Luminance Inside Tunnel Sensor – Geonica

he GEO-ILLIOS Luminance Inside Tunnel Sensor by Geonica is a professional tunnel illuminance photometer designed to continuously measure the level of illuminance inside tunnel bores to ensure safe and consistent lighting conditions for drivers. It helps tunnel operators maintain proper internal lighting levels, preventing sudden visual adaptation problems and improving driver safety during tunnel travel. The sensor is specifically engineered for road tunnels, railway tunnels, and underground transport infrastructure where lighting control is critical. It measures illuminance over a standard range of 0–20,000 lux with high precision and CIE-approved measurement technology. The GEO-ILLIOS uses a highly sensitive silicon photo diode with Vλ filtering, providing a spectral response close to that of the average human eye for accurate real-world lighting measurement. Its cosine-corrected planar illuminance detection eliminates directional error, ensuring stable and dependable readings. Designed for harsh tunnel environments, it features a rugged IP65 / NEMA 4X powder-coated stainless steel enclosure, no moving parts, and low-maintenance long-term operation. Measurements are converted into 4–20 mA output, with additional Modbus RTU (RS485), analog outputs, and relay contacts for seamless integration into SCADA systems and tunnel lighting control platforms.