Dimming problem

A recent request from a client has me a little puzzled. The situation is this. they need the lights to turn on at 50% output, be able to ramp up from this to 100% if needed and finally turn off. easy right! No because it needs to be done on one key. Is it possible and if yes how? thanks in advance.

 

Logic options

Sounds like a tricky one to do without logic.

An intermediate or advanced programmer could do this without to much difficulty but it would be custom logic code to handle the dimming control.

You would need a PAC unit or black and white touch-screen with logic engine, or a colour touchscreen.

Involves making a judgement call, do you want a more simple level of system configuration or does the application warrant a slightly more sophisticated approach.

Maybe one of the more senior guru's can suggest a way to do it without logic but we have done things like this with logic and found the system very flexible to accomodate pretty much anything the client asks for.

The downside of going to custom logic dimming is it is easy to end up with a cumbersome project unless the programmer understands how to make the code relatively simple to work with and efficient for the logic engine to run.

If there is not the desire to go down this road it may be better to sell the client on working with the system in a more 'by the book' or 'out of the box' type approach.

 

If what you want is only that the load is either OFF or between 50% and 100% in brightness, then this will work:

key configured with:
just press = idle
short release = toggle (this gives you the ability to turn OFF the load)
long press = upkey (downcycle would actually work if you needed to adjust level up and down)
long release = endramp

and set minimum brightness on the dimmer to 50%..

On the other hand, if you really need the GROUP level to jump from 0 to 50%, then optionally ramp to as high as 100%, you will need logic as SBL points out