I am looking for the solution which can automatically detect the driver type installed in street light luminary. There are control mechanism which controls and provides the 0-10V and DALI dimming to driver installed in luminary. Now what I want is I to develop mechanism that automatically detect the driver type (DALI/ 0-10V) and provide the dimming interface accordingly. There is 2 wire interface between control mechanism and driver. 0-10V is analog type dimming and DALI is digital interface. How it can be done Any idea.
Analogue drivers act as current sources, producing a maximum voltage of typically 12V into a high impedance, and limited to 2mA into a very low impedance.
Most DALI drivers act as current sinks, producing no voltage of their own but sinking up to 2mA from 9.5V to 22.5V. But there are a few types which have integrated power supplies, typically in the 12V to 16V range, which can source say 50mA, or you could face a lumininare with a discrete DALI supply for up to 250mA.
So a method could be: Before you turn on your bus power supply, measure the voltage on the interface. If there is no voltage, it can't be analogue, so turn on your bus power supply, and you could send a DALI broadcast query which all drivers should respond to and see if there is a response or collision which confirms that DALI drivers are present.
If there is a voltage, you leave your bus power supply off and attempt a DALI broadcast query. No response means it's likely to be an analogue driver. Sending DALI to an analogue driver will just reduce the level to 50% for 20ms, which might not be noticeable depending on the smoothing in the driver.
There is another possible method, if you can determine the light level coming out of the gear. If you hold the interface voltage low for more than 500ms, the 0-10V driver will go off, but a default state DALI driver will go to 100% due to this being the "system failure level". But you cannot rely on the driver settings being in factory default because they may have been changed before you get to see them, for example by the luminaire manufacturer.