SHT45 High-Precision Meteorology Sensor Module

Low driftComponent class

DC 5～36VIsolated wide-range supply

RS485Uplink

IP67Enclosure

Product overview and engineering role

The SimtoLink SHT45 high-precision meteorology module is for weather and microclimate IoT. The sensing element is a Sensirion SHT45: measurement and factory calibration happen on the chip, the digital frame carries a CRC, and the module MCU maps the result to RS485 Modbus RTU registers. A ventilated radiation shield can be fitted to cut solar error, and the sampling and quality-control steps can follow WMO guidance. Terminals unplug, key chips carry a watchdog and a communications redundancy check, and critical firmware can be signature-checked and rolled back, which helps volume delivery and remote maintenance.

RS485 and standard industrial terminals are the default, so the module can join an existing SCADA system, an energy platform, or an IoT platform. SimtoLink supplies southbound point-table templates and northbound MQTT/HTTP push examples to shorten joint commissioning. Volume builds can add a silk-screened shell, a set cable length, a protocol map, and a calibration certificate.

Reliability and field fit

Electrical safety and EMC coverage includes the CCC items that apply to this module. Ports are protected against surge and reversed polarity. Reinforced grounding and a partitioned layout reduce ground-loop and common-mode interference. Outdoor or coastal sites can use a higher ingress rating and a corrosion-resistant coating.

Parameters can be loaded in bulk, thresholds can be set, and alarms can be linked. Configuration and firmware update over the air. On site, run a power-on self-test, sync time on the link, and spot-check temperature and humidity. For metering or compliance use, SimtoLink can help with a third-party metrology submission and can supply type-test documents.

Key hardware parameters

The table is a typical SHT45 module build, for selection and for a technical clause in a tender. For a wider range, redundant power, or an intrinsically safe version, ask SimtoLink for the hardware specification and the installation and commissioning guide. Order codes in the family can differ slightly; the nameplate and the documents shipped with the unit govern.

Parameter	Specification	Notes
Sensing element	Sensirion SHT45	Digital temperature and humidity, I²C/CRC, factory calibrated
Temperature range (element)	-40～125 ℃	Usable span depends on the housing, the cable, and the install
Typical temperature accuracy	±0.1 ℃	Typical; see the Sensirion SHT4x datasheet
Humidity range	0～100 %RH	Non-condensing; SHT45 has an on-chip policy for condensation (see the datasheet)
Typical humidity accuracy	±1.0 %RH	Typical; see the Sensirion SHT4x datasheet
Power	DC 5～36V wide range	Isolated
Communications	RS485 Modbus RTU	Redundancy available
Ingress rating	IP67	Outdoor build can be IP67
Operating power	<0.99 W	Typical
Response time (τ63, element)	About 4 s	Natural ventilation and housing thermal mass lengthen the effective time constant
Long-term stability	Meets the SHT4x specification	Humidity and temperature drift follow the Sensirion datasheet curves

Typical deployments

Three ways this module shows up in an IoT project, for design and for judging payback:

Municipal and utilities

Scattered points and outdoor cabinets. Wide temperature and lightning protection suit long runs and low-latency watch on water, gas, and street lighting.

Campuses and buildings

Join a campus energy system or a building controller for sub-metering, anomaly alarms, and policy linkage, and cut manual meter reads and patrols.

Manufacturing and energy sites

On a line or in a power room, the module joins MES/EMS and uploads key process values or energy data from the edge.

Installation, grounding, and maintenance

Confirm supply range and polarity before power-up. Measure bus voltage and breaker rating if the drawing is unclear.
Use shielded twisted pair, ground the shield at one end, and keep it off long shared routes with high-power cables.
In the lab, finish a two-way read and write and a threshold trip against the platform before the module goes outside.
Outdoor mounts need drainage and airflow. Recheck the sealing face. Lightning-earth resistance must meet the local code.
In service, spot-check a sample and archive logs every 6 months.

Ordering, documentation, and support

SimtoLink can issue the hardware specification, outline drawings, a wiring table, and a sample project. Volume orders can include a sample review and an inspector at the plant. Warranty and calibration follow the contract and the documents packed with the module.

Typical applications

An SHT45-class temperature and humidity element is used for operational weather observation and agricultural microclimate work, and the radiation shield and the ventilation time constant have to be designed together. The cases below cover backbone stations, protected agriculture, and industrial micro-environments, and they differ in the data path and in how they are maintained.

National or regional automatic weather stations

The temperature and humidity element feeds a new collector. Minute values, extremes, and status codes go up together to the provincial quality-control center. A primary and standby pair can be compared, humidity lag can be corrected, and sensor drift can raise an alarm. Operational checks, climate-feasibility studies, and research trials get both the raw metadata and a traceable calibration chain.

Greenhouses and plant factories

Place probes at a representative canopy height and in the return-air section. They close the loop on misting, shade screens, side vents, and the climate algorithm. If the public network drops, the edge node keeps the minute series and, once the link returns, backfills the farm platform on NTP time, so stress indexes and irrigation models stay continuous.

Data halls and clean rooms

Watch the dew-point gap between hot and cold aisles, condensation risk near a wall, and static-pressure change, and link that to the CRAC, fresh-air dehumidification, and alarm thresholds. A low-noise analog front end holds down common-mode noise from VFDs, so the humidity baseline stays readable at the wet edge, for SLA and clean-room grade audits.

Ports and coastal observation towers

A salt-fog-resistant housing and controlled heat-and-dry keep a long record of sea fog and humidity jumps. The data joins port dispatch, pilotage, and maritime warning, and with visibility, wind speed, and wind direction it helps judge the working window and demurrage risk for more resilient port operations.