Thanks, it finally worked. But there's another issue: both the value read by LOGO and the HMI are a virtual number between 0 and 1000, as set in LOGO's analog comparator.

Let's say I have a flowrate of 13 L/s, and this value shows up as 109 in the HMI. How do I convert it back to the analog value of 13 in the HMI?

Here are the LOGO and HMI files. If you have the chance to look at them, thank you!

The analog input and comparator are at the very end of the LOGO file. Other than that, I don't know how to convert that virtual value of 0-1000 back to a voltage and a flowrate on the HMI.

I've found something online telling me to scale the value as well, but I have no idea which function to use. How do I do it?

Here is the HMI file along with the LOGO file. Thank you for your help up to this moment.

I've calculated both the Gain and Offset:

Gain = (500-5)/(5-1) = 123.75 [L/min]/V

Offset = flowrate - Gain*Voltage = 5 - 123.75*1 = -118.75 L/min

But LOGO doesn't accept Gain values above 10. I converted the voltage values to the 0-1000 bit interval, obtaining:

Gain = 1.2375 (approximately 1.24)

Offset = -118.75 (-approximately -119)

I can now calculate the exact flowrate value for my threshold (converted to bits), but I'm not receiving the actual flowrate value that I need to display on the HMI. What else do I need to do?