Environmental Sensor
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Environmental sensors from YADA Electronics — a Guangdong-based manufacturer (Beijing Stock Exchange: 920556) building temperature, humidity and water-immersion detection for switchrooms, data centres and HVAC systems. This category holds 4 models on RS-485 Modbus RTU, with ±0.5 °C accuracy and a measuring range of −20 to +80 °C, 5–95% RH.
Two Different Water Detection Principles — And Why It Matters
A water-conductive sensor detects liquid bridging two electrodes; a photoelectric sensor detects the change in refraction when the tip is submerged. The conductive type is cheaper and works well with tap or condensate water, but it will not reliably detect deionised or oily fluids. The photoelectric type does not depend on conductivity at all. Getting this wrong is the usual reason a leak-detection system fails silently.
| Model | Function | Key Specification | Best Suited To |
|---|---|---|---|
| YD877Y-N2 | Temperature and humidity transmitter | SHT20 element, ±0.5 °C, 5–95% RH, LCD, RS-485 Modbus | Switchrooms and indoor cabinets needing local display plus remote polling. |
| S2-RHT20BD-RS485 | Temperature and humidity combined transducer | SHT20, −20–+80 °C, ±0.5 °C, Modbus RTU | HVAC control and smart buildings. |
| YDN Series | Water immersion, photoelectric or conductive | 50 kΩ ± 10 kΩ, cable <150 m, relay output, screw mounted | Data-centre floor voids and plant rooms. |
| YDE-WDT Series | Water immersion with detecting pole cable | 50 kΩ / 40 kΩ customisable, DO output, 35 mm DIN rail | Cabinet-mounted leak detection on a perimeter cable. |
Environmental Sensor Technical Specifications
| Parameter | Specification |
|---|---|
| Temperature range | −20 °C to +80 °C |
| Temperature accuracy | ±0.5 °C |
| Humidity range | 5–95% RH |
| Sensing element | SHT20 digital temperature and humidity sensor |
| Communication | RS-485 Modbus RTU |
| Display | LCD (YD877Y-N2) |
| Water detection principle | Photoelectric (YDN-WDT) and water-conductive (YDN-WDT10) |
| Detection sensitivity | 50 kΩ ± 10 kΩ; 50 kΩ / 40 kΩ customisable |
| Lead cable length | < 150 m |
| Output | Relay / DO on water-immersion models |
| Mounting | 35 mm DIN rail; screw mounted |
Typical Applications
- Data centres — rack inlet temperature and humidity, plus leak detection under raised floors.
- Switchrooms and substations — condensation risk monitoring inside enclosures.
- HVAC systems — zone temperature and humidity feedback on Modbus.
- Battery and inverter rooms — thermal monitoring where derating depends on ambient conditions.
- Plant rooms — perimeter leak detection with relay output to trip a pump or valve.
How To Select An Environmental Sensor
- Confirm the measured range against the real environment, including worst-case summer and winter conditions inside the enclosure, not room ambient.
- Decide whether local display is needed — the YD877Y-N2 has an LCD; the S2-RHT20BD is transmit-only.
- For water detection, identify the fluid. Conductive sensing needs conductive liquid; use the photoelectric type for deionised or non-conductive fluids.
- Plan the detection cable route. Up to 150 m lets one sensor cover a room perimeter rather than a single point.
- Decide whether detection must trip equipment — if so use the relay / DO output rather than relying on the polling master.
- Confirm free Modbus addresses on the existing RS-485 bus.
Frequently Asked Questions
Which sensing element is used?
The SHT20 digital temperature and humidity sensor, combined with a signal-processing circuit that outputs a digital value for remote measurement and control.
How large an area can one water sensor cover?
The detection cable can run up to 150 m, so a single unit can cover a room perimeter or a full raised-floor void rather than a single point.
Can water detection trip equipment directly?
Yes — the water-immersion models provide a relay / DO output, so detection can act locally without waiting for the monitoring master.
Can these share the bus with the energy meters?
Yes. They use RS-485 Modbus RTU, the same bus as YADA meters, analysers and remote I/O, provided Modbus addresses do not collide.
Related Product Categories
- Remote Signaling & Control Units — collecting sensor relay outputs as digital inputs.
- Power Meters — electrical measurement alongside environmental data.
- AC Energy Meters — energy accounting on the same RS-485 bus.
- Power Quality Analyzers — electrical condition monitoring for the same facility.
- Surge Protection Devices — protecting the instrumentation supply.
Request An Environmental Sensor Quote
Send the temperature and humidity range inside the enclosure, whether local display is needed, the fluid type for leak detection, the cable run required and your Modbus address plan.