Cortex and dimmable fluorescent lamps

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  • stachoo
    Automated Home Jr Member
    • Nov 2009
    • 32

    Cortex and dimmable fluorescent lamps

    In several places throughout my house, I am using dimmable fluorescent lights. Such lights, require special dimmable ballasts.
    There are 3 methods to control such ballasts.

    1. Via analogue 1-10 V input.
    This is the oldest system in the industry. Dimming is performed by varying voltage between 1 and 10 Von a special input in the ballast. It can be easily driven from a QAO output configured as a dimmer, but I cannot completly switch off the light by varying the voltage, since even at minimum power, the lights don't get completly extiguished. An extra relay connection is needed to turn off the light completly. I have managed to automate the relay operation using the 'set on' and 'set off' connections from the QAO Dimmer to the relay, but the solution is quite complicated and uses one QAO and one relay output per light. It also has some stability problems, since sometimes the relay doesn't open when the QAO dimmer is turned off.

    2. Using a Touch DIM interface
    Many fluorescent ballasts (ex. Osram QTI DIM series) can be controlled using a touch dim interface. The ballast is permanently connected to AC power and its operation (ON/OFF/dimming) is performed by briefly powering an additional contact in the ballast. I have connected such a ballast to a QRI relay configured as an ON/OFF (lamp) load and I am able to control the ballast using a follow state/state input connection from a press button. A brief press (pulse) turns the light on or off and a long press dims or undims the light. The problem is I am unable to use lighting automation to control these lights since an ON/OFF load is not a light in Cortex sense. Another problem is that the actual light doesn't really follow the state of the ON/OFF load. It changes from dark to light after every ON/OFF load 'pulse', so Cortex doesn't really know the state of such a light.

    3. Via the DALI interface
    Several manufacturers (Osram, Philips, Tridonic) use an interface standard called DALI to control a network of dimmable fluorescent lights. It can be connected to a PC using a USB or RS232 interface and from there, it should be possible to interface with Cortex - perhaps using the xAP/xPL protocol. Has anyone tried this approach??

    None of these 3 methods is fully satisfactory. I would very much like to use method 2 (Touch DIM) since only 3 wires are needed for each light. Does anyone have an idea how to make an ON/OFF load behave like a light in Cortex sense? Maybe a different type of object could be used for this purpose. What I think would be perfect in a longer term, is a kind of 'logic' dimmer object, that could be bound using appropriate connections to different physical interfaces used for light dimming.

    Thanks for Your input

    Stachoo
  • chris_j_hunter
    Automated Home Legend
    • Dec 2007
    • 1713

    #2
    just a thought, there may be fourth & fifth ways (not tried, on the to-do list) :





    this might also be of interest :

    We are pleased to reveal an exciting addition to the VARILIGHT range of decorative wiring accessories - "Impulse" Push-On/Push-Off Switches....
    Last edited by chris_j_hunter; 10 January 2011, 05:19 PM.
    Our self-build - going further with HA...

    Comment

    • Karam
      Automated Home Legend
      • Mar 2005
      • 863

      #3
      The varilight lamps and some others similar to them can be dimmed using a standard dimmer so could be directly controlled by something like a QLD module. So perhaps it is indeed the case that the answer is to use lamps that are dimmable using standard dimmer technology.

      But going back to the pulse on/off question, one possible method might be to use a 'virtual light' object whose state (change) output then triggers a 'pulse on' in the on/off load object. You could do this by introducing a legacy relay module into your database and connecting its output to a light object. This would be your virtual light. The network enabled checkbox of the object and its parent should not be enabled and the ID should remain as 0000 (so that Cortex doesn't try to communicate with it at a physical level). Now you connect this light into your automation eg. presence, timer, light level inputs and set it up as if it was the real light. Then you connect the State output from this light to the Pulse ON input of the on/off load object that is actually attached to the fluorescent.

