I am constructing a setup that will be able to read values from a SICK WL150-P430 sensor through an arduino uno board. I was hoping to use the digitalread() of the arduino to read the value of the sensor but being a beginner at electronics I am not entirely sure how to connect all making sure not to fry anything. The sick sensor has 4 wires. It requires a 10-30vdc to power it. I am taking care of this by using an external power supply that gives it around 12v. The sick sensor has two other wires blue/black. The voltage being output between these wires is 3,78V measure with a multimeter. I am powering the UNO board from USB from the computer.
Is it safe to connect the black lead to a digital input on the arduino or do I have to construct some sort of voltage devider. And should the negative wire of the sensor connect to the the ground on the arduino breadboard or the powersupply's ground?
I attached an image make it more clear.