I have wasted a lot of time on searching for electromagnetic 24VDC valves. I have the impression that I dug through the whole internet, so maybe some readers will recognize me from my strange queries. None of the companies operating on the Polish market offered DC current valves at reasonable price.
A salesman from Valmark Respondet immediately but offered professional valves at EUR 175/piece. The solution became clear to me when one of the sellers used the words: converter and relays. I needed to forget about 24VDC valves, separate a part of the installation, buy a 24VAC transformer and standard garden valves and control them through relays. This is how it currently looks:
Initially I wanted to buy only 2 simples valves to test how they work. When I contacted the cheapest seller on Allegro, he offered to make a project of my whole garden within the price of the sprinklers. Finally he delivered it all to my house not taking any extra fee. Within a week I had in my garage all the elements of the system and a project in hand. (If you are interested: IRJAZA, www.irjaza.pl). After another month of digging trenches and putting the pipes in the ground the system was ready to be launched:nia:
Since the valves are controlled by relays connected to the PLC I needed just slightly extend the existing program. The control is possible through CoDeSys or a www. This is the visualization:
I can switch each of the valve separately and set timers for automated watering of each zone. I also wrote a function, which after the watering time of each zone is set (in minutes) it adjusted the hours in the timer function blocks so that the zones are turned on in a sequence.
Finally, at a limited cost (24 VAC transformer, 6 relays 1 750-530 module) I was able to extend my existing system and control the sprinklers in my garden.