The Light sensor view can be accessed by navigating to the grid view and clicking the Instance types perspective at the top-right of the grid and then clicking the Light sensor tab.

There are instance and primary target settings that can be changed along with all of the profiles that are assigned to a control system on the right side of the grid. This is where light sensor applications can be created for each profile on a control system.

Row Harvesting

Is a way to instruct the controller to adjust its target at individual rates. When row harvesting is off, each target of the light sensor receives one step command per adjustment. Whilst this is useful for rooms with uniform lighting, this may be problematic when a window contributes much of the light in a room. In this instance, the ideal scenario is that lights closest to the window are dimmed more by lux adjustment than lights that are further away. We can achieve this by turning row harvesting on which adjusts targets based on a configurable ratio. 

Row harvesting strength and targets for a Normal dimming direction

Target placement for different row counts

Twilight Mode

Twilight mode is used by the light sensor to determine what action is to be executed when the twilight lux levels have been reached by the light sensor's current lux reading. If it is disabled then it will have no effect. Each of the twilight modes specify what time of day is set up for to be run at, which will be either nighttime or daytime, as well as the command that will be sent to the fittings once the twilight lux level is reached which include recall max, min, enable PIR and trigger. The levels are determined by the Twilight on and Twilight off columns. The Twilight on and Twilight off columns form a hysteresis, for nighttime mode, the action will not be taken until the light level falls below Twilight on, similarly the off action will not be called until Twilight off has been reached.

Daytime twilight modes require the Twilight on lux to be higher than the Twilight off lux otherwise it will not work as expected. This behaviour is reversed for the nighttime twilight modes meaning the Twilight on lux must be lower than the Twilight off lux.

For instance, a light sensor can be deployed into a car park and configured (through the Nighttime recall max twilight mode) to turn the lights on if the lux goes under the Twilight on threshold (ie. when the sun sets). It will also turn the lights back off once the Twilight off threshold has been reached.

Target lux 

The Target column is used to specify the target lux setting for the sensor. The target lux is used to determine how quickly arc levels step up or down based on what the current lux reading of the light sensor is. The further away the current lux value is from the target lux the faster the arc levels will step up or down.

Behaviour 

The Behaviour field specifies the type of harvesting the lights in the targets list will use, to be able to use row harvesting strength, row harvesting direction or internal lux, you must first enable lux harvesting under the Target column. If the twilight mode is disabled the Twilight on and Twilight off fields will also be disabled.

• Internal lux
  • If the device supports an internal sensor, you may use this option to track each device individually.
  • If this option is not available, or is not enabled the light level will have to be tracked by an external sensor.
• Row harvesting strength
  
  • Sets the severity of the row harvesting
  • High strength means the lights closest to the window will dim at nearly the the same rate as lights further from the window, this leads to the effect of a lot of the rows dimming.
  • Low strength means the lights closest to the window will dim at a much faster rate compared to lights further from the window, this leads to the effect of only the rows closest to the window dimming.
  • Disabled will dim all lights in the targets list at the same time

• Row harvesting dimming direction
  • Sets the direction of the row harvesting
  • Use Normal, if the targets are listed from the window to the inside of the building (Row 1 closest to window)
  • Use Inverted, if the targets are listed from the inside of the building to the window (Row 1 is closest to the inside of the room)
• Row harvesting row count
  • Specifies the number of rows to use for row harvesting

• Twilight mode
  • Specifies the twilight mode

Calibrating light sensors 

If you want your light sensors to read lux from a location below the sensor rather than at the sensor itself then you need to calibrate them to get accurate readings otherwise the lux level will more than likely be incorrect. If you only want lux levels to be from the perspective of the sensor itself then you can skip calibration.

There are 5 fields that must be set in grid view in order for calibration to be completed.

The mode column must be set to meter POV if you want the calibration values to be used otherwise they will be ignored. There are 2 sets of readings that must be taken for the calibration. One when the lights are at their minimum level (lower calibration) and one at their maximum level (upper calibration). For each set of readings you will need one reading from the sensor's perspective and one reading at the desired point where you want the lux levels to be read from which is usually a desk or something similar.

The reading from the sensor's perspective can be easily done by right-clicking the cell and clicking set to current sensor level. This will only work if the control system is online otherwise it will have to be done manually.

After the calibration levels have been set and the mode is correctly set then the lux levels that are used for light sensor configurations will now be calculated based on the where the meter POV readings were done from. 

Light sensor values with an slx suffix signify a light sensor level reading from the sensor. This is usually shown before a sensor has been calibrated. After calibration a light sensor level will appear as lx or if the light sensor is set to meter POV, it may also appear as mlx.