A EX I. Automatic Weather Station:

Transcription

1 A EX I Automatic Weather Station: AWS System Overview: Manufacturer should provide the following items along with all AWS spare parts for at least five years and should notify if and whenever any one of the component becomes obsolete. As each remote station should collect data from its respective sensors, it should record, store data and transmit to Central Station. Highlights of the system are as follows. Weather Stations. 5 AWS (WMO compliant) Data Transmission to Central Station Computer. NEMA 4 type housing containing Data Logger, with input compatible with Sensors Power supply system including solar panel, battery, regulator, and all necessary cabling Combined Wind Speed and Direction Sensor Combined Air Temperature and Humidity Sensor Atmospheric Pressure Sensor Precipitation Sensor (Tipping Bucket) Solar Radiation Sensor Soil Moisture Sensor at 05, 10, 20 cm depth Technical Specifications of Automatic Weather Station (AWS): AWSs should consist of sensors like Wind speed, Wind direction, Soil Moisture, Environment Temperature, Humidity, Atmospheric Pressure, Solar Radiation, Rainfall and Ultrasonic Snow Sensors (where applicable). In AWS, necessary hardware / software must be available to plug-in GSM / GPRS communication system. The AWS be comprised of:- A. HIGH PERFORMA CE DIGITAL DATA LOGGER: A multipurpose Meteorological Data Measurement Logger to receive data from various meteorological sensors and store the values within itself in a solid-state smart media flash card type memory. Data should be measured as frequently as once every 5 sec. and stored in 10- minute intervals with time tags. The stored data should be retrieved by removing the flash card and by delivery to direct interface local computer system. The unit should be able to handle various types of sensors with digital, analog and pulse type outputs. Technical Specifications of Data Logger: Operating System: Stored Program Dedicated to Wind, Solar radiation & Temp logging. Operating Temperature: - 20 ~ + 60 C operation Operating Voltage: 12 V DC operation Processor: 32 bits A / D Converter : 16 bits Inputs: 06 analog inputs & 6 digital inputs 4 counter / Frequency inputs RS 485, 232 & SDI-12 Port V. 1.3 Analog Input Range: 0-5V Full Scale Digital Input: 8 Digital inputs Communication Ports: RS No RS No Simultaneous communication on all ports.

2 Storage: Program Memory 512 KB or more Flash Card Memory 256 MB or more Should be able to store all data, plus separate register for 8 hourly average, 24 hourly average, weekly average and monthly average. LCD Display: Min 2 lines x 20 characters Alphanumeric Display for live and archived data. Watchdog Timer: System reset upon microprocessor failure. Connectors: All exposed connectors must be rugged industrial grade plastic twist lock multi pole type; so that they are corrosion and climate/environment proof. Software: The system must be supplied with the following softwares: PC based - configuration software to configure and install each sensor. PC based - set up program to set how measurements are to be done by sensor and how data is to be stored. PC based software to retrieve data from MMC of the data logger and display different parameters in readable form and export data. PC based Presentation and Display software to display instantaneous and stored data in suitable tabular and graphic format. Software should have ability to transmit data automatically at Central Station PC in BINARY /ASCII format. CASI G FOR LOGGER: The logger must be housed in a Rugged; Water and Dust Proof sealed Stainless Steel Enclosure with pad locks that can with stand direct exposure to harsh environment. The casing should be mountable on the triangular steel tower. In order to protect from excessive heat, the enclosure should be provided with radiation shield. B. SOLAR PA EL: Photo voltaic solar panel; to charge batteries from solar energy, 12Volt and 30-Watts power. Capable of keeping the battery afloat for 365 days. i) CHARGE REGULATOR: Smart Charge regulator to charge 12Volt, 24AHr battery from power supplied by solar panel with intelligent charge control. ii) STORAGE BATTERY: Sealed maintenance free lead acid battery; 12Volt, 24AHr with high quality instrumentation class terminals and # 16 gauge stranded copper connection cable RED+BLACK. iii) BATTERY STORAGE CASI G: The battery must be housed in a weather proof vented outdoor housing (installed adjacent to the logger housing) and connected to the logger housing using environment proof plastic twist connectors. C. SE SORS FOR AWS: i. Combined Wind Speed and Direction Sensor: a). Wind Speed Sensor: The required wind speed sensors should have dirt and water resistant construction and corrosion resistant materials with the following specifications and requisite mounting hard ware and cable. Type of sensor: 03 Cup or Propeller type Measuring range: 0. 5 to 60 m/s

