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Tuning Soil and Rain factors

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  • Tuning Soil and Rain factors


    I'm trying to tune the soil and rain factors for the soil, as the schedule currently has it more than 2 weeks between watering cycles. Currently, all of the areas are set with a soil of 0.5, and rain of 0.75 (as all are outside / receive direct rain), and all of the zones are set to run based on ET with a 5% setting.

    I've read the doco, but not quite sure the best ways to tune it, so I had a couple of questions:
    - Does the ET analysis & algorithms take into account rain, and if so, how?
    - I see that I can do a maximum days without watering (which is good), but if I do this, does it take into account natural rainfall, and if so, how?
    - If I wanted to get it to water more often (ignoring where rain applies), am I correct in assuming that I would reduce the soil (i.e. go down from 1 towards 0)?
    - If i wanted to change the impact of rain on the zone, am I correct in assuming that I would reduce the rain (i.e. go down from 1 towards 0) as well?
    - Is there anything else I need to consider / be aware of, when using this approach?



  • #2
    Soil moisture is based upon amount lost through net evaptranspiration (ET) and gained through net rainfall. It is calculated hourly. It is reset to 100% (2.5 cm depth) upon completion of an irrigation cycle.
    Net ET is estimated as ET0 / SoilFactor. With a value of 0.5 the moisture loss will be twice as fast as nominal.
    Net rainfall is estimated as reported rainfall * RainCoverageFactor. With a value of 0.75 the effective rainfall will be 75% of what is reported.

    Rainfall is not considered in the max days consideration. It is based upon time since prior change of the zone's valve state. I had never thought of rainfall considerations and will need to dwell upon this. Do you have any suggestion?

    When the irrigation cycle is longer than expected the issue is usually associated with the sensor that provides the measure of sunlight intensity. Solar radiation sensors are the best if they are available, but most internet sites do not provide it. The most common second choice is UV. Some provides estimate the next day's UV and mcsSprinklers curve-fits an hourly profile. Some provide hourly measurements. In your summer now I expect high values for both of these so your daily ET should be in the neighborhood of 0.6 cm. Look at the calendar history of the sensor and the ET to investigate. There is also a global solar intensity factor multiplier that will affect the ET0 calculation if you find your radiation/UV to be biased from normal.


    • #3
      Hi Michael,

      So one thing i've noticed, is that whilst i've configured a max of 50 downloads per day, this is being used up by 1pm. Does your algorithm adjust the internet download schedule based on the count/day, or is it on a specific schedule (e.g. every 15 mins). Is this something that could be impacting the calculations?

      Also, since i've done the recent update, the "Evaluate Internet Download" page is coming back blank after it's pressed - it looks like it starts, but then goes to a blank page. This is true for both Internet Explorer and Chrome - i've attached my settings for reference. The error message is as follows:
      Nov-20 10:45:44 PM Error Posting back to plugin web page weather: Object reference not set to an instance of an object.-> at System.Runtime.Remoting.Messaging.LogicalCallContext.Propaga teIncomingHeadersToCallContext(IMessage msg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(Mess ageData& msgData, Int32 type) at HomeSeerAPI.IPlugInAPI.PostBackProc(String page, String data, String user, Int32 userRights) at Scheduler.proxyPage.postBackProc(StateObject& state, String Data)

      In regards to rainfall, as long as this is being included in the soil moisture calculations, then it should be theoretically fine, but i'd still really love an option to force it for 7 days sinec the last rainfall / run. Maybe you could cross-link the minimum and maximum days without watering, with the "Don't with precipation forecast & actual" part, via a checkbox that you could put on the Min/Max area saying something like "apply don't with rules to these days". Not my best wording, but hopefully you get the concept.

      Grateful if you could please check my weather settings and advise if they're correct + advise regarding the weather collection issue, as i'd like to exclude those first if that's okay?

      Attached Files


      • #4
        Looks like WU has turned off their service so I will need to remove it as an option. Since you have a Accuweather license it would seem to be the best to use this source when possible. Open Weather Map is another option for you.

        The download count is on a fixed schedule, but increased when wind is a restriction and has been windy. I forget exactly the timing, but 30 mins for current and 60 mins for forecast should be in the ballpark of what is used. If a download failure occurs then it is retried so it could also be this avenue that is getting to your count prematurely. It could also explain what appears to be a timeout on the download evaluation. There should be some info in the debug log if you have Debug option enabled from the bottom of the Other Page. I can look if you post. You could also email to mcsSolutions at CenturyTel dot net your config\mcsSprinklers.ini so I can use you setup for evaluation on my computer.


        • #5
          Hey Michael,

          I made the change, and the weather downloads appears to be working now, and the values appear to be more along the lines of what i'd expect.

          I'll tune the values now and see the results.

          Thanks for your help.