RH-Combo-Outdoor-Air-Platinum-RTD

Supported Applications

The ACI Relative Humidity with Platinum RTD Outside Air Series is a transmitter designed for use with electronic controllers in commercial heating and cooling building management systems. The series utilizes a thermoset polymer capacitive sensing element to measure relative humidity, featuring an optional integrated temperature sensor for monitoring space conditions.

Operating Conditions & Performance

The RH measurement range is 0-100%, with an operating environment of 0 to 95% RH non-condensing. Accuracy specifications are +/- 1% over a 20% RH Range between 20 to 90% for the RH1 configuration, and +/- 2% or 3% from 10 to 95% for other configurations at 77°F (25°C). The operating temperature range is -40 to 140 °F (-40 to 60 °C), with a storage temperature range of -40 to 149 °F (-40 to 65 °C).

Performance characteristics include an RH response time (T63) of 20 Seconds Typical and stability of less than 2% drift over 5 years. The series features a capacitive sensor with a hydrophobic filter, conformally coated PCBs for moisture resistance, and integral DIP switches for field selection of output signals.

Configuration Options

The series is offered in two primary enclosure types: the Euro style (-EH) and NEMA 4X (-4X). The -EH enclosure utilizes ABS Plastic with UV Protectant (UL94-V0), while the -4X enclosure uses Polystyrene Plastic (UL94-V2, UL94-VO depending on source context; data sheet specifies UL94-V2 for NEMA 4X). Both enclosures carry a rating of NEMA 4X (IP 66).

Output signals are field-selectable via DIP switches. The factory default is a 2-wire 4-20 mA output, with options to configure for 3-wire 0-5 VDC or 0-10 VDC outputs. Power supply requirements vary by load and signal type:

• 4-20 mA: 250 Ω Load requires 15 - 40 VDC / 18 - 28 VAC; 500 Ω Load requires 18 - 40 VDC / 18 - 28 VAC.
• 0-5 VDC: Requires 12 - 40 VDC / 18 - 28 VAC.
• 0-10 VDC: Requires 18 - 40 VDC / 18 - 28 VAC.

The series supports Platinum RTD temperature sensors with the following configurations:

• RHx-100-xW Series: 100 Ω nominal at 32°F (0°C).
• RHx-1K-xW Series: 1 KΩ nominal at 32°F (0°C).

Platinum RTD tolerance is Class A (+/- 0.06%) per DIN EN 60751 (IEC 751), with a temperature coefficient of 3850 ppm/°C. Electrical connections are made via screw terminal blocks accepting wire sizes from 16 AWG (1.31 mm²) to 26 AWG (0.129 mm²). Agency approvals include CE, UKCA, RoHS, and WEEE.

Key Product Differences

Variants differ by accuracy class, sensor resistance value, wire count, enclosure type, and calibration certification:

• Accuracy Class: Models are available with RH1 (+/- 1% over a specified range), RH2 (+/- 2%), or RH3 (+/- 3%) designations.
• Sensor Element: Platinum RTD options include 100 Ω (Code: 100) and 1 KΩ (Code: 1K).
• Wire Configuration: Sensors are offered in Two Wire (2W) or Three Wire (3W) configurations.
• Enclosure Style: The "O" suffix denotes the Euro Enclosure, while "O-4X" indicates the NEMA 4X enclosure. Specific variants may also include aluminum housing options indicated by codes such as -BB in model numbers.
• NIST Certification: A three-point NIST calibration certificate is available (Code: NIST), providing test points at default levels of 20%, 50%, and 80% RH, or five points within a selected 20% range for the 1% accuracy option.