumper Sets J15 J18 During normal operation jumper connections should be left open so as to disable test pulsing With the test jumpers connected either RA6 or RA7 is applied to U36 3 triggering U36 5 high since SQO applied high state to U36 2 Either RAI or RA2 going high will reset the via 041 3 Since RA rises once and RA6 twice during SOPHO single or double pulse is generated respectively Since RA2 rises 400 ns and RAI 200 ns after RA6 or RA7 rising edge respective pulse widths are achieved added by the delay generated by U41 3 and C52 The main function of C52 is to filter out hazard pulses due to slightly non equal timing of the Counter outputs Ref Dwg CT 3536 Test Points are provided for the following signals J16 7 RAO Sample RAM Address 0 J16 6 WEN Sum Write Buffer Enable J16 5 Xl System Clock J16 4 CBO Seq Control Counter Bit O J16 3 CCK Seq Control Counter Clock J21 10 SQI Seq Phase Control 1 J21 9 LTRG Laser Trigger J21 8 LTON Laser Trigger Control J21 7 WSM Sample RAM Write Enable J21 6 LTE Laser Trigger Enable 5 MHz Clock J21 5 RSM Sample RAM Read Enable J21 4 SCK Sample Clock J21 3 SQO Seq F hase Control 0 Inverted J21 and J16 1 GND Logic Ground
149. he RXD output of the modem circuit u2 The power down mode of the modem circuit can be activated when signals SQT and ALB are simultaneously held high by the processor The basic clock frequency of 3 58 MHz for modem circuit U2 1s generated by crystal 71 The onboard 5V regulator U3 uses the 20V voltage supplied through connector Jl pins al4 and cl4 The output voltage of the regulator is adjusted by resistor R16 and R17 The 45V voltage supplied thorugh connector Jl points a2 and c2 15 filtered by capacitors and C16 and inductor L2 to prevent possible interference from entering the power supply CHAPTER 4 FUNCTIONAL DESCRIPTION The Gifft RBC Recorder Interface The general operating principle of the recorder is to produce lines or dots whenever backscattered energy or clouds are detected by the Ceilometer The dots are generated by continuously sweeping the recorder pen over dry electrosensitive recorder paper The Trigger Break signal The sweep of the Gifft RBC Recorder stylus is started by the pro cessor s RBC message output routine through relay KI The processor board provides an active high start pulse through connector Jl pin a27 signal RBCT The pulse width is 80 ms nominally The signal RBCT switches transistor Q3 on The relay contact is opened when RBCT is held high active The high low transition of signal RBCT closes the relay contact A regulated current of 4mA f
150. he capacitance Cl6 is discharged through the 22 k resistor in the POR line Monitor Section and will hold the Reset approximately 400 ms after PWR ON Reset can also be activated manually by actuating the momentary switch SI upwards and so grounding the POR line via the resistors in RAT The Sample Data Latch U19 is a similar transparent type of device as Ul3 In the initial state RL is high thus making the latch transparent via its pin 11 On the other hand it disables the latch output buffers via pin 1 When reading the sample RAM RL 15 strobed low which makes U19 latch the data on the SD bus and output them into the AD bus to be loaded In by the Processor Latching is used because the data on the SD bus changes invalid soon after the falling edge of RL System Clock for the Monitor ADC is provided by the RC oscillator Ul 1 6 RA7 7 8 C9 Two Schmitt trigger gates and 020 6 are unused and their inputs tied to stable levels RS 232C signals IRXD and MRXD are OR ed by diodes in DA2 and filtered by RA7 7 8 and C18 U20 8 inverts the results and also provides level clamp by its integral input protecting diodes which limit the signal level between 5 V and GND 139 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 1 4 2 Input Signals FLAG and CD coming from the outside of the board are transient protected by resistors in RAI and 5 1 V zener diodes DI and D3 lest points are provided for the following signals J3
151. heck supply voltages and check trigger pulse from Al via W9 If voltages and trigger pulse are okay suspect A7 If above checks do not indicate a fault tilt the Ceilometer toward an obstruction within a few thousand feet WARNING MAKE SURE THAT NOBODY VIEWS CEILOMETER FROM CLOSE DISTANCE WITH BINOCULARS OR MAGNIFYING OPTICS If a distance reading is obtained proceed to check A5 according to 6 2 4 and its signal path to Al through A2 Replace faulty board Note If a solar shutter is 1n place tilt the Ceilometer so that the shutter does not cover the transmitter lens by its own weight 273 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 1 1 3 2 6 1 1 3 3 Laser Power LLAS is Below Alarm Limit But Not Close to Zero Note that processor uses maximum pulse frequency 1 e FREQ is 7 Note the Laser Temperature TL It should be below 60 C 140 F If not allow the laser to cool by interrupting operation for a period AUTO OFF Check temperature and laser power again If temperature 15 well below 60 C 140 F readjust the Laser Supply voltage according to Paragraph 6 1 1 3 3 If the alarm remains on replace A7 Laser Power Adjustment Perform this adjustment only at an ambient temperature 60 F 80 F 15 27 Remove equipment covers Remove transmitter board A7 cover WARNING HIGH VOLTAGE Check PAR output message for LNOR value Connect voltmeter between TP3 and GND Increase volt
152. hen activated indicates the presence of a CTH 12 Maintenance Terminal so that messages can be formatted appropriately These signals are positioned as circuits not reserved by the RS 232C standard 171 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 2 4 Parts List Part Designation Number Description D1 D3 D4 D7 4336 Diode 600V IA IN4005 D14 D15 D2 D8 D 13 0555 Bridge Rectifier Varo VM28 D5 D6 1080 Transient Zener 15V 600W Ims BZW06 15B RLR2 4285 Resistor Carbon Film 4 70R 596 0 5W CLC2 C5 C6 6920 C3 C4 Cl0 10005 Capacitor Tantalum 10u 20 35V Capacitor Al Elec 2200u 35V Cl 1 C12 C14 C15 C16 C7 3258 Capacitor Tantalum 100p 20 20V C8 C9 C13 10004 Capacitor Al Elec 2200u 16V L1 L6 1181 Choke 100uH 10 K1K2 10020 Relay SPDT 24V 5A 125VAC SLS2 10018 Switch SPDT C amp KEIOIV30 2951 Fuseholder Schurter 0675 1 0099 Fl 10183 Fuse 10 Slow 0 25 X 1 25 inches F2 F9 F4 F7 10180 Fuse 250mA Slow 0 2 5 x 1 25 inches F3 F8 10181 Fuse 600mA Slow 0 25 x 1 25 inches J1 J6 10010 Connector DIN 64192 64 pos Female 00 J2 J4 2922 Connector 3 pos Female PCB AMP 207609 3 J3 292 Connector 3 pos Male PCB AMP 207635 3 J5 J8 J12 2952 Connector MIL C 83503 10 pos PCB J7 10344 Connector 25 pos Male PCB Cannon DB25P J9 2924 Connector 3 pos Female PCB 90 AMP 207608 3 J10 2932 Connector 18 pos Made PCB AMP 207442 Jil 2927 Conn
153. ht with no clouds gain is 2 and noise is 1 4 If not proceed to check and Al Status message after start up due to local or remote RESET contains no alarms If yes go to Paragraph 6 1 1 Above noise numbers are read with command NOIS see Section 3 4 as difference between middle value and low value columns A reliable performance check can be done by tilting the Ceilometer on its pedestal toward a nearby horizontal obstruction WARNING MAKE ABSOLUTELY SURE THAT THE LASER BEAM IS NOT VIEWED DIRECTLY WITH BINOCULARS OR ANY OTHER MAGNIFYING OPTICS If the above checks do not reveal cause of malfunction arrange for full performance check at authorized Depot or Ceilometer manufacturer 281 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 1 5 SUPERFLUOUS DETECTION If repeated mis hits are experienced without any apparent cause check that all parameter values are intact Perform offset calibration see Section 6 4 If problem persists return Ceilometer to Depot or Manufacturerer for full performance check 6 2 VERIFICATION AND REPLACEMENT 6 2 1 PROCESSOR BOARD CTM 12 REFERENCE AI Verification In many of the failure cases the malfunction may be caused by temporary interference confusing the Processor software To clear abnormal conditions actuate the RESET switch on Al prior to proceeding with verification RESET is also achieved by temporarily off on switching PSICBI or by RESET command provided that the device 1s able t
154. iagram C CT 3105 Mating connectors for Power and J3 Output Interface are supplied with the Ceilometer GROUNDING The power supply connector Jl provides a standard protective ground for the instrument chassis Connection of an external earthing shall be made to the ground terminal of the equipment base reference 3406 for location CONNECTION TO A SOLID EARTH GROUND AT THE INSTALLATION SITE IS MANDATORY FOR ADEQUATE LIGHTNING AND TRANSIENT PROTECTION 19 CHAPTER 2 2 3 INSTALLATION START OF OPERATION LINE POWER ON Before plugging in any connectors check the field cables referred to in the Connection Diagram C CT 3105 Remove the unit covers of CT 12K and make a visual check of the internal connectors subassemblies etc Turn the main circuit breaker CBl to OFF position Plug in the line supply cable to connector Jl after checking the voltage and signals of the power supply cable connector The line voltage indicator DSI in PSI should be lit indicating the line voltage at the main circuit breaker CBI When turning the main circuit breaker CB to the ON position the following shall happen with the monitoring LEDs D4 and D5 on the processor board AI D4 red ON for approximately 5 seconds internal reset performed D5 green After D4 has turned OFF this will start blinkingat a rate of once per second software operates normally If LEDs D4 and D5 operate diff
155. if any of the circuits are faulty Trigger Breaks should open for 80ms every 12s permitting the line voltage to raise to approximately 90V for 80ms The Cloud Signal should be intermittently 120Hz typically 0 5 VAC to 1 5 VAC 160ms ON 160ms OFF for 3 seconds after the Trigger Break starting with an ON period 278 6 1 2 1 CHAPTER 6 TROUBLESHOOTING AND REPAIR If operation was faultless and a missing Cloud Signal caused the initial concern proceed to Paragraph 6 1 4 Cloud Detection Missing If one or both of the circuits failed to operate abort Recorder Test by pressing the ESC ESCape key FSK INTERFACE OPERATION IMPROPER OR MISSING No Message Check at Remote Receiving end With Receiving circuitry disconnected check presence of carrier with AC voltmeter Voltage should be in the O 1V 1 0V range If voltage is close to zero measure loop resistivity with an ohmmeter Resistance should be approximately 50 ohms with short line 1600 ohms with 10 mile line AWG 22 If not proceed to check the line Note If a terminal is connected ohmmeter may not give credible values With terminal connected attempt to open line with RETURN character If successful check that AUTOMATIC MODE is ON AUTO command If not set AUTO ON and CLOSE line If unsuccessful at any stage or messages are still missing proceed to check the Ceilometer At the Ceilometer Connect a Maintenance Terminal and observe if message
156. ignal Sample pulses D CR No 1234567 Storage 2 Gc ga uu e uuu of digitized value into buffer loc No 123456 Time us 0 25 4 842 893 1610 ty depending on laser freq Single pulse a y backscatter 1st pulse 2nd pulse 3rd pulse AA GN HAN L E and transfer Time s 0 Measur t oF emen UID cycle Processing Storage and output FIG 1 DIAGRAM OF INTERNAL CYCLES CT4 411 107 CHAPTER 4 FUNCTIONAL DESCRIPTION The actual subassemblies and modules involved in the measurements are see Dwgs A CT 3401 through ACT 3405 Processor Board Ref Designation Al contains the Amplifier Flash A to D converter Sample Adder and Memory Processor Program Memory and Read Write memory Laser Control circuitry and the Analog Monitoring section Transmitter Board Ref Designation A7 contains the Laser Diode and associated pulse energy circuitry including its voltage regulator Transmitter Optics Light Monitor Board Ref Designation A5 contains a downwardpointing photodiode for monitoring the laser power and associated filtering and amplifying circuits It also has a photodiode for monitoring sky radiation Receiver Optics Receiver Board Ref Designation A6 contains the silicon Avalanche Photodiode Receiver its Filter and a current to voltage Converter Preamplifier Subminiature coaxial cable W9 transfers the Laser Trigger pulse fr
157. ignals are okay and heaters RI and R2 have the specified resistivity see Section 6 2 10 then replace A2 Replacement Unplug Al and A3 disconnect all connectors and unscrew the four 4 screws holding the board to the board frame Unplug the board from the two 2 plastic standoffs and use pliers to press plastic springs Replace in reverse order Check that the switch positions SI ON 52 NORMAL Perform offset calibration as per Section 6 4 287 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 2 3 6 2 4 OUTPUT INTERFACE BOARD CTI 12 REFERENCE A3 Check supply voltages at test points Only 5V is on board regulated from 20V others are supplied via A2 A3 may be unplugged to verify the external supply Do a processor RESET and observe the results of the modem self test With a remote modem on check the carrier detect LED CD This should be ON LIT Check the Gifft RBC Recorder interface with command RECT in AUTO OFF MAINTENANCE MODE The Trigger Break should be visible at the RBCT LED and audible as a relay click click If this is not the case check the input at test point J6 7 this should be HIGH for 80ms every 12s If not the fault is external During the break if a recorder is connected the voltage between test points J9 JIO shall rise to 90V approximately The cloud signal can further be checked by observing LED RBCE test point J5 9 120Hz intermittent and test point J5 7 HIG
158. in 580 mm Dept ax ok ae s 16 5 in 420 mm Weight Total 156 Lbs 71 kg Excluding Pedestal 135 Lbs 61 kg 1 2 2 POWER 115 V 10 45 Hz to 65 Hz 800 W 7 A max 220 240 V optional Power connector 26482 type MS 3110E12 3P male Mating connector type MS 3116F12 3S or equivalent 1 2 3 OUTPUT INTERFACES 1 2 3 1 Output Interface Connector J3 MIL C 26482 type MS 3112E12 8P male Mating connector type MS 3116F12 8S or equivalent Circuit A B FSK Interface Circuit C D Recorder Trigger Break Circuit E F Recorder Inscription Cloud Signal Circuit G Equipment Ground All signal circuits are non polar symmetrical electrically floating to overvoltage protection rating 300V 500V Overvoltage Protection in each circuit Primary Noble Gas Surge Arrester Secondary Wirewound Resistors and Transient Zeners or Diodes CHAPTER 1 GENERAL INFORMATION 1 2 3 1 1 Bell 103 FSK Interface Bell 103 standard Frequency Shift Keyed FSK Full Duplex Modem Interface for serial Asynchronous Data Interchange Baud Rate 300 Answer Mode Standard Frequencies Mark 1 2225 Hz space 0 2025 Hz Originate Mode Optional Signal Level 6 dBm 0 3 V into 600 Ohm standard Jumper Selectable O 3 6 9 21dBm optional Distance to Operate 0 10 miles 0 16 km with AWG 22 0 35 mm2 unshielded twisted pair Standard Character Frame 1 start bit 8 data bits No Parity 1 stop bit St
