How does Closed Loop work and when to use as a Daylight harvesting mode?

If Closed Loop is chosen as the daylight harvesting mode, the daylight sensor will be configured with a particular light level (in 'Lux' or 'V') using any of the three closed loop methods. The aim of our 'Closed Loop' technique is to maintain this light level.

The daylight sensor measures the light falling on it at regular time intervals called Sensitivity. The sensor sends triggers to its associated light devices if the light level detected by the sensor has a deviation from the configured light level. With Tolerance, the sensor will not send triggers right away when a variation is identified but only when the variation is higher than the allowed range.

When the associated light devices receive sensor triggers, their intensity is increased or decreased within the configured Fade time in such a way that the light output matches with the light level configured to the daylight sensor.

When to use Closed Loop as Daylight harvesting mode

Closed Loop systems are generally economical for controlling smaller spaces or larger areas with all the lights controlled in a single zone (e.g., a private windowed office).  

Closed Loop systems measure the combined contribution to light level from both daylight and the electric lighting system and then adjust the light output to maintain the desired illumination level.

Since the daylight sensor measures the electric lighting system’s light output, it “sees†the results of its adjustment and may make further adjustments based on this feedback.

This mode shall be chosen when there are multiple daylight sensors available for the control of different groups.

You can also visit the following sections for more information:
To know the three methods of configuring Closed Loop as the Daylight harvesting mode, click here
To know about Daylight harvesting using Custom mode, click here
To know about Automated Demand Response, click here
To know about Human Centric Lighting, click here