Vaisala FD12P User Manual Download Page 6

Page: 6 / 154

User's Guide _______________________________________________________________________

______________________________________________________ M210296en-A

Optical Arrangement........................................................... 96
FDT12B Transmitter Unit.................................................... 96
FDR12 Receiver Unit .......................................................... 98

Additional Measurements ..................................................... 99

General ............................................................................... 99
DRI21 Interface Board ........................................................ 99
DRD12 Rain Detector ....................................................... 100
DTS14B Temperature Sensor .......................................... 101

FDP12 Control Unit .............................................................. 101
Measurement Signal Processing........................................ 103

Optical Signal Processing................................................. 103
DRD12 Signal Processing ................................................ 104

Algorithm Description ......................................................... 105

Visibility ............................................................................. 105
Detecting Precipitation...................................................... 106
Precipitation Intensity........................................................ 106
Precipitation Accumulation ............................................... 107
Present Weather ............................................................... 108

Precipitation Types ...................................................... 108

Liquid Precipitation ................................................. 109
Frozen Precipitation................................................ 110
Mixed Precipitation ................................................. 111
Unknown Precipitation............................................ 111

Visibility Types ............................................................. 111

Fog.......................................................................... 111
Haze and Mist......................................................... 112

Weather Classes ......................................................... 112
Weather Code Selection.............................................. 113

Applications.......................................................................... 113
Internal Monitoring .............................................................. 114

Built-in Tests ..................................................................... 114
Memory Tests ................................................................... 115
Signal Monitoring .............................................................. 115
Hardware Monitoring......................................................... 115
Contamination Monitoring................................................. 116

CHAPTER 6

MAINTENANCE ......................................................................................... 117

General.................................................................................. 117
Cleaning ................................................................................ 118

Cleaning Lenses and Hoods............................................. 118
Cleaning DRD12 Rain Detector........................................ 118

Calibration ............................................................................ 119

General ............................................................................. 119
Visibility Calibration........................................................... 119

Calibration Check Procedure....................................... 120
Calibration Procedure .................................................. 123
Calibrating the DTS14B Temperature Sensor............. 124

Removing and Replacing.................................................. 126

Removing and Replacing Optical Units ....................... 126
Removing and Replacing the DRD12 Rain Detector .. 129

Summary of Contents for FD12P

Page 1: ...Weather Sensor FD12P USER S GUIDE M210296en A May 2002 ...

Page 2: ...mechanical including photocopying nor may its contents be communicated to a third party without prior written permission of the copyright holder The contents are subject to change without prior notice Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user All legally binding commitments and agreements are included exclusively in...

Page 3: ...tement USA 15 ESD Protection 15 Trademarks 16 Warranty 16 CHAPTER 2 PRODUCT OVERVIEW 17 Introduction 17 Hardware Structure 17 Sensing Elements 19 Electronics Enclosure 20 Structural Elements 20 Operating Principle 21 Using FD12P 22 Equipment Nomenclature 23 Specifications 24 Mechanical Specifications 24 Electrical Specifications 24 Optical Specifications 25 Capabilities and Limitations 26 Visibili...

Page 4: ...ring 43 Communication Cable EMC shielding 46 Connecting a Background Luminance Sensor or a Day Night Switch to FD12P 48 Communication Options 50 Serial Communications Settings 50 Serial Transmission RS 232 50 Serial Multipoint Transmission RS 485 51 Modem DMX21 52 Indicators and Manual Controls 54 Indicators 54 Manual Controls 54 Analog Transmission 55 Connecting the Maintenance Terminal 55 Startu...

Page 5: ...t 76 Heavy Snow Limit 76 Light Snow Limit 76 Snow Pellets Limit 77 Snow Grains Limit 77 Ice Crystals Limit 77 Hail Limit 77 DRD Scale 77 Warm Limit 77 PRW Command 77 CLRS Command 78 WHIS Command 78 System Configuration Commands 79 PAR Command 79 CONF Command 80 BAUD Command 84 BLSC Command 84 Maintenance Commands 85 STA Command 85 CAL Command 87 TCAL Command 87 CLEAN Command 88 CHEC Command 89 FRE...

Page 6: ...107 Present Weather 108 Precipitation Types 108 Liquid Precipitation 109 Frozen Precipitation 110 Mixed Precipitation 111 Unknown Precipitation 111 Visibility Types 111 Fog 111 Haze and Mist 112 Weather Classes 112 Weather Code Selection 113 Applications 113 Internal Monitoring 114 Built in Tests 114 Memory Tests 115 Signal Monitoring 115 Hardware Monitoring 115 Contamination Monitoring 116 CHAPTE...

Page 7: ...nstructions 140 APPENDIX A NWS AND WMO CODES USED IN FD12P 143 The NWS Codes 143 APPENDIX B JUMPER SETTINGS AND INTERNAL WIRING 147 CPU Board 149 DC Regulator 149 DRI21 Interface Board 149 APPENDIX C TRANSMITTER AND RECEIVER TEST POINTS 151 INDEX 153 List of Figures Figure 1 FD12P Weather Sensor Site 18 Figure 2 DRD12 Rain Detector and DTS14B Temperature Sensor 19 Figure 3 FD12P Block Diagram 21 F...

Page 8: ...TS14 Sensor Holder Assembly to Mast 125 Figure 33 Removing the Optical Units 127 Figure 34 Replacing the Optical Units 128 Figure 35 Removing the DRD12 Rain Detector 129 Figure 36 Basic Electronics Enclosure Wiring 148 Figure 37 Test Points Transmitter 151 Figure 38 Test Points Receiver 152 List of Tables Table 1 Manual Revisions 12 Table 2 Related Manuals 12 Table 3 Basic Set 23 Table 4 Options 2...

Page 9: ...ers for DTS14 Temperature Sensor 131 Table 27 Updating Parameters 131 Table 28 Parameters and Commands 132 Table 29 Values for Internal Monitoring 138 Table 30 Internal Weather Types NWS Code 143 Table 31 WMO SYNOP Codes 4680 WaWa 143 Table 32 WMO SYNOP Codes 4680 WaWa 144 Table 33 WMO SYNOP Codes 4680 WaWa 144 Table 34 WMO Code Table 4678 Codes Used by FD12P 145 Table 35 CPU Board Jumpers 149 Tab...

Page 10: ...User s Guide _______________________________________________________________________ 10______________________________________________________ M210296en A This page intentionally left blank ...

Page 11: ...ry contact and warranty information for the product Chapter 2 Product Overview introduces the FD12P Weather Sensor features advantages and the product nomenclature Chapter 3 Installation provides you with information to help you install this product Chapter 4 Operation contains information needed to operate this product Chapter 5 Functional Description gives a functional description on the product...

Page 12: ...1 CCITT Modem LM11T0545 1 2 LM11 Background Luminance Meter Safety General Safety Considerations Throughout the manual important safety considerations are highlighted as follows WARNING Warning alerts you to a serious hazard If you do not read and follow instructions very carefully at this point there is a risk of injury or even death CAUTION Caution warns you of a potential hazard If you do not r...

Page 13: ...ation operation and maintenance WARNING Neglecting to follow these precautions or specific warnings and cautions elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Vaisala Oyj and its Subsidiaries do not answer for the consequences if the customer neglects to follow these requirements Ground the Equipment To minimize the hazard of electrical...

