Automatic Sliding Door Sensors & Reflection
Conor Keightley
Sales Executive for Blacknight who are Ireland's leading website hosting & domain name provider. Helping Irish and international businesses since 2003.
This is just a quick article explaining why you would need to increase or decrease the sensitivity setting on a Automatic Sliding Door Sensor such as the Hotron SSR-3, HR100-CT or the 3HIR14C. There are two types of reflection : specular and diffuse, and can often be misinterpreted.
Shiny surfaces can cause a specular reflection as illustrated in the left illustration in the picture, this can result in a low level of light been reflected from the floor back into the sensor. A marble floor is a typical example. In this case it may be necessary to INCREASE the sensitivity setting so that more light gets reflected back into the sensor. Your initial thought might be to decrease the sensitivity as a marble floor would be seen as high reflection but in fact it is the opposite. Specular Reflection is defined as ''light reflected from a smooth surface at a definite angle''.
On the other hand, a roughly textured floor surface like carpet or asphalt/roadway causes a diffuse reflection (See Second Illustration) and a sufficient amount of infrared light is reflected back into the sensor so middle or lower than middle sensitivity setting is OK. Hotron Sensors are preset to 50% anyway.
Also a black floor surface absorbs infrared light, therefore the level of light reflected back into the sensor is low, so it may be necessary to increase sensitivity. The worst floor condition for the sensor is a shiny, black floor surface like black marble, this causes the lowest reflection back into the sensor and will necessitate a high sensitivity setting on the sensor.
Please be aware that over 90% of installations the sensitivity is left at the middle setting by the installer without any problems.
The above information is worth keeping in mind though in case you have an installer or you are an installer yourself who comes across difficult floor conditions.
Hotron Sensors will blink Green/Red Slowly to let you know reflected infrared signal from floor is very weak. Therefore you will need to increase the sensitivity. Otherwise your good to go which will be 90% of the time!
Author : Conor Keightley, UK Area Manager with Hotron. Email : [email protected]