159. in the Technical Description Unplug W8 at 522 Select Single Pulse 430ns AMSI by jumper sets J15 J18 J23 respectively 285 CHAPTER 6 TROUBLESHOOTING AND REPAIR Simulated Cloud Base should now be detected at ca 6500 ft When Double Pulse is selected by J15 two ranges of signal should be detected one at 3300 ft the other at 9700 ft the latter qualifying as a cloud base With a terminal connected open line for dialogue Enter Maintenance Mode AUTO OFF and command the following GAIN 0 MEAS Device is Busy for 1 Second After This TAB O Now the signal response will be output to the terminal showing bit numbers for each range gate level Check that the output is approximately stable 14 17 for the whole range excluding the simulated base level s For reference see the top figure in CT 3536 TP Response in Sample RAM If the output numbers are within 20 of those in the figure AMSI proceed to check with the higher gain commands GAIN 2 MEAS TAB 0 If the readings are okay also for GAIN 2 figure below the top one the Amplifier Converter and Sequence Control most probably are in order and LRUs other than Al should be suspected When returning back to normal operation set jumpers in J15 J18 and 523 to their original positions replug W8 to 522 and command AUTO ON Replacement of Al Unplug W8 at J22 and W9 at 526 Unplug AI and replace by spare Replace W8 and W9 Check that jumpers are set accordi
160. inal through A2 and Al and OV with terminal connected Use repeated RETURN characters These should produce a LINE OPENED message followed by one prompt arrowhead for every RETURN Observe RXD and TXD voltages by oscilloscope to swing from below 3V to above 3V If an FSK interface is not available check in addition to the above that the Output Interface Board A3 does not short a signal unplug A3 card temporarily and extend the signal levels tracing to Processor Board Al Observe Paragraph 6 2 1 280 CHAPTER 6 TROUBLESHOOTING AND REPAIR Replace board or harness if found faulty Note that a message being transmitted cannot be interrupted 1 e dialogue commencement may be delayed for this reason CLOUD DETECTION MISSING If both Gifft RBC Recorder and FSK or RS 232C data messages are available check that they agree If not proceed to the corresponding Paragraphs If clouds are present and within range without a doubt check that Message contains no alarms If yes go to Paragraph 6 1 1 Parameter settings are intact If not restore them LLAS value is not significantly lower than LNOR value nor significantly higher If so proceed to check A7 5 and Ceilometer lenses or windows are not obstructed by anything If so clear obstructions Noise values and gain selection are credible 1 e during bright daytime and clouds present gain is 0 and noise 1s 4 10 and in darkness and twilig
161. interface The 9V supply voltage is produced from the 12V DC supply by first creating a 153 6 kHz AC voltage transistors Q6 and Q7 and rectifying it diodes D10 and DII The voltage passed on to the display is formed by first limiting the negative voltage to 5V by means of a zener diode The trirmner R22 enables adjustment of the display biasing voltage within the range 5 1V to 5 1V Connection Signals Connector El terminals interface signals colors and the MS connector pins of the standard interface cable of CTH 12 are Table 4 Signals of CTH 12 El MS Terminal Signal Color Pin Explanation Not Used 2 TXD Brown B Data In To Terminal 3 RXD Red C Data Out From Terminal 4 Not Used nmm ences 5 Not Used 6 FLAG Blue G Signalling of Maintenance Terminal Presence GND Green F Common Ground 8 12 White Power Supply 9 Not Used 10 Not Used ior eee eee Table 4 Signals of CTH 12 246 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 3 Jumper Settings The following Table presents the Internal Jumpers of CTH 12 Table 5 Setting of the CTH 12 Jumpers Symbol Connection Function J4 None RS 232C Levels Standard 1 2 Not Used J5 1 2 RS 232C Levels Standard 2 3 Not Used J6 l 2400 Bd Baud Rate 2 2 3 3 4 1200 Bd Baud Rate 5 300 Bd Baud Rate Standard J7 1 2 4 5 Normal Operation Standard Others Reference Operat
162. ion Testing J9 None Normal Operation Standard 1 2 Reference Operation Testing Table 5 Setting of the CTH 12 Jumpers 4 3 9 3 4 Operation Testing The operation of the CTH 12 Maintenance Terminal is easily tested with the internal on board jumper settings Test connector J10 provides most of the major operational signals for the testing These signals are listed 1n Table 6 Jumper J9 internally connects the TXD and RXD signals for testing purposes Test connector J7 provides access to the character coding at the input pins TBR5 TBR6 and TBR8 of the UART 247 CHAPTER 4 FUNCTIONAL DESCRIPTION The self contained functional test of the CTH 12 is performed as follows Connect J9 signals TXD and RXD are connected together No external RS 232C I O source shall be connected to the CTH 12 Connect J7 Pins 2 3 4 5 Press Symbol F on Keyboard Connect J7 Pins 1 2 5 6 Press Symbols 0 9 and A F The display of CTH 12 shall now contain the following characters 0 1 2 3 4 5 6717 8 9 213 lt gt If such a string does not appear In the display the operational test has failed and the CTH 12 needs service Table 6 Test Connector J10 Signals J10 Pin Signal GND removed none 3 5 4 E Signal Enable for the Display Subassembly 5 DA Signal Data Acknowledgement of Keyboard Encoder 6 9V I TRO Transmitter Register Output from UART 6 Baud Generator Frequency 16 x Baud Rate RR
163. ion of laser cloud ceilometer CT 12K requires a concrete foundation and a set of cables to establish the operation Some basic information is needed to guarantee the proper start up of the instrument It is important to carefully follow the installation instructions TRANSPORTATION CONTAINERS The CT 12K is shipped in two containers the larger one containing the Ceilometer without Pedestal and the smaller one containing Pedestal Maintenance Terminal CTH 12 Field Site Spares Kit and installation accessories The main container is provided with unpacking and re packing instructions which are to be observed Containers are suggested to be saved for eventual later transport use Repacking instructions must be carefully observed in that case since the heavy Main Equipment Assembly may otherwise be damaged during transport ORIENTATION The receiver side of CT 12K should preferrably be oriented away from sun e g in the northern hemisphere towards the north and towards the south in the southern hemisphere This will reduce noise of sunlight REQUIREMENTS For mechanical installation requirements refer to Installation Drawing U CT 3282 For electrical connections refer to Connection Diagram C CT 3105 Suggested Cable Dimensions Line AC Supply Cable Standard 3 pronged power cord 3 x min 0 75 mn AWG 18 RS 232C Interface 22 Gage Stranded conductors twisted subset of Maintenance pair with foil shield and drain Termina
164. ion of the Display Initialization Circuit The display module is automatically initialized when power is turned ON The following commands are carried out during initialization 1 Memories Cleared 2 Operating Mode Set as Follows DL 1 O bit bus N Single Line Display F 5 0 0 5 x 7 Display Mode 240 CHAPTER 4 FUNCTIONAL DESCRIPTION 3 Display ON OFF D 0 Display OFF C 0 Cursor Not Visible B 0 No Flashing 4 Selecting Input Mode 1 Address Incrementation I O S 0 No Transfer 5 DD RAM Addressing Selected Note If power for the system is connected incorrectly as far as the display is concerned it is possible that the display 1s not initialized Repeat the connection if necessary 241 CHAPTER 4 FUNCIIONAL DESCRIPTION UPPER 4 BIT HEXADECIMAL 225 aS bp A eee Dee Lo 401 0000 2010 Mit 0100 Cio 1010 1011 1100 j 1101 nm 4 bil xxxx CO 10 0110 Ort tt xxxx00 11 OWER 4 BIT HEXADECIMAL Contents of Character ROM 242 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 8 3 Display Control The 8 bit parallel data received from the UART receiver is taken to the display module as follows The seven 7 lowermost bits are brough directly to the 8 bit bus of the display whereas the upper most data bit RBR8 is used to control the RS input of the display The RS input signal determines whether the information received from the data bus is inter
165. is a portable near pocket size hand held terminal operating over a wide temperature range It is built into a plastic case with a lid covering the display and the keyboard when not in use It operates with standard RS 232C signals The operating power is supplied from the Ceilometer The terminal contains a 16 character LCD display that supports the full ASCII character set It also contains an electro Iuminence light for night readability and a heater element for low temperature operation both controlled automatically by built in Sensors The keyboard is a 16 character hexadecimal pad Specifications Type CTH 12 Part Number 2690 Supply Voltage 2 DC 20 Current consumption 50 with heater on 250mA Operating Temperature Range 40 50 C 40 120 F Mechanical W X D X H Dimensions 5 0 X T X 2 0 inches 127 X 196 x 5 millimeters Cable 1 2m 4 ft Interface RS 232C level RXD TXD Baud Rate 300 Baud Standard Data Frame 1 Start Bit Standard 8 Data Bits Polarity of Unused 8th Bit MSB Same as Stop Bit 1 Stop Bit No Parity 232 Display Night Readability Heating Keyboard 233 CHAPTER 4 FUNCTIONAL DESCRIPTION 16 Character Alphanumeric LCD 5 x 7 Dot Matrix Electro Luminence Light Backlighting Foil Resistor Temperature Sensor Controlled Heating ON Temperature 12 C 10 F Heating OFF Temperature 2 C 28 F Hea
166. ises SQO high and so SQPHI is started The next time the Counter overflows both U50 12 and 6 are high Thus the next clock raises SQI high Prior to this transition U53 12 applies low state to U32 9 CLD which results in Load action on U32 by the rising edge of CCK at the beginning of SQPH3 The last time the Counter overflows the outputs of all three AND gates are high Now U50 8 applying high state to the K inputs of the Flip Flops achieves toggle action on the next falling edge of the clock and so both SQO and SQI return low The Sample RAM U25 is a 2 kB static CMOS RAM of the type HM 65161 mounted on socket It is a fast device doing data access in less than 70 ns The RAM enables its output buffers onto RDO 7 when RSM pin 20 is low It loads in the data on RDO 7 when WSM pin 21 is low The device is continuously activated by its chip select pin 18 grounded The RAM MS address pin 10 grounded permanently disables the high order half of the memory The Read Write Decoder and Control block is composed of the three NOR gates of U44 and AND gate U46 12 the NAND gates U53 8 052 8 and inverters U45 10 12 Read Decoding is made by U44 12 producing its output RSM high when CBO CBI U42 14 13 are low Low active Read RSM is generated by inverter U45 12 During SQPHO RSM is disabled as CBO CBI are high During SQPH3 SQI high disables RSM Write Decoding is carried out by U46 12 U44 8 and U53 8 During SQPHO
167. isplay heating arrangement is necessary in conditions of extreme cold The heater element is attached to the steel frame of the display by self adhesive tape for immediate conduction of heat to the LCD module The method avoids heating the terminal itself and a sufficient temperature rise about 40 C is obtained using a power of approximately 2 5 W This keeps the display operating down to an ambient temperature of about 60 C On the other hand display temperature must not be allowed to rise above 60 C A temperature sensor UI in the heater control circuit has been provided to measure the temperature inside the case is a semiconductor sensor giving an output voltage proportional to temperature 10mV K 244 CHAPTER 4 FUNCTIONAL DESCRIPTION Circuit U3 forms a comparator connecting base current to the Darlington transistor Ol when the voltage over the temperature sensor UI is less than the voltage produced by the voltage divider RI5 and R16 hysteresis of approximately 100mV at the comparator brought about by resistor R14 corresponds to a temperature of approximately 10 C The nominal heater switch on and switch off temperatures are Switch on 12 C 10 F Switch off 2 C 28 F Ql base current is determined by resistor RIO and the base emitter junction of QI is protected against negative voltages by diode D2 Heating power is adjusted by resistor R3 The heater element resistance is 50 ohms With the R
168. l Interface wire 17 CHAPTER 2 INSTALLATION Output Interface Cable 22 Gage stranded conductors 3 Twisted Pairs Preferred twisted pairs with foil shield and drain wire Minimum working voltage 200 volts Window Conditioner Cable 6 x min 0 75 AWG 18 Part of Window Conditioner supplied Maintenance Terminal Cable 8 x 0 75 mm AWG 18 Part of Maintenance Terminal supplied 2 2 SITE PREPARATION 2 2 1 FOUNDATION The suggested minimum dimensions for the foundation are found in Installation Drawing U CT 3282 Mounting hardware is included with the Pedestal If a new foundation is laid the Wedge Bolts and Foundation Screws 4 each are suggested to be cast into the concrete so that 1 to 2 inches 25 to 50 mm of the threads stand above the surface If an existing foundation is used four holes of Diameter 0 5 inches x 6 5 inches 12 mm x 165 mm 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 18 2 22 2 2 3 CHAPTER 2 INSTALLATION CABLING All the cable connectors are located under the equipment base and are referred to as Jl J2 J3 and The location of the connectors are found in Bottom View Drawing ACT 3406 The connector signals and connector types are found in the Connection D
169. l UI5 15 TB Bl E1 8 9 A2 15 15 Al Ul5 14 Connectors BIE1 8 9 W2J2 PSIJ2 PSIP2 A2Jll AIJI Cables W2 BIWI REPLACE NON CONDUCTING PART IF NO FAULT IS FOUND BUT ALARM PERSISTS SUSPECT AI AT CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 1 1 4 3 6 1 1 4 4 6 1 1 4 5 Temperature Alarm with Credible Values If ambient temperature is close to 120 F 49 C exceeds solar radiation Is intense check that the 70 Window Conditioner Blower Bl operates 158F heating is OFF If not so then proceed to check the Window Conditioner TB Probable Cause exceeds 80 C Window Conditioner Blower does not operate 176 F Heater does Proceed to check Window Conditioner Of TB TE Probable Cause exceeds 40 C Window Conditioner Blower does not operate 729 Heater does Proceed to check Window Conditioner Gifft RBC Recorder Signals Alarm If the PROJ lamp of the Gifft RBC Recorder signals an alarm by blinking or not being lit at all connect a terminal to the Ceilometer and proceed according to Paragraph 6 1 1 Gifft RBC Recorder Operation Improper or Missing First check that Ceilometer is in mode AUTO ON If yes then proceed At Recorder site Command Ceilometer to output Recorder test pattern commands AUTO OFF RECT Observe Recorder and Voltmeter or Oscilloscope connected to the Trigger Break and Cloud Signal inscription to determine which
