What are some different levels of SCADA machines and systems?

there are two in basic operation levels.

1 monitoring 

2 monitoring and controlling 

in logic level.

1.pereferal data collection that we can say rtu data collection adc to dac or vis virsa 

2.program process station .where we can say system make decession and make define proreties.

3.master control unit .

7.Layers Network 

1. Application
2. Presentation
3. session
4. Transport
5. Network
6. Data Link
7. Physical