Level 0: Instrumentation
Level 1: Process Control
Level 2: Supervisory Control
Level 3: Advanced Control
Level 3.5: DMZ
Level 4: Plant Information Network
Description
1
Provides increased security between Level 4 and lower levels using a network-attached firewall.
2
Designed for reliability and availability to maintain constant view of the process. It is the backbone for process control and monitoring.
3
Includes the PCN, and may contain instrument asset management systems, computer authentication and authorization services, process data historian servers, and process alarm management servers.
4
Consists of programmable logic controllers that sense and manipulate the physical process.
5
Shall be physically and logically separated from lower levels for availability, integrity, security and information protection of significant and mission-critical systems.
6
The actual physical process, including field instruments and analyzers directly connected to the process equipment.