Tools Required; Location And Support; Installation For Measurement Of Horizontal Global Irradiance; Location - Kipp & Zonen SMP series Instruction Manual

2.2 Tools required

The tools required to fit an SMP series pyranometer to a support are a 4 mm (M5 socket head screw) Allen key and a 8 mm (M5
nut) wrench / spanner. Normally, the drying cartridge for the SMP11 should be hand-tight, but a 16 mm or 5/8" open-ended
wrench / spanner can be used to loosen it.

2.3 Location and support

The instruction sheets contain all the outline information necessary for the correct installation of the pyranometers. Further
detail for specific types of installation and application are given later in this section.
Check the condition of the desiccant in the SMP11 and replace before installation, if necessary; for example after a long storage
period. This is not required for all other SMP's, they have an internal desiccant that is operational 10 years after the last
calibration date as mentioned on the instrument label and calibration certificate.
When using the digital output it might be convenient to set the Modbus® address prior to visiting the site, otherwise a computer
and RS-485 / USB converter may be required during installation.

2.4 Installation for measurement of horizontal global irradiance

The following steps must be carefully taken for optimal performance of the instrument.

2.4.1 Location

Ideally, the site for the radiometer should be free from any obstructions to the hemispherical view from the plane of the detector.
If this is not possible, the site should be chosen in such a way that any obstruction over the azimuth range between earliest
sunrise and latest sunset should have an elevation not exceeding 5 ° (the apparent sun diameter is 0.5 °).
This is important for an accurate measurement of the direct solar radiation component. The di use solar radiation is less
influenced by obstructions near the horizon. For instance, an obstruction with an elevation of 5 ° over the whole azimuth range
of 360 ° decreases the downward di use solar radiation by only 0.8 %.
It is evident that the radiometer should be located in such a way that a shadow will not be cast upon it at any time (for example
by masts or ventilation ducts). Note that hot exhaust gas (> 100 °C) will produce some radiation in the spectral range of the
radiometer and cause an o set in the measurements. The radiometer should be distant from light-coloured walls or other
objects likely to reflect sunlight onto it, or emitting short-wave radiation.
The radiometer should be readily accessible for cleaning the outer dome, checking that it is level and inspecting the desiccant.
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