Hello everyone,

I’m currently working on a project using a Siemens LOGO! controller with a PT100 temperature input. I want to use this signal to control two cooling valves with 4–20 mA outputs.

For the first output, the signal should be 4 mA at 0% controller output and 20 mA at 100%.
For the second output, the signal should also be 4 mA at 0% and 20 mA at 100%.

Could someone advise me on the best way to set this up? I’m having some trouble figuring it out.

The PT100 input is connected to a PI controller in the software. After that, I’ve placed an analog amplifier before each analog output. Does this configuration make sense, or is there a better approach? Any recommendations for the correct settings would be greatly appreciated.

Thanks in advance for your help!

When you use a PI controller, you only specify a setpoint, and the controller regulates automatically.
Depending on the magnitude of the deviation, the controller outputs a value between 0 and 1000 units. You do not need an analog amplifier between the controller output and the analog output module.
However, you must keep in mind that the PI controller can only regulate in one direction. You define this direction in the properties of the "PI Controller" block.