Apogee Instruments SM-500 Full-Spectrum Guardian CEA Multi-Sensor Monitor

The Apogee Guardian is an elegant device that provides accurate measurements of important indoor environmental parameters. The SM-500 is a user-friendly datalogger with multiple integrated sensors to measure PAR, air temperature, humidity, vapor pressure deficit and dewpoint, CO2 concentration, barometric pressure, and daily light integral* and photoperiod* (*only accessible via Bluetooth).

Graphical summaries of these measurements can be downloaded to dataloggers via Modbus or smartphones via Bluetooth with the Apogee Connect app (iOS/Android). While the SM-500 can take measurements as a stand-alone device mounted to a mast (Apogee Instruments AM-270) or hung by thin wires, the SM-500 model is designed to integrate with and be powered by a Modbus controller. Though, data remains accessible via Bluetooth connectivity even when powered via Modbus controller.

To use this as a stand alone Bluetooth-only datalogger, please see the Apogee Instruments SM-500-AC model option, which includes a power cable for use with a standard 120VAC wall outlet.

The SM-500 is constructed from high-quality ASA plastic with low thermal conductivity and a gloss white finish in selective areas to lower emissivity. The Guardian is filled with foam to provide additional thermal insulation. The internal airway utilizes a small venturi constriction to maximize airflow efficiency over the thermistor, which minimizes the thermal boundary layer€™s influence on temperature measurements. Simultaneously, a separate module used to measure CO2, humidity, and pressure is aspirated by a passive, low velocity airstream using a €œfluid entrainment€? principle. Additionally, a quantum sensor is mounted on the top of the shield to measure PAR.

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Apogee Instruments SM-500 Specs

• Calibration Uncertainty: ± 5 %
• Long-term drift (non-stability): Less than 2 % per year
• Measurement Repeatability: Less than 0.5 %
• Measurement Range: 0 to 4000 µmol m-2 s-1
• Spectral Range: 389 to 692 nm
• Field of View: 180°
• Directional Response: ± 5 % at 75° zenith angles
• Azimuth Angle: Less than 0.5 %
• Tilt Error: Less than 0.5 %
• Non-linearity: Less than 1 % (up to 4000 µmol m-2 s-1)
• Response Time: Less than 1 ms
• Temperature Response: -0.11 % ± 0.04 % per C
• Uncertainty in Daily Total: Less than 5 %
• Operating Environment: -40 to 60 C with 0 to 95 % relative humidity
• Housing: White ASA housing
• CO2: Range 0-2000; ± 50 ppm + 2 %
• Temperature: ± 0.2 C
• Humidity: Range 0-95 %; ± 3 % 20-80 %
• Vapor Pressure Deficit (25 C): ± 0.08 kPa
• Barometric Pressure: 70 to 110 kPa
• Connectivity: Modbus (RS232 and RS485) and Bluetooth
• Power Requirements: 5-32 V DC; Typical: 100 mA; Peak: 500 mA
• Data Storage Capacity: 9 months of 1 min data
• IP Rating: IP53 rating for harsh environments
• Dimensions: 105 mm diameter, 157 mm height
• Mass: 392 g
• Cable: 5 meter, 6 conductor, shielded wire with TPR jacket and M8 connector
• Warranty: 4 years against defects in materials and workmanship
• Manufactured: Assembled in the USA