Page 14: ...t constitutes a definite safety hazard WARNING 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 WARNING Keep away from live circuits Component replacement or internal adjustments must be made by qualified maintenance personnel Operating personnel must not remove instrument covers Do not re...

Page 15: ... is in strict accordance with the manufacturer s instructions may cause interference to radio and television reception The Weather Sensor is designed to provide reasonable protection against such interference in an airport installation However there is no guarantee that interference will not occur in a particular installation If this equipment causes interference to radio or television reception w...

Page 16: ...en neither of the above is possible touch a conductive part of the equipment chassis with your other hand before touching the boards Always hold the boards by the edges and avoid touching the component contacts Trademarks Intel is a registered trademark of the Intel Corporation in the U S and other countries Warranty For certain products Vaisala normally gives a limited one year warranty Please ob...

Page 17: ...mine the visibility and precipitation related weather codes in the World Meteorological Organization WMO standard SYNOP and METAR messages The sensor can also be employed as an observer s aid in a semi automatic weather observing system The sensor is also suitable for other weather observing systems providing valuable information for example to road and harbor authorities The versatility of the FD...

Page 18: ...losure with the main data processing and interface units is mounted to the pole mast as seen in Figure 1 below 0201 085 Figure 1 FD12P Weather Sensor Site The following numbers are related to Figure 1 above 1 Transducer crossarm 2 DRD12 Rain Detector 3 DTS14 Temperature Sensor 4 Pole mast 5 Electronics enclosure The FD12P Weather Sensor consists of three parts sensing elements electronics enclosur...

Page 19: ...ownwards Therefore the receiver unit measures light scattered at an angle of 33 The DRD12 Rain Detector outputs a signal proportional to the amount of water on two RainCap sensing elements These elements consist of thin wires protected by an insulating glass coating The presence of water changes the capacitance of the elements The combined capacitance of the plates is measured by the DRD12 electro...

Page 20: ...In addition the DRI21 controls the DRD12 heating and reads the precipitation ON OFF status The FDW13 Mains Power Supply converts the mains voltage to 24 VAC power for the FDS12 regulator and the heater elements The FDW13 includes also the mains voltage selector and the mains ON OFF switch which also functions as an automatic fuse The FDS12 DC Voltage Regulatorconverts the AC or DC input voltage mi...

Page 21: ... 091 Figure 3 FD12P Block Diagram The FD12P evaluates Meteorological Optical Range MOR by measuring the intensity of infrared light scattered at an angle of 33 The scatter measurement is converted to the visibility value MOR after a careful analysis of the signal properties Special processing is used in case of precipitation The FD12P software detects precipitation droplets from rapid changes in t...

Page 22: ...ontrols the timing of the tasks and the interactions between the tasks Using FD12P The FD12P is typically used as a component of a weather observing system The final weather message SYNOP METAR is then coded in the central unit of a weather observation system for example Vaisala MILOS 500 or by a human observer using the FD12P as an observation aid The FD12P output is a digital serial interface wh...

Page 23: ...ons interfacing assembly FDP12 Processor Board FDS12 DC Voltage Regulator FDW13 Mains Power Supply DRI21 Interface Board 16615ZZ Transducer Cable 16737ZZ I O Bus Cable DRD12 Rain Detector FD30513 Pole Mast Standard 2 m mast 13145 Base Plate and Installation Set Table 4 Options Type Name Description FDA13 Visibility Calibration Set FD45094 Maintenance cable RS232 cable with 9 pin D connector Termbo...

Page 24: ...e 16 mm bolts Material anodized aluminum natural gray Electrical Specifications Mains supply 115 230 VAC 20 45 65 Hz Maximum power consumption 35 W 100 W defrosting heaters in cold weather The sensor electronics Lock in amplifier LED power stabilizer Contamination monitor Lens heater The control unit Intel 8031 microprocessor Program memory 64 Kbytes Read write memory 32 Kbytes Outputs Serial data...

Page 25: ...mote alarm relay etc Alarms and warnings hardware failures visibility limits Optical Specifications Operating principle Forward scatter at an angle of 33o and capacitive rain sensor The light transmitter Light source near infrared LED Peak wavelength 875 nm Modulation frequency 2 3 kHz Transmitter lens diameter 71 mm Reference photodiode for light source control Backscatter photodiode for contamin...

Page 26: ... Threshold Definition Accuracy 10 range 10 10 000 m 20 range 10 000 50 000 m Instrument consistency 4 Update interval 15 seconds Weather Sensing Specifications Precipitation detection sensitivity 0 05 mm h or less within 10 minutes Weather type identification 11 different types of precipitation Fog mist and haze smoke sand Weather type reporting WMO code table 4680 with some additions from code ta...

Page 27: ...______________ 27 Precipitation intensity measurement Range 0 00 999 mm h Accuracy 30 range 0 5 20 mm h liquid precipitation Environmental Specifications Operating temperature range 40 55 oC Operating humidity range Up to 100 RH Wind speed Up to 60 m s standard mast Sun orientation Direct and reflected sunlight into the light receiver must be avoided ...

Page 28: ...User s Guide _______________________________________________________________________ 28______________________________________________________ M210296en A This page intentionally left blank ...

Page 29: ...Weather Sensor make a plan of the installation steps The following is an example of how to organize the installation process 1 Surveying the site Find the most representative measurement site Determine orientation of the Weather Sensor 2 Cabling plan is required for the following Grounding cabling layout and cable type Power supply cabling layout and cable type Modem signal cabling layout and cabl...

Page 30: ...requirements for the location of the FD12P are as follows 1 Place the FD12P at a site where the measurements will be representative of the surrounding weather conditions The ideal site has a minimum clearance of 100 meters from all large buildings and other constructions that generate heat and or obstruct precipitation droplets Also avoid shading of trees as this may cause changes in the microclim...

Page 31: ...crease the noise level in the receiver The transmitter and receiver should face away from any obvious source of contamination such as spray from passing vehicles Dirty lenses will cause the sensor to report too high visibility values Excessive contamination is automatically detected by the sensor Harmful reflections are typically avoided if the transmitter beam is directed towards a surface which ...

Page 32: ...h is located under the cable flange See Figure 5 on page 33 A 16 mm jacketed grounding cable is connected to the clamp Depending on the need one to four copper sheathed steel rods are driven into the ground If several rods are needed the alignment from the foot of the base plate must be radial The grounding principles are the following The grounding rod must be isntalled as close to the pole mast ...

Page 33: ...______________________________________________________________ 33 0111 001 Figure 5 FD12P Equipment Grounding The following numbers refer to Figure 5 above 1 Electronics enclosure 2 Junction box optional 3 Mains cable 4 Cable tubing 5 Grounding rods 6 Signal cable 7 16 mm grounding cables 8 Grounding clamp ...

Page 34: ...ket which is located beside the MIL connector in the crossarm See instructions in section Assembling the FD12P on page 40 and Figure 10 on page 43 Grounding for Testing Purposes The FD12P is provided with a two meter mains cable The cable has a grounded plug The plug must be connected only to an outlet that has a ground terminal This grounding is sufficient when the instrument is used indoors for ...

