Proposed Evapotranspiration Algorithm in 3.1.4 Beta

[Michel Kohanim]

Thank you guys. Can you tell me what you are using for Soil Type/Absorption factor and your stations?

 

Thanks and with kind regards,

Michel

[TJF1960]

Hi Michel,

 

Irr. Region: Interior Plains

Absorption: 30%

Water Applied: .25

Allowable Depletion: .075

Station: KBAB (Beale, CA)

 

Thanks,

Tim

[wrj0]

Thanks, Michel.

Absorption Factor/Soil Type: 33% - Clay Loam

Location ID: p10366

[Mark Sanctuary]

Irrigation Region: Interior Plains

Absorption: 67%

Water Applied: 0.5

Allowable Depletion: 0.335

Location ID: CTRSH (Orangevale, CA)

[Michel Kohanim]

Hi Guys,

 

This is very odd ... I tested each and every station and configuration and I do have Irrigation Requirement:

For Tim: 0.3979

For Mark: 0.5003

For wrj0: 0.3898 (assuming Water applied is 0.5)

 

Are you all certain that you do not issue Irrigation | Reset values anywhere?

 

With kind regards,

Michel

[Mark Sanctuary]

I removed the test programs so for me no I am not triggering a Cycle Complete command.

 

When I did the firmware install I just let the ISY reboot. Do you think a power cycle might help instead?

[TJF1960]

Mark,

I have power cycled mine a half dozen times since upgrading but it is still not showing an irrigation requirement other than 0. But in those infamous words "It couldn't hurt."

 

Tim

[Mark Sanctuary]

There might be some nuance in the algorithm that does not stand out as a problem.

 

Michel,

 

Is the timing of the copy to Irrigation_Requriement happening before or after the other vars are being cleared?

[wrj0]

Thanks for checking, Michel.

I am certain that I do not have an Irrigation Reset command anywhere in my code. My current climate tab is shown below, including IrrReq=0 is shown below.

[Michel Kohanim]

Hello wrj0,

 

Thanks so very much for the screenshot.

 

Would you be kind enough to:

1. Let me know the polling interval for your WeatherBug Module

2. Please go to Configuration | System, click on Manually Adjust Clock

3. From the dialog, choose tomorrow's date

4. Wait polling interval amount of time and then check back the Irrigation Requirement

 

What should happen is this:

Water Deficit Yesterday should now be added to Irrigation Requirement. If Irrigation Requirement used to be a negative number, it will stay 0 till it becomes positive. So, if in the past you have called Cycle Complete a LOT of times which may have caused Water Deficit to be come a negative number, then:

1. From your program call Irrigation | Reset Variables

2. Wait a while, make sure that the Water Deficit Yesterday is a positive number

3. Change the data to the next day

4. Wait for polling interval and then check the irrigation requirement again

 

Mark, unfortunately I have no idea what you are talking about.

 

With kind regards,

Michel

[wrj0]

Thanks again, Michel, for your outstanding support.

 

My polling interval is set for 300 seconds. After manually adjusting the clock to tomorrow and waiting more than 300 seconds (watched two weatherbug polls in event viewer after changing to tomorrow), Yesterdays Water Deficit went from 0.0294 to 0.2401; however, Irrigation Requirement remained at 0 before and after changing the date and allowing the two polling cycles.

 

Irrigation Requrement has remained at 0 since installing the Irr/ETo module, and has not been observed to be anything other than zero. Since my program that tests for IrrReq > 0.5 has not run at all, it seems that the Irrigation - Cycle Complete command has not been executed ever on this system. Thats the only program that includes Cycle Complete.

 

Additionally, over the past two days we have had 5 quick power outages during local thunderstorms that caused an ISY system boot 5 times.

 

Anything else that I can test? Thanks again for your help.

[Mark Sanctuary]

I did the first clock change tests you suggested and it is still zero. I even went out several days and still zero.

 

Then built a program and manually triggered the "Irrigation Reset Variables" command and now I have a number in Irrigation_Requirement. The strange thing is since I installed the firmware I have not triggered "Irrigation Cycle Complete" so I don't know why Irrigation_Requirement would have been negative. Is this initialization process something that every user will have to do the first time this module is installed?

 

Also why would there be any negative number affecting Irrigation_Requirement? It's suppose to bottom out at zero and never go lower. Is the code behind the GUI actually storing negative numbers for Irrigation_Requirement?

