Weather Sensor FD12P USER'S GUIDE M210296en-A May 2002
PUBLISHED BY Vaisala Oyj P.O. Box 26 FIN-00421 Helsinki Finland Phone (int.): +358 9 8949 1 Fax: +358 9 8949 2227 Visit our Internet pages at http://www.vaisala.com/ © Vaisala 2002 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice.
_________________________________________________________________________________ Table of Contents CHAPTER 1 GENERAL INFORMATION ..........................................................................11 About This Manual..................................................................11 Contents of This Manual......................................................11 Version Information................................................................12 Related Manuals ...................................
User's Guide _______________________________________________________________________ Grounding for Testing Purposes......................................... 34 Grounding Remote Units and Communication Cable......... 34 Cable Selection ...................................................................... 35 Line Power Cabling............................................................. 35 Communication Cable......................................................... 35 Unloading and Unpacking................
_________________________________________________________________________________ MES Command ...................................................................71 AMES Command............................................................71 Weather Related Commands ..............................................73 WPAR Command ...........................................................73 WSET Command ...........................................................73 Precipitation Limit ............................
User's Guide _______________________________________________________________________ Optical Arrangement ........................................................... 96 FDT12B Transmitter Unit .................................................... 96 FDR12 Receiver Unit .......................................................... 98 Additional Measurements ..................................................... 99 General ...............................................................................
_________________________________________________________________________________ Calibrating FD12P Weather Sensor after Unit Replacement ................................................................130 CHAPTER 7 TROUBLESHOOTING................................................................................133 Warnings ...............................................................................133 Troubleshooting Examples..................................................
User's Guide _______________________________________________________________________ Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Wiring the Connector for the LM11 Background Luminance Meter ........................................................................................
_________________________________________________________________________________ Table 20 Table 21 Table 22 Table 23 Table 24 Table 25 Table 26 Table 27 Table 28 Table 29 Table 30 Table 31 Table 32 Table 33 Table 34 Table 35 Table 36 Table 37 Table 38 Table 39 Table 40 Table 41 Table 42 Commands for Displaying System Parameters and Editing the Current System Configuration ..................................................79 Maintenance Commands..........................................................
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Chapter 1 _________________________________________________________ General Information CHAPTER 1 GENERAL INFORMATION About This Manual This manual is a general information source as well as a detailed operational guide to the FD12P Weather Sensor. Contents of This Manual This manual consists of the following chapters: - Chapter 1, General Information, provides important safety, revision history, contact, and warranty information for the product.
User's Guide _______________________________________________________________________ Version Information Table 1 Manual Revisions Manual Code FD12P-U106en-1.2 M210296en-A Description Weather Sensor, User's Guide This manual. Related Manuals Table 2 Related Manuals Manual Code DMX21T0496-1.1 LM11T0545-1.
Chapter 1 _________________________________________________________ General Information Product Related Safety Precautions The FD12P Weather Sensor delivered to you has been tested for safety and approved as shipped from the factory. Note the following precautions: WARNING Ground the product, and verify outdoor installation grounding periodically to minimize shock hazard. CAUTION Do not modify the unit. Improper modification can damage the product or lead to malfunction.
User's Guide _______________________________________________________________________ cable must be provided. Besides increasing safety, this also protects the Weather Sensor against lightning induced voltages. To prevent operator injury or damage to the Weather Sensor, check that the LINE VOLTAGE SETTING is correct before connecting the line power (See Figure 12 on page 45.) Also ensure that the line power outlet is provided with a protective ground contact.
Chapter 1 _________________________________________________________ General Information CAUTION The component boards including CMOS microchips should be transported and stored in conductive packages. Although new CMOS devices are protected against overvoltage damages caused by static electric discharge of the operator, careful handling is recommended: the operator should be properly grounded. Unnecessary handling of component boards should be avoided.
User's Guide _______________________________________________________________________ To make sure you are not delivering high static voltages yourself, take the following precautions: - Handle ESD sensitive components on a properly grounded and protected ESD workbench. When this is not possible, ground yourself to the equipment chassis before touching the boards. Ground yourself with a wrist strap and a resistive connection cord.
Chapter 2 ___________________________________________________________Product Overview CHAPTER 2 PRODUCT OVERVIEW This chapter introduces the FD12P Weather Sensor features, advantages, and the product nomenclature. Introduction The FD12P Weather Sensor is an intelligent, multi-variable sensor for automatic weather stations and airport weather observing systems. The sensor combines the functions of a forward scatter visibility meter and a present weather sensor.
User's Guide _______________________________________________________________________ units, FDT12B Transmitter and FDR12 Receiver. The DRD12 Rain Detector is fastened to the crossarm. The electronics enclosure with the main data processing and interface units is mounted to the pole mast as seen in Figure 1 below.
Chapter 2 ___________________________________________________________Product Overview Sensing Elements The FDT12B Transmitter emits pulses of near infrared light. It is permanently tilted 16.5º downwards. The optical power is stabilized by a closed hardware loop. The unit also includes a receiver circuit for monitoring lens contamination. The FDR12 Receiver measures the scattered part of the FDT12B light beam. The FDR12 contains also an additional light transmitter for monitoring lens contamination.
User's Guide _______________________________________________________________________ The following numbers refer to Figure 2 on page 19: 1 2 3 4 5 = = = = = Two RainCapTM elements DRD12 Rain Detector Wind shield Assembly clamp DTS14 Temperature sensor Electronics Enclosure The FDP12 Control Unit is the main data processor and communication unit of the FD12P. The DRI21 Interface Board is a Vaisala, general-purpose sensor interface, with several analog and digital input channels.
Chapter 2 ___________________________________________________________Product Overview Operating Principle The FD12P Weather Sensor is a microprocessor controlled, intelligent sensor combining optical forward scatter measurement, capacitive precipitation sensing, and temperature measurement. The main units of the FD12P are shown in Figure 3 below.