170. larm Limits Alarms are reported as asterisks immediately after the alarming value of the Status Message Voltages are in volts they produce alarms if they are less than the corresponding Alarm Limit signs disregarded Temperatures are in degrees centigrade Celsius They produce alarms if they exceed the corresponding Alarm Limit Laser Power is in units of Monitor AD Converter increments It produces an alarm if it is less than the Alarm Limit See also Note 2 Sky Light Power Alarm Limit is of no practical significance in normal conditions since the numerical range 1s O 255 Ground is monitored for self test purposes and produces an alarm if 1t exceeds the Alarm Limit In addition the Monitor A to D Converter internal reference 15 monitored to be 125 131 producing an AN MONITOR ERROR message if out of limits An Alarm Limit Message is obtained by commanding ALIM Specific parameters are changed by adding the corresponding reference designation with standard terminal use or the number code of Appendix 1 CTM 12 Monitored Parameters with Maintenance Terminal CTH 12 and the new limit value Interrogation of individual values is not provided NOTES 1 Alarm Limit changes will not be maintained over a power outage or Reset but a return to default values will take place in these instances 2 The LLAS default alarm limit is 0 7 LNOR and will thus be individual as is LNOR Below are the syntaxes for the ALIM m
171. le Time 1 2 us Instruction Execution Rate 0 83 MIPS 64 kB EPROM 8 kB Static RAM optional 16 kB 1 kB Nonvolatile EEPROM CPU Reset after 5 seconds inoperation FUNCTIONAL DESCRIPTION I O Monitor Serial Communication Speed Frame I P Levels O P Levels Protection Modem Control O P Gifft RBC Recorder O P Solar Shutter 132 LO Signal Interfacing and Monitoring Section RS 232C I O interface for asychronous full duplex serial data mterchange One output TXD two inputs IRXD and MRXD not for simultaneous use 300Bd optionally std ranges 10 2400 Bd practicable 8 data bits 1 stop bit No Parity optionally any std 10 bit frame SPACE Uin lt 1 5V MARK Uin gt 4 5V SPACE 9 typical MARK 9V typical Typical withstanding 50V line transients 1 ms expo Further protection external Two logic level signals ALB loop back test when HI SOT carrier ON OFF Two logic level signals RBCE rec inscribe HI for MARK RBCT rec start HI for BREAK Logic level signal SSON solar shutter forced shut Heating and Window Conditioning Control O P Flag Inputs 133 CHAPTER 4 FUNCTIONAL DESCRIPTION HI Two open collector signals 60V 0 5 BON blower ON LO HON heater ON LO Two automatic Internal Heating control signals RELI REL2 11V 10mA 20W heating ON below 18 C RELI LO REL2 HI OFF above 26
172. ll be erased in approximately one week when exposed to direct sunlight 138 CHAPTER 4 FUNCTIONAL DESCRIPTION The Data Memorv U2 is an 8 k byte static CMOS RAM device type TC 5564 or equivalent mounted on socket Its chip select pin 20 is driven by A14 activating the device only when the RAM area of the I O address space is addressed Its output buffers are enabled with pin 22 driven low by RRO Writing is carried out by driving pin 27 low by RWO Provisions have been made on the board UI for another similar or 2 kB device The RD WR Decoder U9 is a double 2 to 4 line decoder device Low state on its pin 15 activates one of its Read strobe outputs Low state on its pin activates one of its Write strobe outputs The Watch Dog Timer consists of the 14 bit ripple counter U12 clocked by the RC oscillator 1011 8 RA7 5 6 C15 Counter reset pin 12 is activated via 1 2 3 by WDR generated by software If not reset the counter will count up until after 8192 clock pulses ca 5 seconds and it raises PRES high via diode DA2 15 2 thus resetting the processor For testing purposes Jumper J8 can be removed thus eliminating the Watch Dog The Reset circuitry consists of the three Schmitt trigger gates of U20 and some passive components During the PWR ON transition POR is low driving U20 3 high thus resetting the Processor via diode DA2 14 3 U20 11 produces System Reset RS low Via UII I 3 also the Watch Dog counter is reset T
173. lowing messages Identify it and proceed to check the corresponding LRU 268 CHAPTER 6 Message SKY MONITOR SUSPECTED AD MONITOR ERROR SEQUENCE ERROR INTERNAL HEATING SUSPECTED BLOWER HEATER ERROR SHUTTER CONTROL SUSPECTED TROUBLESHOOTING AND REPAIR Suspect LRU A5 A6 or Al AI A R2 Al or A2 PSI TSI or Al Kl A5 In case none of these applies command RESET or toggle switch AISI or turn power off on by PSI CBI for a moment Wait and observe one of the following messages Identify it and proceed to check the corresponding LRU Message EX XXXXX XX XX 1 OFFSET ERROR AMPLIFIER ERROR NOISE ERROR SEQ RAM NOT CLEARED SEQ PULSE COUNTER ERROR ANALOG MONITOR ERROR LASER POWER LOW SEQUENCE HALT MODEM ERROR EEPROM ERROR Suspect LRU Al Al Al Al A6 or W8 Al Al Al A7 5 or PSI Al A3 Al Al If no error message is obtained the fault may be intermittent Reset Ceilometer and observe for proper operation Note 1 X s may be any hex character O F 269 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 1 1 2 Status bit is 1 signalling Supply Voltage Alarm Connect a terminal to the Ceilometer Open line for dialogue and request Status STA The Status will contain one or more voltages being below the alarm limit refer to ALIM command pinpointed by an asterisk after the voltage value If voltage is within boundaries of table b
174. ls VAISALA TECHNICAL MANUAL OPERATION AND MAINTENANCE INSTRUCTIONS LASER CEILOMETER CTI2K VAISALA 100 COMMERCE WAY WOBURN MA 01801 PART NO 66 2292 COPYRIGHT VAISALA 1986 1987 1988 1989 ALL RIGHTS RESERVED This publication Contains proprretary Informacion end may Not be reproduced in any form without prior written permission of VAISALA The contents of instruction manuals are subject to change without d prior notice SAFETY SUMMARY The following general safety precautions must be observed during all phases of operation service and repair of this instrument 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 assumes no liability for the customer s failure to comply with these requirements NEVER LOOK INTO LASER TRANSMITTER WITH MAGNIFYING OPTICS The instrument is intended for operation in an area restricted from public access and pointing vertically up Whenever this is not the case care must be observed so as to prevent exposure to the laser beam through focusing optics Work area access by unauthorized persons during service operations must be prevented GROUND THE INSTRUMENT 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 pl
175. n line for commands 2 Use the commands for CT 12K operation monitoring or parameter setting 3 Close the communication line to return to normal operation The CT 12K ignores operator inputs unless the communication line is opened for commands The user should close the line after each session The line 15 closed automatically after a l minute time out period if no characters have been entered Before closing the line the system must be set to the proper operating mode AUTO ON If the system is left in Maintenance Mode AUTO OFF the automatic standard message output is inhibited Some of the commands can be used only in Maintenance Mode Section 3 5 86 3 53 NUMBER CHAPTER 3 OPERATION COMMANDS TABLE The commands available for the Maintenance Terminal are in the following table Several commands that can be entered from a standard RS 232C data terminal have been omitted from the Maintenance Terminal command set The TAB GRAP and MEAS commands are not necessary for maintenance and troubleshooting The commands are identified with the command numlbers instead of command abbreviations that are used with a standard data terminal In the table are listed o command number Command Table o parameter s 1f needed o corresponding abbreviation used with standard data terminal refer to Section 3 3 o description of the command o notes on use of the command ABBR DESCRIPTION C1 C2 C3 C4
176. nal clock in format hours HH 0 23 one or two digits minutes MM 0 59 one or two digits seconds SS 0 59 none one or two digits Spaces shall separate number groups Seconds may be omitted Time counting restarts from zero after each power down or Reset 75 CHAPTER 3 OPERATION 3 4 5 12 3 4 5 3 Syntax example ST MT gt TIME CR gt C24F 00 08 19 gt 24 00 08 19 gt TIME 12 34 CR gt C24B12B34F TIME IS SET gt C24 12 34 TIME gt next input next input DATE YYYY MM DD Interrogation and setting of the internal calendar in format Year YYYY Four Digits Month MM 1 12 one or two digits Day DD 1 31 one or two digits Spaces shall separate number groups Leap years are observed Date counting restarts from zero after each power down or Reset Syntax example ST MT gt DATE CR gt C25F 0000 00 01 gt 25 0000 00 01 gt DATE 1987 8 18 gt 25 1987138 18 DATE IS SET gt 25 1987 8 18 gt next input next input RESE The command inhibits all operation including Watchdog Refresh leading to a Reset and restart within approx 5 seconds See also START UP paragraph 3 4 3 76 3 4 5 14 CHAPTER 3 OPERATION Syntax example ST MT gt RESET CR gt 27 27 no activity delay delay start up messages start up messages CAL time Offset calibration command Suggested time is 120 240 seconds omitting it will prevent command execu
177. nals down to the millivolt region Drawing CT 3536 illustrates TP generation and signal response waveforms on each test point of the Amplifier also showing the jumper strapping alternatives and data response in the sample RAM The waveforms are typical and may vary some between different devices The Second Amnlifier Stage consists of the three transistors 8 6 and surrounding passive components Oll and Q8 make the amplifier and Q6 is an emitter follower buffering the output which connects to the Signal Buffer via capacitors C40 41 Input is biased by R48 49 to about 3 7 V level R43 and R41 are the emitter resistors for the latter bypassed by C54 and 61 to let through the AC Similar bypassing is done by C46 47 and Q8 collector resistor R35 D12 Schottky diode effectively clamps too high signal levels AC gain of the amplifier is determined by the ratio of the feedback resistor RA2 and emitter resistor R43 148 CHAPTER 4 FUNCTIONAL DESCRIPTION The Gain Selector is formed by Q12 FET transistors Q7 Q10 and some passive components The Gl control when high feeds base current through Q7 to Q10 which so applies 13V to the gate of Q12 This indicates that Q12 1s not conducting which leaves R42 the only path for feedback current and so high gain is selected Gain 2 With Gl low no base current is supplied for Q10 which so leaves Q12 gate floating Now Q12 conducts and R44 is connected in parallel with R42 so
178. neous 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 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 The CT 12K ceilometer digitally samples the return signal every 100 ns from O to 25 4 us providing a spatial resolution of 50 feet from ground to more than 12 500 feet above the surface 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 infinit
179. ng to specifications in the Technical Description Switch Power ON and check that Green LED starts blinking Set LNOR as described in Paragraph 6 2 6 Perform Offset Calibration according to Section 6 4 Check parameters according to 3 3 286 6 2 2 CHAPTER 6 TROUBLESHOOTING AND REPAIR UNREGULATED POWER SUPPLY BOARD CTS 12 REFERENCE A2 Verification supply Voltages Check suspect supply voltage AC input from PSI or TSI Check suspect voltage DC at A2 test points and connectors according to 6 1 1 2 Check voltage with and without loading If loading causes significant reduction check waveform with oscilloscope If full or half wave rectified form is observed replace A2 Signal Connections Trace signal connections from connector to connector with an ohmmeter and or oscilloscope to determine possible break Temperature Control Reiavs Check that switch Sl A2 16 in position ON Apply temperature differences between 10 F 80 F lO C 30 C with cold spray and fingers to Processor Board Al temperature sensor U16 Signals RELI and REL2 swing from approximately 12V to 12V when chilling from 80 F to 10 F first RELI then REL2 If relays operate the sound can be heard Feel the heat at Temperature Control Heaters and R2 The heating can barely be felt at simulated temperatures between 30 F 70 F 0 C 20 C but can be felt very well below simulated temperature 30 F O C If relay drive s
180. nitialize Maintenance Terminal CTH 12 when it is plugged in 37 CHAPTER 3 OPERATION 3 1 4 3 Notations and Abbreviations The following notations are used throughout Chapter 3 of this Manual ST MI CR ABC CAPITALS Y N Hex Standard Terminal or equivalent device communicating in USASCII Maintenance Terminal CTH 12 Carriage Return i e Return ie Enter terminates a line completes and actuates a command opens a closed line for dialog MT Character F Feed Operator action i e input to Ceilometer is underlined in this description output from ceilometer is not Space character One or more spaces must separate different parts of a command MT Character B Command Prompt is output by Ceilometer every time a command has been carried out and a new one may be input Maintenance Terminal MT will leave the last line of the previous command on display until the first character of the new command is input this clears the display Ceilometer does not distinguish between letter cases Output will be in capitals only Yes equals 1 with MT No equals 0 with MT Hexadecimal code 1 e 0 9 0 9 decimal A F 10 15 decimal 38 3 1 4 4 CHAPTER 3 OPERATION Line Closed Line Open The serial digital interface serves both for transmitting measurement data and for communicating e g maintenance information For separation the interface has two distinct stat
