How do I adjust the sensitivity of a twilight switch?

Twilight switch sensitivity adjustment procedure:

• Potentiometer location : Most Socomec photocell relays have external potentiometer screw on front face (marked LUX or LEVEL). Internal models hide potentiometer behind access panel (requires screwdriver).
• Sensitivity scale : Typical range 15–100 lux (lumens per square meter ambient light intensity). Lower lux = lights trigger earlier (more sensitivity); higher lux = lights trigger later (less sensitivity).
• Adjustment procedure : 1. Install photocell in final outdoor location (pole, building soffit, ~2.5m height, facing south/open sky). 2. At dusk (30–60 min before sunset), observe when lights should activate. 3. If lights too late: turn potentiometer counterclockwise (increase sensitivity, lower lux threshold). 4. If lights too early: turn potentiometer clockwise (decrease sensitivity, higher lux threshold). 5. Each adjustment ~5 lux change; typical 1/4–1/2 turn rotation per calibration cycle. 6. Wait 2–3 minutes after adjustment (relay response time) before testing further.
• Hysteresis setting : Advanced models include ON-threshold and OFF-threshold (hysteresis gap prevents rapid on/off cycling at twilight). ON at 30 lux, OFF at 80 lux typical. Gap prevents flicker during cloud passage.
• Factory default : Most arrive pre-set to ~40 lux (reasonable dusk threshold). Seasonal adjustment rarely needed unless geolocation or building orientation changed dramatically.
• Testing methodology : Cover photocell with hand briefly to simulate darkness. Lights should click ON instantly if sensitivity correct. Uncover; lights OFF after 5–10 sec relay delay.
• Maintenance note : Dirty/dust-covered photocell reduces sensitivity perception. Annual cleaning (soft cloth + water) essential for accurate operation.

Socomec PIL photocell modules rated IP65 (weather-sealed). Typical drift ±5 lux/year due to sensor aging. Optim-Elec installs and calibrates photocells per site requirements. Adjustable range accommodates building height, street lighting interference, vegetation shade. Contact optim-elec.com for commissioning.