Check out any DALI configuration software or documentation and chances are that the term ‘Direct Arc Power’ will be used at some point.
For example, a DALI Short address (single Luminaire) or DALI Group Address (a number of luminaries) can be set to go to a particular light level by issuing a ‘Direct Arc Power Command’
in simple terms, for example ‘all lights in DALI Group 3 go to Direct Arc Power 50%’ etc
What the % power (Watts – W) is referring to equates to the amount of power going to the lamp, not the amount of light coming from the lamp (Lumens – lm)
You may think that the difference between % power to the lamps and % light from the lamp would be closely matched but in fact they are not.
For example, with LED lamps reducing the power (W) to the Lamp from 100% (W) 100% (lm)to 50%(W) results in a light output that is still over 80%(lm) as seen by your eyes
To compound this, DALI configuration software will refer to the target brightness of a lamp in % – but this is actually Arc Power % (W) not brightness % (lm).
So setting a scene to 50% results in the lamps in that scene going to around 85% brightness.
To get a DALI scene to go to 50% you need to send a Direct Arc Command of 3%!
That’s right! 3% of the power (W) gives 50% of the light output (lm)
Not Just for DALI Dimming
RAPIX DALI relays have the unique feature of being able to set to a ‘turn on threshold’.
If you had 11 high bays, by setting a number of RAPIX DALI relays in a DALI Group to different levels (using the light output % scale) then each of the high bays can be individually switched on at different times automatically without any special macro or scripting.
By sending a ramp up to 100% over 10 seconds as an example, with the first on turning on a 0.1% the second at 10% the third at 20% and so on – up to the 11th at 100% – and all the high bays would turn on at 1 second intervals thus reducing the inrush current through the MCB.
Simple DALI Visualisation
RAPIX configuration now shows Light output % by default wherever it appears. from scenes to min and max brightness settings – bringing a human dimension to setting up a DALI Lighting Control System
Everything used to commission a DALI system – from scene setting to min. and max. brightness settings is treated this way dependent on which option is chosen. Bringing a human dimension to setting up a DALI Lighting Control System making DALI simpler, faster and easier.