Page 35: ...AC divide the maximum distances by four Table 5 Mains Cable Selection Maximum Distance from Voltage Source One wire Cross section Area Nearest AWG gauge Typical Non armored Cable Diameter 2 km 1 5 mm2 No 15 AWG 10 mm 4 km 2 5 mm2 No 13 AWG 14 mm 8 km 4 0 mm2 No 11 AWG 18 mm NOTE Cables with diameters more than 12 mm require a separate junction box which is also available from Vaisala Communication...

Page 36: ...he optics Electronics enclosure FDB12 with radiation shield Pole mast Two persons can easily move the cases from a truck to the installation site NOTE Handle gently the case containing the optical parts Do not drop either end of the case Unpacking Procedure 1 Read the packing list supplied within the delivery documents Compare the packing list against the purchase order to make sure that the shipm...

Page 37: ...onstructing the Foundation Cast a concrete foundation or use an existing construction that is level and rigid The recommended minimum dimensions for the foundation are illustrated in Figure 6 below It is easiest to mount the foundation screws while casting the pad If the pad was casted earlier drill three holes into the concrete for the wedge bolts 0110 179 Figure 6 Casting a Concrete Foundation ...

Page 38: ...ng the base plate Mounting When Casting the Pad 1 Fasten the three reinforcing plates to the lower end of the foundation screws with six M16 nuts See Figure 7 C top view on page 39 2 Fix the template to the upper ends of the foundation screws with six nuts 3 Embed the assembly in the concrete foundation as shown in Figure 7 on page 39 4 After the concrete has set remove the template Mounting to an...

Page 39: ...________________________________________________________________ Installation VAISALA________________________________________________________________________ 39 0110 180 Figure 7 Constructing the FD12P Foundation ...

Page 40: ...ew 10 M10 4 pieces 11 Baseplate Assembling the FD12P 1 Mount the base plate and level it with the six M16 nuts 2 Mount the pole mast pedestal and the tilting support on the base plate with four M10 bolts Figure 7 on page 39 C top view 3 Attach the electronics enclosure to the pole mast with two clamps and four M6 Allen screws 4 Tilt the mast See Figure 8 on page 41 5 Feed the crossarm cable and te...

Page 41: ...ilting supporters To be installed under the fastening screws Attaching the DTS14B Temperature Sensor to the Mast To attach the DTS14B Temperature Sensor to the mast do the following 1 Pull the DTS14B temperature sensor out of the side hole of the mast 2 Then attach the holder to the mast in the following way Open the fixing screw fully part 3 below Push the screw head to the holder with you finger...

Page 42: ...___ M210296en A Insert the crossarm to the pole mast and lock it in the right position with two 8 mm bolts Erect the mast Lift the DRD12 Rain Detector to an upright position Tighten the clamp 0201 088 Figure 9 DTS14B and the Sensor Holder Assembly to Mast The following numbers refer to Figure 9 above 1 Sensor holder 2 DTS14 3 Fixing screw ...

Page 43: ...____________________ 43 0110 182 Figure 10 Connecting Internal Grounding The following numbers refer to Figure 10 above 1 Crossarm 2 Ground terminal socket 3 Grounding flat connector 4 Pole mast 5 MIL connector Connecting Cables Basic Wiring To do the basic wiring do the following 1 The electronics enclosure includes a power cable Remove the plug ...

Page 44: ...he electronics enclosure The selected method depends on the thickness of the power cable which should be checked before the installation The electronics enclosure has a cable outlet with a diameter of 10 12 mm 3 Feed Neutral N normally blue and protective earth PE normally yellow green via separate conductors 4 Feed the communication cable through one of the two cable feedthroughs For cable shield...

Page 45: ...at the factory check the voltage setting of the FDW13 Mains Power Supply alternatives 115 VAC and 230 VAC You can find the line voltage setting switch on the left side of the FDW13 unit see Figure 12 below 0110 183 Figure 12 Line Voltage and ON OFF Switches The following numbers are related to Figure 12 above 1 Electronics enclosure 2 Pole mast 3 DMX21 modem 4 DC regulator FDW13 5 ON OFF switch 6 ...

Page 46: ...rough Communication Cable EMC shielding The electronics enclosure has one cable outlet for a cable diameter from Ø7 to Ø10 mm which is reserved for a signal or modem cable Although the shielding of the cable may be just grounded after cable inlet an efficient procedure against RF interference requires special care Ground the cable gland to keep EMI levels within specifications For a proper RF grou...

Page 47: ...with rubber cylinder onto the cable 4 For a thin cable add a shrinkable tube to increase cable diameter 5 Slide two metal rings on the shielding and squeeze it evenly between the rings 6 Secure with a shrinkable tube 7 Tighten the cable with the cable gland and proceed with the wiring 8 Connect the signal cable to the screw terminals in the electronics enclosure 9 Ground the signal cable with the ...

Page 48: ...erface board and then converted into background luminance by the FD12P software The conversion uses a scaling factor which needs to be configured by the user For details see section BLSC Command on page 84 In certain applications it is necessary to calculate night visibility separately using a formula that differs from MOR In these cases a simple day night photo switch is sufficient for discerning...

Page 49: ...__________________________________________________ Installation VAISALA________________________________________________________________________ 49 9610 006 Figure 15 Wiring the Connector for the LM11 Background Luminance Meter ...

Page 50: ...ring the Day Night Photo Switch Communication Options Serial Communications Settings NOTE The factory default settings of the FD12P serial communications port are 300 baud Even parity is 7 data bits 1 stop bit Serial Transmission RS 232 For the RS 232 communication connect the signal wires to screw terminal X18 CTR lines not needed at CPU board FDP12 See Figure 17 on page 51 ...

Page 51: ...ission standard allows several FD12Ps to communicate half duplex with the host computer using a single twisted pair For the RS 485 communication connect the signal wires to 4 pin screw connector X21 at the CPU board See Figure 18 on page 52 In the multidrop configuration where several FD12P Weather Sensors are on the same communication line units are differentiated by an ID Set a different unit ID...

Page 52: ...guration where several FD12P Weather Sensors are on the same modem line the units are differentiated by an ID Set a different unit ID to each FD12P with the CONF command In the multidrop configuration only one FD12P modem carrier can be active at the time To set the modem carrier under the FD12P software control set jumper X2 to position 1 3 in the modem interface board as shown in Figure 19 on pa...

Page 53: ...the answer mode and the modem of the host computer in the originate mode In the standard FD12P system the S3 switch on the DMX21 board is in the DOWN position and the answer mode is selected When the switch is in the UP position the originate mode is selected The transit frequencies of the DMX21 modem are presented in Table 7 below Table 7 Transmit Frequencies of the DMX21 Modem Board Originate Mo...

Page 54: ...D Indicates when a carrier frequency is detected To make date interchange possible the modems must first detect the carrier frequency LED V19 TxD Transmitted data stream when the data is 1 the LED is lit LED V20 RxD Received data stream When the received data is 1 the LED is lit Manual Controls The manual controls and their positions are listed and described in Table 9 below Table 9 Manual Control...

Page 55: ...nnector X20 pin 3 sink at the CPU board In the drawing a remote voltage supply is used and the return signal is wired from pin 4 gnd See Figure 20 below For more information of the analog output port functioning and configuring see section Analog Output Commands on page 91 9607 007 Figure 20 Analog Current Loop Option Connecting the Maintenance Terminal Any computer equipped with a terminal emulat...

