Product Overview
The OHTS1093 is a fully automatic solar radiation tracking measurement device based on the thermoelectric effect principle. It utilizes a dual-mode positioning system combining optical tracking and GPS tracking to achieve unattended, all-weather monitoring of solar radiation parameters. The device employs a wire-wound electroplated thermopile sensing element, coupled with a multi-layer shading ring structure, to measure direct and diffuse solar radiation within the spectral range of 0.3 ~ 3 μm.
The system incorporates a built-in solar position algorithm that automatically calculates solar elevation angle, azimuth angle, and sunrise/sunset times, achieving high-precision tracking through real-time light intensity analysis. The tracking gimbal provides vertical rotation from 0° ~ 90° and horizontal rotation from 0° ~ 300°, with a tracking accuracy of 1°. The device features an RS-485 interface and supports the standard ModBus-RTU communication protocol, directly outputting parameters such as Normal Direct Irradiance (DNI), Horizontal Direct Irradiance, diffuse radiation, sunshine hours, and GPS coordinates.
Features
- Dual-Mode Tracking System: Integrates optical tracking sensors and GPS positioning, supporting three operating modes: optical tracking, GPS calculation, and hybrid optical plus GPS tracking, ensuring tracking continuity under cloudy and overcast conditions.
- Thermoelectric Radiation Sensing: Employs wire-wound electroplated multi-junction thermopiles with sensing surfaces coated in high-absorptivity black coating; sensitivity 7 ~ 14 μV·W⁻¹·m², response time less than or equal to 30 s (95% response).
- Wide-Spectrum Measurement: Covers the 0.3 ~ 3 μm waveband, with a measurement range of 0 ~ 2000 W/m² and resolution of 1 W/m².
- Environmental Adaptability: Aluminum alloy enclosure structure, operating temperature -30 °C ~ +60 °C, relative humidity 0% RH ~ 95% RH (non-condensing), suitable for long-term field monitoring.
- Standard Communication Interface: RS-485 physical interface, configurable baud rate 1200 ~ 115200 bit/s with default 4800 bit/s, supporting ModBus-RTU protocol.
- Multi-Parameter Output: Real-time output of Normal Direct Irradiance, Horizontal Direct Irradiance, diffuse radiation, sunshine hours, solar elevation angle, azimuth angle, GPS coordinates, and device status.
Applications
- Performance monitoring and evaluation of solar photovoltaic power generation systems
- Efficiency testing for solar thermal utilization engineering
- Building solar resource assessment and optimization
- Standard radiation measurement in solar energy laboratories
- Photosynthetically Active Radiation (PAR) research for agricultural and forestry ecosystems
- Solar radiation flux monitoring at meteorological stations
- Radiation budget measurement for climatology research
- Renewable energy site resource assessment
- Solar radiation monitoring networks for environmental science
- Atmospheric optics and radiation transmission research
Technical Specifications
Auto-Tracking Parameters
| Parameter | Specification | Remarks |
|---|---|---|
| Tracking Accuracy | 1° | Angular error |
| Payload Capacity | 10 kg | Maximum gimbal load |
| Vertical Adjustment Angle | 0° ~ 90° | Elevation range |
| Horizontal Adjustment Angle | 0° ~ 300° | Azimuth rotation range |
| Tracking Mode | Optical + GPS tracking | Configurable for single or hybrid mode |
Radiation Measurement Parameters
| Parameter | Specification | Conditions/Remarks |
|---|---|---|
| Sensitivity | 7 ~ 14 μV·W⁻¹·m² | Thermopile output |
| Internal Resistance | 200 ~ 400 Ω | Sensing element resistance |
| Response Time | less than or equal to 30 s | 95% response |
| Non-linearity Error | less than or equal to ±3% | Full scale |
| Directional Response Error | less than or equal to ±30 W/m² | - |
| Temperature Response Error | less than or equal to ±3% | -30 °C ~ +50 °C |
| Spectral Range | 0.3 ~ 3 μm | Wavelength range |
| Measurement Range | 0 ~ 2000 W/m² | Irradiance |
| Resolution | 1 W/m² | Minimum detectable change |
| Measurement Accuracy | ±3% | - |
| Annual Stability | less than or equal to ±3% | Long-term drift |
| Cosine Response Error | less than or equal to ±5% | Angle of incidence response |
| Tilt Response Error | less than or equal to 2% | Mounting tilt effect |
| Zero Drift | less than or equal to 6 W/m² | Offset under no-radiation conditions |
General Parameters
| Parameter | Specification | Remarks |
|---|---|---|
| Supply Voltage | 12 V DC | DC input |
| Communication Interface | RS-485 | Standard ModBus-RTU protocol |
| Power Consumption | 8.5 W | Rated operating power |
| Operating Temperature | -30 °C ~ +60 °C | Ambient temperature |
| Operating Humidity | 0% RH ~ 95% RH | Non-condensing |
Physical Specifications
| Parameter | Specification | Remarks |
|---|---|---|
| Protection Rating | Outdoor type | Aluminum alloy structure |
| Mounting Interface | M6/M8/M5 threaded holes | See installation instructions |
FAQ
Q: What tracking modes are available and what are their limitations?
A: The device supports three operating modes: optical tracking, GPS calculation, and hybrid optical plus GPS tracking. When using optical-only tracking mode, tracking deviations may occur during cloudy and overcast weather where the strongest light position does not coincide with the actual solar position. GPS-only mode has high requirements for installation orientation accuracy and requires strict calibration. The default GPS plus optical hybrid mode can mitigate weather effects but cannot completely eliminate them.
Q: What are the installation orientation requirements?
A: The device main control side must face true north, and compass calibration is recommended during installation. When using GPS-only tracking mode, installation position errors must be eliminated by adjusting azimuth and elevation calibration values to ensure that under clear weather conditions, sunlight passes through the upper aperture of the direct radiation sensor and illuminates the center of the lower aperture.
Q: What is the measurement principle of the radiation sensor?
A: The device employs a wire-wound electroplated thermopile sensing element based on the thermoelectric effect principle. The sensing surfaces are coated in high-absorptivity black coating with sensitivity of 7 to 14 microvolt per watt per square meter and response time less than or equal to 30 seconds for 95 percent response.
Q: What parameters can be read through the ModBus communication protocol?
A: The device supports standard ModBus-RTU protocol through RS-485 interface. Readable parameters include Normal Direct Irradiance, Diffuse Radiation, Horizontal Direct Irradiance, Sunshine Hours, GPS coordinates, solar elevation angle, azimuth angle, and device status. Configurable parameters include light threshold, radiation calibration values, tracking interval, magnetic declination, and angle limits.
Q: What maintenance procedures are required?
A: Regularly check that the arrow inside the black hemisphere at the front of the solar tracking transmitter points downward. Check that the four-channel light intensity values of the optical tracker are consistent. Confirm the diffuse radiation protective cover has been removed. Regularly check GPS positioning status and system time accuracy. If diffuse radiation reading is zero, check if protective cover is removed, weather conditions, and wiring correctness.