I need to build a circuit that has 4-20mA input and can power sensors from the loop with 2-wire connection.

Could someone explain the principle of the power circuit built in such sensors?
I would be grateful if someone drew a simplified schematic.

Example (images from manufacturer website and manual):

[![enter image description here](https://i.stack.imgur.com/5EEqw.png)](https://i.stack.imgur.com/5EEqw.png)

[![enter image description here](https://i.stack.imgur.com/5czDn.png)](https://i.stack.imgur.com/5czDn.png)

[![enter image description here](https://i.stack.imgur.com/FrvrE.png)](https://i.stack.imgur.com/FrvrE.png)

Please notice that this "transmitter" has just 2 wires to connect with "receiver", there is no VCC and loop negative is GND.

<https://www.vega.com/en/products/product-catalog/level/radar/vegapuls-62>

At this moment I have some devices with input built similar to this:

[![enter image description here](https://i.stack.imgur.com/iaRwD.png)](https://i.stack.imgur.com/iaRwD.png)