Page 56: ...y FDW13 3 Check that the red LED on the CPU board is lit for a few seconds after which the green LED should start blinking If not continue with troubleshooting 4 After startup the FD12P outputs VAISALA FD 12P V1 XX 19YY MM DD SN ID is also included if configured 5 Wait for one minute and enter the command mode with the OPEN command Check with the STA command that no hardware errors or warnings are...

Page 57: ...al sensors must have distinct identifiers ID The baud rate should not be changed if the optional 300 baud modem is used The commands for changing the default settings are listed in Table 11 below Detailed descriptions of the commands can be found in Chapter 4 on page 59 Table 11 Commands for Changing the Default Settings Operation Command Baud rate selection BAUD Polled or automatic mode message t...

Page 58: ... threshold value For details see the description of the WSET command in section WSET Command on page 73 When the precipitation intensity and amount measurement is not factory calibrated higher accuracy can be achieved by adjusting a scaling factor with the WSET command The new scaling factor can be calculated by comparing the FD12P against a reference rain gauge For details see the description of ...

Page 59: ...xiting the Command Mode on page 61 The FD12P Weather Sensor has seven different standard message formats for data message output The FD12P presents the weather type using the World Meteorological Organization WMO code table 4680 WaWa Present Weather reported from an automatic weather station Code numbers 77 snow grains 78 ice crystals and 89 hail are from the code table 4677 because the types are ...

Page 60: ...ds Table 14 Routine Command for Maintenance Operation Command Sensor cleaning CLEAN optional Visibility calibration CHEC CAL Temperature calibration FREQ TCAL Weather algorithm parameters WSET The standard output messages contain a status character which presents the results of the internal diagnostics to the host computer or the user If the sensor indicates a warning or an alarm in a standard out...

Page 61: ... each other by a space character Every user command must be ended with ENTER illustrated in this manual by The system output is illustrated as Courier type font for example BACKSCATTER INCREASED Entering Exiting the Command Mode Before any commands can be given to the FD12P the communication line in the FD12P has to be assigned to the operator Otherwise it is assigned to automatic messages or poll...

Page 62: ...automatic data messages by typing CLOSE The FD12P answers LINE CLOSED Automatic Message Sending In the automatic CLOSEd mode the FD12P sends the predefined message at selected intervals The automatic message is selected by the AMES command AMES Message_number Message_interval where Message_number The valid range is 0 7 refers to section Message Types on page 63 Selects the corresponding message An...

Page 63: ... section MES Command on page 71 Message Types All the data messages are of fixed length and the data is in fixed fields Message 2 is intended to be used as the standard present weather message The length of the status message depends on the possible alarm and warning states The FD12P adds frame strings to the polled and automatic messages The content of the frame strings is presented in the follow...

Page 64: ...essage 0 Message 0 displays only the one minute average visibility truncated to 19900 and the offset frequency of the optical measurement hardware 00 6800 126 87 offset frequency one minute average visibility 1 hardware error 2 hardware warning 1 visibility alarm 1 2 visibility alarm 2 An example with frames is as follows FD 1 00 6800 126 87 FD 1 00 6800 126 87 012345678901234567890123456 Message ...

Page 65: ...ather code 0 99 instant present weather code 0 99 instant present weather NWS codes visibility ten minute average max 50000m visibility one minute average max 50000m 1 hardware error 2 hardware warning 1 visibility alarm 1 2 visibility alarm 2 An example with frames is as follows FD 1 00 6839 7505 L 52 61 61 0 33 12 16 0 FD 1 00 6839 7505 L 52 61 61 0 33 12 16 0 01234567890123456789012345678901234...

Page 66: ...S0101 CR LF ETX receiver 2 status two spaces receiver 1 status transmitter status S status heading background luminance value cd m2 option B background luminance heading contamination compensated visibility reserved not supported by FD12P CV compensated visibility heading non compensated visibility m V visibility heading unit ID one character only ID start indicator STX ID 1 V 1050 CV B S0101 1234...

Page 67: ...MEAS MODE ON 1 ECON MODE OFF 2 OPTICAL SURFACE TRB warning or alarm 3 POWER SUPPLY VBB power supply 4 HEATING VH lens heater current 5 FLASH LAMP LEDI LED intensity control 6 BL METER BL meter interface DRI21 connected 7 MEASUREM LOOP SIGNAL Table 17 Receiver Status Correspondence between MITRAS and FD12P BIT MITRAS FD12P 0 MEAS MODE ON 1 SPARE 2 OPTICAL SURFACE REC BACKSCATTER warning or alarm 3 ...

Page 68: ...ardware warning 1 visibility alarm 1 2 visibility alarm 2 RA instant METAR weather codes RERA recent METAR weather RE criteria used An example with frames is as follows FD 1 00 6839 7505 R 61 61 61 0 33 12 16 0 23 4 RA RERA FD 1 00 6839 7505 R 61 61 61 0 33 12 16 0 23 4 RA RERA Message 7 consists of four lines METAR present weather codes are output on the second and third lines These lines are not...

Page 69: ... message as the default polled message Any negative message number is converted to 0 Message_interval Negative or zero interval is used to disable the automatic sending This is used when messages are polled For example AMES 0 0 selects message 0 and cancels the automatic sending The polling command format is the following ENQ FD SP id SP message_number CR where ENQ ASCII character 05 hex SP ASCII ...

Page 70: ...dged the request When the carrier is switched on additional characters will appear before the SOH 01 hex character The FD12P waits about 100 ms after turning the carrier on before it starts to send the message When the FD12P has sent the message it turns the carrier off This will also generate additional characters which have to be ignored by the host FD12P Command Set HELP Command The operator re...

Page 71: ...SET PRW reference values DRY ON Sets DRD dry offset WET ON Sets DRD wet scale BLSC Sets Displays background luminance scale MES Command After opening the line for operator commands see section Entering Exiting the Command Mode on page 61 a data message can be displayed using the MES command There are eight messages available for different uses and they numbered from 0 to 7 Refer to section Message...

Page 72: ...en the previous interval setting is used Message_interval Given in multiples of 15 seconds the measuring interval Therefore intervals 15 30 45 are valid Other intervals are converted to integer multiples of 15 seconds The maximum sending interval is 255 seconds 4 minutes 15 seconds Negative or zero interval ignores the automatic sending This is used when messages are polled Refer to section Messag...

Page 73: ...eather analysis parameters Typing WPAR displays the following output WEATHER PARAMETERS PRECIPITATION LIMIT 40 WEATHER UPDATE DELAY 6 HAZE LIMIT 9000 RAIN INTENSITY SCALE 0 80 VIOLENT RAIN LIMIT 50 HEAVY RAIN LIMIT 8 0 LIGHT RAIN LIMIT 2 0 DRIZZLE LIMIT 15 HEAVY DRIZZLE LIMIT 30 LIGHT DRIZZLE LIMIT 3 WARM LIMIT 8 0 SNOW LIMIT 5 0 HEAVY SNOW LIMIT 600 LIGHT SNOW LIMIT 1200 SNOW PELLETS LIMIT 30 SNO...

Page 74: ... 1 5 WARM LIMIT 8 0 The parameters are described in detail below Precipitation Limit The Precipitation limit parameter is the threshold of accumulated particle magnitudes in FD12P internal units that reports the precipitation on state The typical parameter value is 40 The smaller value represents a more sensitive operation and faster response at the beginning of an event Weather Update Delay The W...

