RH-Combo-Sun-Shield-Temp-Transmitter

Supported Applications

The ACI Relative Humidity and Temperature Transmitter in a Sun Shield housing is a weather-proof combination transmitter that protects the sensors from error-producing solar radiation and precipitation. Nine molded white plastic plates form a highly reflective, wedge-shaped shield that maximizes airflow around the sensors while minimizing direct sun exposure and thermal error.

Designed for outdoor measurement of ambient humidity and temperature, the shield should be placed in an open area with unrestricted airflow, away from large radiant heat sources and building exhaust. It pairs ACI's capacitive RH transmitter with a TT100 or TT1K temperature transmitter, delivering a 4 to 20 mA output to electronic controllers in building management systems.

Operating Conditions & Performance

The RH measurement range is 0 to 100%, with an operating range of 0 to 95% RH, non-condensing. At 77 °F (25 °C), RH accuracy is ±2% from 10 to 95%. The capacitive RH element responds in 20 Seconds Typical (T63), while the platinum RTD responds in 8 Seconds nominal, and stability is less than 2% drift over 5 years.

Temperature accuracy is ±0.2% for spans below 500 °F (260 °C) and ±0.5% for larger spans. The temperature transmitter is powered from 8.5 to 32 VDC, and the family load-resistor guidance uses a 249 Ω load resistor for a 1-5 VDC output at 13.5 V minimum supply and a 499 Ω load resistor for a 2-10 VDC output at 18.5 V minimum supply.

• Outputs: 4 to 20 mA (2-wire, loop powered), field-selectable 0-5 VDC or 0-10 VDC, and a temperature output of 1 to 5 VDC or 2 to 10 VDC.
• Output load: 700 Ohms maximum on 4 to 20 mA, or 4K Ohms minimum on the voltage outputs.
• Operating temperature: -40 to 140 °F (-40 to 60 °C); storage -40 to 149 °F (-40 to 65 °C).
• Enclosure: NEMA 4X (IP 66); the shield overall length is 14.95" (379.7 mm), with a depth of 3.70 in (94.0 mm).
• Wiring: polarity-sensitive screw terminal blocks with a PG11 watertight fitting and a 1/2" NPT conduit fitting.
• Approvals: RoHS2 and WEEE.

The internal sensor probe measures 0.740" (18.80mm) in diameter and 6.83" (173.48mm) long, and the assembled shield weighs 4.16 lbs (1.89 kg).

Configuration Options

All four models in this series use the fixed RH2 ±2% accuracy grade in the O-SUN outside sun-shield configuration with a NEMA 4X rating. Models differ by the temperature-sensing element and the transmitter output.

Temperature Element

The TT100 code uses a 100 Ohms RTD element and the TT1K code uses a 1K RTD element, both feeding the 4 to 20 mA temperature transmitter, so the shield can match an existing controller's RTD input.

Transmitter Output

Models without an output suffix use the default 4 to 20 mA output, while the -2 suffix specifies a 2 to 10 VDC voltage output for controllers that accept a voltage signal.

Key Product Differences

A catalog number is assembled from the A/ prefix, the RH2 accuracy grade, the temperature sensor code, the O-SUN configuration, and an optional output suffix, with a calibrated span and optional NIST certificate specified at ordering. For example, A/RH2-TT1K-O-SUN-2 pairs a 1K RTD with a 2 to 10 VDC output.

The four configurations are:

• A/RH2-TT100-O-SUN — 100 Ohms RTD with the default 4 to 20 mA output.
• A/RH2-TT100-O-SUN-2 — 100 Ohms RTD with the 2 to 10 VDC output.
• A/RH2-TT1K-O-SUN — 1K RTD with the default 4 to 20 mA output.
• A/RH2-TT1K-O-SUN-2 — 1K RTD with the 2 to 10 VDC output.

A 3-point NIST calibration certificate can be added as an RH-only option at ordering.