User's Guide _______________________________________________________________________ The output of the DRD12 is proportional to the water amount on the capacitive sensing surfaces while the optical intensity is proportional to the total volume of the reflecting particles. The ratio of optical and capacitive intensities is used to determine the basic precipitation type. The crossarm temperature (TS) is measured with the DTS14B Temperature Sensor connected to the DRI21 interface card.
Chapter 2 ___________________________________________________________Product Overview Equipment Nomenclature The standard equipment nomenclature and common names are listed in Table 3 and Table 4 below.
User's Guide _______________________________________________________________________ Specifications Mechanical Specifications - Dimensions: 2.3 m × 1.6 m × 0.6 m (H × W × D) - Weight: 35 kg, excluding the installation plate for the pole mast - Mounting: on a concrete foundation with three ∅16-mm bolts - Material: anodized aluminum, natural gray Electrical Specifications - Mains supply: 115/230 VAC ± 20 %, 45 ...
Chapter 2 ___________________________________________________________Product Overview The output data: - Automatic or polled data message - Visibility, present weather, precipitation and status data - Automatic message type and interval is selectable at 15 seconds to n × 15 seconds (n < 18) intervals The analog visibility output: - Selectable range and mode (linear or logarithmic) - Status control bit for remote alarm relay, etc.
User's Guide _______________________________________________________________________ Capabilities and Limitations Visibility Measurement Specifications Measurement range of Meteorological Optical Range (MOR): - 10 ... 50 000 m according to a 5 % Contrast 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.
Chapter 2 ___________________________________________________________Product Overview 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.
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Chapter 3 ________________________________________________________________ Installation CHAPTER 3 INSTALLATION This chapter provides you with information to help you install this product. NOTE Before installation, read section Product Related Safety Precautions on page 13. Organizing Installation Before you begin to install the FD12P Weather Sensor, make a plan of the installation steps. The following is an example of how to organize the installation process. 1.
User's Guide _______________________________________________________________________ 6. Installing the base plate and the pole mast: - Install the base plate with the bolts on the concrete block. - Level the plate. - Mount the pole mast on the base plate. - Mount the junction box to the pole mast (optional). Junction boxes are available from Vaisala. 7. Connecting cables: - Connect the mains and signal cables of the site to the junction box or have them ready for direct connection to the sensor. 8.
Chapter 3 ________________________________________________________________ Installation The receiver and transmitter optics should not point towards powerful light sources or, in bright daylight, reflective surfaces such as snow or sand. The receiver should point north in the Northern Hemisphere and south in the Southern Hemisphere. The receiver circuit may become saturated in bright light, and the built-in diagnostics will indicate a warning.
User's Guide _______________________________________________________________________ 3. Power supply and communication lines must be available. When the site for the FD12P is selected, take into consideration the available power supply and communication lines. This influences the amount of work and accessories needed and thus, the actual installation costs.
Chapter 3 ________________________________________________________________ Installation 0111-001 Figure 5 FD12P Equipment Grounding The following numbers refer to Figure 5 above: 1 2 3 4 5 6 7 8 = = = = = = = = Electronics enclosure Junction box (optional) Mains cable Cable tubing Grounding rods Signal cable 16 mm² grounding cables Grounding clamp VAISALA ________________________________________________________________________ 33
User's Guide _______________________________________________________________________ Internal Grounding The electronics enclosure and the bottom plate of the FD12P are secured by a 1.5-mm², yellow-green ground cable and the crossarm is grounded through the transducer cable shield. The other parts of the crossarm are in galvanic contact with each other.
Chapter 3 ________________________________________________________________ Installation Cable Selection Line Power Cabling The FD12P is supplied with a two-meter power cable. If a local terminal for 115/230 VAC power supply is not available, use an extended mains cable from the FD12P to the nearest power source. This cable should be armored and of underground type. The armored reinforcing acts as a mechanical shield and also provides protection against lightning. Ground the cable screen at both ends.
User's Guide _______________________________________________________________________ For a modem and RS signal cable, use a screened, 2 × 0.22-mm² twisted pair cable with a minimum diameter of 5 mm. For details, see section Communication Options on page 50. Unloading and Unpacking The contents of the delivery in question are specified in the packing list included with the delivery documents.
Chapter 3 ________________________________________________________________ Installation Installation Procedures Constructing 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.
User's Guide _______________________________________________________________________ The following numbers and letters refer to Figure 6 on page 37: A = 1 2 3 4 5 = = = = = Watertight plastic for conducting rainwater away (recommended) Concrete block Surface horizontal to ±0.
Chapter 3 ________________________________________________________________ Installation 0110-180 Figure 7 Constructing the FD12P Foundation VAISALA ________________________________________________________________________ 39
User's Guide _______________________________________________________________________ The following numbers and letters refer to Figure 7 on page 39: A 1 2 3 4 5 6 7 B 6 8 9 C 10 11 = = = = = = = = = = = = = = = Mounting when casting the pad A10.
Chapter 3 ________________________________________________________________ Installation 0110-181 Figure 8 Tilting the Pole Mast The following numbers refer to Figure 8 above: 1 = 2 = Pole mast. For tilting, loosen the upper and remove the lower M10 × 100 bolts. Tilting 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.
User's Guide _______________________________________________________________________ - 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.
Chapter 3 ________________________________________________________________ Installation 0110-182 Figure 10 Connecting Internal Grounding The following numbers refer to Figure 10 above: 1 2 3 4 5 = = = = = Crossarm Ground terminal socket Grounding flat connector Pole mast 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.
User's Guide _______________________________________________________________________ If you use another, longer cable, make sure to connect the wires in a correct way, especially the protective ground wire (usually yellow-green). Refer to Figure 11 below. 2. Connect the power cord to the screw terminals in a junction box or bring the power line directly to the electronics enclosure. The selected method depends on the thickness of the power cable, which should be checked before the installation.
Chapter 3 ________________________________________________________________ Installation NOTE If the line voltage used differs from 230 V (the initial setting 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).
