ISA-95 and ISA-88 Hierarchical Structures

The ISA-95 standard provides a framework for integrating enterprise and control systems, ensuring a structured approach to managing manufacturing operations. It is widely used in industries to help businesses define a clear separation between business processes (Enterprise Resource Planning - ERP) and production processes (Manufacturing Execution System - MES), thereby ensuring a smooth information flow.

The ISA-95 hierarchy organizes assets and systems into multiple levels, ranging from business systems to the plant floor. Each level represents a specific layer of responsibility and function, helping to ensure clarity and control in manufacturing operations.

The ISA-95 Hierarchical Levels

  • Level 4: Business planning and logistics systems (ERP systems).
  • Level 3: Manufacturing Operations and Control—Manufacturing execution systems (MES) that manage production workflows and real-time operations.
  • Level 2: Supervisory Control—Systems that control and supervise production processes, often through SCADA or HMI systems.
  • Level 1: Automation Control—Controllers such as PLCs (Programmable Logic Controllers) or DCS (Distributed Control Systems) that manage physical processes.
  • Level 0: Physical Processes—Actual machines, sensors, and actuators in the production environment.

The ISA-95 Equipment Hierarchy

The ISA-95 Equipment Hierarchy outlines how physical assets and control systems are structured within an organization. This structure ensures that each level interacts appropriately with higher and lower levels, creating a clear operational flow from the enterprise systems down to individual machines.

The ISA-95 equipment hierarchy is broken into the following levels:

  • Enterprise—The top level, representing the entire organization. This includes overall business processes and decision-making entities, typically supported by ERP systems.
  • Site—Represents a specific geographic location or facility. Each site can have its own management systems and local production control.
  • Area—An operational division within a site, often a functional area such as packaging, assembly, or warehousing.
  • Process Cell—The basic unit of manufacturing within an area. It encompasses all the equipment required to produce a specific product or perform a specific function.
  • Unit—A distinct part of the process cell, responsible for a specific function such as mixing, heating, or assembling.
  • Equipment Module—A modular piece of equipment that performs a specific task within a unit. For example, in a mixing unit, the module could be a heating element.
  • Control Module—The lowest level representing individual devices or controllers such as sensors, pumps, actuators or PID control loops that handle direct control of physical processes.

Level 4 activities from the ISA-95 hierarchical levels typically deal with the Enterprise, Site and Area levels of the hierarchy, while Level 3 activities typically deal with the Process Cell and Unit levels.

ISA-88 and Its Relationship to ISA-95

ISA-88 is a standard that focuses on batch control processes, providing a model for automating and controlling batch production. It defines a modular structure for physical and procedural elements in batch manufacturing. While ISA-88 emphasizes the batch control and procedural automation at the production level (especially Levels 1 and 2), ISA-95 bridges the gap between the production (Levels 0–2) and the business systems (Levels 3–4). Together, ISA-88 and ISA-95 complement each other by providing a comprehensive guidance from automation control to business integration, enabling both effective batch processing and enterprise-wide coordination.

Assets and the ISA-95 Hierarchy

Assets, as a part of GENESIS, is designed to adhere to the principles of ISA-95 by organizing assets into a hierarchical tree that mirrors physical, organizational, and process structures. This structure simplifies the management of enterprise and production assets by aligning equipment and processes across the ISA-95 levels. Here's how Assets follows the ISA-95 hierarchy:

  • Asset Tree—The asset tree in Workbench can be structured to reflect the ISA-95 levels, allowing the user to represent an enterprise at the top level (such as headquarters or divisions) and drill down through the manufacturing units, processes, and physical equipment. Each node in the tree can represent a business unit, production area, or a specific machine or sensor.

  • Unified Data Management—Assets centralizes the configuration of assets across multiple systems and integrates data from various sources like OPC servers, databases, and web services, ensuring all data aligns with the hierarchical structure of the ISA-95 model.

  • Scalable Distributed Architecture—Assets supports distributed architectures that enables connecting multiple local systems to form a unified global structure, ideal for large enterprises with multiple plants. This is in line with the ISA-95 goal of integrating plant and enterprise systems across geographic locations.

  • Equipment Classes—To reduce engineering time and maintain consistency, Assets allows the creation of equipment classes, which act as templates for equipment configuration. These classes can represent standard equipment models used across multiple sites, ensuring that all assets follow the ISA-95 hierarchical standards when instantiated across the system. Learn more

Conclusion

The ISA-95 hierarchical structure ensures seamless integration of enterprise and production systems, while ISA88 focuses on the batch process control in production. Assets is essential for companies looking to implement both standards, as it provides a structured, scalable solution for managing enterprise-wide assets, aligning with the ISA-95 model.