DFRobot
RS485 Photosynthetically Active Radiation (PAR) Sensor (400-700nm)
· MPN: SEN0641
The RS485 PAR Sensor measures photosynthetically active radiation in the 400–700 nm wavelength range — the light spectrum that plants use for photosynthesis....
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The RS485 PAR Sensor measures photosynthetically active radiation in the 400–700 nm wavelength range — the light spectrum that plants use for photosynthesis. It converts incident radiation into a signal proportional to light intensity, with cosine-corrected angular response for accurate readings at varying sun angles.
Built for outdoor deployment with an IP67-rated aluminium housing and a specially treated dust cover, this sensor delivers reliable measurements in harsh environments. It communicates via RS485 using the Modbus-RTU protocol and operates on a wide 5–30V DC supply, making it easy to integrate with Arduino and other platforms.
Key Features
- 400–700 nm Spectral Range – Measures the full PAR band used by plants for photosynthesis
- 0–2,500 µmol/m²·s Range – Covers low-light to full-sun conditions
- ±5% Accuracy – At 1,000 µmol/m²·s, 550 nm, 60% RH, 25°C
- 1 µmol/m²·s Resolution – Fine-grained measurement for research applications
- 10 µs Response Time – Near-instantaneous readings
- Cosine Corrected – ≤±10% cosine response for accurate angular measurements
- RS485 Modbus-RTU – Standard industrial communication protocol
- IP67 Rated – Dust-tight and waterproof for outdoor installations
- 5–30V DC Supply – Wide voltage range, <10 mA working current
Specifications
- Measurement Range: 0–2,500 µmol/m²·s
- Wavelength Range: 400–700 nm
- Accuracy: ±5%
- Resolution: 1 µmol/m²·s
- Non-Linearity: <±1%
- Annual Stability: ≤±2%
- Operating Temperature: -25°C to +60°C
- Protection Level: IP67
- Sensor Cable Length: 20 cm
- Adapter Cable Length: 70 cm
Ideal For
- Agricultural monitoring and crop growth optimisation
- Greenhouse light management
- Photovoltaic and solar radiation monitoring
- Environmental and ecological research
Package Contents
- 1× RS485 PAR sensor
- 1× Adapter cable
- 1× Screw package
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- DC
- DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.
- IP67
- An ingress protection rating meaning the enclosure is dust-tight and can survive temporary immersion in water under specified test conditions. This matters when choosing a sensor for outdoor, wet, or wash-down environments.
- Modbus
- Modbus is an industrial communication protocol used by many meters, sensors, PLCs and automation devices. When a product lists Modbus support, it is generally easier to integrate with existing industrial equipment that speaks the same protocol.
- ModBus-RTU
- ModBus-RTU is a common industrial protocol for sending readings and control commands over serial links such as RS485. Knowing a device uses ModBus-RTU helps you choose software libraries, data loggers, or controllers that can request and interpret its data.
- RS485
- RS485 is a robust differential serial communication standard often used in factories, farms and buildings where cables may be long or electrically noisy, and it can link many devices on a single pair of wires. When a product lists RS485, it can communicate with industrial sensors, meters and control equipment over longer distances than typical hobby serial wiring.
- Torque
- A twisting force that causes something to rotate, usually measured in newton-metres or kilogram-centimetres. It matters when choosing motors, servos, gears, and tools because higher torque is needed to lift heavier loads, turn larger wheels, or move mechanisms without stalling.
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Sensors & Input
Supplier page — dfrobot.com
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