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OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Pi (OSPi) › OpenSprinkler – run concurrent and sequential

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  • July 1, 2013 at 10:02 pm #22499

    bentsod
    Participant

    I have 180 irrigation heads/solenoids.
    Solenoid specs are:
    24Vac
    .47A 11.3Va inrush
    .32A 7.7Va holding

    Can Opensprinkler
    *run concurrent up to a limit – i.e. maximum 6 zones at one time based on pump capacity.
    *require certain zones to run sequentially based on piping limits (could specify as part of the name).

    Thanks for the guidance.

    July 2, 2013 at 6:18 pm #24612

    Ray
    Keymaster

    Concurrent running shouldn’t be a problem. Each zone has its own individual triac, which supports 800mA continuous and several amps inrush current. As long as your sprinkler transformer has a sufficient current rating, I see no problem turning on 6 zones at the same time.

    180 zones is beyond the software limit of the microcontroller-based OpenSprinkler (honestly I am quite impressed that you have 180 zones…) However, OpenSprinkler Pi does not have any software limit on the number of zones.

    Regarding concurrent vs sequential running modes, currently the only option is to globally switch between the two (i.e. either all stations run sequentially, or all stations are allowed to run concurrently). There is currently no support for subsets of sequential groups.

    July 5, 2013 at 7:43 pm #24613

    djMax
    Member

    I’m confused at this answer… Let’s say I have a 24V 300mA transformer (I do), which is 7.2 VA. And let’s say I have 9 Weathermatic solenoids with a 6.6VA inrush and a 5.5VA hold current (I do!) – I *have* to run sequential right? Because two solenoids active at once would be 11VA? In this guys case he’d need a huge-mongous transformer. Related question – I have two of said transformers and OSPi+expansion board. Is there a way to wire it so that both transformers can be used (assuming I handle the software side of it)

    July 6, 2013 at 5:39 am #24614

    Ray
    Keymaster

    1) if your transformer is only 7.2VA, you won’t be able to run activate two zones at the same time — if you do so, the transformer voltage will drop very rapidly and the valves will reset.
    2) I don’t recommend wiring two transformers in parallel, especially since different transformers have slightly different output voltages, and I don’t know what would be the consequence if you connect them in parallel.

    July 14, 2013 at 5:24 pm #24615

    djMax
    Member

    Looks like the sequential option is no longer and it’s always sequential?

    July 14, 2013 at 7:47 pm #24616

    Ray
    Keymaster

    If your firmware version shows 1.8.2, then yes it doesn’t have concurrent running mode. If your firmware shows 1.8.3 then it should have the ‘sequential’ option.

    July 14, 2013 at 11:59 pm #24617

    doczaius
    Member

    Although my yard isn’t terribly large, I have two water sources. I’m also under annoying water restrictions that only allow watering in a small window once a week, so running as many zones as possible at the same time is crucial.

    Not sure if I missed it or if 1.8.3 came out after I began my OSPi journey but I needed concurrent runs and it wasn’t available in the interval program. My solution was to just install a crontab script that would kick off the valves using the GET commands provided by the interval program. You can access the crontab editor with “crontab -e”… You will see simple instructions on how to write entries… or you can use the Corntab online GUI: http://www.corntab.com/pages/crontab-gui

    Below is a version of my crontab that I was experimenting with. I’ve already gone a few weeks using this method without major issue (I mixed up a couple of zones the first run 🙄 ). It shouldn’t be necessary with the duration variable, but as a safety measure I run a turn off command when each zone is supposed to turn off. Note that if you have an issue with water hammer, you could also use this method to overlap runs slightly (1 minute resolution).

    IP is obscured..

    0 19 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn1=1&t=90
    25 20 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn1=0

    45 19 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn2=1&t=90
    10 21 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn2=0

    15 21 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn7=1&t=75
    25 22 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn7=0

    30 22 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn5=1&t=75
    40 23 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn5=0

    45 23 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn6=1&t=75
    55 0 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn6=0

    0 19 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn4=1&t=75
    10 20 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn4=0

    15 21 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn3=1&t=75
    25 22 * * 4 /usr/bin/wget http://xx.xx.xx.xx/sn3=0

    July 15, 2013 at 12:59 am #24618

    djMax
    Member

    So doczalus, out of interest how many zones and what’s the rating on your transformer?

    July 15, 2013 at 1:28 am #24619

    doczaius
    Member

    I salvaged the transformer from a Hunter X-Core controller. According to the spec doc from their site, the rating is “24 VAC, 1.0 A. Maximum output per station shall be 24 VAC, 0.56 amps.”

    With my hybrid method I have at most three zones open at one time for a 45 minute overlapping period and two zones for 75 minutes.

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OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Pi (OSPi) › OpenSprinkler – run concurrent and sequential