Dimmable electronic ballasts for fluorescent lamps often use the analog signal 0 to 10 V, or 1 ÷ 10 V to controlling dimming.
Any analogue output of the Foxtrot system can be used for brightness control.
Some ballasts do not completely switch off the fluorescent lamp, even if the voltage is 0; it is necessary to turn off the ballast power supply to switch the lamp off. This also reduces the unnecessary permanent power consumption of the ballast.
Selection of the relay output of the system for switching the ballast power supply needs to be addressed with regard to the maximum ballast switching current (the cold start); in some ballasts this value reaches 40 A (for detailed description see Chapter 6.6.4.Switching power supply to ballasts DSI, DALI, etc).
If several ballasts are controlled simultaneously, maximum current in the analogue output must be observed (typically 10 mA - see the respective module data), but what must mainly be observed is the maximum switching current of the relay output. When switching a higher number of ballasts (in industrial halls, etc.), they must be divided into several groups and multiple relay outputs must be used.
It is also necessary to take into account the front-end protection, to avoid its tripping. When ballasts are divided among a number of relay outputs, it is recommended to arrange their consecutive switching and thus decrease the current surge on the upstream protection.