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Proposed Evapotranspiration Algorithm in 3.1.4 Beta


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Mark -

 

Sorry. My frustrations with many things got the better of me there. I know everyone's been making their best efforts (myself included) to learn about this stuff.

 

Back to the point of the discussion, I think a 1st release would have been better with the ISY performing the absolute minimum of calculations, but it looks like we'll have soil absorption factored into our irrigation for us. I think that complicates matters, but if we're headed down that path I hope we'll at least have the appropriate configuration variables to work with...

 

Cheers,

Peter

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Peter,

 

I prefer doing all the name changes in 3.1.4 and not confuse everyone with changes in names and meanings.

 

Although I understand your comments from an irrigation expert perspective, I suspect that most users would not know what Allowable Depletion should be. Where as they would immediately know what Water Applied Per Irrigation means. Is there a better and more user friendly name for Allowable Depletion?

 

In short, changing the UI to derive Water Applied Per Irrigation from Allowable Depletion is not a problem. The problem is that I believe most users would not know what Allowable Depletion should be without consulting the PDF you are referring to.

 

With kind regards,

Michel

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Michel -

 

I agree that Allowable Depletion is not as intuitive as Water Applied per Irrigation. But I'm not suggesting we eliminate Water Applied per Irrigation, only "Actual Water Applied per Irrigation".

 

I think "Actual Water Applied..." will confuse matters more (because it isn't describing the water applied - it's describing the effect of the water applied).

 

Allowable Depletion (explained as "How much water will I allow to leave (be depleted from) the soil before I irrigate?") and Water Applied per Irrigation ("How much water must I apply - given my soil absorption - to make up for the Allowable Depletion?") complement each other conceptually. I think it's easier to understand the irrigation strategy if you're able to think of (even if we can't today actually write) the program condition as:

 

IF Irrigation Requirement >= Allowable Depletion

 

(because that is logically what the user will be writing when they select a constant equal to Allowable Depletion for this comparison).

 

Unfortunately, ET is not simple. But I am certainly willing to try to come up with simple explanations like those above to help people start to use and learn about ET-based irrigation. And, if that simple explanation isn't enough to understand Allowable Depletion, at least by our using a standard term for it they should be able to read that PDF (or others) to help learn more.

 

 

So to sum up, I propose that:

1. The user should enter "Allowable Depletion", and be shown "Water Applied per Irrigation Cycle" ((100/Soil_Absorption_Factor)*Allowable_Depletion).

 

2, When the "Irrigation Cycle Complete" action occurs, the ISY decrements the "Irrigation Requirement" balance by "Allowable Depletion".

 

Example:

- Target H2O in soil is 30mm. (Not entered/shown in ISY, this is a decision the user must make based on the types of plants they have.)

- Soil type is Sandy Loam (83%).

- Allowable Depletion entered as 15mm.

- Water Applied per Irrigation Cycle calculates to (and displays) 18.0725mm

- IF Irrigation Requirement >= 15mm THEN irrigate (apply 18.0725mm so 15mm will be absorbed)

- Irrigation Cycle Complete: Irrigation Requirement = Irrigation Requirement - Allowable Depletion (15mm is the loss we made up for when we added 18.0725mm).

 

 

Thanks,

Peter

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Hello all,

 

Release 3.1.4 (Beta) is now available which includes support for the Irrigation Module:

viewtopic.php?f=25&t=6547

 

Peter, Mark, IM, and ryarber, please do send me your UUID so that I can activate the irrigation module for you (support@universal-devices.com).

 

Irrigation Module is an optional module the cost of which is $19.00. For the next month, there's a promotion of $15.00 off when you use coupon code irrigation-promo-11 at checkout.

 

With kind regards,

Michel

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Michel and all who worked on the new Irrigation and Evapotranspiration module,

 

Many thanks for the effort that went into making this module available! May I request that the UDI Wiki entry for 'Evapotranspiration and Irrigation' be updated to include a primer on this new functionality and perhaps also include some suggestions on ISY program implementation? Thanks.