User's Guide _______________________________________________________________________ 0110-184 Figure 13 Electronics Enclosure Feedthroughs The following numbers refer to Figure 13 above: 1 2 3 4 = = = = 5 6 7 = = = Grounding DTS14 cable feedthrough Temperature sensor (TE) Cap (Pg 13.
Chapter 3 ________________________________________________________________ Installation 3. Remove the cap of the cable gland, including the rubber cylinder and the metal rings. Slide the cap 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.
User's Guide _______________________________________________________________________ Connecting a Background Luminance Sensor or a Day/Night Switch to FD12P The FD12P Weather Sensor supports two different methods for ambient light sensing. The Background Luminance Meter LM11 can be connected to the FD12P for accurate ambient light measurement. The LM11 sensor and necessary wiring are included in option FD12PLM11 (see Figure 15 on page 49 for the wiring details).
Chapter 3 ________________________________________________________________ Installation 9610-006 Figure 15 Wiring the Connector for the LM11 Background Luminance Meter VAISALA ________________________________________________________________________ 49
User's Guide _______________________________________________________________________ 9610-007 Figure 16 Wiring 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.
Chapter 3 ________________________________________________________________ Installation 9509-013 Figure 17 Communication Option The Vaisala recommendation for the maximum length of the RS-232 cable is 150 m (500 ft). Serial Multipoint Transmission RS-485 The RS-485 transmission 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.
User's Guide _______________________________________________________________________ 9509-014 Figure 18 RS-485 Communication Option Modem DMX21 The Modem DMX21 is a CCITT V.21 modem, operating at 300 bps. Connect the signal wires to MODEM LINE 1 and 2, and screw terminals 7 and 9 on Interface board 16127FD. See the wiring diagram in Figure 19 on page 53. In the multidrop configuration, where several FD12P Weather Sensors are on the same modem line, the units are differentiated by an ID.
Chapter 3 ________________________________________________________________ Installation 9509-012 Figure 19 Wiring the Modem Usually, the modem of the FD12P operates in 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.
User's Guide _______________________________________________________________________ Indicators and Manual Controls This section describes the alternatives of the indicators and manual controls available in the FD12P DMX21 modem. Indicators The LED indicators of the DMX21 modem are listed and described in Table 8 below. Table 8 LED Indicators of the DMX21 Modem LED Indicator LED V16 R LED V17 ON LINE LeV18 CD LED V19 TxD LED V20 RxD Description Ring indicator, normally off.
Chapter 3 ________________________________________________________________ Installation Analog Transmission For 4-20 mA analog visibility measurement only two wires are needed. Do the following: 1. Connect the voltage supply either from remote or internal supply (from +Vb = 12 V or +Vbb = 23 V) to resistor R (for example, 100 ohm). 2. Connect the signal wire to screw connector X20 pin 3 "sink" at the CPU board.
User's Guide _______________________________________________________________________ To connect the maintenance terminal, do the following: 1. Disconnect the serial line screw connector or modem interfacing cable (or the RS-485) from X18. 2. Plug the maintenance cable into X18. 3. Refer to Figure 17 on page 51 (RS-232). Startup Testing Before closing the cover of the electronics enclosure, a short startup must be done as follows: 1.
Chapter 3 ________________________________________________________________ Installation message type. The sensor can also be used in a polled mode, that is, a data message is only sent when the host computer requests one with a special command. In addition, the baud rate of the serial line can be changed to a higher value. The default communications settings are listed in Table 10 below.
User's Guide _______________________________________________________________________ Local practice may require changes, especially in the precipitation intensity limits and the haze 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.
Chapter 4 _________________________________________________________________ Operation CHAPTER 4 OPERATION This chapter contains information needed to operate this product. Introduction The FD12P Weather Sensor is a fully automatic instrument for continuous weather measurement. Normally, the FD12P Weather Sensor is either set to send a data message automatically or it is polled by a host computer. In addition, a set of user commands is provided for configuring and monitoring the system performance.
User's Guide _______________________________________________________________________ When the sensor has been installed, the user may need to change some of the default settings. For details, see section Initial Settings on page 56. Table 13 below lists the settings and the corresponding commands.
Chapter 4 _________________________________________________________________ Operation Markings Used in This Manual The general format of the command is the following: COMMAND parl...parn ↵ where Command parl...parn ↵ NOTE = An FD12P command given by the user = Possible parameters of the command = Symbolizes pressing the ENTER key All the command parameters are separated from each other by a space character. Every user command must be ended with ENTER, illustrated in this manual by ↵.
User's Guide _______________________________________________________________________ The FD12P answers LINE OPENED FOR OPERATOR COMMANDS If no input is given within 60 seconds, the FD12P closes the line automatically. CLOSE Command Line can be released to 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.
Chapter 4 _________________________________________________________________ Operation Message_interval - Given in multiples of 15 seconds (= measuring interval). Therefore, intervals 15, 30, 45 ... are valid. Other intervals are converted to multiples of 15 seconds. The maximum sending interval is 255 seconds (4 minutes 15 seconds). For example, typing AMES 1 60 ↵ selects message number 1 to be sent once in a minute.
User's Guide _______________________________________________________________________ NOTE The contents of messages 0, 1, 2, 5, 6, and 7 are illustrated as follows: 10 6800 ↓↓ ↓ <- The first row is the output. 110.96 ↓ --------- offset frequency ì Field ------- one minute average visibility ídescriptions - 1=hardware error, 2= hardware warning î - 1= alarm 1 2= alarm 2 Example with frames □FD 1□10 6800 110.96□ !FD 1"10 6800 110.
Chapter 4 _________________________________________________________________ Operation An example with frames is as follows: FD 1 00 6839 52 0.3 !FD 1"00 6839 52 0.3#-* 0123456789012345678901234567 Message 2 Message 2 is intended as the standard present weather message used in data loggers or display units and it is set as default at the factory. 00 6839 7505 L 52 61 61 0.33 12.16 0 -----cumulative snow sum,0...999mm ------- cumulative water sum,0...