Page 75: ...r a few rainfalls with 5 mm or more of total accumulated rain A new scaling factor can be calculated using the following formula Newscale Oldscale Ref_Amount FD12P_Amount where Oldscale Old value of Rain Intensity Scale Ref_Amount Amount measured with the reference rain gauge FD12P_Amount Corresponding amount measured by the FD12P Violent Rain Limit The Violent rain limit parameter defines the min...

Page 76: ...nes the maximum number of droplets detected in 15 seconds when drizzle is light Snow Limit The Snow limit parameter specifies the minimum ratio of optical precipitation intensity to surface sensor DRD12 precipitation intensity when the precipitation is snow A half of this value is used for separating sleet and ice pellets The typical value for Snow limit is 5 A smaller value directs the FD12P to r...

Page 77: ...al internal criteria are used before the precipitation type is determined to be ice crystals Hail Limit The Hail limit parameters refers to the minimum particle size in FD12P internal units which is detected as hail Additional internal criteria are used before the precipitation type is determined to be hail DRD Scale The DRD scale parameter is the scaling factor for the calculated intensity of the...

Page 78: ...llowing command format ESC FD id C CR Then the FD12P responds to the accepted command with the following ASCII character ACK 06 hex WHIS Command The WHIS command displays the instant precipitation type codes NWS for one hour Type WHIS to get the results shown on the next page PRW HISTORY L L L L L L L L L L L L L L L L R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R...

Page 79: ...1200 2400 4800 9600 Par E 7E1 N 8N1 BLSC Set display background luminance scale PAR Command The current system parameters can be displayed by using the PAR the System Parameters command When you type PAR the system output is shown on the next page SYSTEM PARAMETERS VAISALA FD12P V 1 83 1999 11 19 SN 46401 ID STRING AUTOMATIC MESSAGE 2 INTERVAL 15 ALARM LIMIT 1 0 ALARM LIMIT 2 0 OFFSET REF 130 50 C...

Page 80: ... is not updated if the user only presses the key You can modify the following system parameters using the CONF command Vis Alarm Limits Offset Freq Reference Temperature TE Scale Password Characters Unit Id Characters 2 References And Limits for Contamination Monitoring Analog Output Minimum Visibility Analog Output Maximum Visibility Analog Output Lin Log To prevent unauthorized change of the sys...

Page 81: ...IT UPDATED ALARM LIMIT 5 0 RECEIVER CONTAMINATION LIMITS WARNING LIMIT 100 ALARM LIMIT 500 600 ALARM LIMIT UPDATED ANALOG OUTPUT MODE 0 LINEAR 1 LN 0 ANALOG OUTPUT RANGE MAX VISIBILITY 10000 MIN VISIBILITY 50 END OF CONFIGURATION The questions asked by the system are described below First the system asks for a new password CONF PASSWORD 4 CHARACTERS MAX This question is asked when there is no vali...

Page 82: ...9 The default value is the current temperature If it is not correct a new value must be typed as the answer The new value is used to correct the internal TE scaling factor The TE temperature is used as a backup in FD12P The temperature is used in the visibility measurement to control the precipitation effect correction algorithm Snow and rain have a different kind of effect on the scattering signa...

Page 83: ... expressed in volt V The measurement range is 0 to 13 V where 0 V is a blocked lens The limit value is given as a positive value although the signal becomes smaller when contamination increases A contamination change of 5 V represents about a 10 decrease in the transmitter s lens transmittance as also does the same increase in the visibility indication RECEIVER CONTAMINATION LIMITS WARNING LIMIT 3...

Page 84: ...hanged Other baud rates than 300 baud are not allowed with the DMX21 modem The BAUD command displays the current baud rate and communication type For an example see the following BAUD RATE 300 E71 BLSC Command The Vaisala LM11 Background Luminance sensor can be connected to the FD12P for ambient light measurement Each LM11 sensor has an individual scaling coefficient which is defined at the factor...

Page 85: ...report it as a background luminance value of 1 day or 0 night The FD12P firmware will read the switch if the background luminance scaling factor is set to 0 Maintenance Commands The maintenance commands are listed in Table 21 below Table 21 Maintenance Commands Command Description STA Displays status CAL Calibrator_frequency Calibration TCAL Temperature measurement calibration CLEAN Sets clean ref...

Page 86: ...OR The LEDI signal is more than 7 V or less than 8 V 15 V POWER ERROR The receiver transmitter power is less than 14 V or more than 16 V OFFSET ERROR The offset frequency is zero cable is disconnected SIGNAL ERROR The signal frequency is less than 50 of the offset frequency RECEIVER ERROR Too low signal detected in the receiver backscatter measurement DATA RAM ERROR The error is in RAM read write ...

Page 87: ...easurement The calibration is done by using opaque glass plates with known scatter properties The command type is the following CAL Calibrator_signal_value Type for example the following CAL 985 The calibrator signal value is printed on the labels of the glass plates Typically the signal is close to 1000 Hz The FD12P calculates a new scaling factor and stores it in the non volatile memory EEPROM R...

Page 88: ...L TS 0 0 makes a zero calibration if the temperature sensor DTS14B is in an ice bath or otherwise at a temperature of 0 C The following command TCAL TS 0 0581 59 0 sets both scaling factors The system output is as follows DRI TEMPERATURE SCALES TS 1 0 0581 TS 0 59 0000 TS 2 8 CLEAN Command The CLEAN command has no parameters and it is used to set the clean references for contamination control This...

Page 89: ...essage should be the same as printed on the calibrator glass plate In clear air the value should be near zero When you type CHEC the output is the following SCALED FREQUENCY AVE 2 MIN 999 9938 999 9880 FREQ Command The FREQ command is for hardware monitoring Message 4 gives the same data line as the FREQ command An example of the output is the following freq SIGNAL OFFSET DIST SWID MAXI OWID TE LE...

Page 90: ...arameter shows the scaling factor that normalizes the DRD12 signal change from the dry state to the wet state to 1 00 A typical value is 0 0015 An example is shown in the following WET DRD WET SCALE 0 00169 The WET ON command is used to set the parameter The DRD12 measuring surfaces must be coated with a wet cloth or immersed in water when the WET ON command is given An example of the command is g...

Page 91: ...re set in the configuration session A hardware error is indicated by 0 mA The ACAL command sets two bit values 4000 and 800 to the digital to analog converter The corresponding currents measured by a multimeter must be given as answers to the questions asked in the commands The analog output scaling factors which define the bits mA relation are then calculated by the software The scaling factors a...

Page 92: ... value and maximum visibility to the 20 mA calibrated value In linear mode DACBITS visibility min visibility scale 1 scale 0 In logarithmic mode DACBITS ln visibility ln min visibility scale 1 scale 0 If visibility is less than minimum visibility then DACBITS bits4mA scale 0 If visibility is more than maximum visibility then DACBITS bits 20mA Hardware Check The DAC bit value from 0 to 4095 can be ...

Page 93: ... for maintenance purposes To display the current system time type TIME The system output is for example the following 10 11 12 To set the time use the following command TIME hh mm ss where hh Hours mm Minutes ss Seconds NOTE Reset the time after a power break DATE Command The DATE command is used to display the current date Type DATE To set a new system date use the command DATE yyyy mm dd where y...

Page 94: ...______________________________________________ 94______________________________________________________ M210296en A RESET Command The RESET command makes the hardware reset by the watchdog circuitry The command format is the following RESET ...

Page 95: ...MOR must be handled separately Usually these particles are precipitation droplets The FD12P optical arrangement allows for individual droplets to be detected from rapid signal changes The FD12P software calculates the precipitation intensity by analyzing the amplitudes of these changes This intensity estimate is proportional to the volume of the precipitation droplets The optical signal also conta...

Page 96: ...s scatter light in a different manner than fog Thus their contribution to visibility must be analyzed separately The FD12P can detect and measure precipitation droplets from the optical signal and use this information in processing the scatter measurement results The FD12P has a small sample volume of about 0 1 liters see Figure 21 above This enables independent particles to be measured even at qu...

Page 97: ...The LEDI feedback voltage is channeled through the analog multiplexer to the CPU for monitoring The feedback loop compensates for temperature and aging effects of the light emitting diode On the other hand the active compensation slightly accelerates the LED aging For this reason the initial LED current is set to a value which guarantees several years of maintenance free operation A reset pulse RE...

Page 98: ...is used for heating the lenses for the transmitter LED heating and for producing both 5 V digital and 15 V analog supplies The 15 V supply is located on the FDT12B board FDR12 Receiver Unit The Receiver Unit consists of a light receiver preamplifier voltage to frequency converter backscatter measurement light source LED and some control and timing electronics 9611 003 Figure 23 FDR12 Receiver Bloc...

Page 99: ...for monitoring An extra IR LED is needed for backscatter or contaminant measurement The light level is sampled and converted into frequency using the same method of detection described with the scattering signal measurement Additional Measurements General The FD12P includes the DRD12 Rain Detector for estimating the water content of precipitation and the DTS14B Temperature Sensor for measuring the...

Page 100: ...ed into a voltage signal for direct analog measurement With dry surfaces the DRD12 outputs about 3 V and with totally wet surfaces 1 V Refer to Figure 29 on page 104 section DRD12 Signal Processing on page 104 A droplet detector monitors the voltage signal When a new droplet hits the DRD12 sensing surface the voltage changes rapidly and the detector circuit reacts The detector triggers a delay cir...

Page 101: ... extremely sensitive to all moisture in the air DTS14B Temperature Sensor The DTS14B is a PT100 temperature sensor with a special mechanical construction The temperature is measured once a minute using the DRI21 temperature channel The DTS14B is attached to the sidewall of the mast to achieve direct thermal contact with the mast surface The temperature TS is used to select the default precipitatio...

Page 102: ...ala peripheral units The memory includes a 512 kbit EEPROM for program code and a 256 kbit static RAM for data and working parameters For configurable parameters there is a serial non volatile EEPROM The special frequency measurement circuitry measures the optical signal that is converted into frequency in the Receiver Unit FDR12 The watchdog circuit monitors the 5 V level as well as the system op...

Page 103: ...y 8 ms on the average The raw samples are first classified by frequency to get a signal distribution The distribution is then analyzed with a proprietary algorithm which selects a part of the distribution for signal average calculation Figure 27 below The difference of the signal average and offset average is used in the visibility calculation 9807 033 Figure 27 Optical Raw Data in Rain Precipitat...

Page 104: ...96en A 9807 034 Figure 28 Optical Signal Amplitude Distribution in Rain DRD12 Signal Processing The DRD12 output voltage is measured once a second by the DRI21 interface board With dry surfaces the voltage is approximately 3 V and drops when the sensing elements become wet Figure 29 below 0110 186 Figure 29 DRD12 Surface Signal Heavy Rain Beginning ...

Page 105: ...recipitation The software disconnects the heating after one hour from the previous precipitation detection When precipitation or moisture is detected again the heating is turned on for at least one hour Algorithm Description Visibility The optical signal analysis calculates the difference of the measurement signal and offset averages for the visibility algorithm The difference value frequency is g...

Page 106: ...ON OFF signal is used in lowest precipitation intensities The DRD12 is also used for some cross checking of the optical detection The precipitation ending is detected when the summed optical signal amplitudes decrease below another lower threshold value The summing interval depends on the detected precipitation intensity Typically the FD12P will detect precipitation ending within a few minutes but...

Page 107: ... the FD12P multiplies the optical intensity with a scaling factor to get an estimate of the water equivalent intensity This scaling factor is calculated from the DRD12 and optical intensities New intensity estimates are calculated every 15 s and averaged to get the one minute intensity value which is shown in the output messages Precipitation Accumulation The FD12P calculates the accumulation of w...

Page 108: ...m limit 8 C it is unknown P or 40 In some areas a more flexible snow reporting temperature limit is required The Warm limit which is the upper limit for reporting snow is a user definable parameter with the nominal value of 8 C The parameter can be defined between 4 C and 8 C Changing the limit temperature affects the discrimination of the following parameters Snow and hail if the ratio of optical...

Page 109: ...quid Precipitation In liquid precipitation the optical and the DRD12 intensities are near each other or the DRD12 intensity is higher Rain and drizzle are separated by the highest peak signal largest droplet If liquid precipitation is detected below 0 C TS it is indicated as freezing rain or freezing drizzle ZR ZL NOTE The FD12P freezing precipitation detection is based on the practical definition...

Page 110: ... frozen if the ratio of optical intensity measurement to DRD12 is high a Snow For snow the intensity ratio optical DRD12 must be larger than the Snow limit parameter and crossarm surface temperature TS less than 8 C warm limit b Snow grains For snow grains the droplet signal size must be less than the Snow grains limit in size Also the DRD12 intensity must be very small as the small snow grains ea...

Page 111: ...cipitation Precipitation type is unknown in the following cases When the default value is shown When the TS is between 5 C and 8 C warm limit Before enough data is available for better analysis When intensity is very low When the intensity ratio is not reliable Visibility Types When precipitation is not detected the weather type is determined from visibility The visibility types for FD12P can be d...

Page 112: ...est 20 minute average earliest 20 minute average is less than zero and the difference is more than 30 of the new 20 minute average Haze and Mist If no precipitation is detected a visibility code is generated The HAZE code 04 is used when the DRD12 estimated relative humidity is low and the visibility during the 10 minute average is less than the Haze limit If the estimated humidity is high the MIS...

Page 113: ...AY number of samples by majority occurrences The instant type is reported using both the NWS and WMO codes For the 15 minute and one hour WMO weather codes the latest one hour of instant precipitation types is stored in a buffer The last 15 minute and one hour parts of this table are then analyzed The number of each precipitation type in the buffer is counted The counts are stored in a table in de...

Page 114: ...us voltages are measured and corresponding alarm and warning limits are checked Optical contamination of both the transmitter and the receiver is continuously monitored by measuring the backscattered light For this purpose an additional transmitting LED is installed in the receiver The software generates alarms if visibility is less than the given limits The FD12P generates warnings of suspected f...

Page 115: ... in the status message The EEPROM checksum is calculated and checked during every updating of saved parameters Signal Monitoring The FD12P measures signal receiver backscatter and offset as frequencies in about eight millisecond samples As the measuring times are 10 s 1 s and 4 s correspondingly they must have different numbers of samples in a batch The FD12P checks that the frequencies are not ze...

