Hooking up the K8046 to two power supplies

I’m planning on integrating the K8046 in my domotica system. As a core for the whole system I use a PLC, working at 24V dc. The K8046 can not handle this voltage and will be powered from a seperate 9V dc supply, hooked up to the GND-Vb connectors.

I’m wondering
a) if I can use my 24V dc supply for signals and hook it up to the COM and + supply at the keyboard side
b) if I need to connect the 0V signals to have a common ground
c) if this connection can damage my power transformers or if special precautions need to be taken.

Thanks for the help.

hello,

Personally, i would use a relay board like the k8056, just incase there is a problem and relays would also separate the two circuits and voltages.
However I am very cautious with mixing different voltages and it would be a shame to destroy something accidentally. I hope I may have helped… :slight_smile: