A lighting control system comprising: a plurality of current sensors that includes a first current sensor and a second current sensor wherein the first current sensor is configured to measure a first current of a first LED channel, the second current sensor is configured to measure a second current of a second LED channel, and a sum of currents through the plurality of current sensors is a total current; and characterised by a microprocessor configured to store a plurality of smallest average values of the total current, each of the smallest average values being calculated from measurements taken by the plurality of current sensors over a plurality of sampling periods; set a setpoint based on a largest of the plurality of smallest average values, wherein the setpoint defines a maximum current for a dimming profile of a lighting fixture comprising the first LED channel and the second LED channel; and control a melanopic to photopic ratio, M/P ratio, output by the lighting fixture according to the dimming profile, wherein the dimming profile correlates the M/P ratio to a percentage of the maximum current, and wherein the M/P ratio is a ratio of a melanopic lux to a photopic lux; wherein a maximum M/P ratio is output by the lighting fixture when the total current is equal to or greater than the setpoint. a plurality of current sensors that includes a first current sensor and a second current sensor wherein the first current sensor is configured to measure a first current of a first LED channel, the second current sensor is configured to measure a second current of a second LED channel, and a sum of currents through the plurality of current sensors is a total current; and characterised by a microprocessor configured to store a plurality of smallest average values of the total current, each of the smallest average values being calculated from measurements taken by the plurality of current sensors over a plurality of sampling periods; set a setpoint based on a largest of the plurality of smallest average values, wherein the setpoint defines a maximum current for a dimming profile of a lighting fixture comprising the first LED channel and the second LED channel; and control a melanopic to photopic ratio, M/P ratio, output by the lighting fixture according to the dimming profile, wherein the dimming profile correlates the M/P ratio to a percentage of the maximum current, and wherein the M/P ratio is a ratio of a melanopic lux to a photopic lux; wherein a maximum M/P ratio is output by the lighting fixture when the total current is equal to or greater than the setpoint. store a plurality of smallest average values of the total current, each of the smallest average values being calculated from measurements taken by the plurality of current sensors over a plurality of sampling periods; set a setpoint based on a largest of the plurality of smallest average values, wherein the setpoint defines a maximum current for a dimming profile of a lighting fixture comprising the first LED channel and the second LED channel; and control a melanopic to photopic ratio, M/P ratio, output by the lighting fixture according to the dimming profile, wherein the dimming profile correlates the M/P ratio to a percentage of the maximum current, and wherein the M/P ratio is a ratio of a melanopic lux to a photopic lux; wherein a maximum M/P ratio is output by the lighting fixture when the total current is equal to or greater than the setpoint.