It was a Conflict between two USB ports. Solved the problem. Now de relays are available in device tab.

Thanks for the help.

Dear All,

I bought a KMTronic USB eight channel relay controller. In Domoticz I have selected KMTronic gateway USB. But how can I control the 8 relays? I can't select de KMTronic as hardware when making a new switch. Or do I have to make a LUA script?

Thanks for your help