User's Guide _______________________________________________________________________ Message 4 Message 4 is for hardware monitoring. The same data line is obtained by using the FREQ command. 0.51 126.82 0.91 15 3 5 2.7 5.6 1280 19.5 1.8 >FREQ SIGNAL+ OFFSET DIST SWID MAXI OWID TE LEDI BACKS VBB TS 0.59 126.83 0.91 17 2 6 2.7 5.6 1280 19.4 1.8 0.59 126.83 0.91 17 2 6 2.7 5.6 1280 19.4 817 819 DRD 816 1.
Chapter 4 _________________________________________________________________ Operation The status bits emulate the MITRAS status as shown in Table 16 and Table 17 below. Table 16 Transmitter Status Correspondence between MITRAS and FD12P BIT 0 1 2 3 4 5 6 MITRAS MEAS MODE ECON MODE OPTICAL SURFACE POWER SUPPLY HEATING FLASH LAMP BL METER 7 MEASUREM.
User's Guide _______________________________________________________________________ Message 7 Message 7 is meant mainly for aviation specific purposes. The message contents are as follows: 00 23.4 12345 ------background luminance cd/m2 ------ surface temperature ----- cumulative snow sum ------- cumulative water sum ------- precipitation water intensity,mm/h (1 minute average) --- one hour present weather code, 0 ... 99 --- 15 minute present weather code, 0 ... 99 --- instant present weather code, 0 ...
Chapter 4 _________________________________________________________________ Operation Message Polling In the polled (CLOSEd) mode, the FD12P sends a data message when the host computer transmits a polling command. The message polling mode is selected by the following command: AMES Message_number Message_interval ↵ where Message_number - The valid range is 0 ... 7, refer to section Message Types on page 63. - Selects the corresponding message as the default polled message.
User's Guide _______________________________________________________________________ This format is also used when several devices are on the same line. Use character 1 as the id if the id has not been set but a specific message type is polled. The FD12P does not echo the polling character string. The answer message format is the following: FD id text The id field always contains two characters.
Chapter 4 _________________________________________________________________ Operation Command CHEC CAL Calibrator_frequency CLRS ACAL TIME hh mm ss DATE yyyy mm dd BAUD rate par AN channel DAC data RESET WHIS WSET DRY ON WET ON BLSC Description Displays average signal Calibration Clears precipitation sums Analog output calibration Sets/displays system time Sets/displays system date Baud rate setting (Rate 300, 1200, 4800, 9600) (Par E(7E1) or N(8N1) Analog channel (0,1,3,8 ...
User's Guide _______________________________________________________________________ The format of the AMES command is the following: AMES Message_number Message_interval where Message_number - The valid range is 0 to 7. - Selects the corresponding message. Any negative message number is converted to 0. - The message number is also the default number for the MES command and polling. - If only the message number is given, the previous interval setting is used.
Chapter 4 _________________________________________________________________ Operation Weather Related Commands To display or set the weather analysis parameters and results, use the commands listed in Table 19 below.
User's Guide _______________________________________________________________________ Type WSET↵ and the output is as follows: SET PRESENT 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) LIGHT RAIN LIMIT ( 2) DRIZZLE LIMIT ( 15) HEAVY DRIZZLE LIMIT ( 30) LIGHT DRIZZLE LIMIT ( 3) SNOW LIMIT ( 5.
Chapter 4 _________________________________________________________________ Operation Rain Intensity Scale The Rain intensity scale parameter is multiplied by the measured raw intensity, which gives the reported precipitation intensity (optical). The rain amount is scaled with the same coefficient because the amount is a direct integral of 15-second intensities. The typical value for the Rain intensity scale is 0.8.
User's Guide _______________________________________________________________________ parameter value relates to the square of droplet radius. The relationship is the following: X = 240× R2 where X R = = Parameter value Droplet radius Parameter value 30 would correspond to about a 0.7-mm droplet diameter. Heavy Drizzle Limit The Heavy drizzle limit parameter refers to the minimum number of drizzle droplets detected in 15 seconds. They must be detected before drizzle becomes heavy (dense).
Chapter 4 _________________________________________________________________ Operation Snow Pellets Limit The Snow pellets limit parameter specifies the minimum particle size (in FD12P internal units), which is detected as snow pellets. (Additional internal criteria are used before the precipitation type is determined to be snow pellets.) Snow Grains Limit The Snow grains limit parameters refers to the maximum particle size (in FD12P internal units), which is detected as snow grains.
User's Guide _______________________________________________________________________ When you type PRW↵ the system output is the following: PRESENT WEATHER MODERATE DRIZZLE VISIBILITY RAIN INTENSITY SNOW INTENSITY TEMPERATURE TS DRD SUM 7161 m AVE 10 MIN 7533 0.16 mm/h CUMULATIVE SUM 12.16 0.0 mm/h CUMULATIVE SUM 0 2.7 1.8 22.04 CLRS Command The CLRS command resets (to 0.00) the cumulative sums of precipitation.
Chapter 4 _________________________________________________________________ Operation System Configuration Commands Table 20 below lists the commands that can be used to display system parameters and to edit current system configuration.
User's Guide _______________________________________________________________________ CONF Command The configuration command, CONF, is used to set or update system parameters and to adjust certain calibrations, reference values, and limits. You can limit the use of this command by protecting it with a password. New parameter values are saved in the non-volatile memory (EEPROM). The CONF command displays the parameters one by one and asks for a new value.
Chapter 4 _________________________________________________________________ Operation When no password has been set, the command format is the following: CONF ↵ The system response to the CONF command is presented below (The bold text refers to user actions.) CONF.
User's Guide _______________________________________________________________________ also included in the data message heading. ID 1 is used as a default in the message heading if no other ID is given. The current ID can be removed by pressing " - " as an answer to the question. In the multidrop configuration, where several FD12 Weather Sensors are on the same communication line, the units are differentiated by the ID. The next CONF parameters are hardware- or system-dependent.
