OWNER’S MANUAL ASPIRATED RADIATION SHIELD Model TS-100 APOGEE INSTRUMENTS, INC. 721 WEST 1800 NORTH, LOGAN, UTAH 84321, USA TEL: (435) 792‐4700 FAX: (435) 787‐8268 WEB: APOGEEINSTRUMENTS.COM Copyright © 2013 Apogee Instruments, Inc.
TABLE OF CONTENTS DECLARATION OF CONFORMITY……………………………..……………………. 3 INTRODUCTION…………………………………………………………………………….. 4 SENSOR OPTIONS....................................................................... 5 SPECIFICATIONS……………………………………………………………………………. 6 DEPLOYMENT AND INSTALLATION……………………………………………….. 9 OPERATION AND MEASUREMENT……………………………………..…………. 11 MAINTENANCE AND RECALIBRATION………………………………….......... 15 TROUBLESHOOTING AND CUSTOMER SUPPORT…………………………… 16 RETURN POLICY AND WARRANTY………………………………………………….
DECLARATION OF CONFORMITY CE and ROHS Certificate of Compliance We Apogee Instruments, Inc.
INTRODUCTION Properties of materials and nearly all biological, chemical, and physical processes are temperature dependent. Temperature is also a fundamental weather variable. As a result, temperature is perhaps the most widely measured environmental variable. Aspirated radiation shields are designed to shield temperature and humidity sensors from incident solar radiation while maintaining equilibrium with ambient air through fan aspiration.
SENSOR OPTIONS TS-100 aspirated radiation shields accommodate multiple air temperature and humidity sensors using sensor port adapters.
SPECIFICATIONS TS-100 Radiation-induced Temperature Increase (RITI): There is no reference standard for the elimination of radiation effects on air temperature measurement, but well-designed aspirated shields minimize this effect.
digit in the IP rating indicates protection against particle entry. A 5 indicates minimal dust entry with no interference with fan operation. The second digit indicates water protection. A 5 indicates that water sprayed on the fan from any direction shall have no harmful effects. Typical fans have particle and water protection ratings of 2 to 3, indicating moderate particle and water protection, but no dust protection.
ST-300 (Platinum Resistance Thermometer) Measurement Range: -50 to 70 C Measurement Uncertainty: 0.2 C (from -40 to 60 C) Measurement Repeatability: < 0.01 C Non-stability (Long-term Drift): < 0.05 C per year Equilibration Time: 15 s Operating Environment: -50 to 70 C 0 to 100 % relative humidity Input Voltage Requirement: 2.1 V DC excitation (recommended, see OPERATION AND MEASUREMENT section) Output Voltage Range: 16 to 27 mV DC (assuming continuous input excitation of 2.1 V DC) Current Drain: 0.
DEPLOYMENT AND INSTALLATION TS-100 aspirated radiation shields come partially pre-assembled and have few parts, facilitating easy transport, deployment, and maintenance. Avoid placing the shield near buildings, paved surfaces, or any other locations which may create a microenvironment significantly different than ambient environment. The World Meteorological Organization (WMO) recommends a mounting height of 1.25 to 2 meters above ground.
The underside of the hat has eight flat surfaces where one or more included cable tie mounts may affix. Using the cable tie mounts is optional, but provides an anchor to zip-tie cables to, providing strain relief and extra shading.
OPERATION AND MEASUREMENT Connect the sensor to a measurement device (meter, datalogger, controller) capable of inputting 2.5 V DC, and measuring and displaying or recording a millivolt (mV) signal (an input measurement range of 02500 mV is required to cover the entire temperature range of the ST-110 air temperature sensor). In order to maximize measurement resolution and signal-to-noise ratio, the input range of the measurement device should closely match the output range of the sensor.
An excitation voltage of 2.5 V DC is recommended to minimize self-heating and current drain, while still maintaining adequate measurement sensitivity (mV output from thermistor per C). However, other excitation voltages can be used. Decreasing the excitation voltage will decrease self-heating and current drain, but will also decrease thermistor measurement sensitivity.
Measurement of PRT resistance is very similar to measurement of thermistor resistance, where a halfbridge measurement is used. An excitation voltage is input across the bridge resistor and an output voltage is measured across the PRT. An excitation voltage of 2.1 V DC is recommended to minimize current drain, while still maintaining an adequate voltage signal. However, other excitation voltages can be used.
Fan Operation: Under some environmental conditions (e.g., high wind speed, low solar radiation), accurate measurements can be made without running the fan at full speed. Fan speed and power consumption can be decreased using a pulse width modulation (PWM) signal. The PWM signal should have a frequency of approximately 20 kHz and a duty cycle of 50 to 100 %, where a duty cycle of 100 % is full power and 50 % is low power.
MAINTENANCE AND RECALIBRATION At full duty, the fan is designed to last 50,000 hours (5.7 years). Ultimately, this depends on operating conditions, and actual results may vary. If the fan runs less than approximately 4500 RPM at full power, then there may be a blockage or the fan may need to be replaced. The fan is secured by four nylon screws and can be easily removed.
TROUBLESHOOTING AND CUSTOMER SUPPORT Independent Verification of Functionality: Apogee ST-110 temperature sensors yield a resistance proportional to temperature. A quick and easy check of sensor functionality can be accomplished with an ohmmeter. Connect the lead wires of the ohmmeter to the black and red wires from the sensor. The resistance should read 10 k (10,000 ohms) at 25 C. If the sensor temperature is less than 25 C, the resistance will be higher.
compatible measurement device should have resolution of at least 0.008 mV, in order to produce temperature resolution of less than 0.1 C across the entire temperature measurement range. To operate the fan, a 12 V DC power supply capable of supplying at least 80 mA is required. All fans also include pulse width modulation (PWM; allows for reduction of fan speed under certain conditions) and a tachometer (allows for monitoring of fan speed).
RETURN AND WARRANTY POLICY RETURN POLICY Apogee Instruments will accept returns within 30 days of purchase as long as the product is in new condition (to be determined by Apogee). Returns are subject to a 10 % restocking fee. WARRANTY POLICY What is Covered All products manufactured by Apogee Instruments are warranted to be free from defects in materials and craftsmanship for a period of four (4) years from the date of shipment from our factory.
3. Please write the RMA number on the outside of the shipping container. 4. Return the item with freight pre-paid and fully insured to our factory address shown below. We are not responsible for any costs associated with the transportation of products across international borders. 5. Upon receipt, Apogee Instruments will determine the cause of failure.