      So what happens is when the lighting automation turns the virtual light on you get a pulse outputted from the on/off load and similarly when the light turns off you get another pulse. So this will acheive the automation of switching on/off. Of course as you pointed out it can easily become desynchronised because Cortex can't track the absolute state if some other input decides to directly operate the on/off load rather than the virtual light

      Comment

      • stachoo
        Automated Home Jr Member
        • Nov 2009
        • 32

        #4
        Thanks Karam,
        This is exactly the kind of solution I was looking for. I didn't know it was possible to have virtual relay objects that don't have a corresponding physical module. I will try it ASAP.

        Comment

        • stachoo
          Automated Home Jr Member
          • Nov 2009
          • 32

          #5
          Well,
          It took me while to get back to the problem, but I got it working the way Karam suggested. I have configured a 'virtual light object' and connected its State output to the 'pulse on' object of my on/off load object that represents my fluorescent dimmable lamp. Works great and doesn't get out of sync as long as nobody tries to drive the on/off load object directly.
          What I would now like to achieve is using the same push button I use for on/off functionality to drive the dimmer functionality of my fluorescent dimmer. I tried to use a virtual dimmer object in a similiar way I am using a virtual light object, but there is no way to translate the 'set level' analogue output of the dimmer object into a pulse length that would drive the actual dimmer (unless a macro could be used?).
          What I can do is connecting a separate press button to the 'follow state' input of the on/off load and use that button to dim the light - but then I need a separate button and my light may go out of sync with the light object. So the best solution would probably be to use the same button for switching on/off and for dimming (short press to turn on/off, long press to dim).
          Is there a way to make a button issue one command/connection on a short press and a different one on a long press? I have tried to use general logic/monostable/delay gates, but the 1 second minimum time resolution is too low for short presses, as I need to wait a whole second before the light would turn on. Maybe some reflex programming could do the trick?
          Thanks for Your ideas!

          Comment

          • Karam
            Automated Home Legend
            • Mar 2005
            • 863

            #6
            Perhaps the attached example macro might be a way to do it. The idea is that the macro is triggered by the button you wish to use to control the virtual light (virtual light 1 in macro example). So the macro waits a short period. If after that period it finds that the button is still pressed then it directly switches the relay controlling the fluorescent ON and then waits until the button is released in order to then switch that relay OFF. ELSE if after the short time wait the button is found to be not pressed the virtual light is toggled instead which then leads to a relay pulse action based on the logic of my previous post. It is important that the virtual light is toggled rather than just directly issuing a pulse ON to the relay since this will allow Cortex to keep track of the light state.

            I have chosen a wait timing of 0.3s which I think might suit expectations, but you may have to play with this. Since Cortex is doing the timings, such small timing intervals may or may not be reliable if your system is heavily loaded at the time.
            Attached Files

            Comment

            • tizwaz
              Automated Home Sr Member
              • Aug 2007
              • 59

              #7
              Evening all, just for info I've bought myself a couple of these to work with a new QLD I've installed to dim the lounge table lights.



              They do indeed dim, but they are rather hit and miss. They are not subtle and you only really notice the dim if you do big gradients. i.e 50% - 60% not really noticable, 50% - 75% getting better.

              The same gradient with a normal bulb is fine. Plus when they are dimmed they hum, ok if you are watching the telly. Not so good if you want a quiet read.

              Eco-friendly yes, but I annoying too.

              Chris.

              Comment

              • chris_j_hunter
                Automated Home Legend
                • Dec 2007
                • 1713

                #8
                interesting, thanks for posting ...

                some, if not all, dimmable CFLs, seem to be fussy about dimmer details - leading, trailing, minimum load, whatever ... reviews of various brands of bulb (on Amazon, and elsewhere) seem to vary from one extreme to the other (ie: same bulb, different opinion, presumably according to with what & how it was used - difficult to unravel) ...

                there are also switch-dimmable CFLs, as against dimmer-dimmable, CFLs ...

                ===







                Last edited by chris_j_hunter; 1 March 2011, 10:05 AM. Reason: ie: ...
                Our self-build - going further with HA...

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