Correcting Chinese DMX302 dimmer channels

[NickV]

Hi all,

I'm in the embryonic stage of a Loxone build for my about-to-be-built extension.  Having read up extensively on this forum I thought I'd buy some cheap DMX302 dimmers from China for the less important lighting channels to keep costs down.  They work as expected, but don't accurately dim to zero (again not unexpected).  I'm testing with a 4w bulb (which I'm aware is a pretty extreme case) but hopefully serves as a good example here:

Disconnecting the dimmer from the DMX bus and operating it manually I could see that the range at which it lights the bulb is from 255 down to 77.  I then tried configure the DMX output to compensate for that.

As I see it 77/255 = 30.2%, so assuming that the input is a percentage between 0-100 (which is what it appears to be?) I need to output 30% when the input is 0% so the light is just off, and output 100% when the input is 100%.  This all *seemed* fairly straightforward with the correction parameters until I programmed it in and watched it on LiveView, however the screenshot attached shows that it seems what's happening is that it's compressing the 0-100 value into a 0-70 range (which is what I wanted), but then outputting this as 0-70 rather than 30-100.  Any other tweaks (like mapping 1 to 30 instead of 0 to 30) produce even more confusing results.

I presume I'm being stupid somewhere, either by reading the live view wrong or not understanding how the correction algorithm works, but I can't for the life of me work out how to get it to do what I want!  Any help or hints would be greatly appreciated.

Cheers,

Nick

[Duncan]

you have your dmx output device set as a smart actuator - try changing it to a standard one and see what happens

also, try setting the perception correction to off - with it on it stretches out the bottom end of the dimming range by applying a log curve, but your bottom end isnt doing anything.