181. not the case replace A5 If the sun is shining then a suitably positioned mirror can be used instead of the lamp Solar Shutter Driver With D3 covered check that voltage at TP4 is 2V 0 1V Adjust at R13 if necessary Check that driver Q2 is fully conducting 1 solenoid is energized and flap is open If not check that force on signal SSON is LOW If it is replace A5 otherwise suspect Al A2 or W5 Check that processor control status is SHUTTER OFF Place an intense focused light above D3 Observe V TP2 to exceed 2V Observe V TP4 to decrease to approximately IV Observe the shutter to turn ON 1 de energize and release the flap to cover the transmitter lens If not check Solar Shutter Kl and replace faulty part Remove light Shutter should open Command SHUT ON and SHUT OFF in Maintenance Mode AUTO OFF Shutter shall follow If not check signal SSON If not HIGH or more after SHUT ON command check Al A2 or W5 Solar Shutter CTD 12 Reference Kl Solenoid resistivity should be approximately 40 ohms check Check mechanical parts Adjust or replace if necessary 289 CHAPTER 6 TROUBLESHOOTING AND REPAIR 6 2 5 Replacement of A5 Turn Ceilometer power OFF Release connectors Unscrew the two 2 screws holding board mounting block to Optics Frame Replace new board in reverse order Turn Ceilometer ON Observe commencement of normal operation Replacement of KI Follow installation pro
182. nsitivity 1s approximately 0 4 A W Pointed directly toward the sun in a clear atmosphere sky approximately 1200 W m2 produces a current of l ImA typically A clear blue sky produces a current of lOu A typically and indoor conditions produce less than luA The current produced by the sky light in photodiode D3 is converted to a voltage across resistor R4 21k4 and filtered by capacitor C3 IOuF which yields a time constant of 214 ms The voltage is buffered by voltage follower 1 4 Ul the output of which can be measured at test point TP2 It is fed to the Solar Shutter Driver circuitry and to the board output at connector Jl pin 9 It is referenced as LSKY and may be monitored as analog channel 9 monitor command ANY or AN LSKY The voltage range of the monitor A D converter of the processor board 0V 5V will yield a useful sky light power range of 0W m2 50W m2 based on assumption of clear direct sun being 1200 W m2 CHAPTER 4 FUNCTIONAL DESCRIPTION Solar Shutter Driver The voltage output of the Sky Light Monitor is brought to comparator 1 4 Ul pin 13 Its trip voltage is set by trimpot to a value which is measured at test point TP4 Standard value is 2 0V corresponding to a sky light power of approximately 32 W which provides for adequate margin with respect to all sources of inaccuracy regarding the protection of the laser transmitter against focused sunlight from zenith Positive feedback resistors RIO and RII cr
183. o 12 650 ft This data is now transferred by the processor to its Read Write memory area for the actual processing and the Sample Summing Memory is cleared for the next acquisition cycle Before the next acquisition cycle starts the processor checks the average laser power measured by the Laser Power Monitor during the previous cycle This is done with the Monitor A to D Converter by selecting the channel in question by one of the processor tasks operating concurrently with the acquisition cycle storing the value in Read Write memory Based on the laser power value measured a new value for the pulse frequency is calculated to keep average laser power as close as possible to the nominal value without exceeding it Average laser power is thus controlled automatically by adjusting the pulse repetition rate Also before the next acquisition cycle begins the processor checks the measurement signal and noise levels and selects the gain to be used for the next cycle High gain is desirable but the active range of the A to D converter must not be exceeded The processor then starts a new measurement and data acquisition cycle and commences to process the data of the previous cycle concurrently with new data being gathered A diagram summarizing the different operational cycles is shown in Drawing 4411 106 CHAPTER 4 FUNCTIONAL DESCRIPTION Time ws 0 010203 Laser trigger pulse Laser pulse AAA Backscatter s
184. o receive commands Operating Voltages Check that the following voltages are inside limits J6 8 5 0 0 25V 5V Logic Supply 5 10 122V 0 8 V 12V Interface Supply J5 9 12 2V 0 8 V 12V Interface Supply J9 5 90 0 5 9V Flash ADC Supply J14 2 12 7V 0 8 V 13V An HI Supply J19 6 12 7V 0 8 V 13V An HI Supply J19 3 0 3 V 6V An LO Supply J19 4 61V 03 V 6V An LO Supply J6 7 5 0V 0 05V V5 Mon ADC Ref J9 4 83V 0 1V RP Flash ADC HI Ref J9 3 0 05V RC Flash ADC LO Ref J9 2 09V 0 1 V IN Flash ADC Input J16 10 71V 03 V 7 1 Level Shifter Source J16 9 19 0 3V 1 9 Level Shifter Return J19 7 43V 03 V AT2 Amp Test Point 2 J19 5 30V 05 V ATI Amp Test Point 1 All the op voltages are on board regulated Their source supplies can be checked from the STATUS message Al may also be unplugged to verify the source supplies on A2 5V and 12 are fed via A2 to A3 which may overload them Unplug A3 to detect this 282 CHAPTER 6 TROUBLESHOOTING AND REPAIR CPU Status Observe the LED indicators on Al Green LED should be blinking once a second and Red LED should be dark If not so check that 5V and its source supply 10VD are inside limits If they are replace AI Error Messages Concerning Al Internal Onerations Reset the Processor and observe one of the following messages AD MONITOR
185. of one PXHV 140 P10R 10 2 MRHV 382 data item at SIGNAL STATUS time LLAS 155 LSKY 1 GND 0 TEMPERATURE STATUS TL 30 TE 20 TI 34 TB 22 67 CHAPTER 3 OPERATION 3 4 3 HEATER OFF BLOWER OFF AUTOMATIC MODE GAIN 2 i LASER FREQUENCY 3 LASER FREQ 3 gt next input A gt LASER FREQ 3 next input START UP At start up a series of self checks are made and reported through the Digital Interface followed by a Status Message The format should be as follows ST MT VAISALA CT12K VERSION 2 42 SN 97023 V2 42 87023 DATA MEMORY OK DATA MEMORY OK SEQUENCE OK SEQUENCE OK MODEM OK 2MODEM OK EEPROM OK EEPROM OK CT12K STATUS CT12K STATUS 00 0000000000 forwarding with POWER STATUS F or C output 8 5 201 21 1 M201 20 4 P25V 27 3 one data item M20A 20 6 P20A 19 3 P12M 12 9 P10X 9 8 at a time PXHV 140 P10R 10 1 380 SIGNAL STATUS LLAS 209 LSKY 0 GND 0 TEMPERATURE STATUS TL 30 TE 18 TI 32 TB 20 HEATER OFF BLOWER OFF AUTOMATIC MODE GAIN 0 LASER FREQUENCY 0 LASER FREQ 0 A NOTES 1 With MT message will not exit automatically Use Key to Abort 2 Last digit of software revision identification 2 42 may change as a result of minor improvements not in conflict with the content of this manual 68 CHAPTER 7 OPERATION ALARM LIMITS The internal voltages temperatures and light power levels reported in the Status Message are monitored against A
186. oltages capable of causing death are present in this instrument Use extreme caution when handling testing and adjusting 1 11 11 AMENDMENTS TO CEILOMETER CT 12K TECHNICAL MANUAL REVISION E SEPT 1989 AMENDMENT NEW AMENDMENT DESCRIPTION OR NEW DATE NUMBER REVISION PARAGRAPHS AFFECTED SOFTWARE EFFECTIVE 111 Please note that the following pages without text or diagrams were intentionally left blank 11 X 2 12 13 14 16 28 29 30 34 91 92 116 118 212 222 224 256 257 258 260 263 264 266 302 303 304 CHAPTER CHAPTER CHAPTER CHAPTER TECHNICAL MANUAL LASER CEILOMETER CT12K TABLE OF CONTENTS Safety Summary Amendments to this Manual Table of Contents List of Drawings and Illustrations List of Tables GENERAL INFORMATION safety and Handling Specifications RBC Angle Height Table INSTALLATION General Site Preparation Start of Operation Performance Verification Drawings OPERATION General Standard Outputs Parameters and Operation Modes Performance Monitoring and Alarms Operation with Maintenance Terminal CTH 12 FUNCTIONAL DESCRIPTION Operation Principles Technical Description Module Descriptions PAGE CHAPTER 5 5 1 22 2 9 CHAPTER 6 6 1 6 2 6 3 6 4 PERIODIC MAINTENANCE Monthly Check of Message Alarms 90 Day Check of Window Cleanliness and Cleaning Procedure Monthly Check of Window Conditioner Blower TROUBLESHOOTING
187. om Processor Board to Transmitter Board Subminiature coaxial cable W8 transfers the preamplified backscatter signal from Receiver Board to Processor Board Ribbon Cable W5 transfers the Laser Power Measurement signal from Light Monitor Board to Unregulated Power Supply Board A2 Unregulated Power Supply Board Ref Designation A2 tranfers the Laser Power Measurement signal to Processor Board Monitor A to D converter 108 2 252 CHAPTER 4 FUNCTIONAL DESCRIPTION The Output Interfaces The Output Interfaces of the Ceilometer are Ref Block Diagram CT 2295 RS 232C Interface RS 232C interface of CTS 12 A2 is mainly for maintenance and service purposes routed to the Equipment base connector J4 with internal cablings FSK Bell 103 Interface Standard modem interface is provided by CTI 12 A3 one line pair routed with internal cablings to the Equipment base connector J3 Gifft RBC Recorder Output Interface for Gifft RBC Recorder is provided by CTI 12 A3 two line pairs routed with internal cablfngs to the Equipment base connector J3 The FSK and RS 232C interfaces are internally combined into one serial two way processor interface so that outputs from the Ceilometer are identical at both interfaces Inputs from the two interfaces are OR ed so that any one may serve as input simultaneous inputs are forbidden the latter lead to erroneous input characters The RxD and TxD signals are connecte
188. one decimal preceded by minus sign if negative Degrees Celsius OF FS Offset of zero signal relative to Data Table minimum 0 in units of ADC increments Two digits two decimals XX algorithm related internal processing information 2 digits PP A two digit number representing calculated extinction coefficient values of the ten lowest range gates 0 500ft This two digit number will determine if the obscuration is ground based Data Line Format HHD D D D D CR LF Data scaled to hexadecimal number O FE decimal 0 254 Overflow indicated by FF Leading zero replaced by space character Data values are presented for each 50 ft range gate Height of the first value in the line in thousands of feet Two digits leading zero replaced by space Twenty 50 ft values per line starting with 0 ft next line 1000 ft 13 lines altogether Last line 12000 ft has 10 values 47 CHAPTER 3 OPERATION Compression and Scaling The data item 1s compressed and scaled according to the following formula DD 50 x In RAWDATA MINV 1 where DD is the data item for a particular range gate in 2 digit hexadecimal format In symbolizes the natural logarithm RAWDATA is the raw data value measured for the range gate in question MINV is the smallest raw data value measured The raw data value differential is retrieved with the following formula RAWDATA MINV 25 1 NOTE The data values
189. one have been transferred from the Sample Buffer Memory to consecutive locations in the Sample Summing Memory When the second laser pulse 1s transmitted the backscatter signal from that is digitized exactly the same way as that of the first one When done the values in the Sample Buffer Memory are added by the Sample Adder to those of the first pulse and the sums are stored in the Sample Summing Memory in consecutive locations 105 CHAPTER 4 FUNCTIONAL DESCRIPTION In this way the operation proceeds until the end of the preset time Now the 254 locations of the Sample Summing Memory contain the sums of thousands of samples arranged by height If the number of pulses has been for instance 10 000 a useful signal 1s 10 000 times stronger than that of one pulse while normal random white noise is only 100 times stronger according to the laws of probability The improvement in signal to noise ratio is thus 10 000 100 2 100 For instance a signal with an instantaneous amplitude one tenth of the RMS value of the noise will now be ten times the RMS value of the noise Noise is not all bad however With the aid of noise a signal that is a fraction of the A to D converter resolution in magnitude can be measured with an accuracy far exceeding this resolution After this sampling digitizing and summing process the Sample summing Memory now contains a raw profile of the received backscatter power with 50 ft resolution from 0 t
190. ormed WARNING 2 If clouds or obscuration exists beween the Ceilometer installation height and the level of interest e g runway the Ceilometer output will not be representative of the sky condition situation at the level of interest 63 CHAPTER 3 OPERATION RMOD Recording MODe Controls the presentation of non cloud obstruction of the Gifft RBC Recorder output included if ON See also 3 2 3 BMOD Base MODe Controls the presentation of a second cloud height and cloud penetration in all outputs maximum amount of output data available if OFF See paragraph 3 2 EMOD Extinction MODe Controls the availability of extinction normalized inverted range gate data with Digital Message No 3 see Paragraph 3 2 Extinction normalized data available if ON ON setting seen as Digital Message Status Line 1 bit Sy 1 CONF CONFiguration Determines if the output is feet F or meters M and tells the software whether a Solar Shutter is installed Y or not N The command is interactive asking the operator above questions No CR is needed for input of configuration parameters Meters setting seen as Digital Message Status Line 1 bit S8 1 SEND SEND Selects Digital Message No 2 or 3 for output AUTO AUTOmatic mode Sets the ceilometer in Automatic Mode which is the normal operating mode SERN SERial Number Arbitrary serial number option Range 0 999999 Only numericals allowed Stored in the Proce
191. place fuse 1f blown Remove loading 1f fuse repeatedly blows Suspect A2 if fuse blows without load except for PXHV and MRHV suspect PSI Replace subassembly in question if identified as cause of fuse blowing Suspect A2 if voltage at test point Is low and AC input 15 okay except for PXHV and MRHV suspect PSI Suspect PSI if single or a few AC inputs are low and line input is above 103 VAC except for P25V suspect If PXHV at PSIJ8 is above the limit but alarm persists check GND connection through W9 and replace W9 or part with bad connector If MRHV at PSIAI TPI TP2 is above limit but alarm persists check GND connection through W8 and replace W8 or part with bad connector If all voltages are okay but alarm persists suspect Al If line voltage is below 103V a problem may exist with the line voltage Check the line for proper operation 212 6 1 1 3 6 1 1 3 1 CHAPTER 6 TROUBLESHOOTING AND REPAIR Laser Power Low Alarm Laser Power LLAS 1s close to zero Check to see that Supply Voltages are Okay Nothing prevents the Light Monitor Board 5 photodiode Dl from seeing the lens e g solar shutter The laser normal LNOR parameter value has been entered properly and is the same as the factory calibrated value marked on the Transmitter Board Verify LNOR with commands LNOR or PAR See Section 3 3 Voltages and waveforms of transmitter board A7 are correct See Section 6 2 7 If not rec
