EKO INSTRUMENTS CO., LTD. MS-56 Pyrheliometer Manual Ver.5
Pg. 21
2. Temperature Dependency (Typical)
In general the sensitivity of optical detectors depends on the temperature of the instrument because of
material properties, known as the temperature coefficient (TC). However the MS-56 sensor construction has a
built in special passive compensation network which reduces the temperature dependency to less than
+/-0.5% between
–20
o
C and +50
o
C. To achieve this low temperature dependency the sensitivity of each
sensor is measured and compensated individually in manufacturing process. For the measurement of the
temperature dependency a highly stable 1000 W/m
2
light source (<0.3% variance (during total measurement
sequence)) is used. With each MS-56 measurement report (Temperature Dependency Test Report) is issued
indicating the measured temperature dependency of responsivity (each output at every 10
℃
compared
against output at 20
℃
).
3. Zero Offset (Typical)
Due to a well balanced and light weight detector construction the Zero Offset caused by changing instrument
temperature is negligible. The typical Zero Offset was measured according to the ISO 9060 definition at a
temperature response of 5K/h change in ambient temperature. A thermally balanced detector is important to
guarantee the best measurement stability during variable environmental and solar irradiance conditions.
Figure 7-2. Temperature Dependency Measurement
Figure 7-3. Zero Offset Measurement
Zero Offset (5K/h)