3 Starting threshold: <0.5 m/s Accuracy: +/- 0.3 m/s Operating temperature: -10 to +60C Relative Humidity: %. b). Wind Direction Sensor: The required wind direction sensors should have dirt and water resistant construction and corrosion resistant materials with the following specifications and requisite mounting hard ware and cable Type of sensor: Potentiometer Measuring range: 0 to 360 Deg. Starting threshold: < 1.0 m/s Accuracy: +/- 3 Deg. Operating temperature: -10 to +60C Relative Humidity: %. ii. Combined Air Temperature and Humidity Sensor with multiplate Free Flowing shield: a) Temperature Sensor: The required temperature sensors should have dirt and water resistant construction and corrosion resistant materials with the following specifications and requisite mounting hard ware and cable Measurement range: -20 ~ +60 C Output: Linear analog output voltage Accuracy: +<0.1C. b) Relative Humidity Sensor Continuous measurement relative humidity sensor; Range: 0 100% Accuracy: + 1% RH from 3 to 95%. Excellent linearity and sensitivity with fast response and long-term stability. Requisite Cable. Operating temperature range: - 20 ~ +60 C iii. Atmospheric Pressure Sensor: Range: 600 ~ 1100 hpa. Solid State, RS-232-C, RS-485 or SDI-12, and Linear analog output voltage hpa accuracy. Weatherproof PVC casing. iv. Rain Gauge: Type of Sensor: Tipping bucket / reed switch. The bucket tips for each 0.25 mm of precipitation empties and operates the output switch. Switch: Rugged Magnetic Proximity Switch Accuracy: ± 0.5% at 0.5 in./hr (1.27 cm/hr.) ±2% at 2 in./hr (5.08 cm/hr) to 60mm/hr Mounting with three mounting legs; with requisite cable. Stainless Steel Housing Stainless steel fasteners. Sensitivity :0.2mm Switch closer time: <10 millisecond. v. Solar Radiation Sensor: Type: Pyranometer type solar radiation sensor. Spectral range: to nm Sensitivity: 10 Micro volts/w/m2 Response Time: 10 Sec

4 Maximum irradiance: 3000 W/m2 Non-Linearity ( W/m): +/- 10 W/m2 Non-Stability (change/year): +/- 0.5 % Field of View: 180 Degrees Should have required cable, made of weatherproof anodized aluminum with acrylic diffuser and stainless steel hardware. UV / PAR Sensor (Silicon Pyranometer): Spectral Range: nm Accuracy Calibrated against an Eppley Precision Spectral Pyranometer (PSP) under natural daylight conditions. Error under most of these conditions is <5%, typical ±5%. Sensitivity Typically 90 µa per 1000 W/m2 Linearity Maximum deviation of 1% up to 3000 W/m2 Stability < ± 2% change over one-year period Response Time 10 µs Temperature Dependence: ± 0.15% per C maximum Cosine Correction Cosine corrected up to 80 angle of incidence Azimuth < ±1% error over 360 at 45 elevation Tilt No error induced from orientation Relative Humidity 0% to 100% RH Detector High stability silicon photovoltaic detector (blue enhanced) Sensor Housing Weatherproof anodized aluminum case with acrylic diffuser and stainless steel hardware Cable Length: As required. vi. Ultrasonic Snow Level Sensor: Distance measuring type non-contact sonic Or laser range type snow gauge, With aluminum type target platform; One measurement every 3 seconds, Measurement range 0.5 to 10 meters, Accuracy: 1 cm or.4 % distance to target, Resolution: 3 mm, temp. Range: -40 to + 55C, with required cable. Temperature accuracy +/- 0.2 deg C. The snow collection platform of 5ft dia with an aluminum plate top. To be supplied with a 10ft cantilever type stabilized measurement arm made of 1½ dia GI pipe, and aluminum top snowfall target platform. vii. Soil Moisture Sensors (05, 10, 20, 30, 50, 100 cm depth): Dielectric Probe Soil Moisture Sensor for cultivated and stony soil. Quote separately for cultivated soil and stony soils. Measurement rang: From completely (oven dry) to fully saturated. Output: Analog voltage 0 5 V / SD 1 12 (quote separate price) Precision: +0.06% volume Temperature effect: +3%, 5 to 35 C Operating range: 5 to +60 C Sensors Setup: Sensors setup for averaging be sampled, every 5 seconds. The averaged values should then be calculated when all sensors are logged. Additionally, AWS can be programmed to run and compute the following values every 10 seconds, in some cases with a 5 second offset. #RAI Amount of rain since last measurement #LASTR Holding variable for Tiny BASIC #R0 Amount of rain since midnight #P1 Sunlight threshold #P2 Unused #GUST Peak instantaneous wind speed in a two minute interval. O E Used for processing unit vector wind direction