[Michel Kohanim]

wrj0, thank you and my pleasure. The problem is that irrigation requirement is set to 0 when negative. There are two cases when irrigation requirement is calculated:

1. Every time Irrigation Cycle Complete is called

irrigationRequirement -= (waterAppliedPerIrrigation*absorptionFactor);
if (irrigationRequirement 	irrigationRequirement = 0.00;

 

2. At the beginning of every day (i.e. 12:00 AM):

etoYesterday = etoTally/sampleCount;
waterDeficitYesterday = etoYesterday-(rainYesterday*absorptionFactor);
irrigationRequirement += waterDeficitYesterday;
if (irrigationRequirement 	irrigationRequirement = 0.00;

 

So, in short, the only ways Irrigation Requirement can be 0 are:

1. If cycle complete was called

2. Yesterday's Water Deficit was a large negative number

3. Reset Values was called

 

As far as power outage, all information is stored and persisted in the file system so power outage should not have any effects except for inaccurate et0 values.

 

Mark, the unit starts with all variables at zero.

 

With kind regards,

Michel

[Mark Sanctuary]

Sounds good. Thanks!

[wrj0]

Michel and Mark: Thanks!

 

I've not triggered Irrigation-Cycle Complete or Irrigation-Reset Variables previously. However, after trying Mark's suggestion of building a new (disabled) program and manually launching the Irrigation-Variables Reset command, I now, for the first time, have a non-zero value for Irrigation Requirement. Who Hoo!

[TJF1960]

Michel and Mark: Thanks!

 

I've not triggered Irrigation-Cycle Complete or Irrigation-Reset Variables previously. However, after trying Mark's suggestion of building a new (disabled) program and manually launching the Irrigation-Variables Reset command, I now, for the first time, have a non-zero value for Irrigation Requirement. Who Hoo!

Creating the program as Mark suggested worked for me as well.

I second wrj0's Who Hoo!

 

Thank You,

Tim

[Mark Sanctuary]

Everyone,

 

I am going to recap on the module initialization process for future users. If you have installed the Irrigation module and your Irrigation_Requirement equals zero, then create this temporary program below. After creating it right click on the program in the folder tree and select "Run Then" to reset the module. Finally go over and check again Irrigation_requirement and you will see a number.

 

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

Then
       Irrigation - Reset Variables

Once you have done this initialization process you can delete the temporary program.

 

Thanks,

[Michel Kohanim]

Hi all, thanks so very much for testing.

 

Mark, would you be kind enough to put this in the WiKi? I do appreciate it.

 

With kind regards,

Michel

[Mark Sanctuary]

No problem, I will add it.

 

The wiki server seems to be really slow right now so I will try a bit later.

[oskrypuch]

Yes, now working for me too.

 

* Orest

[TJF1960]

Question about Irrigation requirement:

 

My settings are:

Interior plains

Absorption: 30%

Water Applied per cycle: .5

Allowable Depletion: .15

 

Currently:

Evapotranspiration: .541

Irrigation Req.: .2785

Yesterdays def.: .5341

 

After running the program which completes the irrigation cycle the new irrigation requirement figure is .1285 inches which is Irrigation req. minus Allowable depletion. Is this correct? I would have thought the Irrigation req. figure would have dropped by .5 inches (Water Applied).

 

Thanks,

Tim

[peterd]

Tim -

What you're seeing is correct behavior. You should set Allowable Depletion to a value representing how much water your plants can tolerate leaving the soil. Then set up your program to run whenever Irrigation Requirement >= Allowable Depletion (you can't actually write the program this way - you have to copy the Allowable Depletion value into your program). Finally, using the Water Applied per cycle value which ISY calculated for you, you have to calculate how long to run your valves so that depth of water is applied (and put the appropriate WAIT statements in your program). One way of doing this (for sprinklers - not drip) is using a "catch can" test. Another is using a PC program which helps you do these calculations. (See my post early in the thread for a link to a website with info on both of these.)

 

Cheers,

Peter

[Michel Kohanim]

Hi Tim,

 

Yes, that's correct.

 

With kind regards,

Michel

[TJF1960]

Oh my, I was way off base.

 

Thanks very much!

Tim

[peterd]

Oh my, I was way off base.

 

Thanks very much!

Tim

Tim -

Don't feel bad - so much has evolved. Your original view of things was correct... halfway back in the thread.

 

I had to stop & think a moment before my reply.

 

Peter