Page 116: ...nation on the lenses The alarm and warning limits are given in the configuration session If the alarm limit is exceeded data is set to and an alarm is generated The measured values are used only for warnings and alarms No compensation for the visibility signal is calculated Transmitter backscatter is measured by an analog circuit using the transmitter LED as a light source Its identifier is TRB in...

Page 117: ...he periodic maintenance of the FD12P Weather Sensor includes Cleaning the transmitter and receiver lenses and hoods Cleaning the DRD12 Rain Detector Visibility calibration check and calibration if needed Calibration of the DTS14B Temperature Sensor Before any commands can be given to the FD12P the communication line must be opened Open the communication line by typing the following OPEN The FD12P ...

Page 118: ...REASED To clean the lenses do the following 1 Moisten a soft lint free cloth with isopropanol alcohol and wipe the lenses Be careful not to scratch the lens surfaces The lenses should dry up indicating that the lens heating is functioning 2 Check that the hoods and lenses are free of condensed water or ice and snow deposits 3 Wipe the dust from the inner and outer surfaces of the hoods 4 After the...

Page 119: ...ange is within the repeatability of the calibration procedure If any mechanical damage changes or weakens the optical measurement path that is either the receiver or the transmitter heads or the crossarm supporting them recalibration is needed If the receiver unit FDR12 transmitter unit FDT12B or the CPU unit FD12P is changed both visibility and contamination measurements need recalibration Also c...

Page 120: ...o the following 1 For blocking the light path place the blocking plate near either of the lenses preferably near the receiver 2 Wait for 30 seconds 3 Give the CHEC command Then wait at least two minutes The signal value must be between 0 1 Hz If it is not there may be a hardware error Check the connectors 4 Remove the blocking plate and terminate the CHEC command by pressing the ESC key To install...

Page 121: ...ent and place it between the hood tips Then lift the glass plates until they touch the ruler Tighten the clamp bolts Leave the calibrator clamp in place for the next calibrations Extra clamps can be purchased as optional items 4 Move away from the optical path and wait for 30 seconds 5 Give the CHEC command 6 After two minutes read the displayed signal 7 The signal value must be close to the one p...

Page 122: ...er s Guide _______________________________________________________________________ 122 _____________________________________________________ M210296en A 0201 087 Figure 31 Assembling the FDA13 Calibrator ...

Page 123: ...cording to the calibration check do the following 1 Give the CAL calibrator signal value command for example CAL 985 The calibrator signal value is printed on the labels of the glass plates Typically the signal is close to 1000 Hz The FD12P calculates a new scaling factor and stores it in the non volatile memory EEPROM 2 Type CHEC to learn the new scaling factor that should be equal to the calibra...

Page 124: ...lide the holder downwards as long as it goes 4 Pull the holder and sensor away from mast hole 5 Open the screw holding the DTS14 and pull the sensor out of the holder 6 Hang a thermos flask with a S shaped hook to the hole for example 7 Put the DTS14B temperature sensor into the ice bath 8 To see the current scaling factors and current TS give the TCAL command Then give the FREQ command Wait for f...

Page 125: ...___________________Maintenance VAISALA_______________________________________________________________________ 125 0201 088 Figure 32 DTS14 Sensor Holder Assembly to Mast The following numbers refer to Figure 32 above 1 Sensor holder 2 DTS14 3 Fixing screw ...

Page 126: ...either end of the crossarm by loosening the four screws holding the cover Use the Allen key for removing the screws 2 Remove the black round flange that covers the optical unit by pulling the screw in the middle of the flange See Figure 33 on page 127 3 Loosen the three hexagon socket locking bolts with the 5 mm T handle Allen key until the optical unit is loose 4 Disconnect the ribbon cable conne...

Page 127: ...___________________________________________________ 127 0110 187 Figure 33 Removing the Optical Units The following numbers are related to Figure 33 above 1 Hood tube 2 FDT12B transmitter FDR12 receiver 3 Round flange 4 Cover 5 4 screws M6 x 16 DIN7991 6 5 mm Allen key 7 3 locking bolts 8 Connector 9 Ribbon cable ...

Page 128: ...ee Figure 34 below 2 Connect the ribbon cable connector with the optical unit 3 Tighten the three hexagon socket locking bolts with a 5 mm T handle Allen key 4 Replace the round flange firmly Note the ribbon cable path and make sure the cable is run along the path safely 5 Finally fasten the outer cover with four screws 6 Perform visibility calibration Figure 34 Replacing the Optical Units The fol...

Page 129: ...he assembly clamp Refer to Figure 35 below The DRD12 Rain Detector is attached to the crossarm with its cable only 2 Detach the windshield by loosening the bolt 3 Remove the cover of the DRD12 unit by loosening the four screws 4 Loosen the hexagon nut of the cable feedthrough and detach the wires from the screw terminal inside the DRD12 unit Then pull the DRD12 cable out of the unit 5 Deliver the ...

Page 130: ...inal as shown in Figure 35 on page 129 2 Tighten the hexagon nut of the feedthrough 3 Place the cover on the DRD12 unit and fasten the four screws 4 Fix the windshield with the bolt Place the assembly clamp and fasten the DRD12 to the crossarm by tightening the two nuts Calibrating FD12P Weather Sensor after Unit Replacement The hardware of FD12P electronics unit has been checked and tuned at the ...

Page 131: ...emperature Sensor Parameter Type of Parameter Command to Change the Parameter Offset value Calibration constant TCAL TS Scaling factor Calibration constant TCAL TS If any electronics units are replaced some or all of the parameters may need to be updated Table 27 below describes the necessary operations for each unit Table 27 Updating Parameters Unit Necessary Operations Commands FDT12B Transmitte...

Page 132: ...matic or polling message type and weather type decision thresholds are also stored in the EEPROM If the processor board is replaced these parameters should also be checked and updated The parameters and commands are listed in Table 28 on page 132 Table 28 Parameters and Commands Parameter Checking Command Changing Command Sensor ID PAR CONF Message type Sending mode PAR AMES Weather parameters WPA...

Page 133: ...rous voltage of 230 VAC CAUTION Servicing the equipment must be performed by qualified personnel Troubleshooting Examples Message Indicating Warning or Alarm 1 Open the command mode and check the status information with the STA command or poll Message 3 for the same information 2 See section STA Command on page 85 for descriptions of the status message errors and warnings 3 Check the monitoring va...

Page 134: ...y opening the FD12P electronics enclosure cover to check if the LEDs are blinking 5 If no LED is on do the following Check that the main switch is on FDW13 Check the mains fuse 250 mA and replace it if needed WARNING The main fuse contains dangerous voltages of 230 VAC Check the low voltage fuse on the regulator board and replace it if needed Check that all the connectors are properly inserted Che...

Page 135: ...ons in section Removing and Replacing on page 126 when removing the units Check that the ribbon cable connector is properly connected Pull out the circuit boards first of the receiver loosen the bolts and then the transmitter Visually inspect the condition of the electronics Visibility Value is Continuously Too Good This can be caused by several reasons some of which are listed below Most probably...

Page 136: ...on detection When the temperature is above 0 C the DRD12 detection is used in cross checking the optical detection and false detection can only be caused by problems in both measurements 1 Check that there are no flashing lights close to the FD12P Flashing lights may cause the FD12P to detect peaks in the optical signal 2 Check that there are no foreign objects in the sample volume Tree branches o...

