help needed to connect cheap optocoupler to miniserver

[Gast]

I am in the testing phase for designing my Loxone setup. I have a requirement to use Panasonic AMN31112J sensors. The output of this sensor is connected to a ULN2803A darlington array to increase the output current. The ULN2803A connects to an optocoupler (DST-1R4P-N). The optocoupler is connected to 24V and GND of the miniserver.

When motion is detected, the led at the input and output side light up. In my opinion this means the circuit is working.

Now my need for help. When I connect the output of the optocoupler to a digital input of the miniserver, the led at the output side of the optocoupler lights up and stays powered on. Resulting in a 1 at the Loxone miniserver. When motion is detected, the output side led stays on. No difference.

How can I connect the output of the optocoupler to the miniserver in a way that when no motion is detected, the output signal is low and when motion is detected the output signal is high? Any help is highly appreciated!

[Gast]

A 4K7 pull-up resistor did the trick. The output side led is poorly lit now when not detecting motion, enough to bring the signal down. Does it make sense to use a slightly bigger resistor, 10K for example?