192. placed before the CB s to indicate whether power is applied regardless of the state of the breakers Circuit Breakers CBl and CB2 double as ON OFF switches and circuit protectors The dual pole configuration enables the use of a floating or non specified line supply supplies the Ceilometer equipment and connects power to Terminal Block J5 where the over voltage protectors R2 and R3 are located 1 e Metal Oxide Varistors From J5 power is divided to internal transformers Tl and T2 and via J3 to the external Temperature Control Transformer In 115V operation of all transformer primaries are connected in parallel 43737 Window Conditioner Control Circuit Breaker CB2 supplies line power to the contacts of relays and K2 and from these to the output connector J2 and K2 are controlled by signals BLOWER ON BON and HEATER ON HON from connector P2 Kl and K2 are active when BON and HON are at ground potential respectively The relay contacts are so arranged that heating cannot be supplied unless the blower is ON The Window Conditioner monitoring temperature sensor signals TB and TB are connected via PSI from connector J2 to connector P2 4 3 7 3 3 High Voltage Outputs The High Voltage Transformer 2 secondaries are connected via fuses Fl and F2 to High Voltage Power Supply Board PSI Al Fuses Fl and F2 values shah be 60mA 1 16A when using 0 25 x 1 25 inch fuses and 50mA when using 5 x 20 millimet
193. preted as a control command or as character data RS RS 0 Control Command Character Data The uppermost data bit DB7 of the display bus is controlled by a separate register U7 provided with separate set and reset control commands See Section 4 3 9 3 1 8 4 The data read timing signal E is derived from signal DR of the UART received via circuit U6 12 The signal is also taken to test connector J10 pin 4 In its normal state signal E is the same as signal DRR inverted In addition to inverting the signal DR OR gate 6 provides two safeguards Further passage of an extra DR signal generated during power up is prevented by holding by means of signal MR signal E LOW for the duration of the initial reset function Also if a character received from the serial data path is faulty and FE fault is created 1 the stop bit is not found at the correct point this character is not sent to the display because the DR pulse is prevented by signal FE from reaching E In principle it 1s possible to read the contents of the memories of the display module This feature however cannot be used to advantage in the CTH 12 Also the R W control input is permanently connected to position W so that only data writing into the display module memories is possible 4 3 9 3 1 8 4 DB7 Control Logic The most significant data bit RBRS8 of UART receiver is used to control the RS input of the display Separate set and reset commands are
194. put The forced OFF state is inhibited via the FSK or RS 232C serial line by sending two subsequent ACK characters Control F 06 hex to the Ceilometer After this the normal control will resume operation and the heater may be turned on within 15 seconds Syntaxes ST MT BEL BEL Cntr G Cntr G equivalent Window Conditioner Heater shuts OFF within 20 ms Next digital message status BIT 510 ACK ACK Cntr F Cntr F no equivalent Window Conditioner Heater is released to be turned ON if other conditions call for it Next digital message status BIT S10 0 43 CHAPTER 3 OPERATION 3 2 STANDARD OUTPUTS 3 2 1 DIGITAL MESSAGE NO 2 3 2 11 General This message contains detailed range gate data and internal monitoring data for the most important variables Message is output automatically every 30 seconds in Automatic Mode when line is closed Activation is done with command SEND 2 This cancels any previous message activation only one digital message may be active at a time The following is the command and Ceilometer response omitting the parameter 2 will cause the current selected message to be announced ST MT gt SEND 2 CR gt C3IB2F AUTOMATIC MESSAGE 2 AUTO MES 2 gt next input gt _ next input The Message number selection will remain in effect over a Restart or Power down Message can be output with command MES see Section 3 4 2212 Format STXCRLF s
195. puts are in high impedance state When no key is being pressed all line inputs are ones ls this being affected by the internal pull up resistors 234 CHAPTER 4 FUNCTIONAL DESCRIPTION Thus for example when key 0 is pressed and while scanning proceeds column Cl state goes LOW and closure of the switch pulls down the line output signal state This interrupts the scanning activates the contact debounce circuit and locks up the other line output states The key code transmitted is a combination of the counter s stopping value and the decoded line s input value When the operating time of the debounce circuit 1s used up the data ready pin state goes HIGH In the presence of contact bounce key scanning goes ON and the debounce circuit is reset Only when the contact has been closed over a set period of time it 1s recognized as a key depression and the data 1s locked 4 3 9 3 1 3 Keyboard Codes Codes corresponding to the keyboard keys are shown in Table 1 The codes have been selected so as to correspond to ASCII codes as regards the keys from 0 9 Table 1 Key Codes KEY HEX ASCII 30 37 32 34 35 36 37 38 39 3B 3D 1 DW 09 PR O 3E Table 1 Key Codes 235 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 4 UART Circuit The universal asynchronous Receiver Transmitter circuit designated U4 is of type IM 6402 The circuit is used to convert the parallel ke
196. r the following precautions are to be noted and followed during service and maintenance of the instrument o The CT 12K uses invisible laser radiation which may harm human eyes o Never look directly into the transmitter with magnifying glasses binoculars telescopes etc o When operating avoid looking at the unit from the beam direction o Only trained personnel should perform maintenance functions o Follow all WARNING labels WARNING label used with CT 12K DANGER NON INTERLOCKED INVISIBLE LASER RADIATION PROTECTIVE WHEN OPEN HOUSING AVOID DIRECT EXPOSURE WARNING LABEL TO BEAM 1 1 1 2 High Voltage High voltage will be readily accessible when the transmitter A7 or receiver A6 covers are removed and the unit is powered High voltage 15 present in the High Voltage Power Supply PSI and Window Conditioner WARNING labels used with CT 12K DANGER RECEIVER A6 AND HIGH VOLTAGE INSIDE TRANSMITTER A7 THIS COVER COVER WARNING LABELS DANGER HIGH VOLTAGE HIGH VOLTAGE INSIDE POWER SUPPLY PSI THIS ENCLOSURE WARNING LABELS CHAPTER 1 GENERAL INFORMATION 1 1 2 HANDLING Handling of the Optics Assembly The VAISALA cloud ceilometer CT 12K uses laser radiation produced by a GaAs semiconductor diode for detecting cloud levels The laser radiation 15 accurately collimated by internal optics and provides beam of 904 nm invisible laser light During the factory alignment procedure
197. r in parallel controller is situated on the processor board Al and uses a monolithic l m V K temperature sensor This is connected to two voltage comparators which have reference set points at about 0 C 32 F and 20 C 68 F The comparators drive relays and K2 on the Unregulated Power supply Board A2 which connect power from Temperature Control Transformer Tl to RI and R2 The processor has no control over the heating but does monitor the temperature In indoor conditions and warmer both relays are OFF and no heating power is connected Between 0 C 32 F and 20 C 68 F relay Kl is ON connecting the resistors to the transformer in series Heating power will be approximately 20 W Below O C relay K2 in ON and relay is forced OFF connecting RI R2 in parallel to Tl Heating power will be approximately 80 W Without heating internal temperature will be 5 C 10 C 10 F 20 F above ambient after stabilizing With full heating internal temperature will be 20 C 30 C above ambient after stabilizing The time constant of the internal temperature 1s about 2 hours in calm conditions 113 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 2 2 4 22272 4 2 2 6 Internal Monitoring The hardware for the internal monitoring consists mainly of the Scaling network Selector and Monitor A to D Converter of the Processor Board Al The actual alarm limits and algorithms are implemented in softw
198. ram CTM 12 Processor Board Circuit Diagram 1 4 CPU CTM 12 Processor Board Circuit Diagram 2 4 Monitor CTM 12 Processor Board Circuit Diagram 3 4 Seq Cont CTM 12 Processor Board Circuit Diagram 4 4 Amp CTM 12 Processor Board CPU Cycle Timing CTM 12 Processor Board Component Layout CTM 12 Processor Board Pulse Diagram CTS 12 Unreg Power Sup Circuit Diagram CTS 12 Unreg Power Sup Components Layout CTI 12 Output Interface Circuit Diagram Vli PAGE 24 25 26 27 57 58 59 60 60 97 107 112 117 119 120 121 122 123 124 125 126 127 I57 158 159 160 161 162 163 164 165 166 175 174 183 DRAWING NO OR ILLUSTRATION NO C CT 3278 CT 3564 U CT 3560 A CT 3410 CT 3593 C CT 3596 CT 4594 CT 4417 CT 3120 CCT 2210 CT 3289 U CT 1200 C CT 3207 CT 4290 U CT 1300 U CT 2311 A CT 3416 CT 2284 CCT 3493 REV DESCRIPTION WWW Pran PU OD CTI 12 Output Interface Components Layout CTL 13 Light Monitor Board Circuit Diagram CTL 13 Light Monitor Board Components Layout CT 12K Light Monitor Board CTL 13 Assembly CTR 13 Receiver Board Circuit Diagram CTR 13 Receiver Board Components Layout Typ Temp Dependence of MRHV Laser Diode Temp Curve TP3 Volt Curve Form CIT 12 Transmitter Board Circuit Diagram CTT 12 Transmitter Board Components Layout CTP 12 HVPS Circuit Diagram CTP 12 HVPS Wiring Diagram CTP 12 HVPS Components Layout Window Conditioner Bl Connection Diagram CT 12K Heat
199. rence voltage of D7 12V via scaling network of resistors R16 R17 and R18 R17 is an NTC type resistor sensing the operating temperature of the laser diode Therefore the scaling of the network 1 e the base voltage of Q6 changes according to the sensed temperature Refer to Figure 1 When the reference voltage value of the error amplifier increases at the base of Q6 the output voltage of the regulator 1s increased This temperature compensation is needed due to the operational characteristics of the laser diode The error amplifier adjusts the output voltage to such a value that the feedback voltage at the base of Q7 equals the reference voltage at the base of Q6 The Q7 collector current via R24 adjusts the base voltage of the control stage transistor Q8 and therefore the output voltage 204 4 3 6 3 2 CHAPTER 4 FUNCTIONAL DESCRIPTION Laser Diode Pulse Circuit Thyristors Q4 and Q5 are normally in a non conducting state which allows the voltage regulator to charge the pulse energy capacitors C9 C12 and C14 to the regulated voltage Resistors RIO and RII assure that the voltage is divided evenly over the thyristors When the ultrafast thyristors Q4 and Q5 are triggered through transformer Tl capacitors C9 C12 and C14 are discharged through the laser diode D6 in less than 200ns peak current being in the order of 50A This wil cause DO to lase PC board implemented inductor Ll limits the peak current and shapes
200. rom the Field Junction Box of the Gifft Recorder passes through the relay contact to the recorder open circuit voltage approximately 90V When signal RBCT is held high LED DI 3 RBCT 1s on The inductive transients caused by the coil of KI are suppressed by diode D7 The Trigger Break signal for the Recorder is available at output connector J2 pins 9 and 10 signals RBCTI and RBCC2 179 CHAPTER 4 FUNCTIONAL DESCRIPTION The Cloud Data Signal A modulating signal referred to as 120 Hz 1s applied through connector Jl pin a28 The frequency of the 120 HZ signal is obtained from the Power Line supply The signal is filtered by inductor Ll resistor Rl and capacitor C3 The transmit level of the signal can be adjusted by jumper J3 in the range of 2dBm 5dBm Refer to the jumper setting table of the Circuit Diagram CT 2277 When the recorder sweep has reached a position proportional to the height of a cloud hit signal RBCE 15 raised high by the processor This signal is applied through Jl pin a22 The RBCE signal high switches the modulating 120 Hz signal via transistors QI and Q2 and the coupling transformer Tl to the output connector Jl pins 5 and 6 signals RBCEI and RBCE2 LED D14 RBCE indicates the presence of the cloud data signal at the output of gating transistor Ql Line transients suppressed by transient zeners DI and D2 4 3 3 4 CHAPTER 4 FUNCTION
201. rther passage of RF interference Jumper J5 enables selection of two distinct inputs When using the RS 232C interface jumper J5 must be in position 1 2 The level change from RS 232C 12V is effected by NAND gate 5 Diodes in series at the input of the circuit limit incoming voltage to between OV and 5V and at the same time the circuit inverts the signal so that it can be fed directly into the UART receiver The signal for the UART is taken to test connector J10 pin 9 238 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 7 Baud Clock The baud clock of the terminal is a crystal oscillator providing the fundamental frequency 2 4576 MHz By dividing this in an asynchronous counter the required baud frequencies for the UART are obtained The baud clock frequency corresponding to a certain baud frequency is 16 times that baud frequency Jumper J6 is used to select the frequency taken to the UART s clock inputs Selection can be made between the data transfer rates of 300 baud 1200 baud and 2400 baud Frequencies of the baud clock corresponding to these rates are given in Table 2 Table 2 Baud Clock Freauencv Settings Data Baud Transfer Clock J6 Rate Frequency Setting 330 bd 4800 Hz 4 5 1200 bd 19200 Hz 2 3 or 3 4 2400 bd 38400 Hz 1 2 Table 2 Baud Clock Frequency Settings Frequencies available from the baud generator are also employed to provide the voltage 9V 153 6 kHz see Section 4 3 9 3 1 8 9 and the AC voltage 16
