![]() In this update I am adding one more section (previously I had 3 and used relays in the Loxone Extension, now I will have 4 sections and will use Loxone’s analog outputs instead) so I had to change the PCB to be able to fit the four relays there and also make a space for fourth transformer 230V AC –> 24V AC, or better said fourth channel. Yes, I could design it with just one common transformer and switch the individual outputs, but then the transformer would need to be bigger (taking into consideration the load in case multiple sections are in operation, and would be working 24/7 unless an additional relay would be added to switch it ON/OFF. ![]() The thing is that the transformers are in operation only if the irrigation section is in operation. The relay coil is rated for 12V DC (works perfectly on 10V from Loxone’s AO) and the relay contacts are switching the mains voltage for each mini-transformer to get the 24V AC for solenoid valves. Each section is connected to 230V AC (!) and controlled by 0-10V output from Loxone, triggering corresponding relay to turn the relevant section ON/OFF. So to describe the design of the circuits, there are four identical sections each for one solenoid. ![]() Two relay candidates I found that would fit the purpose – these are only illustrative images, not the proper voltage ratings is shown Takamisawa JV-12S-KT U=12V DC, I=17mA, switching 230V! / 5A max.Relay that has tiny DC coil to not consume much (less than 20mA) but at the same time the contacts robust enough to survive some load with the space in between that can safely interrupt 230V circuit. ![]() These are two constraints that are almost mutually exclusive. But at the same time we need a relay to be able to switch the mains voltage of 230V. The only limitation is that from Loxone’s analog output we can draw 20mA maximum! This limits the selection of the potential relay candidates to usually a smaller components. Instead of using the Loxone Relay outputs I have added four relays to my custom control board which I modified a bit, and using the 0-10V signal from Loxone’s analog output I will be able to control all four of these external relays. With the solution below I was actual able to free last three relays and move the solenoid control towards the analog outputs 0-10V which I do not use in that particular place and that extension.ĭanger! This design of the board below and the circuits wiring combines low voltage and mains 230V on the same board! This can represent serious hazard for people without proper understanding of the principles and technical knowledge. My cellar (decentralized) mini cabinet has a just two small DIN rows and there is no way of fitting an additional Loxone component. Now, the reason for this all is not to save a couple of Euros for another Extension, but to expand my current setup, without to have to throw away everything I have done so far. I this example I am using external box with separate switch board I made as a part of the solution for solenoid valve control, but the principle can be used for any other similar applications. This way I will be feeding external relays to control the garden irrigation. The idea here is to move away from Loxone relay outputs and use the four available analog outputs from the Loxone Extension instead. With the newly added section I would be at 4 relays just for the solenoids controlling the garden irrigation, not talking about the pump and other related stuff. In the previous design I used three of the extension relays outputs (one relay per solenoid). The main reason for this update is an additional section/solenoid valve added to the system which I want to control with Loxone. This post is an update of an earlier article I did for garden irrigation.
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