Type： TLD-500（single channel） TLD-600（double channel） Operating voltages： 220V AC±10% Power consumption： ＜5W Output： Relay output Frequency range： 20kHz to 170kHz (4 grades adjustable) Reaction time： 20 ms Sensitivity： 10 grades adjustable Loop inductance: Ideal 100～300µH (include connecting wiring) Max 50µH～1000µH (include connecting wiring) Loop conn. Wiring: Max. 100m, twisted at least 20 times per meter, Total resistance <10 Ohm Operating temp.: -30℃ to +75℃ Storage temp.: -40℃ to +85℃ Relative humidity: ≤ 95% Connection: 11-pin socket Shell: PC + ABS engineering plastics Installation: DIN rail Dimensions: 110×60×100 mm (L×W×H) Net Weight: 400g (include socket) 3. Principle It is based on a change in the inductance within the loop which is caused by the metallic components of passing vehicles. The changes are picked up and evaluated by a microprocessor.