202. s Resistor Metal Film 681R 1 0 25W Resistor Metal Film 10k 1 0 25W Capacitor Alum El 224 350 Capacitor Ceramic loon 03V Capacitor Polyest 68n 630V Connector 3 pos AMP 207608 3 CHAPTER 4 FUNCTIONAL DESCRIPTION EMEN dnd 21 wr wea N gt ADE9 A OSE ugg 5009 7 eS 7163 er 892 9 X X Suq gt 10 OS dl1 S 60 10 P N 2688 V TN 8 7L7NI 9q 7 gt O a T a O a lt O e r A M ee gt 08 26 85 KK und JOL X 818 73 8115 7 Y iY gt OLY IOSLA 2 438 1 a 5 3 6 81 AE 99 Wee VI i SLVISZZA 18 v T M v OI IVA 072 LA C 2 Re TO 680k ADD R19 680k 87 07 30 PK DZ 220 CHAPTER 4 FUNCIIONAL DESCRIPTION GRY BRAWHT BLKWHT WHT BRN BRN BLK BLU BLK BLKYEL YEL YELGRN WHTGRN T1 SCREEN GRNWHT T2 SCREEN GRNWHT T1 SCREEN BLKYEL TI PRI BLU 1 2 BLK T1 PRI BRN T1 PRI BLKWHT T1 PRI BRN CB1 4 BRNWHT T1 PRI BRN CB2 4 BLU CB2 2 BRN CB2 3 BRN CB1 3 BLU CB2 1 BLU CB1 1 YELGRN P1 18 YELGRN J1 5 YELGRN J3 6 BLKGRN T1 SEC BRNYEL T1 SEC ORN T1 SEC ORNWHT T1 SEC REDWHT TY SEC WHT TI SEC WHTRED T1 SEC VIOWHT T1 SEC VIO 1 5 WHTBLU T1 SEC LBLU TH SEC BLUWHT T1 SEC RED TI SEC DBLU TI SEC YEL 1 5 GRY 1 5 RED J2 6 GRN 42 5 v1O K2
203. s are sent Observe TXD LED on if lighting conditions permit If messages are not being sent check that Ceilometer is in AUTOMATIC MODE If not set AUTO ON If unsuccessful or if messages are still missing suspect AI 279 CHAPTER 6 TROUBLESHOOTING AND REPAIR If messages appear on Maintenance Terminal check A3 according to Section 6 2 3 Replace if faulty If A3 is okay check connection through W3 and external connections fault cannot be localized at Ceilometer check Receiving end connections and equipment 6 1 2 2 Message Improper Check line resistivity as in Section 6 1 2 1 Check for abnormal interference in line At the Ceilometer observe with Maintenance Terminal that message is proper If not suspect Al Raise Transmit Level of A3 to maximum If messages remain improper suspect A3 If still not successful proceed to check line and receiving equipment 6 1 2 3 Remote Dialogue Not Operating Check with Maintenance Terminal at Ceilometer If dialogue operates proceed to check A3 according to Section 6 2 3 Replace if faulty If dialogue does not operate suspect Al 6 1 3 LOCAL RS 232C INTERFACE OPERATION IMPROPER OR MISSING If the FSK Modem interface is operational check the RXD TXD and GND connections via connector J4 harness W4 and board A2 If Maintenance Terminal CTH 12 is used check further the 12V supply PI2M and the FLAG signal The latter shall be 5V without term
204. s of multiple lines These outputs have to be viewed line by line on the CTH 12 terminal The command format is the same as other commands After entering the command the display is cleared and the first line of the output is displayed In order to view the rest of the output lines the view control keys the alphabetic keys of the hexadecimal keyboard see Paragraph 3 5 1 are used The alphabetic keys have different functions in viewing messages than in entry of commands A key ABORT DISPLAY key B key BACK STEP key C key CONTINUOUS DISPLAY key D key not used E key not used F key FORWARD STEP key 85 CHAPTER 3 OPERATION 222224 1 ABORT DISPLAY key is used to stop the output and return to the ready state prompt gt is displayed when ready 2 BACK STEP B key is used to display the previous line of the message one line per key stroke 3 FORWARD STEP F key is used to display the next line of the message one line per key stroke 4 CONTINUOUS DISPLAY C key is used to display the output continuously line by line BACK STEP or FORWARD STEP key determines the direction of the continuous display If BACK STEP is pressed prior to CONTINUOUS DISPLAY the output advances backward if FORWARD STEP is pressed prior to CONTINUOUS DISPLAY the output advances forward Operating Session The use of the Maintenance Terminal CTH 12 can be divided into three phases 1 Open the communicatio
205. sed for std USASCII 1 MSB is normally TRUE but used for 8 bit special characters when initiating the display of the Maintenance Terminal No Parity Stop bit Total character count 1s 10 Due to the last data bit being TRUE in std ASCII communication the character appears to have two stop bits The FSK Interface is Bell 103 compatible transformer coupled and balanced It is based on a monolithic single chip modem with a Jumper to operate either in Originate or Answer mode the latter 1s standard Its transmission rate 1s a fixed 300 Baud The output signal level can be set with a jumper to five different levels 110 CHAPTER 4 FUNCTIONAL DESCRIPTION Outputs for the Gifft RBC Recorder are Trigger break which initiates the recorder sweep Inscription signal which when active makes a mark on the recorder chart These outputs are controlled by the processor and its software via two output ports The signals are routed via the Unregulated Power Supply board A2 to the Output Interface board A3 where the Trigger Break operates a normally closed relay contact and the Inscription Signal connects a 120 Hz signal derived from the line frequency 60 Hz by full wave rectification via an isolation transformer to the output line The inscription signal resolution is 20 ms corresponding to 80 ft the full sweep 1s 3 s corresponding to 12 000 ft The inscription signal timing starts at the end of the trigger break signal R
206. selecting low gain Gain 0 In practice the source drain resistance of 012 adds typically 40 ohms to the parallel resistor value Capacitors C55 87 are to filter off the 10 MHz system noise but they also reduce the slew rate of the amplifier The Signal Buffer is input biased by the resistor divider R24 25 fed from VR Diode DA3 1 16 compensates for temperature dependence of Q4 base emitter voltage drop Schottky diode D 1 0 clamps too high signal levels Transistor Q4 1s connected as an emitter follower straight driven from 9V Although Q4 emitter is pulled down to 13V by R28 negative voltages do not normally appear except by undershoot caused by high signal levels D8 protects the ADC input against undershoot The Flash ADC U23 is a 6 bit CMOS device of type CA3300 In its input stage 64 paralleled comparators simultaneously compare the input voltage with the tap voltages of a resistor ladder fed by the reference supplies Conversion is done simply by decoding the comparator output results into 6 bit digital form plus overflow transferred into output registers The ADC outputs are enabled by pin 5 high Sampling and conversion 1s operated by the clock applied to pin 7 SCA The Level Shifter is a quad AND gate U32 of type 74HCTO08 which features TTL level inputs 0 Uin lt 0 8V P Uin gt 2 0V It is powered from the resistor zener connection R47 46 30 Dll which gives approximately 7V supply and 2V to pins 14
207. sembly Drawing U CT 2311 MAINTENANCE TERMINAL CTH 12 9 Introduction 9 2 Specifications 9 3 Functional Description 94 Parts Lists 5 Drawings Block Diagram A CT 3416 Circuit Diagram CT 2284 Components Layout C CT 3493 96 213 219 215 217 220 221 223 225 225 226 228 229 230 231 232 232 234 249 255 254 255 4 1 CHAPTER 4 FUNCTIONAL DESCRIPTION OPERATION PRINCIPLES Basic Principle of Oneration The Speed of Light The operating principle of the CT 12K 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 9929x 10 m s 29 8356 x 10 ft s a reflection from 12 000 ft will be seen by the receiver after t 24 4 us The general expression connecting time delay t and backscattering height h IS h ct 2 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 Drawing 4413 Pulse transmitted Return slgnal Vision blocked received by cloud S EE Cloud n Q SC ending precipitation Time in us 0 10 20 25 _ mA vo s Height in ft 0 5 000 10 000 12 500 FIG 1 ACTUAL RETURN SIGNAL CT 4413 9 7 CHAPTER 4 FUNCTIONAL DESCRIPTION The instanta
208. shunt voltage of 10 mV K making it approx 3 V at room temperature This can be measured at TP4 For differential temperature changes K equals C and 1 8 x F U4 is a zener like voltage shunt It is fed by a constant current source 1 4U3 output pin with surrounding resistors creating a reference voltage of 4 90 5 10 V at TP5 The bias voltage is adjusted at trimpot R19 to a value which gives a responsivity of 40 A W using a factory procedure The resulting bias voltage along with the corresponding output of U2 are marked on a sticker on the board Qp amp 1 4U3 input pin 5 sensed the voltage at voltage divider R16 R20 R21 R22 connected between the bias voltage and U2 and via series pass transistor Q3 which drives the bias voltage so that its input voltage difference is zero This makes the bias voltage temperature dependence R20 R21 R22 R16 10 mV C E259 Vie oL VE 195 CHAPTER 4 FUNCTIONAL DESCRIPTION The negative input at J2 pin 3 Is connected through current measuring resistor R4 to the photodiode circuit forrned by DI R5 2 and the photodiode D2 itself photodiode DC current can be measured as a voltage drop across RA between test points TP and 2 Resistor R5 serves for current limiting Capacitor C9 restores a low impedance level and filters interference Photodiode D2 transforms the light power incident upon it into a DC current proportional to the light power Rapid current chang
209. sistor RA12 5 6 The channel i p full scale level and conversion resolution for all the Monitor inputs are defined in Table 3 140 CH APTER 4 FUNCTIONAL DESCRIPTION The Pre Multiplexer 015 is a type 4051 CMOS analog MUX It is an 8 channel device capable of switching also negative signal levels provided that negative bias is applied to its pin 7 Multiplex address is applied to pins 11 9 P14 16 Multiplex output from pin 3 is filtered by RA2 6 5 and and then buffered by U14 7 op amp prior to feeding it into the Amplifier Section MB where it is inverted and brought back MI to the Mon ADC pin 12 CH 10 The monitor ADC U8 is a CMOS device of type TLC 541 It converts one by one the signals applied to its 11 channel inputs into digital 8 bit form The twelfth channel internal self test voltage brings out about a half of the full scale reading 128 3 The ADC control section provides for serial address data interchange with the host The I O clock 18 carries out clocking in the channel address 17 and clocking out conversion data 16 Pin 15 1s the low active chip select input The ADC reference voltage V5 which originates in the Amplifier Section is applied to pin 14 As supplied by an op amp powered from 13 V the line is protected by the DAI diodes This applies also to the signal input MI Conversion signal ADC MUX FS Level Resolution ID pin s Channel Channel on Jl per bit P201 aca 0 X 27 1 V 108 mV P20
210. ssor Board EPROM Will thus require reprogramming if Board or EEPROM is replaced Has no effect on operation Changing of number once input requires string space space NEW with standard terminal or string space space 123 with Maintenance Terminal to be added after the new number before entering line with CR Example session showing syntaxes of above commands ST MT gt CLIM CR gt C6K CLOUD LIMIT CLIM 0 1600 gt CLIM 0 1600 gt CLIM 15 CR gt C6BD15F CLOUD LIMIT CLIM 0 1000 gt CLIM 0 1500 64 gt SLIMICR SIGNAL LIMIT gt 5 25 CR SIGNAL LIMIT gt DEV CR DEVICE SCALE gt DEV 1l CR DEVICE SCALE gt NSCA CR NOISE SCALE gt NSCA 3 CR NOISE SCALE gt SCAL CR OUTPUT SCALE gt SCAL 10 CR OUTPUT SCALE gt LNOR CR LASER NORM gt LNOR 164 CR LASER NORM gt TOTA CR TOTAL SIGNAL LIMIT 6 CURRENT SIGNAL SUM 25 gt 5 CR TOTAL SIGNAL LIMIT 5 CURRENT SIGNAL SUM gt RAT CR GAIN RATIO gt HOFF CR HEIGHT OFFSET gt EMOD CR SLIM 0 SLIM 0 DEV 1 DEV Ls NSCA 2 NSCA 3 SCAL 20 SCAL 10 LNOR 162 LNOH 164 25 HOFF 0 EXTINCTION NORMALIZED MODE EMOD ON gt EMOD_ OFF CR HEIGHT SQUARE NORMALIZED MODE EMOD OFF 65 2600 2500 2000 000 5000 0000 0000 000 00 63 00 63 7012 CHAPTER 3 OPERATION gt C10F gt SLIM 0 2600 gt C10BD26F _ gt SLIM 0 25
211. ssor Self Always OFF check Alarm Al D5 Green Processor OK Blinking once per second A3 DIO Yel Data Transmitted Blinking when Ceilometer on FSK line transmits digital cha racters ON in between A3 DII Yel Data Received Blinking when Ceilometer on FSK line receives digital char acters ON in between A3 DI2 Green Carrier Detect ON when Ceilometer detects on FSK line carrier received on digital FSK line D13 Yel Trigger Break ON when Ceilometer for Gifft RBC activates Break Recorder D14 Yel Cloud Signal ON when Ceilometer for Gifft RBC marks recording paper Recorder A5 D4 Red Laser Power Always ON except if optional Solar Shutter is ON 36 3 1 4 1 3 1 4 2 CHAPTER 3 OPERATION USE OF SERIAL DIGITAL INTERFACE General The serial digital interface of Ceilometer CT 12K may be accessed remotely through the FSK line connector 13 or locally up to a few hundred yards or meters through the RS 232C port connector J4 These are functionally equivalent Maintenance Terminal CTH 12 connects to the RS 232C port Its presence will convert ceilometer communication to the Maintenance Terminal mode when the line 1s opened Frame Code and Speed Communication is asynchronous 300 Baud using the following character frame Start Bit 8 Data Bits No Parity Stop Bit Character code is USASCII and the unused eighth bit equals the stop bit in polarity MARK except for a few special characters which i
212. t Top View A CT 3405 Internal Layout Bottom View A CT 3406 93 FUNCTIONAL DESCRIPTION PAGE 97 102 102 103 103 109 113 114 114 114 115 117 119 120 121 122 123 124 125 126 121 4 3 MODULE DESCRIPTIONS 4 3 1 PROCESSOR BOARD CTM 12 REF AI 4 3 1 1 General 128 4 3 1 2 Specifications 130 4 3 1 3 General Overview 137 4 3 4 Functional Description 138 4 3 1 4 1 CPU Section 138 4 3 1 4 2 Monitor Section 140 4 3 1 4 3 Sequence Control Section 144 4 3 1 4 4 Amplifier Section 148 4 3 1 5 Parts List 152 4 3 1 6 Drawings Jumpers and Connections CT 4407 157 Main Functions and Primary Data Control Flow CT 4532 158 Principal Block Diagram CT 3501 159 Circuit Diagram 1 4 CT 3385 160 Circuit Diagram 2 4 CT 3386 161 Circuit Diagram 3 4 CT 3387 162 Circuit Diagram 4 4 CT 3388 163 CPU Cycle Timing CT 3544 164 Components Layout CT 2492 165 Timing Diagram CT 3536 166 REFERENCES MCS 5 1 Family of Single Chip Microcomputers User s Manual Intel Corporation 1981 4 3 2 UNREGULATED POWER SUPPLY BOARD CTS 12 REF A2 4 3 2 Introduction 167 4 9 2 2 Specifications 167 2 Functional Description 169 4 3 2 4 Parts List 172 4 3 2 5 Drawings Circuit Diagram CT 3196 173 Components Layout CT 2294 174 94 4 3 3 4 3 5 4 3 6 OUTPUT INTERFACE REF A3 4 3 3 1 Introduction 4 3 3 2 Specifications 4 3 3 3 Functional Description 4 3 3 4 Parts List 4 3 3 5 Drawings Circuit Diagram CT 22H Components L