Chapter 4 _________________________________________________________________ Operation In the above example, alarm Limit 2 receives a new value, 300 m. When the visibility now weakens below Limit 2, then the data message (0 to 2) data status is set to 2. The visibility alarm is not shown in the status message. The backscatter/contamination control is done by comparing the current values of backscatter signal with the reference values given with the CLEAN command.
User's Guide _______________________________________________________________________ BAUD Command The baud rate and communication type can be changed by typing following the operator command: BAUD value communication_ type The baud rates are 300, 1200, 2400, 4800, and 9600. The communication types are E (7E1) and N (8N1). The new value is saved in EEPROM and it is used also after reset or power up. The default baud rate set at the factory is 300 baud (7E1). Defining the communication type is optional.
Chapter 4 _________________________________________________________________ Operation If the LM11 is not connected, the scaling factor should be negative. Value -1.0 has been set at the factory as the default value. If a positive value is used, the sensor expects a signal from the LM11. For an example, see the following: >blsc BL SCALE -1.000 >blsc 10.4 BL SCALE 10.
User's Guide _______________________________________________________________________ SIGNAL 0.39 OFFSET 126.83 DRIFT REC. BACKSCATTER 1281 CHANGE -1 TR. BACKSCATTER 10.3 CHANGE 0.1 TE 2.7 VBB 19.4 VH 0.6 LEDI 5.6 P15 15.1 M15 -15.0 BGND -0.1 AMBL 0.1 DUTY 1.6 DRI21 MEASUREMENTS TS 1.8 DRD INST 811 DRY 915.6 HARDWARE : OK 0.14 An asterisk (*) before a value indicates an exceeded limit. In the end, there are verbal comments on the combined errors detected.
Chapter 4 _________________________________________________________________ Operation Warning text CONNECTED TS SENSOR ERROR DRD12 ERROR LUMINANCE SENSOR ERROR TE SENSOR ERROR VISIBILITY NOT CALIBRATED Description The DTS14B measurement is off limits. The DRD12 analog signal is close to zero. The LM11 signal is zero (not checked if the BLSC is negative). Box temperature sensor TE measurement is off limits. The visibility calibration coefficient has not been changed from the default value.
User's Guide _______________________________________________________________________ the command initializes the two-point calibration sequence, where two temperatures must be simulated. When you type TCAL TS DTS14B_temperature ↵ a single-point calibration to the TS is made. That is, the scaling factor TS 0 is adjusted by the command routine. The following command TCAL 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 .
Chapter 4 _________________________________________________________________ Operation CHEC Command The CHEC command is used in the visibility calibration procedure to display the two-minute average signal frequency in hertz. The command has no parameters. The display is terminated by pressing ESC. Pressing any other key will pause the display. In the beginning, the eight-location buffer is filled with the first value.
User's Guide _______________________________________________________________________ The DRY command is used to set the dry signal end of the DRD12 signal normalization calculation. When you type DRY ↵ the output is, for example, the following: DRD DRY OFFSET 915.6 The DRY OFFSET value must be between 850 and 980 when the DRD12 hardware operates normally. The DRY command shows this parameter. The parameter is set by the DRY ON command.
Chapter 4 _________________________________________________________________ Operation Type AN AMBL ↵ WAITING FOR MULTIPLEXER ANALOG INPUT, 118 119 AMBL 0.1 0.3 Analog Output Commands Analog Output Calibration The DAC output voltage is converted to current, 0 to 22 mA unscaled. This current is then software-calibrated to give 4 mA at the minimum visibility and 20 mA at the maximum visibility. The minimum and maximum visibility values are set in the configuration session.
User's Guide _______________________________________________________________________ When you type ACAL ↵ the command gives, for example, the following output: MEASURED CURRENT (mA) 22.16 MEASURED CURRENT (mA) 4.52 Data Scaling The FD12 scales the visibility value to a binary number for the DAC ( = DACBITS) so that the minimum visibility corresponds to the 4 mA-calibrated value and maximum visibility to the 20 mAcalibrated value.
Chapter 4 _________________________________________________________________ Operation Other Commands TIME Command The TIME command is useful 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 = mm = ss = NOTE Hours Minutes Seconds Reset the time after a power break. DATE Command The DATE command is used to display the current date.
User's Guide _______________________________________________________________________ RESET Command The RESET command makes the hardware reset by the watchdog circuitry.
Chapter 5 _______________________________________________________ Functional Description CHAPTER 5 FUNCTIONAL DESCRIPTION This chapter gives a functional description on the product. General The FD12P Weather Sensor is an optical sensor that measures visibility (meteorological optical range, MOR, and precipitation intensity and type. The FD12P measures visibility using the forward scatter measurement principle.
User's Guide _______________________________________________________________________ Optical Measurement Optical Arrangement 0110-185 Figure 21 FD12P Optical System The following numbers refer to Figure 21 above: 1 2 3 = FDT12 transmitter = FDR12 receiver = Sample volume The FD12P measures light scattered at an angle of 33°. This angle produces stable response in various types of natural fog. Precipitation droplets scatter light in a different manner than fog.
Chapter 5 _______________________________________________________ Functional Description 9611-002 Figure 22 FDT12B Transmitter Block Diagram The transmitter unit electronics pulses the IR-LED at a frequency of 2.3 kHz. One PIN-photodiode monitors the transmitted light intensity. The transmit level measurement is used to automatically keep the LED's intensity at a preset value. The "LEDI" feedback voltage is channeled through the analog multiplexer to the CPU for monitoring.
User's Guide _______________________________________________________________________ An extra photodiode measures the light scattered backwards from the lens, other objects, or contaminants. This signal as well as several internal signals are monitored via MUX-line. The CPU board supplies only one voltage Vb = 10 - 13 V for both the transmitter and receiver. This is used for heating the lenses, for the transmitter LED heating and for producing both +5 V digital and +15 V analog supplies.
Chapter 5 _______________________________________________________ Functional Description The lock-in circuits take two samples of the background level and one sample of the active signal level while the transmitter LED is lit. The difference between the sampled voltages is amplified and then converted into frequency. The frequency signal is buffered by a differential line driver and sent to the CPU board for accurate counting.
