Quantum PAR PR1

ICT International's "smart" solar radiation sensors have been designed to meet specific application needs. The PR1 Photosynthetic Active Radiation (PAR) sensor has a similar construction to the SR2 but with a spectral response range from 400 to 700 nanometres. Designed to measure light that promotes photosynthesis in the plant cell, the PR1 can be used above or within a canopy crop growing under either natural or artificial lighting (such as in glasshouses). Through the use of a shaped Teflon diffuser, which houses the photovoltaic sensor, the sensor is able to correct for the changing angle of incidence as the sun moves across the sky. The "cosine correction" follows the theoretical spectral curve to within 2 per cent.

Sophisticated measurement

The sensing element of the PR1 sensor is connected to an integrated 16-bit resolution microprocessor with control and alarm outputs and software switchable dual output signals. When used with an ICT Smart Logger the sensors truly become "plug and play" without the need for programming. With most other systems, changeover of a sensor requires either re-calibration of the system or resetting/programming of parameters in the data logger. The "smart" sensor eliminates this requirement as the on-board microprocessor ensures all PR1 sensors exhibit the same electronic specifications and therefore, identical performance. Each unit is provided with a multi-point calibration curve for maximum accuracy across the range. Sensors are supplied with individual calibration certificates to enable software conversion to engineering units (mmol.m^-2.s^-1). In serial mode, the sensor reports in engineering units and the global algorithm is implemented internally.

Applications	Features
Meteorology	PAR and global response versions
Agriculture and horticulture	Cosine corrected (within ±2% from 10° to 90° )
Greenhouse management	Robust design
Solar radiation intensity	Dual control/alarm-output
Evapotranspiration calculations	Stainless-steel body
Emergency services	Mounting options available