The CMP 3 pyranometer is the smallest instrument in the CMP Series for measuring solar irradiance. The CMP 3 uses a 64-junction thermopile sensing element with a highly absorptive and spectrally flat black coating to capture incoming radiation and covert it to an electrical signal. This detector is protected by a high quality 4mm thick glass dome. The electrical output is provided as a mV signal and is expressed in Watts per meter square. The CMP 3 is designed for continuous indoor and outdoor use, plus the sealed construction and waterproof connector allows the unit to be used underwater (limited to 1m depth for a duration of 30 minutes).

The CMP 3 is fully compliant with all ISO-9060 Spectrally Flat Class C pyranometer performance specification criteria. It is intended for shortwave global solar radiation measurements in the spectral range from 310 to 2800nm. Units are supplied with a comprehensive, traceable calibration certificate.

Diagram

Specification

Mounting Options

The CMP 3 comes with two holes for 5mm screws. Two each of stainless steel screws, washers and nuts are provided in the fixing kit. The pyranometer should first be secured lightly with the screws to a solid and stable mounting stand or platform. We can supply mounting fixtures which incorporate a rod and a plate to mount a radiometer on one side only, or on both sides (facing upwards and downwards). We also have a bracket available to enable easy attachment of a mounting rod to a pole or wall and a kit to mount the unit at an adjustable angle.

Each CMP 3 has a threaded hole suitable for a screw-in mounting rod for easier mounting. A CMB 1 mounting bracket then allows this mounting rod to be secured to a suitable pole, mast or wall. The pyranometer can be leveled by rotating and tilting the rod. The bracket includes u-bolts for fixing for poles and masts from 22 to 60mm diameter.

An Adjustable Tilt CMP Mounting Kit is available to allow the CMP 3 to be mounted at any angle from 0° to 90° to provide an accurate reading for the position and angle of fixed photovoltaic panels. The position and angle of solar panels make a big difference to the performance and return on investment of a solar energy power plant. A horizontally mounted pyranometer measures the global short-wave radiation from the sun and sky in a way that is easily comparable with other sites and with solar energy database information. However, for fixed angle (non-tracking) PV panels it is important to know the energy available within the ‘view’ of the panel. The kit can be fixed to a horizontal surface and has a clear scale in degrees, and a secure locking device, for easy adjustment of the angle of a pyranometer from horizontal to vertical. It can also be fitted to the CMF 4 mounting fixture for simple attachment to walls and poles using the CMB 1 mounting bracket.

A simple, low cost metal disc bracket is also available that can be used to mount the CMP directly to a mast or wall. The disc will be drilled to suit the SP-Lite2 or CMP and the sensors can be leveled in the normal way once secured to the wall or mast.

The CMP 3 features a snap-on white sun shield, integrated leveling and a weatherproof connector which can be supplied pre-wired with a 10m cable, with optional cables available at 25m, 50m or 100m cable lengths. The cable is a special low impedance cable that won't affect the calibration with longer cable lengths. A CMP 3 supplied with 10m of cable is normally available from stock.