Smart SMP Pyranometers

The SMP series pyranometers are based on the well-known CMP 3 and CMP 11 and use the same sensor technology and housing design. Our smart  pyranometers have been created to meet the requirements of industrial applications, such as solar energy monitoring, where a digital interface is a distinctive advantage.

RS-485 Modbus
SMP’s have a 2-wire RS-485 serial bus with Modbus® RTU protocol to communicate with PLC’s, industrial data acquisition systems or computers. Real-time measurements of solar irradiance, body temperature and power supply voltage are available through the supplied software.  Instrument-related information
such as calibration history, instrument type and serial number can also be requested. Available settings are the Modbus® configuration, filtering, temperature compensation, scaling and firmware updates.

The RS-485 structure allows up to 247 devices to be connected in parallel to the 2 wire bus.  Other meteorological sensors are already available with RS-485 interface, so with the addition of a SMP smart pyranometer a complete digital automatic weather station can be assembled without the need for traditional data loggers.

Low power consumption and a built-in analogue amplifier
The SMP’s are available in two versions:
SMP3-V and SMP11-V have RS-485 Modbus® and a 0-1 V analogue output;
SMP3-A and SMP11-A have RS-485 Modbus® and a 4-20 mA analogue output.

Both versions consume very low power, 55 mW for –V and 100 mW for –A, and have a wide supply voltage range from 5 – 30 VDC. There is protection against reverse power polarity and short circuited outputs.

Digital temperature correction and faster response
An integrated temperature sensor and polynomial functions provide correction for the temperature sensitivity of the detector. A digital signal processing
algorithm speeds up the response time.

Interchangeable pyranometers
All SMP’s are programmed to have identical sensitivity and output levels, making them easily interchangeable for recalibration or service.

First launch feedback
The introduction of the new SMP pyranometers took place simultaneously in Europe and the USA; at the Meteorology Technology World Expo in Brussels and at Solar Power International in Dallas. The new pyranometers were shown running off a 9 Volt PP3 battery, with a RS-485 to USB converter and a software program on a PC. A halogen desk lamp over the pyranometer resulted in a display of more than 700 W/m²(see screen shot) and the enhanced response time could be easily demonstrated.

The new pyranometers drew a lot of attention from both solar energy and meteorology customers. They were quick to realize the advantages of the RS-485 Modbus® protocol, the digital signal processing and the ease of interfacing.

The SMP3-V and SMP11-V pyranometers are available from January 2012 with the –A versions following a few weeks afterwards.