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April 12, 2014 at 2:37 am #22831
I have the OpenSprinkler BeagleBone set up to control solenoids for a hydroponic setup. The water comes from an accumulator tank that is filled by a 24VAC booster pump connected to a pressure switch. In some situations I would like to have the pump controlled directly by a timer instead of the pressure switch. The pump uses a 24VAC power supply rated at 2A. Can I connected this to three stations of the OpenSprinkler in parallel to provide enough current to run the pump directly or will I need to use a relay to power on the pump transformer? Thank you.
KerryApril 12, 2014 at 5:01 am #26467
Are you sure the booster pump is rated at 2A? It seems rather high. You can probably connect three stations in parallel to provide that much current; another option is to make use of the on-board relay (which is rated at 120V / 2A).April 12, 2014 at 5:35 am #26468
The pump is an Aquatec 8851 that I run at 80 psi, the power supply that comes with it is rated at 2A. I’ve attached the current draw table. I’m guessing it would be easier to connect the three stations in parallel, but is there documentation on using the on-board relay? Thank you for your advice.
KerryApril 12, 2014 at 5:00 pm #26469
The attachment.April 13, 2014 at 7:13 pm #26470
OK, looks like it is indeed 2A. It’s true that connecting three stations in parallel would be the easiest, as no software change is needed. But I have never tried running a 2A device so I can’t say definitely it will work or not. If you decide to try this out, also note that OSBo has a on-board 2A fuse, which you either need to upgrade or solder a wire across it to bypass it.
The relay is connected to pin P9.16. Writing a high to this pin will activate the relay and low will deactivate the relay. Using the relay does require some software modifications. Probably the easiest is to conceptually assign the relay to a specific station (say station 1). Then you just need to go into the software and find where stations are activated and deactivated, then add a couple of lines of code to wirte HIGH or LOW to P9.16 if the station index matches the pre-assigned station.April 14, 2014 at 2:44 am #26471
Thanks. Programming for the board is something new for me, so I might try the parallel method first. Appreciate the great support.
KerryApril 14, 2014 at 6:03 am #26472
The latest OSPi software comes with a module for triggering the relay’, and its GPIO is defined internally as pin_relay; but yeah making this automatic with the start of a program would require a lil modification..
It seems like it would be a decent idea to have an option to configure the master station to be the onboard relay though; It shouldn’t be too hard to implement.. maby Dan can help you out as he is the resident python expert, I dont think a module can hook into the interval loop so it would be a hack to the core code.April 15, 2014 at 4:46 am #26473
@nayr: I had the same thought that an option can be provided to associate the relay to the master station. This should be useful in many situations. On the other hand, the master station only activates when there is another station scheduled to activate, so this puts some restrictions on the flexibility.April 16, 2014 at 8:55 am #26474
true; then you’d need a configuration option for stations if they require master or not; kinda like the rain sensor.. this would be very useful for garden/greenhouse/hydroponic irrigation…
My greenhouse plans involve a goldfish pond for retaining water with a auto top off for the pond; this should slowly change out the fish pond and use there waste nitrate for the plants.. all the greenhouse stations will work off a solar powered pump… sooner or later (next spring I hope) if this isint in the software I’ll figure out how to to do it and send dan a patch heh
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