User's Guide _______________________________________________________________________ 9807-031 Figure 24 DRI21 Block Diagram in the FD12P Application DRD12 Rain Detector The DRD12 analog signal is proportional to the water amount on the sensing surfaces. Water on the DRD12 changes the capacitance of the sensor elements. The capacitance of the elements controls the output frequency of an oscillator. This frequency is amplified and also converted into a voltage signal for direct analog measurement.
Chapter 5 _______________________________________________________ Functional Description Figure 25 DRD12 Block Diagram The DRD12 sensing surfaces are heated by heating elements built into the surfaces. The heating power varies automatically (by built-in temperature control), but it can be switched off with a digital control signal. When the heating is off, the surfaces become extremely sensitive to all moisture in the air.
User's Guide _______________________________________________________________________ 9611-004 Figure 26 FDP12 Control Unit Block Diagram The controller is based on an Intel® 8031 microprocessor. Besides data acquisition and internal controlling, the FDP12 takes care of communication through the RS-232 serial port. The alternative RS-485 interface allows a simple method for multiple FD12P Weather Sensors to communicate on the same line.
Chapter 5 _______________________________________________________ Functional Description Measurement Signal Processing Optical Signal Processing The software running in the FDP12 CPU controls the measurement hardware and reads the data samples.
User's Guide _______________________________________________________________________ 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).
Chapter 5 _______________________________________________________ Functional Description The software normalizes the measured signal and then estimates the precipitation intensity using an empirical algorithm. The estimate is proportional to the amount of water on the DRD12 surfaces. The signal normalization is calibrated at the factory with dry and completely wet surfaces. When the heating of the sensor elements is switched off, the sensor elements become very sensitive to ambient moisture.
User's Guide _______________________________________________________________________ MOR = (4×signal+0.1)×NEW MOR+(1-(4×Signal+0.1)×OLD MOR where OLD MOR = NEW MOR = The previous average value A new instantanous value The lower the signal value, the less the new instantaneous value is included in the average. The minimum influence of the new sample is 10 %. This filtering reduces noise in the output values.
Chapter 5 _______________________________________________________ Functional Description The DRD12 data is used to calculate another estimate of the precipitation intensity. This intensity is calculated from low pass and high pass filtered, one-second samples. The intensity is scaled with the DRD scale parameter. For normal operation in liquid precipitation, the scaled DRD12 intensity estimate should be higher than the optical intensity.
User's Guide _______________________________________________________________________ Present Weather Precipitation Types The ratio of the optical intensity and the DRD12 intensity estimates is the key factor used in the precipitation type decision (see section Precipitation Intensity on page 106). Some filtering is used in calculating intensity ratio to get the parameter that is used in the type finding procedure.
Chapter 5 _______________________________________________________ Functional Description 0201-092 Figure 30 Precipitation Type Determination Principle The precipitation types can be divided into four main categories: - Liquid precipitation - Frozen precipitation - Mixed precipitation - Unknown precipitation The types and their detection criteria are listed below. Liquid Precipitation In liquid precipitation, the optical and the DRD12 intensities are near each other, or the DRD12 intensity is higher.
User's Guide _______________________________________________________________________ minute average intensity limits in mm/h used to set the rain intensity type. b. NOTE Drizzle: Drizzle consists only of small droplets. The maximum droplet size allowed for drizzle is set by the Drizzle limit parameter. The Light drizzle limit and Heavy drizzle limit are the number of droplets in 15 s (average) that are used to determine the drizzle intensity.
Chapter 5 _______________________________________________________ Functional Description Mixed Precipitation The FD12P reports either rain and snow (WMO codes 67 and 68) or ice pellets (WMO codes 74, 75, and 76) when the intensity ratio is between one and Snow limit. The intensity is determined by estimating the water equivalent intensity and using the rain intensity limits. a.
User's Guide _______________________________________________________________________ a. Fog patches: Fog patches (code 31) are detected from rapid changes in visibility across the one-kilometer fog limit. If the visibility of the one-minute average is more than twice or less than half of the two-minute average, then the internal patch indicator is set for about 30 minutes. b.
Chapter 5 _______________________________________________________ Functional Description However, if more than 30 minutes has elapsed from the last detected precipitation, the PRECIPITATION DURING THE PRECEDING HOUR code is used. Weather Code Selection The FD12P presents the weather type using the World Meteorological Organization (WMO) code table 4680. Some code numbers have been adopted from code table 4677 as these codes are not included in table 4680.
User's Guide _______________________________________________________________________ measurement can be used to select between smoke, fog, mist, and haze. The 15-minute code might be a good selection for WaWa. The one-hour values can then be used for W1 and W2 coding. Drizzle should not be reported until all the three codes show a drizzle type. This prevents the small droplets at the beginning and end of a shower or in intermittent rain to be reported as drizzle.
Chapter 5 _______________________________________________________ Functional Description During the offset measurement, the yellow LED is off. In normal operation, the red LED is off. Memory Tests After resetting, the FD12P tests and clears its SRAM data memory. It indicates an error by the red LED blinking. After 50 blinks, the FD12P tries to start the program anyway. Usually, this causes a watchdog reset, if the SRAM is really faulty.
User's Guide _______________________________________________________________________ Contamination Monitoring The FD12P monitors both the transmitter and receiver contamination by measuring the backscattered signal. The CLEAN command is used to set the clean reference values of the backscatter signals. The deviation of the backscatter signal from the clean values is proportional to the contamination on the lenses. The alarm and warning limits are given in the configuration session.
Chapter 6 _______________________________________________________________Maintenance CHAPTER 6 MAINTENANCE This chapter describes the overall maintenance of the product. General No initial calibration of the FD12P is needed because the sensor has been calibrated at the factory. The 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.
