Veter_myasnoy wrote:But the problem is that when I connect the GPI pins to ground (dry contact) nothing happens. I even dont hear the sound of a relay closure.
You shouldn't hear anything on the GPI side, the relays are on the GPO side, the GPI is just voltage and ground.
What RCPs are you using? You should hear the relay click on the RCP touchdown unless you're using a Blackmagic RCP which doesn't have a traditional GPO.
Good Luck