213. t a Receiver Filter with a narrow bandwidth 50 nm 15 used for blocking most of the background radiation noise from interfering with the measurement The photodiode converts light signals into electrical current The preamplifier of the Receiver Board converts current into a voltage signal which is then transferred to the actual data acquisition circuitry Band pass is from 2kHz to 1 so both DC and unwanted high frequency noise 16 blocked The Data Acquisition circuitry contains a processor controlled Amplifier a Flash Analog to Digital Converter a Sample Adder a Sample Buffer Memory and a Sample Summing Memory When the Laser Control circuitry issues a Laser Trigger pulse the Data Acquisition circuitry get initiated at the same moment The A to D converter takes a sample of the received and amplified backscatter signal digitizes it and inputs it into the first location of the Sample Buffer Memory This all takes place within 100 ns Exactly 100 ns after taking its first sample the A to D converter takes the next sample This will now represent backscatter from a height 50 ft above that of the first sample After digitizing this second sample is stored in the second location of the Sample Buffer memory 104 CHAPTER 4 FUNCTIONAL DESCRIPTION In this way samples are taken every 100 ns for 25 4 us which provides 254 useful samples stored in consecutive locations in the sample Buffer memory These samples represent the
214. tatus data line I gt CR LF status data line 2 gt CR LF data table CR LF sz CR LF ETX CR LF ON OFF data is accordingly Other data is decimal or hexadecimal numbers 44 CHAPTER 3 OPERATION Coding is USASCII STX CR LE ETX are Start of Text Carriage Return Line Feed and End of Text characters which format the message but are not visible in a printout Total length of message is 636 characters Printout is 15 lines width 1s max 44 characters whereof 42 are visible 3 2 1 3 Status Line 1 Identical in all messages NSB H H H H H T T T T T H H H 4 T T T T T S S S S S S S S S S C RLF no significant backscatter clear air one layer detected two layers detected sky 1s fully obscured but no cloud base can be detected from echo signal received e g fog or precipitation sky is partially obscured and no cloud base 15 detected WN Z ZZZZ 0 no alarm status bits 51 54 ON for more than 5 mm 1 at least one alarm status Sl S4 ON for more than 5 min space if 5 0 bel character if S 1 Because bel is a nonprinting character the alarming line appears one character shorter in a printout than normally N 0 or 4 H H T T Z II 1 or 2 H H H H H the lowest detected cloud height in 5 digits Leading zeroes not suppressed T T T T T range of backscatter of first layer if not defined 45 CHAPTER 3 OPERATION 3 2 1
215. th shutter Dimensions W X D X H 6 7 X 2 1 X 0 9 inches 170 X 54 X 23 millimeters 185 CHAPTER 4 FUNCTIONAL DESCRITPION 4 3 4 3 Laser Power V LLAS 0 9V 4 5V at nominal laser power Monitor Filtering Time constant 100ms Factory calibrated transmitter specific 100 value to be input in CT 12K for parameter LNOR sky Light V LSKY 1 V 16 W typ from solid angle Monitor 0 03 srad Bandwidth 300 nm 1100 nm Filtering Time Constant 0 2 s solar Shutter Factory set trip level 32 W typ from Driver solid angle 0 03 srad Hysteresis 16 W typ Functional Description Laser Power Monitor Laser power is detected by photodiode DI which in its normal operating position is pointed downward toward the laser transmitter converts the short powerful light pulses to current pulses These are transferred via Schottky diode D2 to capacitor C2 100nF The charge collected by capacitor C2 discharges via resistor R3 1 Megohm The time constant C2 x R3 1s 100 ms thus the laser pulse frequency which is 620 Hz 1120 Hz 1 6 ms 0 9 ms will be converted to a DC voltage across R3 the magnitude of which will equal in volts the average of the pulse current in microamperes The voltage will never rise so high that the negative bias across photodiode DI will be significantly reduced Ambient light current which at peak magnitude is much less than the laser pulse current passes to ground via resistor Rl Diode D2 pre
216. the Lidar Equation represents the portion of light which is reflected back towards the Ceilometer e g by water droplets It is obvious that the denser a cloud 15 the stronger the reflection will be The relationship can be expressed as f h k h where k is a constant of proportionality 5 h is the extinction coefficient 1 e the attenuation factor in a forward direction 99 CHAPTER 4 FUNCTIONAL DESCRIPTION The extinction coefficient relates to visibility in a straightforward manner If visibility is defined according to a 596 contrast threshold World Meteorological Organization definition for horizontal visibility then o 3 V where O is the extinction coefficient V is 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 0 024 and higher in low humidities to 0 05 However in precipitation of various kinds k will have quite different values Assuming a value 0 03 srad for k and visibility in clouds being in the range 15m 150m 50 500 ft gives the range of value for B 0 0006 0 006 0 6 6 km sr
217. the pulse Ll also causes the capacitors to be discharged to a slightly negative voltage which assures the turn off of thyristors Q4 and Q5 Diode D5 prevents the laser from being reverse biased The charge discharge cycle can be measured at TP3 See Dwg 4417 WARNING Voltage in excess of I00V at TP3 205 CHAPTER 4 FUNCTIONAL DESCRIPTION PXHV 200 150 100 50 50 40 30 20 10 0 10 20 30 40 50 FIG T LASER DIODE SUPPLY VOLTAGE TEMPERATURE DEPENDENCE LASER VOLTAGE 100 TYPICAL t 900 1600 us FIG 2 TP3 VOLTAGE CURVE FORM CT 4417 4 3 6 3 3 4 3 6 3 4 CHAPTER 4 FUNCTIONAL DESCRIPTION Laser Diode The laser diode D6 emits the laser light when subjected to a current pulse in excess of ISA The operating temperature of the laser diode is monitored by a semiconductor sensor UI integrated circuit and by NTC type resistor R17 sensor Ul provides a temperature monitoring signal for the processor referred to as TL signals TL or TL Laser Temperature and can be measured between test points TP5 and TP6 R17 senses the laser temperature for the high voltage regulator controlling circuits to provide a temperature compensation based on the operating temperature of the laser diode The laser diode supply voltage is therefore increased as shown in Figure 1 when the laser diode temperature increases Maximum laser temperature allowed is 70 C 158 F At this limit the processor
218. ting Power 2 5 W 16 Key Hexadecimal Keyboard Module with Symbols 0 9 and CHAPTER 4 FUNCTIONAL DESCRIPTION 45 93 Functional Description 4 3 9 3 Operation 4 3 9 3 1 1 4 5 9 3 12 Keyboard A 16 key matrix coded hexadecimal keyboard is used with the keys 0 9 and A F as follows Column H G F E M 0 1 2 3 L 4 5 6 7 Line K 8 9 A B J C D E F The keyboard module is wired so that when a key 15 depressed the key switch shorts a certain line to a certain column For example when the key 0 is pressed line connects to column H Designations of the columns H to E and lines M to J refer to pin designations of keyboard module connector The connector pins are arranged as follows seen from the left to the right when viewing the keyboard from the normal operating direction M L K JH GFE Keyboard Control Circuit Keyboard reading is controlled by a 16 key encoder 74C922 designated U9 The circuit is provided with internal pull up resistors and a contact debounce circuit The Data Ready DA signal goes HIGH when the key is pressed and returns LOW when the key is released The speed of the scanning circuit 1s approximately 600 Hz and the operating time of the debounce circuit is about 101 The circuit operates as follows The circuit clock feeds a two bit counter which pulls down one column output Cl C4 at a time through the decoder while the other column out
219. ting supply at 256 F 6 F 124 C 3 C The processor gets no information of its operation however The heat and the airflow are also used for stabilizing the immediate environmental conditions of the Ceilometer In cold weather T 14 F 10 C the heating is always ON together with blowing and in hot weather gt 86 F 30 C the blowing is always ON and heating OFF to keep heating by solar radiation at a minimum In intermediate temperatures the Operation is software controlled to keep both heating and blowing ON always when there are clouds being detected in low visibility conditions and in 5 minute periods every 60 minutes to insure recovery in all situations and to keep dust contamination at a minimum 22 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 8 4 Parts List Bl 10250 Blower Motor and Fan Cl 10251 Motor Capacitor HRI 2744 Heater TS2 2746 Temperature Sensor 51 2745 Thermostat Subassembly EI 10011 Terminal 4 pin 0 11 inch 1923 Wire Terminal 0 11 inch in Female AWG 18 27131 Connection Cable Subassembly 10045 Cable Alpha 45068 Pl 2944 Connector MS 3 116F16 8P 228 CHAPTER 4 FUNCTIONAL DESCRIPTION GRNYEL TS TS WINDOW CONDITIONER B eve VAISALA P N2736 115 V zr CONNECTION DIAGRAM OCC 743212 4 LW M3 iP NUT M3 4 V 1 4 LW H3 NUT M 2 PCS lt 4 LW M PC MUT M3 2PCS
220. tion Operates only in Maintenance Mode WARNING COMMAND MAY CAUSE UNDETECTED ERRONEOUS OPERATION IF MISUSED USE ONLY AS INSTRUCTED IN SECTION 6 Syntax example ST MT gt CAL 120 CR gt C40B12F OFFSET BASE UPDATE OFFSET BASE UPDATE 120 sec terminal inactivity 120 sec inactivity OFFSET TO EEPROM OFFSET TO EEPROM INPUT DATA AVE INPUT DATA AVE 15 9500 0 16 0140 one data item at a time with C or F 0 16 0140 15 9650 16 0890 15 9470 15 9720 250 16 0180 16 0880 16 0940 15 9810 15 9930 500 16 0270 16 0238 16 0205 16 0173 16 0140 750 16 0108 16 0075 16 0043 16 0010 15 9978 1000 15 9945 15 9913 15 9880 15 9848 15 9815 ESC aborts output of table A gt next input 77 gt next input CHAPTER 3 OPERATION 3 4 5 15 The command outputs the Standard Terminal command set with short descriptions Maintenance Terminal equivalent is available ESC will abort output Syntax example ST gt HELP CR MT no equivalent VAISALA CT 12K VERSION 2 42 SN 87023 TIME DATE MES PAR STA CONF CLIM SLIM DEV TOTAL NSCA SCAL LNOR EMOD RMOD BMOD AUTO RESET LASE SEQ RAT MEAS HOFF FREQ NOIS AN GAIN HEAT BLOW SHUT ALIM RECT HH MM SS YYYY MM DD AUTOMATIC DATA MESSAGE DISPLAY PARAMETERS STATUS MESSAGE SYSTEM CONFIGURATION lt LIMIT gt CLOUD LIMIT lt LIMIT gt SIGNAL LIMIT SET DISPLAY DEVICE SCALE lt SIGNAL SUM SET p
221. tivation is done with command SEND 3 This cancels any previous message activation only one digital message may be active at a time The following is the command and Ceilometer response omitting the parameter 3 will cause the current selected message to be announced ST MT gt SEND 3 CR gt C3IB3F AUTOMATIC MESSAGE 3 AUTO MES 3 gt next input gt _ next input The Message number selection will remain in effect over a Restart or Power Down Message No 3 1s intended to be used with the EMOD control parameter set to EMOD ON see 3 3 Format STX CR LF status data line 1 gt CR LF lt backscatter data line gt CR LF ETX CR LF Status Data Line 1 is identical to that of Message No 2 ON OFF data is I O accordingly Other data is decimal or hexadecimal numbers 50 32 2 2 24 2223 CHAPTER 3 OPERATION Coding is USASCII STX CR LF ETX Start of Text Carriage Return Line Feed and End of Text characters which format the message but are not visible in a printout Total length of message is 112 characters Printout is 2 lines width 1s max 66 characters whereof 64 are visible Time for message transmission at 300 baud 15 3 73 s status Line 1 Identical to that of Digital Message No 2 see 3 2 1 3 Backscatter Data Line D where n to 64 is single ASCII coded hexadecimal character O F where each bit of the 4 bit nibble of the hex character expressed in binary form represents one
222. ts Example Dialogue with standard settings ST gt PAR CR SYSTEM PARAMETERS CLOUD LIMIT CLIM 0 1000 SIGNAL LIMIT SLIM 0 2000 DEVICE SCALE DEV 1 2400 NOISE SCALE NSCA 4 5000 OUTPUT SCALE SCAL 100 0000 LASER NORM LNOR 164 TOTAL SIGNAL TOTAL 10 0000 GAIN RATIO RAT 3 7012 HEIGHT OFFSET HOFF 0 HEIGHT SQUARE NORMALIZED MODE EMOD OFF DATA UNIT FT MEASURED DATA RECORDING RMOD ON ALL CLOUD DATA BMOD OFF gt SHUT CR NO SHUTTER gt SEND CR AUTOMATIC MESSAGE 2 gt AUTO CR AUTOMATIC MODE gt SERN_ CR VAISALA CT 12K VERSION 2 42 SN 87023 next input 61 MT gt C4F SYSTEM PARAMETER F CLIM 0 1000 F SLIM 0 2000 F DEV 1 2400 F 5 NSCA 4 5000 F SCAL 100 0000 F LNOR 164 F 5 TOTA 10 0000 F RAT 3 7012 F HOFF 0 E EMOD OFF F DATA UNIT FT F 4 _RMOD ON F _BMOD OFF F gt C22F 3 gt NO SHUTTER gt C31F 2 _AUTO MES 2 gt C11F gt AUTOMATIC MODE gt C33F gt V2 42 87023 next input CHAPTER 3 OPERATION NOTES 1 All these parameters reside in non volatile memory 2 SEND may be 2 or 3 see Section 3 2 3 Response to SHUT is SHUTTER IS OFF or eventually ON if one is installed See also CONF 4 If meters output is used DATA UNIT FT line will read DATA UNIT M See also CONF 5 LNOR and DEV values are instrument specific 6 In addition to proper parameter settings a proper Noise Off set Calibration must be in memory See Section 6 in case of
223. ue CURRENT SIGNAL SUM or SUM see Digital Message No 2 If SUM exceeds TOTA then full obscuration is concluded and first status bit N of Digital Message Status Line l is 1 2 or 3 If SUM is less than TOTA but exceeds 0 4 TOTA then partial obscuration is concluded and N is 4 No height values are output in message If SUM is less than 0 4 TOTA then no significant obscuration is detected Parameter DEV multiplies SUM RAT RATio Ratio of GAIN 2 GAIN 0 Multiplies results of measurement using GAIN 0 for normalization Value must always be 3 7 HOFF Height OFFset Parameter for offsetting the heights reported in case the Ceilometer is installed considerably higher positive value or lower negative value than the level of interest e g the runway The HOFF value will be added to the Cloud Height and Range Limit values Cloud Penetration or Vertical Visibility values will not be affected except that Vertical Visibility will be set equal to Range Limit if the latter is lower Negative values will be replaced by zeroes The Height Offset will offset the Range Gate output string of Digital Message No 3 correspondingly Digital Message No 2 range gate data and Gifft RBC Outputs will not be affected The HOFF value must be expressed in the same units feet or meters as the output 15 WARNING 1 If output units are changed from feet to meters or vice versa the HOFF value must be changed manually No automatic recalculation is perf
224. ugged into an approved tlhree contact electrical outlet or the instrument must be carefully earthed to a low resistance safety ground DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE 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 KEEP AWAY FROM LIVE CIRCUITS Operating personnel must not remove instrument covers Component replacement and internal adjustments 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 DO NOT SERVICE OR ADJUST ALONE Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT 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 DANGEROUS PROCEDURE WARNINGS Warnings such as the example below precede potentially dangerous procedures throughout this manual Instructions contained in the warnings must be followed WARNING Dangerous v
