Shutter relay fine tuning

Discussion in 'C-Bus Automation Controllers' started by geoffrhunter, Oct 1, 2018.

  1. geoffrhunter

    geoffrhunter

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    I have 10 groups of venetian blinds operated by L5501RBCP C-Bus Shutter Relays. While they work fine to lift and drop, they tilt by going to the bottom stop and reversing taking approx 1.3 seconds to go from tilt closed down to tilt closed up. Because of the latency of the c-bus system it is often very difficult to get the desired tilt using the buttons and even worse using the eDLT.
    I want to try preset tilt angles and have started some logic code off a single bell push;

    if (GetLightingState("Blind Nudge") = On) then
    begin
    SetLightingLevel("Bed 1 Blinds",100%,"0s");
    delay (0.5);
    SetLightingLevel("Bed 1 Blinds",2%,"0s");
    end;

    This sort of works but instead of it running for 0.5 seconds it is anything between 0.02s and going all the way up. I assume the system latency is within the c-bus network.
    I have also tried turning off Level Translation Mode and setting a value that increases by 1 each bell push but this seems to get confused as well. The log shows random group on/off commands being generated by the Wiser2 at entry or exit from the code.
    Anyone any ideas how I can stabilise this?
    Geoff
     
    geoffrhunter, Oct 1, 2018
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  2. geoffrhunter

    Ashley

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    Not sure what you mean here. Are you saying that the blind is fully lowered at less than 100% and the travel from there tilts the blinds, and when you raise from 100% they tilt first then raise? If so I doubt you would ever get that to work reliably. The shutter relay works out its position using the fail-safe timer which in practice isn't very accurate because it's limited to 1 second increments and the blind speed will vary over it's travel and direction.

    Also, logic modules are run every 200mS. When a module gets to a delay it stops that module and moves onto the next. Each successive scan when that module is run it checks if the delay has expired and if so continues after the delay. If the delay has not expired the module is skipped. This means that delays are effectively rounded to multiples of 200ms.

    Cbus latency depends on activity. If you have lots of broadcasting groups latency can be an issue. If all your activity is user initiated, latency isn't usually a problem.

    I'm not sure how the timer work internally, but the delay must be at least 0.4 seconds since the module will be skipped at least once. The only way to get a 0.02 second delay is if the first command is delayed on the bus for a long time which is unlikely. You need to run the cbus diagnostic utility see what is actually happening. Also, run the logic from PICED and use the log commands to print out the time when it issues each command.


    Can you post the log. Things don't happen randomly. It is doing what you are telling it to. Again, run the diagnostic utility and see what is really happening.

    Finally, your use of the IF command and bell press is not recommended here. With the IF command, if you hold the button down, as soon and the delay expires you will repeat the code on the next scan. Use the ONCE command. Also, with the bell press, since the logic is run only every 200mS if you press and release the button within this time period (easy to do), you will miss the press completely. The way to do this is to set the switch to the ON function only, then reset the group at the end of the module.
     
    Ashley, Oct 2, 2018
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  3. geoffrhunter

    geoffrhunter

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    Thanks Ashley
    This explains my problem. I have tried the tweets you suggested in your last para and it did help a little but I can't get it accurate enough to be useable. I have therefore ordered a programable inverter drive that I can use to slow down the tilt to 5 seconds (switched in by a c-bus relay from 50Hz to 20Hz) so i can use the standard macros.
    Should sort it!
    Geoff
     
    geoffrhunter, Oct 2, 2018
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