User's Guide _______________________________________________________________________ Cleaning Cleaning Lenses and Hoods The lenses of the FD12P transmitter and receiver units must be relatively clean to obtain reliable results. Dirty lenses give too high visibility values. Clean the lenses every six months or more often depending on the conditions (for example, if there are roads nearby). Use the STA command for monitoring the system performance.
Chapter 6 _______________________________________________________________Maintenance To clean the rain detector, do the following: 1. Clean the DRD12 rain detector carefully with a soft, lint-free cloth moistened with a mild detergent. Be careful not to scratch the surface. 2. Check that the detector and the windshield are free of ice and snow deposits. Calibration General The FD12P has been calibrated at the factory.
User's Guide _______________________________________________________________________ When the calibrator is used in precipitation, the error will be proportional to the area of the scatter plates, which are covered by droplets. Make sure that this area is negligible compared with the total area. Bright sunlight shining on the calibrator plates will increase noise in the scatter measurement and make the CHEC command output less stable.
Chapter 6 _______________________________________________________________Maintenance plates. In the correct position, the upper edges of the plates are at the same level with the receiver and transmitter hood tips (see Figure 31 on page 122). Tighten the clamp bolts. NOTE Take a 30-cm ruler or equivalent 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.
User's Guide _______________________________________________________________________ 0201-087 Figure 31 Assembling the FDA13 Calibrator 122 _____________________________________________________ M210296en-A
Chapter 6 _______________________________________________________________Maintenance The following numbers refer to Figure 31 on page 122: 1 2 3 4 5 6 7 8 9 10 = = = = = = = = = = Crossarm Grooves M8 x 40 DIN912, 2 pieces Calibrator clamp Center of crossarm Tie rod Pole mast Label Left opaque glass plate Right opaque glass plate Calibration Procedure If calibration is needed according to the calibration check (see section Calibration Check Procedure on page 120), follow the instructions below.
User's Guide _______________________________________________________________________ Calibrating the DTS14B Temperature Sensor Calibration of the DTS14 Temperature Sensor is recommended to be carried out once a year. For the sensor accuracy, only 0 °C temperature is important as this temperature is used to identify freezing rain. The TCAL command is used for the calibration of the surface temperature (TS) measurement.
Chapter 6 _______________________________________________________________Maintenance 0201-088 Figure 32 DTS14 Sensor Holder Assembly to Mast The following numbers refer to Figure 32 above: 1 2 3 = = = Sensor holder DTS14 Fixing screw VAISALA _______________________________________________________________________ 125
User's Guide _______________________________________________________________________ Removing and Replacing This section describes in detail how to remove and replace the optical units, the FDT12B Transmitter, FDR12 Receiver, and the Rain Detector DRD12. You can remove the units when you suspect that malfunction of the FD12P is caused by faults in the optical units or the rain detector. Removing and Replacing Optical Units WARNING The equipment contains dangerous voltage of 230 VAC.
Chapter 6 _______________________________________________________________Maintenance 0110-187 Figure 33 Removing the Optical Units The following numbers are related to Figure 33 above: 1 2 3 4 5 6 7 8 9 = = = = = = = = = Hood tube FDT12B transmitter/FDR12 receiver Round flange Cover 4 screws (M6 x 16 DIN7991) 5 mm Allen key 3 locking bolts Connector Ribbon cable VAISALA _______________________________________________________________________ 127
User's Guide _______________________________________________________________________ To replace the optical unit, do the following: 1. Insert the FDT12B Transmitter/ FDR12 Receiver unit into the hood. Note that the position of the unit is correct, see 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, Thandle Allen key. 4. Replace the round flange firmly.
Chapter 6 _______________________________________________________________Maintenance Removing and Replacing the DRD12 Rain Detector To remove the DRD12, do the following: 1. Remove the two nuts of the 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.
User's Guide _______________________________________________________________________ The following numbers refer to Figure 35 on page 129: 1 2 3 4 5 6 7 8 9 10 = = = = = = = = = = Wind shield Two RainCap™ elements Assembly clamp White Red Blue Yellow Green Black Pressure compensation element To replace the DRD12, do the following: 1. Pull the DRD12 cable through the feedthrough of the DRD12 unit and attach the six wires to the screw terminal as shown in Figure 35 on page 129. 2.
Chapter 6 _______________________________________________________________Maintenance Table 24 Parameters for Optical Measurement Parameter Type of Parameter Transfer function scaling factor Offset reference value Transmitter backscatter reference value Receiver backscatter reference value Calibration constant Command to Change the Parameter CAL (FCAL) Internal monitoring Internal monitoring CONF CLEAN Internal monitoring CLEAN Table 25 Parameters for DRD12 Precipitation Detector Parameter Typ
User's Guide _______________________________________________________________________ The parameters controlling the operation mode (automatic 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.
Chapter 7 ____________________________________________________________ Troubleshooting CHAPTER 7 TROUBLESHOOTING Warnings WARNING The equipment contains dangerous 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.
User's Guide _______________________________________________________________________ Message Missing 1. Check that your terminal has the correct settings. The FD12P default is 300 bit 7E1. If the settings are not correct, you can - Change the baud rate, for example, to 300 baud. - Check that you have seven data bits, even parity, one stop bit. 2. Try the OPEN command (see section Entering/Exiting the Command Mode on page 61) and try other commands to see if the FD12P is already in the command mode. 3.
Chapter 7 ____________________________________________________________ Troubleshooting Visibility Value is Missing 1. The FD12P control electronics is probably working. Check the following: - Check the status information with the STA command (see section STA Command on page 85). If there are active hardware alarms, visibility values are removed from data message. - Check especially P15, M15, BACKSCATTER and LEDI. See section Values for Internal Monitoring on page 137 for the limits. 2.
User's Guide _______________________________________________________________________ Visibility is Constantly Too Low Usually there is something disturbing in the sample volume. Check the following: 1. Check the condition of the hoods. If the hoods are slightly twisted, try to align them as well as possible. 2. Try to find a better direction for the receiver/transmitter optics. See section Location and Orientation on page 30. 3. There may be an electrical fault.
