Arduino TX-RX pins to Domotica interface with optocoupler search schematic

Hello,

I am looking for a working schematic . I have a arduino that i want to connect to a domotica interface pins RX-TX are used to do the connection.
The system is working for the moment with a arduino mini without optocouplers between rx-tx since the arduino mini is using a small current and is getting power of the domotica interface.

Since i need a arduino Uno or Mega with his own power supply i need to use optocouplers between the RX-TX so i can separate the power supplies without any risc to the domotica interface.

For the moment the arduino mini is using power from the domotica system but this is limited so i need to use a optocoupler between the rx-tx so that i can use a separate power supply for the arduino. I have read that is it nog a good idea to connect to 2 GNDs together and must use optocoupler.


i have here optocouplers ILD2 .

I there anyone that can give me a working schematic ? I have also read that there a sometimes problems when using optocouplers that the signals are inverted . So that may no be in my case.

Thanks !

Hi,

If it's now working without Rx Tx isolation, then it will work in future, too.
Just use an isolating power supply.

Follow the safety rules of your country.

Klaus

KlausST said:

Hi,

If it's now working without Rx Tx isolation, then it will work in future, too.
Just use an isolating power supply.

Follow the safety rules of your country.

Klaus

Click to expand...

Maybe i was not 100% clear what i need to do . For the moment there is a Ardruino mini wich is taking power from the domotica interface . But i need to use a Arduino Uno or Mega and that one cannot be powered by the KNX Bus since the higher current needed.
I have read that it is not allowed to connect another GND of a Power supply to the GND of the KNX bus.(interference)
So that is the reason why i want to isolate the RX-TX with a optocoupler to be 100% safe and at that point i can use a separate power supply without any risc.

Any suggestions are welcome if possible with a schematic.

Thanks !!