RH-Combo-Sun-Shield

Supported Applications

The ACI RH Sun Shield series provides relative humidity and temperature sensing in a weather-proof housing designed for outdoor monitoring where overhang or shade is unavailable. The passive shield utilizes nine highly reflective white wedge-shaped plates to minimize direct exposure to sunlight while maximizing airflow around the sensors, protecting them from error-producing solar radiation and precipitation. This configuration ensures that air conditions inside the shield represent outside ambient levels.

Documented applications include:

• Outdoor humidity and temperature monitoring
• Commercial heating and cooling building management systems (BMS)
• Sites requiring protection from rain, snow, and solar thermal effects

Operating Conditions & Performance

The series operates within a relative humidity range of 0 to 95% RH, non-condensing. The operating temperature range is -40 to 140 °F (-40 to 60 °C), with a storage temperature capability from -40 to 149 °F (-40 to 65 °C). Enclosures are rated NEMA 4X (IP 66) and constructed of Polystyrene Plastic or Polyethylene Plastic, UL94-V2.

Performance specifications for the relative humidity transmitter include:

• RH Accuracy @ 77°F (25°C): ±1% over a 20% RH range between 20 to 90%, or ±2%, 3%, or 5% from 10 to 95%
• RH Response Time: 20 seconds typical (T63)
• RH Stability/Repeatability: Less than 2% drift / 5 years; Repeatability of 0.5% RH
• Sensor Type: Capacitive with Hydrophobic Filter

The optional temperature sensor response time is 10 seconds nominal for thermistor elements.

Configuration Options

The series supports multiple configuration options across output signals, sensor types, and calibration certifications. All units are shipped from the factory set up for a 4-20 mA output unless otherwise specified.

• Output Signals: Field selectable between 2-wire 4-20 mA (Factory Default), or 3-wire 0-5 VDC and 0-10 VDC. The transmitter can also include an optional temperature sensor for monitoring space temperature.
• Power Supply Requirements:
  • 4-20 mA: 15 - 40 VDC / 18 - 28 VAC (Reverse Polarity Protected)
  • 0-5 VDC: 12 - 40 VDC / 18 - 28 VAC
  • 0-10 VDC: 18 - 40 VDC / 18 - 28 VAC
• Load Resistance: 700 Ω maximum for 4-20 mA; 4K Ω minimum for 0-5 VDC or 0-10 VDC.
• Sensor Elements (Optional Temperature):
  • Nickel RTD: 1 KΩ nominal, Din Standard DIN 43760
  • Platinum RTD: 100 Ω or 1K Ω nominal, Class A ±0.06% tolerance (Tolerance Formula: +/- °C = (0.15 °C + (0.002 * |t|)))
  • Thermistors: Various NTC series including 1.8KΩ, 3KΩ, AN (Type III), CP (Type II), CSI, and others with nominal resistances ranging from 1.8 KΩ to 100 KΩ.
• Calibration: Three-point NIST calibration certificates are available for Temperature & RH (Default Test Points: 20%, 50%, & 80%).
• Electrical Connection: Screw Terminal Blocks, polarity sensitive. Wire size support is 16 AWG (1.31 mm²) to 26 AWG (0.129 mm²). Torque rating: 4.43 to 5.31 lb-in (0.5 to 0.6 Nm).

Key Product Differences

The series is differentiated by the specific temperature sensor element selected and the accuracy class of the humidity transmitter.

• Nickel RTD Models: Feature a standard Nickel RTD with 1 KΩ nominal output. Accuracy varies by temperature: ±0.72 °F (0.4 °C) at 32 °F, ±0.34 °F (0.17 °C) at 70 °F, and ±1.00 °F (0.56 °C) at 130 °F.
• Platinum RTD Models: Offered in 2-wire or 3-wire configurations with 100 Ω or 1K Ω nominal outputs. These models adhere to DIN EN 60751 (IEC 751) standards and provide ±0.06% Class A accuracy.
• Thermistor Models: Available in multiple series including AN, CP, CSI, and specific resistance values like 1.8K or 20K. Accuracy for most thermistors is ±0.36 °F (0.2 °C) from 32-158 °F, with exceptions such as the 1.8K Series at ±0.9 °F (0.5 °C) @ 77°F.
• Accuracy Classes: The humidity transmitter is available in RH2 (±2% from 10 to 95%) and other accuracy classes depending on the specific model configuration.