Feedback Commands From Ramp To Level

Discussion in 'C-Bus Serial Protocols' started by mark_curd, Jun 10, 2011.

  1. mark_curd

    mark_curd

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    Hi Guys,

    I am hoping that someone might be able to shed a little light for me. I know some others have asked this simular type of question but I can't find a definiative answer to this.

    I’m currently using a 3rd party app (Command Fusion) to interface my iPad with my cinema and C-bus system. Interface between the app and C-bus is achieved as follows: C-bus <> PCI <> RS232-IP <> Router <> iPad.

    I currently have setup....

    Commands being issued for on/off/dim control of group addresses
    Feedback from groups to toggle button status
    Commands being issues for variable slider values
    Feedback of requested group values

    I am now setting up feedback to update the sliders and this is where I keep going round in circles. PCI is set for no check sums and at the moment I’m not using a confirmation letter. I can get feedback working perfect if I issue a command onto the C-bus network eg; \0538000A0101<cr>, \0538000A0102<cr> etc, as I am issuing the exactly level, but I cannot get the slider values to track changes from key input units. The only messages I am seeing coming from the C-bus network when I ramp from the key input are; \050638000A01FF or \050638000A0100 followed by the terminate ramp command and then the final value when the button is released. The problem I am having is I can’t track the current level, am I missing something here or is that just how it is? I can update the slider but not in a good manger, ie; when the command is issued from the key input unit to ramp the group up to FF the slider will max out, once I release the button when I have the desired level it will then update with correct value. Same for issuing a ramp to 00 it will set the slider to min value and the after to the correct. What the best options to be able to track the live values? I know I can requests group values all the time but for me this is the wrong way of doing it as I will be polling the network constantly.

    Thanks in advance

    Mark
     
    Last edited by a moderator: Jun 10, 2011
    mark_curd, Jun 10, 2011
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  2. mark_curd

    ashleigh Moderator

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    During a ramp, to track the current level, you have to do it yourself.

    There is no constant feedback.

    The way C-Bus works - EVERYTHING models the level independently, and the terminate or instand-ramp-to-level at the end of a ramp operation brings things back in line if they should have diverged.

    So, for example, if you know the current level is (hex) 0x30, and you see a ramp to 0x60 @8 seconds, then you have the ramp rate (ie full scale over 8 seconds), so you can work out the number of increments per second that this corresponds to - or the number of increments per 10 milliseconds, or whatever. Then you feed regular ticks into your model, which calculates the new level.

    Every single C-Bus device that shows a level (eg a touchscreen, or a dimmer) works like this.
     
    ashleigh, Jun 11, 2011
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  3. mark_curd

    mark_curd

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    Thanks Ashleigh, that's answered my question nicely. Cheers
     
    mark_curd, Jun 11, 2011
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