KC868-A16S Analog input 4-20mA connection

[nicolouts]

Hello,
I have a KC868-A16S device and I want connect 3 Analog sensor on it.
My sensor provide a 4-20mA signal with 24VDC voltage.

So I need to convert one of my signal to 0-5V with 250 ohms resistor and connect to CH1 or CH2
But I want to be sure, if I can connect directly my 4-20mA directly to CH3 and CH4 without damage the ADC of the ESP32.

I know that maximum voltage for ESP32 ADC is 3.3VDC, is there a protecting circuit on KC868-A16S to prevent damage?
What the purpose of LM224 on the drawing?

Thank in advance.

Regards

Nicolouts