An LED controller, for connecting to an LED string, comprising: an input terminal configured to receive a light-control-signal representative of a received-profile-identifier; a local memory configured to store a plurality of profile-data, wherein each of the plurality of profile-data defines an association between a plurality of light-values and a plurality of sequence-numbers; a processor configured to: determine one of the plurality of profile-data as selected-profile-data in accordance with the received-profile identifier; and determine a set of LED control signals for the LED string in accordance with light-values of the selected-profile-data for a set of sequence-numbers.