The SNiP-SQ3 is a 'Sensor Node Integrated Package' for LoRaWAN communication of the real-time spatial average of photosynthetically active radiation in a plant or canopy's inception of light, for continuous plant, light and environmental monitoring.
The Apogee SQ-313 Line Quantum Sensor measures a spatial average of photosynthetically active radiation, using 3x internal sensors. Photosynthetically active radiation (PAR), or photosynthetic photon flux (PPF), is the wavelength range from 400 to 700 nanometers and is strongly correlated with plant growth. Gardeners, greenhouse managers, growth chamber users and salt-water aquarists measure PAR to insure optimal specimen health.
Further parameters can be added to SNiP-SQ3, without requiring loggers to match each distinct sensor, substantially reducing the cost of getting a fuller picture on the application.
Radiation that drives photosynthesis is called photosynthetically active radiation (PAR) and is typically defined as total radiation across a range of 400 to 700 nm. PAR is often expressed as photosynthetic photon flux (PPF): photon flux in units of micromoles per square meter per second (µmol m-2 s-1 , equal to microEinsteins per square meter per second) summed from 400 to 700 nm (total number of photons from 400 to 700 nm). While Einsteins and micromoles are equal (one Einstein = one mole of photons), the Einstein is not an SI unit, so expressing PPF as µmol m-2 s-1 is preferred.
Sensors that measure PPF are often called quantum sensors due to the quantised nature of radiation. A quantum refers to the minimum quantity of radiation, one photon, involved in physical interactions (e.g. absorption by photosynthetic pigments ). In other words, one photon is a single quantum of radiation.
Typical applications of quantum sensors include incoming PPF measurement over plant canopies in outdoor environments or in greenhouses and growth chambers, and reflected or under – canopy (transmitted) PPF measurement in the same environments.
Apogee Instruments SQ series quantum sensors consist of a cast acrylic diffuser (filter), photodiode, and signal processing circuitry mounted in an anodised aluminium housing, and a cable to connect the sensor to a measurement device. Sensors are potted solid with no internal air space, and are designed for continuous PPF measurement in indoor or outdoor environments. SQ series sensors output an analogue voltage that is directly proportional to PPF under sunlight (e.g. model SQ-110) or electric lights (e.g. model SQ-120). The voltage signal from the sensor is directly proportional to radiation incident on a planar surface (does not have to be horizontal), where the radiation emanates from all angles of a hemisphere.
The AD-NODE is designed for those requiring precision in their analogue and digital measurements. With a 24-bit ADC, the AD-NODE supports two RTDs, a 0–10V with compressing range and a 4–20mA input. Each of the four dry-contact digital inputs is capable of simultaneously sampling at 1 kHz, with periodic reporting. Settings on the device can be altered remotely via LoRaWAN™ or locally via USB.
|Sensitivity:||0.2 mV per µmol m-2 s-1|
|Calibration Factor:||5.0 µmol m-2 s-1 per mV (reciprocal of sensitivity)|
|Calibration Uncertainty:||± 5%|
|Non-stability (Long-term Drift):||< 2% per year|
|Non-linearity:||< 1% (up to 2500 µmol m-2 s-1 )|
|Response Time:||< 1 ms|
|Field of View:||180°|
|Spectral Range:||410 nm to 655 nm|
|Directional (Cosine) Response:||± 5% at 75° zenith angle|
|Temperature Response:||-0.06 ± 0.06% per C|
|Operating Environment:||-40 to 70°C, 0 to 100% relative humidity, can be submerged in water up to depths of 30 m|
|Dimensions:||70 cm length, 1.5 cm width, 1.5 cm height|
|Mass:||375 g (with 5m of lead wire)|
|Cable:||5m of shielded, twisted-pair wire. Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions). Pigtail lead wires|
|Power Supply:||Self Powered|