Page 137: ...e Decrease the scaling factor if the FD12P rain amount is too high Otherwise increase DRD scale Have Jumper Settings Been Changed If you have reason to believe that the original jumper settings have been changed see Appendix B on page 147 Values for Internal Monitoring The typical values are according to factory testing and are allowed to be changed within the given minimum maximum limits For exam...

Page 138: ...Check that the jumper X13 CPU is 1 2 or 2 3 OFFSET The lowest frequency for measurement signal 130 Hz 120 Hz 150 Hz 120 Hz 150 Hz 1 Check other parts of the STA message 2 Change the receiver REC BACKSCATTER Measurement signal from the receiver contamination control circuit Clean value Rec backscatter CHANGE Instant backscatter clean back scatter alarm limit BACK SCATTER HIGH Alarm that there is ob...

Page 139: ...the near future Change the transmitter TE Ambient temperature 40 C 50 C 60 C 50 C at any rate Sensor disconnected Sensor or cable is short circuit Check X14 connection on CPU board Check temperature sensor cable on CPU board SIGNAL Frequency of the transmission signal between transducer and CPU Hz is inversely proportional to visibility Freq Corr Visibility 1 Hz 4 5 km 10 Hz 800 km 100 Hz 150 km 0...

Page 140: ...0 V DC DC converter is overloaded or working wrong 1 Check flat cable between transmitter receiver 2 Change the transmitter 3 Change the receiver BGDN Ground potential for the transducer i e voltage loss in transducer cable 0 V 0 5 V 1 V 0 5 V 1 V Check transducer cable Getting Help For technical support or comments on the manual contact the Vaisala technical support E mail helpdesk vaisala com Te...

Page 141: ...eral failures in one unit What was connected to the product and to which connectors Input power source type voltage and list of other items lighting heaters motors etc that were connected to the same power output What was done when the failure was noticed 4 Include a detailed return address with your preferred shipping method on the Problem Report 5 Pack the faulty product using an ESD protection ...

Page 142: ...User s Guide _______________________________________________________________________ 142 _____________________________________________________ M210296en A This page intentionally left blank ...

Page 143: ...tation P Drizzle L Rain R Snow S Ice pellets IP Sleet IP Hail A Ice crystals IC Snow grains SG Snow pellets SP Freezing drizzle ZL Freezing rain ZR The NWS codes are used with intensity indicator for heavy for light and none space for moderate For example R means heavy rain Table 31 WMO SYNOP Codes 4680 WaWa Code Weather type 00 Clear 04 Haze or smoke or dust in suspension in the air visibility eq...

Page 144: ...g in patches 32 Fog or ice fog has become thinner during the past hour 33 Fog or ice fog not applicable change during the past hour 34 Fog or ice fog has begun or become thicker during the past hour 40 PRECIPITATION 41 Precipitation slight or moderate 42 Precipitation heavy 50 DRIZZLE 51 Drizzle not freezing slight 52 Drizzle not freezing moderate 53 Drizzle not freezing heavy 54 Drizzle freezing ...

Page 145: ...violent 32 mm h 85 Snow showers light 86 Snow showers moderate 87 Snow showers heavy 89 Showers of hail with or without rain or rain and snow mixed not associated with thunder from WMO 4677 Table 34 WMO Code Table 4678 Codes Used by FD12P Qualifier Weather Phenomena Intensity 1 Descriptor 2 Precipitation 3 Obscuration 4 Light Moderate no qualifier Heavy BC Patches SH Shower s FZ Freezing DZ Drizzl...

Page 146: ...User s Guide _______________________________________________________________________ 146 _____________________________________________________ M210296en A This page intentionally left blank ...

Page 147: ...________________________________ Jumper Settings and Internal Wiring VAISALA_______________________________________________________________________ 147 APPENDIX B JUMPER SETTINGS AND INTERNAL WIRING See Figure 36 on page 148 ...

Page 148: ...r s Guide _______________________________________________________________________ 148 _____________________________________________________ M210296en A 020 090 Figure 36 Basic Electronics Enclosure Wiring ...

Page 149: ... crossarm transmitter receiver X16 Not in use X17 Supply voltage pin 4 10 12 VDC pin 6 GND X18 RS 232 connector pin 1 GND pin 2 RxD pin 3 TxD for remote and maintenance use X19 RS 232 control signals for DMX21 or other options X20 Analog current output sinking type X21 RS 485 alternative use to RS 232 DC Regulator Table 37 DC regulator Connectors Connectors Description X1 Pin 1 3 output for hood h...

Page 150: ...O Analog mux channel Mux GRY X15 8 H 8 GRY Channel bit 1 backsc led Cb1 WHT X15 9 J 9 WHT Channel bit 0 led off Cb0 BLK X15 10 K 10 BLK Supply voltage Vb BRN B 11 BRN Timing reset Res RED 12 RED Ambient light Ali ORN 13 ORN Analog voltage 15 V YEL 14 YEL Analog voltage 15 V GRN 15 GRN Analog ground spare AGND BLU 16 BLU DRD12 supply voltage 12 V YEL GRN X15 2 R RED DRD12 heater GND GND A WHT Enclo...

Page 151: ...151 APPENDIX C TRANSMITTER AND RECEIVER TEST POINTS There are some test points TP on the FD12P circuit boards for testing They are as follows Table 41 Transmitter Test Points Test Point Description TP1 Reference voltage 2 5 V 1 TP4 Feedback signal TP5 Control voltage for LED driver 8 V 7 V X1 1 15 V X1 2 15 V X1 3 5 V X1 4 GND 9611 005 Figure 37 Test Points Transmitter ...

Page 152: ...iver Test Points Test Points Description TP1 Synchronizing pulse for factory tests TP2 Reference voltage 2 5 V 1 TP3 5 V TP4 Measurement signal after high pass filter TP5 P15 15 V 1 V TP6 M15 15 V 1 V TP7 GND TP8 Measurement signal after 2 stage amplifier AC TP9 Measurement signal 0 10 V before V F converter 9611 006 Figure 38 Test Points Receiver CPU TP1 GND TP2 GND ...

Page 153: ... Communication Cable EMC shielding 46 Communication Options 50 CONF 80 Connecting Cables 43 Connecting Internal Grounding 43 Connecting the Maintenance Terminal 55 Constructing the Foundation 37 Contamination Monitoring 116 crossarm17 18 19 20 22 30 34 40 42 87 99 102 110 111 119 120 123 126 129 130 149 D DAC command 92 DATE 93 Detecting Precipitation 106 DRD12 Rain Detector 100 DRD12 Signal Proce...

Page 154: ...h 20 45 OPEN 61 Operating Principle 21 Optical Measurement 96 Optical Signal Processing 103 Organizing Installation 29 P PAR 79 Polling 69 power cable 13 14 35 43 44 46 134 Precipitation Accumulation 107 Precipitation Intensity 106 Precipitation Types 108 PRW 77 R Related Manuals 12 Removing and Replacing 126 Removing and Replacing the DRD12 Rain Detector 129 RESET 94 S Safety 12 Safety summary 13...

Search results

Summary of Contents for FD12P

Reviews:

Related manuals for FD12P

Brands by name

Popular brands

Vaisala FD12P, User Manual

Search results

Summary of Contents for FD12P

Reviews:

Related manuals for FD12P

Brands by name

Popular brands