225. ully automatic and no intervention is needed A digital data message is sent at predetermined intervals without any polling action over both the FSK Interface and the RS 232C Interface Framing content and timing are identical See para graph 3 2 for use and interpretation of Digital Messages The Gifft RBC Recorder signals are operated at 12 second intervals See paragraph 3 2 3 for use and interpretation of these The requirements for obtaining normal operation are along with the corresponding paragraphs of description in brackets Power On and all switches in correct positions 3 1 2 3 1 3 Automatic Mode of Operation 3 1 5 Line Closed 3 1 4 Correct parameters inserted 3 3 No alarms detected 3 4 SWITCHES The following are the switches of Ceilometer CT 12K along with Reference Designation and normal operation position Ref Description Position PSI Power On Off doubles as on up Circuit Protecting Breaker PSI CB2 Window Conditioner On Off on up doubles as Circuit Protecting Breaker Al Sl Reset Normal spare Normal middle A2 Sl Internal Heating On automatic Off On right AD 92 Interface Control Normal Line Normal left 35 CHAPTER 3 OPERATION INDICATORS The following is a summary of all Ceilometer CT 12K indicators with reference designations and indications in normal operation Ref Color Description Normal Operation PSI 051 Red Line Power Always ON Al D4 Red Proce
226. um since the environment changes For example clouds move Return Signal Strength The instantaneous return signal strengtb is in general form the Lidar Equation h Pr h E A ON where Pr h is the instantaneous power received from height h Watts W E 1s the effective pulse energy taking all optics attenuation into account Joules J 1J 1 Watt second C is the speed of light meters per second ms A is the receiver aperture m2 98 CHAPTER 4 FUNCTIONAL DESCRIPTION h is the height in question m bh is the volume backscatter coefficient at height h m sr sr steradian is the atmospheric transmittance and accounts for 20 z dz the transmitted and backscattered power by extinction z m 0 at various heights 7 between transceiver and height in question 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 height 1 e the strength of a signal from 10 000 ft 15 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 The Backscatter Coefficient The volume backscatter coefficient b h of
227. unctional Description Refer to Circuit Diagram CT 3190 The following Ceilometer CT 12K parts are connected to the board Connector Part Processor Board AI J2 Temperature Control Heater RI J3 Temperature Control Transformer TI J4 Temperature Control Heater R2 J5 Light Monitor Board A5 via W5 J6 Output Interface Board A3 J7 RS 232C external connector J4 via W4 doubles as Maintenance Terminal interface J Transmitter Board A7 via W7 J9 Temperature Sensor TSI J10 High Voltage Power Supply PSI J11 High Voltage Power Supply PSI J12 Receiver Board A6 via W6 168 4 3 2 3 1 Power Supply CHAPTER 4 FUNCTIONAL DESCRIPTION The following voltages are fuse protected rectified filtered Input Input Fuse Output Test Soft Supplied To Connector Voltageand Voltage Pointware Value Ref J10 1 2 8 VAC F2 250mA 10VDC TP8 A6 J12 J10 4 5 8 VAC F3 600mA 10VDC TP4 P10D Al 71 J10 3 6 15 VAC F4 250mA 2OVDC TP6 P20A 1 J1 J10 9 12 15 VAC F5 250mA 20 TP5 M20A 1 J1 J10 7 8 15 VAC F6 250mA 20VDC P20I Al J1 J10 10 11 15 VAC F7 250mA 20VDC TP2 M201 A1 J1 23 06 J10 13 14 10 VAC F8 600mA 12VDC TP7 12 J7 1 J10 16 17 8 VAC F9 250mA 10VDC TP9 P10X 7 J8 J3 1 3 20 VAC F1 10A 20 VAC Zu R1 J2 R2 74 25 VDC P25V A5 J5 PS1 J11 Notes 1 The connector for external RS 232C supplies 12V to the Maintenance Terminal via circuits not reserved by RS 232C standard All volt
228. valanche Photodiode Responsivity at 904 nm 40 A W factory adjustment 0 0314 inches 0 8 mm 904 nm 880 940 nm typical 85 typical 60 minimum 5 91 inches 150 mm 4 65 inches 118 mm 2 7 mrad 90 typical 97 typical clean CHAPTER 1 GENERAL INFORMATION 1 2 6 OPTICAL SYSTEM 1 24 1 2 8 ENVIRONMENTAL CONDITIONS Lens Distance Transmitter Receiver Laser Beam Entering Receiver Field of View Laser Beam 90 Within Receiver Field of View PERFORMANCE Measurement Range Resolution 12 000 ft Acquisition Time System Bandwidth Tolerance to Precipitation Ambient Temperature Humidity Salt Spray Wind Shock 10 12 20 inches 310 mm 100 feet 30 m 1000 feet 300 m 0 12 650 feet 50 feet 30 s maximum 10 MHz at Low Gain 3db 3 MHz at High Gain 3db to 0 3 inches per hour 7 5 mm per hour range limited 60 120 F S1 C 49 C 100 RH MIL STD 810C Method 509 1 100 kt 50 m s 4 inch drop 10 cm 1 3 CHAPTER 1 GENERAL INFORMATION RBC ANGLE HEIGHT TABLE The table below converts the RBC angle in degrees on the Gifft RBC Recorder to a cloud height determined by the VAISALA CT 12K The scale is linear 1 degree equals 133 3 feet with 0 to 90 degrees representing 0 to 12 000 feet GIFFT RBC RECORDER CEILOMETER VAISALA CT 12K ANGLE HEIGHT degrees feet 0 0 130 2 270 400 4 090 D 670 6 600 1 930 8 1070 9 1200
229. vents it from being transferred to capacitor C2 because of the positive bias required for it to conduct 0 3V 0 4V in all practical cases exceeding the voltage across RI On the other hand RI is big enough not to create any considerable error in actual laser pulse current measurement Capacitor Cl and resistor R2 block the sharp current pulse from the rest of the circuitry Op amp 1 4 Ul LM124 amplifies the voltage across R3 to a level suitable for measurement by the processor board monitor A D converter 0V 5V Gain is factory set 186 CHAPTER FUNCTIONAL DESCRIPTION The resulting signal can be measured at test point TPI It also drives red LED D4 It 1s brought out at connector Jl pin 10 It 1s referenced in the processor software as LLAS and measured by monitor A D converter channel 8 analog monitoring command AN 8 or AN LLAS Because of the variation between individual photodiodes each laser power monitor is factory calibrated The norm value which corresponds to 100 of nominal laser power is marked as the value of parameter LNOR on the Ceilometer Transmitter board This value is to be input in the processor prior to use Skv Light Monitor Sky light power is monitored by upward pointing photodiode D3 through an aperture which limits the viewing solid angle to approximately 0 03 srad Deflection from vertical is approximately 5 7 average non circular cross section because of the rectangular detector chip Its se
230. ver and window conditioner ON cover the transmitter side aperture of the Window Conditioner with dark non reflecting cloth If done indoors use a desk lamp positioned over the receiver as the constant light source If done outdoors make sure that ambient light conditions are stable For example wait for a long break in the clouds if there is a broken cloud cover C Perform command sequence AUTO OFF Output MAINTENANCE MODE GAIN 0 LASE ON SEQ ON CAL 240 300 CHAPTER 6 TROUBLESHOOTING AND REPAIR After 4 minutes the unit has recorded its offset signature and responds With OFFSET TO EEPROM and starts listing the offset values obtained This can be interrupted by hitting the ESC key Restore normal operation by commanding AUTO ON CLOS and removing the transmitter aperture cover Observe that performance 1s okay 301 302 303 304
231. vide for the Heating Relay coil drives RELI and REL2 through 100R resistors The other couple of 100R resistors in the HC line together with the 47k feedback resistors RA9 3 4 1 2 achieve typ 200 mV hysteresis in the control system The on board Temperature Sensor Ul6 LM 335 biased through RA12 3 4 controls the circuitry through its linear temperature dependent voltage drop The 5 V Regulator U29 is a special PNP type device LM 2935 mounted on heat sink It features very low voltage drop between its input 1 and output 2 Only 5 6 volts 15 needed at the input for maintaining the regulation The Regulator s output pin 4 produces active low PWR ON Reset signal POR fed through 22k resistor RA20 7 8 to the CPU section Pin 5 is a separate 5 V output intended to be used as low current standby supply not used in this application and therefore pulled up by resistors to avoid oscillation The unregulated input voltage 10VD is filtered by LI and C26 Bypass capacitors total number of 18 are connected to the 5 V line Diode D9 protects against reverse voltages The Regulator is capable of producing 750 mA output current Less than half of this is used in the system The 12V Regulator U6 is of adjustable type LM317LZ Its output voltage is determined by the adjust resistors in the following way 1 R4 R3 x 1 25 V R3 x 504A 12 2 V The input and output capacitors C5 C4 do the by passing as does C17 between the
232. w The electronics of the CTM 12 can be functionally divided into four Main Sections namely CPU Section 2 Monitor Section 3 Sequence Control Section 4 Amplifier Section The operation of each of these 1s described in the following System division into Main Sections is shown in the drawing CT 3501 Principal Block Diagram A less detailed illustration of the system as a whole is given in the drawing CT 4532 Main Functions and Primary Data Control Flow For each of the Main Sections a separate Circuit Diagram is provided CT 3385 Circuit Diagram 1 4 CPU CT 3386 Circuit Diagram 2 4 Monitor CT 3387 Circuit Diagram 3 4 Sequence Control CT 3388 Circuit Diagram 4 4 Amplifier Component locations on the PC Board are given in the drawing CT 2492 Components Layout Two timing diagrams are provided for illustrating the operation of the CPU Section and Monitor Section namely CT 3544 CPU Cycle Timing The second diagram concerns Monitor Section devices ADC EEPROM RS 232C Channel controlled by the Processor in the CPU Section One timing diagram illustrates the operation of the Test Pulses 3536 Pulse Diagram Test Pulse Timing and Forms 137 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 1 4 4 3 1 4 1 Functional Description CPU Section The Microprocessor U4 is an 8031 type single chip NMOS device mounted on a socket Beside the typical processing elements it contains
233. ware Add and Store sequencing by 1 25 MHz data rate Laser Trigger and Frequency Control lO0ns range gate 25 8us total range 256 samples whereof 254 useful 800ns byte to byte add 3 2us total sum for one level three bytes 816 lus total range 255 sums whereof 254 useful 51 2 768us in 8 steps Cycle Time 893 1 Cycle Frequency 621 1102 Hz 2 kB Static RAM 1 kB of capacity utilized Access Time 70065 Impedance 100 ohm O P conn coaxial SMB Timing 60ns single pulse repeated every 893 1 1609 95 Echo Signal Amplifier and Converter Two Stage AC Amplifier and Buffer with two software selectable gains Flash Analog to Digital Converter with two slope conversion scale Impedance 50 ohms to GND Signal Range 0 33mV non clamped I P Connector coaxial SMB CHAPTER 4 FUNCTIONAL DESCRIPTION Amplifier Gain Flash ADC Conversion output Testing Aids First Stage ca 60 trim pot adjustable Second Stage Software alterable Gain 0 ca 4 Gain 2 ca 16 Total Gain Factory Adjusted to Values Gain 0 250 Gain 2 930 Conversion Rate 10MHz Conversion Resolution O lt Uin lt I N 33 steps 52mV each Uin lt 8 3V 31 steps 213mV each 6 bits overflow Test Pulse Feed to Amplifier I P Jumper selectable pulse forms Width 230 430ns Occurrence single double Amplitude three alternatives 4 3 1 3 CHAPTER 4 FUNCTIONAL DESCRIPTION General Overvie
234. wing CT 4532 and further described below 128 CHAPTER 4 FUNCTIONAL DESCRIPTION Main data processing in the unit is carried out by an 8031 type of microprocessor and its related hardware 64 k byte EPROM for instruction memory and 8 k byte RAM for data memory Furthermore the on board EEPROM provides for 1 k bit nonvolatile storage for scaling factors and other important parameters Through its integral UAR T and two integral timers the processor maintains serial asynchronous communication and time keeping in the system A watch dog timer provides for forced resetting of the processor in case of temporary malfunction The echo signal from the Receiver Board 15 first amplified and then converted into a digital form by a 6 bit Flash ADC taking one sample every 100 ns This corresponds to 50 ft 15m steps in backscattered laser light pulse path These 254 converted samples are stored into the fast RAM and then added by hardware to the respective sum of previously taken samples The cumulated samples sums which form the integrated results for each 50 ft range gate are then stored into the fast RAM Monitoring the power supply voltages and other relevant system parameters is carried out by a specific 19 channel ADC circuitry which features S bit conversion resolution and a bit by bit serial interface for interchanging channel addresses and conversion results with the processor The operating voltages of the CTM 12 are all supplied by on bo
235. yboard entry data into serial form and the incoming serial data into a suitable parallel form to be used by the display module The Receiver of the circuit converts the serial data into parallei form checks for correct form of transmission parity and location of the stop bits The Transmitter of the circuit converts the parallel form data into serial form data and adds it to the start bits parity and stop bits The meanings of these bits and the number of data bits can be changed by means of the control input signals of the circuit The inputs have been fixed as follows Figure 1 Serial Data Format Pi Symbol Meaning 35 PI 1 Parity Not Used 30 EPE 1 Don t Care 38 CLS 1 Number of Data Bits 8 37 CLS2 1 Number of Data Bits 8 36 SBS 1 2 Stop Bits The serial data thus takes the form illustrated below _ MSB _ A 48 1 m One 1 Eight 8 Data Bits Two 2 start stop Bit Bits Figure 1 Serial Data Format Note This format applies to transmission only Ceilometer uses one stop bit Due to interchange being asynchronous only one stop bit is mandatory Additional stop bits cause no errors 236 CHAPTER 4 FUNCTIONAL DESCRIPTION 4 3 9 3 1 4 1 UART Transmitter The serial data transmitter receives the information keyed in TBRI TRR8 and transmits it serially via pin TRO When the key has been depressed over a period determined by the contact debounce logic the stat

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