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Hi all -

 

As I've already told Michel, I've had an initial look at the irrigation module and am pleased with what I see. At the moment, we're in the midst of a major home renovation project - which as a side effect had our entire irrigation system apart until this week. As a matter of fact I was testing the irrigation valves just today.

 

Things are very busy for me over the next week, but I hope to be able to sit down soon (may not be until week after next) and do my flow rate & runtime calculations for all 20 zones. Once that happens I'll be configuring the irrigation module and will report back via the forum.

 

When I do, I'll try to walk through what I've done and learned which hopefully can be used to enhance the Wiki entry.

 

Cheers,

Peter

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Thanks, Gents.

Although only active for a couple of days, the Irr/ETo module seems to be working fine for me. The effort you all have put into this is greatly appreciated.

In advance of more detailed documentation, may I ask under what condition(s) one should issue the 'Irrigation - Reset Variables' command?

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[...] may I ask under what condition(s) one should issue the 'Irrigation - Reset Variables' command?

I think for most people, this is going to be a last resort. If, for example, you had en extended outage (ISY down, broadband down, etc.) which meant that you could no longer count on the Irrigation Requirement value to accurately reflect the balance of water depletion from the soil then you might want to reset everything and make a clean start.

 

That said, Mark did come up with at least one creative way to use this if for some reason you wanted to irrigate for 2 different durations (rather than my trying to explain it you could look back through the thread if interested in the specifics of his approach).

 

Cheers,

Peter

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I am currently testing this to make sure everything is functioning before I switch my irrigation over to ET control.

 

Irr Req Met 0.5

If
       Time is 11:00:00PM
   And Module 'Climate' Irrigation Requirement >= 0.50

Then
       Send Notification to 'Mark's Email'
       Wait  12 hours 
       Run Program 'Irr Cycle Complete' (Then Path)

Irr Cycle Complete

If
  - No Conditions - (To add one, press 'Schedule' or 'Condition')

Then
       Send Notification to 'Mark's Email'
       Irrigation - Cycle Complete

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Michel/Peter,

 

How many days does it take to see anything in Irrigation_Requirement?

 

I am on the third day since I installed the module and Irrigation_Requirement still says zero. And this is the first day I have seen anything in Yesterday's_Water_Deficit. I thought it should have at least two days worth of Irrigation_Requirement added up today.

 

 

Thanks,

post-10-140474154155_thumb.png

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I may well be missing something here, but it appears that my Irrigation Requirement variable ${mod.weather.irrig.req} does not seem to change from day to day, and remains at zero. The Irrigation/ETo calculation at midnight seems to be applying the selected absorption factor (0.33) and is decrementing the value for Water Deficit Yesterday. But, for the past three midnight calculations, Irrigation Requirement does not seem to be adding yesterday's Water Deficit to the Irrigation Requirement. Email notifications just before and just after midnight last night provided:

 

Pre/Post ETo Vars 2011/07/04 23:58:00

Called from: Pre/Post ETo Vars

ET=0.4361 inches/day

IrrRqmt=0 inches

WaterDefictYesterday=0.4449 inches

 

Pre/Post ETo Vars 2011/07/05 00:05:00

Called from: Pre/Post ETo Vars

ET=0.4355 inches/day

IrrRqmt=0 inches

WaterDefictYesterday=0.3073 inches

 

So, am I missing something here? Thanks.

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My “Irrigation Requirement†has been at 0 inches also since upgrading the day it was available. I though it was something in my configuration so I have been adjusting the numbers everyday but so far nothing……

 

Tim

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Hi Tim/Mark,

 

Please note that every time you issue Irrigation - Cycle Complete in your programs, the Irrigation Requirement is decremented by Allowable Depletion.

 

To test, you can manually change the day in Configuration | System tab. Mine is at 101 inches because I never apply Cycle Complete.

 

With kind regards,

Michel

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Hi Michel,

 

I did issue irrigation complete commands a couple of times but not in the last 4 days. My yesterdays water deficit is at .6, allowable depletion is at .12 and irrigation req. at 0 still.

 

I changed the date as you suggested but it lowed my yesterdays water deficit down to .3, still no change to irrigation req.

 

Thanks,

Tim

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