5 #DP Calculated Dew Point #PSP Calculated solar radiation #HR Hours of sunlight etc. Example of a Typical AWS Data Logging System The AWS Data Logger should measure a value (or compute an average) for the following sensors every 2 minutes. WDI Wind Direction Measured (Instantaneous) RH Relative Humidity Measured (Instantaneous) AT Air Temperature Measured (Instantaneous) PSP Pyranometer Measured (Instantaneous) TB Tipping Bucket / Rain Gauge Measured (Instantaneous) WSI Wind Speed Measured (Instantaneous) WSA Wind Speed Averaged WDA Wind Direction Averaged BARO Barometer Measured (Instantaneous) SOILM Soil Moisture (Tension) 5. Central Recording Station at Met. HQs: A PC Based Central Receiving Station installed at Met. HQs Office. Data from each AWS will be pooled or collected by Central Receiving Unit using GSM / GPRS communication system. The Data should be pooled at user defined interval. The Software should have capabilities to pool Current Real time data as well as Archived historical data at a pre-defined interval programmed in the base station software automatically without user intervention. Central Station should have a Database Management Software System in addition. 6. Data Communication System: GSM based packet communication modem system; using any of the Cape Verde GSM networks (that may have service in the area of installation) using SMS and GPRS service. Complete endto-end system, to transmit data from remote loggers to the MET control office at preprogrammed intervals, or alternately respond to Polls from MET control station. Self contained requiring only DB-9 (RS-232C) interface with main logger. Should be housed in weather proof housing (Same as the data logger). Power to be supplied by the common system battery. 7. Certification Required for Sensors: The sensors provided should come calibrated from the factory with Certificates of Calibration. Manufacturer should perform comparative measurements with known well-calibrated sensors to ensure that all sensors are working during the installation phase. All sensors should be supplied with cables that are UV proof to ensure good performance for years. All sensors should have military style connectors specially keyed for each sensor to ensure proper connection between the sensor and the DCP. The sensors should be high-quality professional instruments. All support arms holding sensors should be manufactured from anodized aluminum or galvanized steel and fitted to the tower-scaffold by means of stainless steel and/or hot galvanized clamps and stock of screws. Consideration should be taken to avoid vibrations due to high winds. All sensors connected to the Datalogger should be easily identifiable with labels for each cable. 8. SY OP/METAR (WMO) MESSAGE GE ERATIO : The data collected at meteorological data monitoring computer be processed according to WMO Applications at the Observing Station for preparation of: METAR Hourly SPECI When Requested Main SY OP 00;00, 06:00, 12:00, 18:00 Intermediate SY OP 03:00, 09:00, 15:00, 21:00 on Standard SY OP (only if specified) 01:00, 02:00, 04:00, 05:00, 07:00, 08:00, 10:00, 11:00, 13:00, 14:00, 16:00, 17:00,

6 19:00, 20:00, 22:00, 23:00 ( ote that all these times correspond to GMT time) 9. Availability of Spare Parts: Manufacturer should guarantee that all spare parts will be available for a period of 10 years. In the event that a part is no longer available, Manufacturer should identify a substitute item that is identical in function, and similar in form and fit. 10. Packaging: The AWS should be package to withstand expected environmental conditions during normal delivery through air, land or sea, including land transportation over rough roads dust and rain. Packaging should permit visual inspection of the goods.