DMX Gateway for rgb strip and intensity

Discussion in 'C-Bus Wired Hardware' started by raykelly, Jun 7, 2021.

  1. raykelly

    raykelly

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    Hi Guys,
    Looking at configuring the DMX and I cannot see that the gateway can control rgb at all.
    All that it seems to do is put slots into a group - which doesn't seem much for such an expensive unit.
    How would I get an intensity level for each of the RGB to get my custom colour.
    Cannot see any examples anywhere.
    Thanks
     
    raykelly, Jun 7, 2021
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  2. raykelly

    Ashley

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    That's all any gateway does. Convert from one protocol to another. It converts a cbus lighting group address to DMX slot number, so changing the ga will change the corresponding dmx slot. What you do with that is up to you.

    For RGB you create 3 group addresses for R, G and B then map them to the starting DMX address of your strip lights (you are using DMX strip lights I assume?) Put these 3 group addresses on a switch in dimmer mode and you can control each colour.

    I you want to do anything fancy, you can use scenes or logic to control the ga's. I have some code posted in the logic section that allows you to control rgb leds via hue, value and saturation which is a lot more intuitive.
     
    Ashley, Jun 8, 2021
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  3. raykelly

    raykelly

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    Thanks for the reply.
    Sorry what is a - ga.

    What I am after is to create scenes - by pressing one of reflection switches - so a particular selection wants to create say a violet colour so turn on the RGB lights - with the right levels of hue, value and saturation to achieve the colour I want at the brightness I want.

    In the attachment I was hoping that in the example where you type in the DMX slot data - 4,5,6 - there are a more substantial list of commands for controlling the light properties - because 4,5,6 will just turn on the Red, Green and Blue lights.
    The pascal controller is cute but too expensive, but I cannot see how the DMX Controller can control the colour variations.
    Thanks
     

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    raykelly, Jun 9, 2021
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  4. raykelly

    Ashley

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    'ga' is the abbreviation for Cbus Group Address.

    A Cbus group address controls a single load (i.e. light). You can set its value from 0 to 255 where 0 is off, 255 full on, and anyway inbetween. Ga's ('cos typing Cbus Group Address gets a bit tiring :)) are analogous to DMX slots. A DMX universe (i.e. one cable) contains 512 slots, each of which can be set a value from 0-255 to control whatever is assigned to them. For a dmx rgb strip light you need 3 consecutive slots and you set the address of the first slot on the light. The CBus DMX gateway maps Cbus group addresses to DMX slots, so you would create 3 new ga's (in Toolkit) and them assign them to the appropriate slots in the gateway.

    The picture you posted is a bit misleading because it shows you how to control multiple dmx slots from a single ga, but all the slots will be set to the same ga value. Not what you want. You need to create the 3 ga's and assign them to consecutive slots.

    Now if you set the value of each cbus ga it will set the same value in the dmx slot and hence control the appropriate colour intensity

    To set a colour from a switch, create a scene in the switch containing the 3 ga's and set their value appropriately. Then assign that scene to a button.

    You can also assign each ga to 3 separate switches set up as dimmers, then control each colour r,g and b directly.

    If you want to control the colour by Hue, Value and Saturation you either need to find a DMX led strip that supports HSV or use logic to do the conversion in cbus as in the code I posted. This will require some form of logic device.
     
    Ashley, Jun 10, 2021
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  5. raykelly

    raykelly

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    Thank you Ashley - its clicked now and I understand.
    Probably will go with Raspberry Pi running C-Gate and my own code as the logic device driving MOSFETs.
    Had my C-Bus system for many years now and its rock solid.
    Doing kitchen renovation - so have to add led lights:rolleyes:
     
    raykelly, Jun 11, 2021
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