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Thread: Maximum PH Deviation for Alarm

  1. #1
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    Default Maximum PH Deviation for Alarm

    Hi

    I was wondering why the min deviation for the ph alarm is 0.5

    Does this mean I can only set an alarm if the ph swings from say 8.3 (my nominal value) to 8.8?

    If so this seems like a very large swing before an alarm is triggered. Is there no way to set the alarm deviation to say 0.15?

  2. #2
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    Default

    I have also noticed that the minimum hysteresis for the ph is 0.1

    is there no way of setting this lower to 0.02 for example?

  3. #3
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    the alarm deviation is for + and -
    which means you have a swing of 2 x deviation, in this case pH 1
    -> I think there is a problem if the value swings so much
    if it swings really so much than the alarm makes no sense in my opinion, it should be switched off then

    a hysteresis of 0.1 is already a very small value, reducing it even more increases the switching frequency of actuators (e.g. solenoid)
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  4. #4
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    Thanks for this Matthais

    Do you mean the alarm would trigger anything over 0.25 + or - the nominal value? If so, that is fine.

    With regards the to the hysteresis, I wanted to dose a ph buffer using the dosing pump if the ph fell 0.02 below 8.3 (ie 8.27) so that i could keep the ph constant at 8.3.

    Do you think i am being too accurate here? I am new to the hobby and thought that the more stable i could keep the ph the better for my corals and my anemone

    Quote Originally Posted by Matthias View Post
    reducing it even more increases the switching frequency of actuators (e.g. solenoid)
    I am not quite sure what this means?

  5. #5
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    the complete measurement chain (probe + electronics) has a latency and it takes some time until the water and the buffer is mixed, so it is no possible to react as fast as you want in this example -> does not work what you planned to do

    alarm deviation of 0.5 means +0.5 and -0.5 -> please check the manual for that
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  6. #6
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    Ok Thanks for this advice!

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