Control and Information System Diagrams

To facilitate communication with project and operations personnel, it is desirable to add a CIAD and a CIND diagram to the usual diagrams such as P&IDs, Loop Diagrams, Control Logic Diagrams, etc.

The Control and Information Architecture Diagram (CIAD) communicates an overview of the physical architecure of the enterprise systems and networks from the plant sensors and control devices to the corporate board room.

The Control and Information Network Diagram (CIND) provides a graphic view of all control, HMI, network devices, and the networks that connect them. The CIND includes redundancy, communication rates, and protocols. Multiple identical end devices such as workstations, PLCs, radios, etc., may be shown in tables (see CIND Example).

It is important to stanardize what is represented on each type of diagram in order to speed understanding among the many personnel who use them.

CIAD

The Control and Information Architecture Diagram should include:

• Major computing systems.
• Connection lines represent main networks or data links.
• Weight or color of Connection Lines may be used to indicate relative bandwidth.
• The "Level" of each system and network is shown according to its 4Rs (Reliability, Repairability, Response and Resolution).
• Zones and Conduits (see IEC/ISA 62443) may also be indicated.
• Workstations are shown "generically" rather than by user group.
• Redundant systems are not drawn (but may be indicated).

The CIAD is developed during the Conceptual Engineering Phase, in parallel with the Process Flow Diagram (PFD) or Mechanical Flow Diagram (MFD).

Here is an example CIAD from a typical process industry facility.

This second CIAD example shows conceptually how a Safety Instrumented System (SIS) may be combined with PERA Levels and ISA 62443 "Zones and Conduits".

CIND

The Control and Information Network Diagram is more detailed than a CIAD, and should include the following:

• All major computing Servers
• Connection lines represent all networks and links.
• Each network including an indication of network type, speed, and protocol.
• All network specification changes (e.g., at routers).
• Depiction of the "Level" of each system and network (according to its 4Rs)
• The extent and exact boundaries of Zones and Conduits (see IEC/ISA 62443) is also indicated.
• Workstations for all major user groups are indicated
• Redundant systems and networks are shown
• Major Data Repositories are shown

The CIND is developed during the Preliminary Engineering Phase, in parallel with the P&ID.
Like P&IDs, CIND diagrams are definitive documents that are progressively developed during the Engineering Design Phase including use during HAZOPs, Cybersecurity "Zone and Conduit Analysis, and design audits.

Here is an example CIND from a world-scale facility that includes mulitple "Areas" including process control rooms, on-site project offices, warehouses, and remote EPC design institutes. These are connected by Level 4 site networks, Level 5 national, and Level 6 international networks.

The Central Control Room manages multiple oil fields, oil and gas processing plants, and international pipelines. The Control Room Systems and associated Level 0 to Level 4 systems and networks in hazardous plant areas, are documented on multiple similar CIND drawings. In addition to the (Level 3.5) firewall, a split Process Data Historian is also located in the Central Control Building, along with certain special-purpose Level 4 systems.

After startup CIND diagrams should be regularly updated as they provide essential information for:

• Cybersecurity Monitoring
• Security Audits
• Asset Management (of system and network devices) in both IT and Automation and Control Systems.

Note that each area contains a table of systems and devices in that area.