CHP1-L Pyrheliometer

Expand AllCollapse All

1. How often should the CHP1-L window be cleaned?

   Ideally, the window should be cleaned every morning.

2. How often should the CHP1-L be calibrated?

   Every two years.
3. Is a two-axis tracker needed for the CHP1-L?

   Absolutely. Because the CHP1-L measures the direct beam solar irradiance, it must follow the sun and remain within the limits of the 5 degree field of view to provide accurate measurements.
4. Does the CHP1-L require a power supply?

   No.
5. Can the output signal from a CHP1-L be negative?

   Yes, but only under certain conditions. The most common condition for a negative output signal occurs during nighttime measurements when the temperature of space is less than the sensor’s temperature.
6. What type of sensor is the CHP1-L, and what does it measure?

   The CHP1-L is a pyrheliometer, manufactured by Kipp & Zonen, that measures the direct beam irradiance from the sun within a 5 degree solid angle around the sun.
7. Does the CHP1-L have an internal temperature sensor?

   Yes. The internal temperature can be measured using either the PT100 or thermistor built into the sensor.
8. How does the CHP1-L work?

   A pyrheliometer, such as the CHP1-L, has a window through which sunlight enters. The sunlight, or incident solar short-wave radiation, is directed onto an electronic device called a thermopile. Using the thermoelectric effect, the thermopile acts as a large thermocouple that measures the temperature of a particular body—in this case, the sun. The thermal energy is converted into a voltage output signal that can be recorded by Campbell Scientific data loggers.

9. What type of tracker can be used with the CHP1-L?

   The CHP1-L is typically mounted to a user-supplied sun tracker, such as Kipp & Zonen’s Solys2 or EKO Instruments’ STR-21G/22G.