Digital pin connected to SS relay: voltage is 2V across control inputs when digital pin is supplying 5V
The open drain output from your ED-008 provides a switched connection to ground for a device that can control things like relay coils powered by up to 34V and can switch enough current to turn on that SSR.







simulate this circuit &ndash; Schematic created using CircuitLab

To drive the relay you want to connect the positive side of the input to a voltage source, and the negative side to the output of your device. When it's "off" the output of the device will be high and no current will be allowed to flow. When it's "on" the output will be low and current will flow through your SSR turning it on.