Apogee Instruments SU-205 소유자 매뉴얼 - 페이지 15

{카테고리_이름} Apogee Instruments SU-205에 대한 소유자 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. Apogee Instruments SU-205 18 페이지. Ultraviolet-a sensor
Apogee Instruments SU-205에 대해서도 마찬가지입니다: 소유자 매뉴얼 (18 페이지)

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TROUBLESHOOTING AND CUSTOMER SUPPORT

Independent Verification of Functionality

Apogee SU-202 and SU-205 sensors provide an amplified voltage output that is proportional to incident UV-A

radiation. A quick and easy check of sensor functionality can be determined using a DC power supply and a

voltmeter. Power the sensor with a DC voltage by connecting the positive voltage signal to the red wire from the

sensor and the negative (or common) to the black wire from the sensor. Use the voltmeter to measure across the

white wire (output signal) and black wire. Direct the sensor head toward a light source and verify the sensor

provides a signal. Increase and decrease the distance from the sensor head to the light source to verify that the

signal changes proportionally (decreasing signal with increasing distance and increasing signal with decreasing

distance). Blocking all radiation from the sensor should force the sensor signal to zero.

Compatible Measurement Devices (Dataloggers/Controllers/Meters)

-2

SU-202 UV-A sensors are calibrated with a standard calibration factor of 0.04 W m

per mV, yielding a sensitivity of

-2

25 mV per W m

, and the SU-205 UV-A sensors are calibrated with a standard calibration factor of 0.02 W m

per

-2

mV yielding a sensitivity of 50 mV per W m

. Thus, a compatible measurement device (e.g., datalogger or

-2

controller) should have resolution of at least 25 mV or 50 mV to provide a measurement resolution of 1 W m

respectively.

An example datalogger program for Campbell Scientific dataloggers can be found on the Apogee webpage at

http://www.apogeeinstruments.com/content/UV-Sensor.CR1.

Zero Offset Error

With the use of certain dataloggers it is possible to measure a non-zero voltage (zero offset) when the sensor

output should be zero (no UV irradiance incident on diffuser). This offset can be corrected by adding or subtracting

the measured offset from the sensor output. However, if the offset is substantial, and your sensor is outputting

unrealistic values then it may need to be recalibrated. In this case, contact Apogee customer support to recalibrate

the sensor.

Cable Length

When the sensor is connected to a measurement device with high input impedance, sensor output signals are not

changed by shortening the cable or splicing on additional cable in the field. Tests have shown that if the input

impedance of the measurements device is greater than 1 mega-ohm there is negligible effect on the calibration,

even after adding up to 100 m of cable. All Apogee sensors use shielded, twisted pair cable to minimize

electromagnetic interference. For best measurements, the shield wire must be connected to an earth ground. This

is particularly important when using the sensor with long lead lengths in electromagnetically noisy environments.

Modifying Cable Length

See Apogee webpage for details on how to extend sensor cable length at

http://www.apogeeinstruments.com/how-to-make-a-weatherproof-cable-splice/.