HELP - variable switching point

Hello first of all, i am new here! 

I am working with a LOGO 0BA8

I need some help. What i have; 2 analog inputs 4-20mA. 

input 1; speed. 0-1500 rpm

input 2 press: 0-10 bar

and a digital output that must close when the pressure is too low.

What i want to make is een speed depending alarm setpoint. So for example. at 500 rpm i want a closed digital output when the pressure is 1 bar. and at 1000 rpm i want a closed digital output at 2 bar. 

I tried to make a graph as an explanation. The red line is the switching value of a digital output. depending on rpm 

I would be very helpful if anyone has a solution, thank you in advance! 

First of all, thanks for your response!

The output needs to be closed from the limit and higher. 

Sorry, my bad.

I mean lower! 

Hello again,

this is almost exactly what I need. just a little fine tuning. Thank you very much!

Hello Goodmorning everyone,

I upgraded it. I have another question. If the pressure sensor is broken, so the value falls below 4 mA, then output Q1 and Q2 should not switch. how do i make this?