Chapter 7 ____________________________________________________________ Troubleshooting 3. If everything else seems to be functioning correctly, change the parameter settings as follows: - If possible, check the accumulated water sum against a reference rain gauge This will indicate how close Rain intensity scale is to the optimal value. Decrease the scaling factor if the FD12P rain amount is too high. - Otherwise, increase DRD scale.
User's Guide _______________________________________________________________________ Table 29 Message Typical DUTY 1.6 V Indicates the pulse ratio in lock-in amplifier circuit. AMBL Ambient light. -0 V Min/ Max +1 V/ +2.5 V Values for Internal Monitoring Fault Description Action <1 V >2.5 V Synchronizing signal from the receiver to the transmitter is missing. 1.Check condition and contact of -flat cable -connectors 2. Change the receiver. 0.
Chapter 7 ____________________________________________________________ Troubleshooting Message Typical TR. BACKSCATTER Control signal for the transmitter contamination. Clean value. LEDI 0 V ... Actuating signal for 6.5 V the LED control (transmitter). TE Ambient temperature. -40°C ... +50°C SIGNAL Frequency of the transmission signal between transducer and CPU (Hz) is inversely proportional to visibility. 0.00 Hz ... 10000.00 Hz Freq. Corr. Visibility 1 Hz 4.
User's Guide _______________________________________________________________________ Message Typical Min/ Max +14 V/ +16 V Fault Description Action <+14.0 V >+16.0 V DC/DC converter is overloaded or working wrong. M15 -15.0 V Negative voltages of the DC/DC converter for the transmitter/receiv er -16 V/ -14 V >-14.0 V <-16.0 V DC/DC converter is overloaded or working wrong. BGDN ~0 V Ground potential for the transducer, i.e., voltage loss in transducer cable. -0.5 V/ +1 V <-0.5 V >+1 V 1.
Chapter 7 ____________________________________________________________ Troubleshooting 3.
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Appendix A _________________________________________NWS and WMO Codes Used in FD12P APPENDIX A NWS AND WMO CODES USED IN FD12P The NWS Codes Table 30 Internal Weather Types, NWS Code Weather Type No precipitation Precipitation Drizzle Rain Snow Ice pellets Sleet Hail Ice crystals Snow grains Snow pellets Freezing drizzle Freezing rain Code C P L R S IP IP A IC SG SP ZL ZR The NWS codes are used with intensity indicator '+' for heavy , '-' for light, and none (space) for moderate.
User's Guide _______________________________________________________________________ Code figures 20 to 25 are used, if precipitation or fog was observed during the preceding hour but not at the time of observation. Table 32 Code 20 21 22 23 24 25 WMO SYNOP Codes (4680, WaWa) Weather type Fog PRECIPITATION Drizzle (not freezing) or snow grains Rain (not freezing) Snow Freezing rain or freezing drizzle The following code figures are used if precipitation or fog is observed at the time of observation.
Appendix A _________________________________________NWS and WMO Codes Used in FD12P Code 80 81 82 83 84 85 86 87 89 Weather type SHOWERS OR INTERMITTENT PRECIPITATION Rain showers, light Rain showers, moderate Rain showers, heavy Rain showers, violent (>32 mm/h) Snow showers. light Snow showers. moderate Snow showers. heavy 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.
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Appendix B ___________________________________________ Jumper Settings and Internal Wiring APPENDIX B JUMPER SETTINGS AND INTERNAL WIRING See Figure 36 on page 148.
User's Guide _______________________________________________________________________ 020-090 Figure 36 Basic Electronics Enclosure Wiring 148 _____________________________________________________ M210296en-A
Appendix B ___________________________________________ Jumper Settings and Internal Wiring CPU Board Table 35 Jumpers X2 X5 X7 X11 X13 Table 36 Connectors X3 X14 X15 X16 X17 X18 X19 X20 X21 CPU Board Jumpers Description Memory selection 1-2 for 27256, 2-3 for 27512 Watchdog ON 1-2, reset 2-3 TM PICOBUS powering Not in use Lens heating 1-2, on 2-3 with on/off driver CPU Board Connectors Description PICOBUS (for DRI21 interface board) Temperature sensor (FDE12) To transducer crossarm (transmitter/receiver
User's Guide _______________________________________________________________________ Table 39 Connectors X1 X2 X4 Table 40 Description Ground Supply voltage Lens heating Ground Frequency non-inverting Frequency inverting Channel bit 2/offset mode Analog mux. channel Channel bit 1/backsc.
Appendix C __________________________________________ Transmitter and Receiver Test Points 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 Test Point TP1 TP4 TP5 X1/1 X1/2 X1/3 X1/4 Transmitter Test Points Description Reference voltage +2.
User's Guide _______________________________________________________________________ Table 42 Receiver Test Points Test Points TP1 TP2 TP3 TP4 TP5 TP6 TP7 TP8 TP9 Description Synchronizing pulse for factory tests Reference voltage -2.
___________________________________________________________________________ INDEX INDEX A Additional Measurements Algorithm AMES Analog output commands ACAL Analog Output Commands Analog Transmission Applications Assembling the FD12P Automatic Message Sending 99 105 71 92 91 55 113 40 62 B Basic Wiring BAUD BLSC Built-in Tests 43 84 48, 84 114 C Cable Selection Cabling Principle CAL Calibrating the DTS14B Temperature Sensor Calibration Capabilities and Limitations Capacitive precipitation sensing CHEC
User's Guide _______________________________________________________________________ Hardware Structure 17 Precipitation Accumulation 107 HELP 70 Precipitation Intensity 106 Precipitation Types 108 I PRW 77 Initial Settings 56 R Installation Procedures 37 Internal Grounding 34 Related Manuals 12 Internal Monitoring 114 Removing and Replacing 126 Removing and Replacing the DRD12 Rain L Detector 129 RESET 94 line voltage setting switch 45 Location and Orientation 30 S M Safety 12 Safety summary 13 Mains Power
