Relative humidity and temperature sensor 3S-RH&AT-MB

RS-485Modbus RTU24VDC

Product overview
The SEVEN 3S-RH&AT-MB is a capacitive sensor designed to measure relative humidity and ambient temperature. A variant (3S-RH/AT/PS-MB) adds barometric pressure measurement. The sensor is supplied with mounting hardware and protected from direct solar radiation by a multi-plate plastic radiation shield that allows free airflow.

Applications and impact
Used in solar energy systems, industrial sites, storage and transport monitoring, and production facilities to monitor humidity-related effects on equipment and processes. Data supports assessment of PV plant spectral variations, module performance, heat transfer calculations, refractive effects on incoming radiation and determination of wetness/condensation periods when combined with temperature data.

Working principle and communications
The device uses a UV-resistant protective shield and a capacitive RH element for stable measurements. Measured values are output via an RS485 serial interface using Modbus RTU up to 38400 Baud for integration with PLCs, data loggers and monitoring systems.

Technical specifications
Item code: 3S-RH&AT-MB | 3S-RH/AT/PS-MB
Measured data: Relative humidity; Ambient temperature | Relative humidity; Ambient temperature; Pressure (PS model)
Sensor type: Capacitive
RH range: 0% to 100% — Accuracy: ±1% RH (20–70%) at 25 °C — Resolution: 0.1%
Temperature range: -40 °C to +85 °C — Accuracy: ±0.1 °C (5–60 °C) — Resolution: 0.1 °C
Pressure (PS model): 260 to 1260 hPa — Accuracy: 0.5 hPa — Resolution: 0.1 hPa
Data output: RS485 up to 38400 Baud — Protocol: Modbus RTU
Power: 12 to 30 V DC — Consumption: 20 mA max @ 24 VDC
Cable: 3 m LIYYC11Y PUR, UV and weather resistant
Enclosure: ABS box; shield ABS; sensor housing stainless steel tube with membrane filter
Dimensions: Box 64 x 68 x 35 mm; Shield Ø 105 x 100 mm — Weight: 0.5 kg — Protection: IP65
Standards: Class A per IEC 60751:2022 (Temperature) and IEC 61724-1:2021 (Relative Humidity)

Where is 3S-RH&AT-MB used?

• Solar energy systems (PV performance monitoring)
• Industrial environments and production facilities
• Storage areas for moisture-sensitive products
• Transportation and refrigerated vehicles monitoring
• Environmental monitoring networks

Installation
Before mounting, verify unit operation at ground level. Install the shielded sensor away from heat sources, reflective surfaces and localized thermal disturbances. For rooftop mounting, place on the building side exposed to prevailing wind. Installation: fix the mounting structure first, then secure the sensor to the framework.

Key benefits

• Accurate measurement: High-resolution RH and temperature data for precise monitoring.
• Outdoor readiness: UV-resistant shield and IP65 enclosure for long-term outdoor use.
• Standard interface: RS485 + Modbus RTU simplifies integration with SCADA and dataloggers.

Frequently asked questions (selected)
Class: All 3S-RH&AT-MB and 3S-RH/AT/PS-MB units are Class A per IEC 60751:2022 (Temperature) and IEC 61724-1:2021 (Relative Humidity).
Warranty: 2-year warranty.
Price range (indicative): Approximately 225–445 EUR depending on model and configuration.
Lead times (indicative): Small orders (≤20 pcs): ~2–3 weeks; bulk (20–100 pcs): ~6–8 weeks.
Included cable: 3 m LIYYC11Y PUR cable supplied; other lengths available on request.

Technical specifications (summary)

• Model: 3S-RH&AT-MB (option: 3S-RH/AT/PS-MB)
• Measured parameters: Relative Humidity, Ambient Temperature (optional Pressure)
• Sensor type: Capacitive
• Ranges & accuracy: RH 0–100% (±1% RH @20–70%); T -40–+85 °C (±0.1 °C @5–60 °C)
• Pressure (PS): 260–1260 hPa (±0.5 hPa)
• Output: RS485 up to 38400 Baud, Modbus RTU
• Power: 12–30 V DC, 20 mA max @24 VDC
• Cable: 3 m LIYYC11Y PUR (UV/weather resistant)
• Dimensions & protection: Box 64 x 68 x 35 mm; Shield Ø105 x 100 mm; IP65
• Materials: ABS enclosure & shield; stainless steel sensor tube with membrane filter
• Standards: Class A IEC 60751:2022 and IEC 61724-1:2021