ISA 95 – The Analytics enabler framework behind Smart Manufacturing

Why this sudden interest in Smart Manufacturing?

With emerging technologies like IoT and IIoT grabbing headlines, the interest in Smart manufacturing  or “The factory of the future” has peaked. Many providers have developed and launched products and platforms that allows manufacturing organizations to convert their manufacturing floors into smart factories (sample representation below).

So what are the primary drivers behind this peaked interest in Smart manufacturing? Some of the drivers are no brainers are the ones that we are more familiar with like:

  • Reduced sensor costs
  • Evolution of Technology (like IoT gateways and hubs that can handle massive amount of data, computing power, technologies like Blockchain)
  • Evolution of data management and Data processing platforms (NoSql and distributed databases)

However, unknown to many, ISA-95, a set of standards has silently helped evolve Smart manufacturing from a concept to getting very close to a mature technology platform. The same standard provides a connectivity framework that allows flow of data from devices all the way to ERP systems.

ISA-95 helped standardize the Smart manufacturing architecture which in turn allows organizations to implement Smart manufacturing leveraging a standard framework.

What is ISA-95 and why you need to know about it

What is ISA-95?

The ISA-95/ISA-88 standard provides a common model for production processes and resources, and a standard interface to expose the model to higher-level ERP systems and lower-level control systems.

The ISA-95 standard was originally developed to bridge the gap between low-level machine control and high-level ERP systems that are responsible for planning and scheduling. Currently, ISA-95 is the international standard for the integration of enterprise and control systems, and consists of both models and terminology. These can be used to determine what information has to be exchanged between systems for sales, finance, and logistics and systems for production, maintenance, and quality. For those interested in additional details, please refer the Appendix section below.

Why you need to know about it?

ISA-95 model was the basis of developing the Smart Manufacturing Computer Integrated Manufacturing (CIM) pyramid. The CIM pyramid allows integration of control systems all the way up to ERP data. As an Analytics professional, it allows you to tap into data generated by Smart factories without being an expert in manufacturing control systems.

The CIM Pyramid

We know that there are specific software applications for automating and coordinating the different activities in a manufacturing organization like:

  • ERP: For managing tasks such as logistics, production management, accounting, personnel, purchases, warehouses, project and sales management, and plant and distribution management
  • Computer-aided design (CAD) and computer-aided engineering (CAE): Software tools for designing, testing, and validating the product against the specification or requirement
  • Computer-aided process planning (CAPP) and MES: Software applications for automating and optimizing the planning process

Operating in Silos, these systems lead to the creation of automation islands that are not integrated with each other. A huge improvement can be achieved by integrating all subsystems at the company level. This can be done :

  • By implementing a structured design of the whole information technology stack
  • By managing the flow of information between the various devices at different levels
  • By coordinating factors involved in the production cycle, including the human factor

As we know, in all production processes, there is a trade-off between the variety and the quantity of the production in terms of the number of parts or the output. Typically, higher the quantity of the production, lesser is the variety.

A flexible production system that uses highly configurable machinery allows us to shift the threshold of this trade-off. This machinery can be setup for different uses and allows for a strict interaction and integration between the information systems of the production process and the support activities, as depicted in the diagram below:

 

Please refer to the appendix section for a detailed description of Computer Integrated Manufacturing architecture

Benefits of this architecture for analytics professionals

The reasons this framework benefits analytics professionals are:

(1) Provides the visibility into flow of data across systems for Data Engineers

(2) Knowledge of integration flows allows to create cubes that merge data from multiple sources in the ISA-95/CIM hierarchy

(3) Optimal sourcing decisions regarding Smart manufacturing hardware and software platforms can be made keeping integration in mind

Conclusion

ISA-95 provides a robust model that can help you define your Smart manufacturing integration. However, the key benefits of Smart integration go beyond technical architecture. The key is to implement a flawless integration so that you have consistent quality data available for analytics.

Appendix

ISA-95 Model

The ISA-95 equipment model is a hierarchy of various logical entities that are used to model aspects of production. The general structure of the ISA-95 equipment model is shown in the following diagram:

95
Picture courtesy- ISA-95 standards website

ISA- 95 model has a number of important characteristics. These include the following:

  • There are similarities between the process cell, the production line, and the production unit. These are essentially the same levels of entity that are applied to batch, continuous, or discrete production.
  • Storage zones and storage units are independent of the type of production.
  • Equipment modules can contain other equipment modules, and control modules can contain other control modules. This allows you to build a complex hierarchical model of a piece of equipment.
  • Equipment modules and control modules are not a part of the base ISA-95 standard. They are added as extensions of the model to unify the model with the ISA-88 standard, which includes these objects.

SA-95 equipment entities

The equipment model hierarchy shown in the previous section describes the various equipment entities and their relationships in the ISA-95 model. These entities are described in detail as follows:

  • Enterprise: An enterprise is an organization that has a definite mission, goals, and objectives. It could represent an entire company, a division within a company, or a functional component of a company dedicated to a product or service. Corporate, divisional, and business unit activities are decided at the enterprise level.
  • Site: A site is generally a physical or geographic grouping of a portion of an enterprise. A factory could be a site, an entire complex containing multiple factories, or a single building. The exact determination of a site depends on the size of the enterprise and the organization of the various activities within it.
  • Area: An area is a physical, geographical, or logical grouping that’s determined by the site. It can contain process cells, production units, production lines, and storage zones.
  • Work center: A work center is a facility that consists of equipment in a role-based hierarchy. It performs production, storage, material movement, and any other self-contained activity.
  • Production line: A production line is a work center that contains equipment dedicated to the manufacturing of a discrete product or a family of products. A production line contains all of the equipment required to make a discrete product or a component of a product.
  • Production unit: A production unit is a work center that contains production equipment that converts, separates, or reacts with one or more feed stocks to produce intermediate or final products.
  • Process cell: A process cell is a work center that contains production equipment to carry out a processing step in batch operations.
  • Storage zone: A storage zone is a work center that can be a location and/or a piece of equipment dedicated to the storage of materials and/or equipment.
  • Work unit: A work unit is an entity in the factory that adds value to a product. The way a piece of equipment is used determines whether it is classified as a work unit. If the device requires a sequence of steps, or specific settings to carry out its production function, it is a work unit. Work units in ISA-95 are differentiated based on whether they are used in batch or continuous operations, discrete manufacturing, or storage. There are three types of work unit:
    • Unit: A unit is a work unit defined for batch and continuous production
    • Work cell: A work cell is a work unit defined for discrete manufacturing
    • Storage unit: A storage unit is a work unit within a storage zone that can be a location and/or a piece of equipment that is dedicated to the storage of materials and/or equipment

     

Computer Integrated Manufacturing (CIM)

The CIM model is often depicted as a pyramid made up of six functional levels, as shown in the following diagram:

                                              

 

The CIM pyramid

  • Level 1—field: This level includes all devices that interact directly with the process, such as sensors and actuators.
  • Level 2—command and control systems: This level includes the devices that interact directly with the sensors and the actuators, such as PLCs, micro-controllers, proportional-integral-derivative (PID) controllers, robot controllers, and computer numerical controllers (CNCs).
  • Level 3—cell supervisory: In a cell, a complete sub-process of production is executed through various devices and machines that must be coordinated with each other. The main functions of the control devices placed in this level are the following:
    • The receipt of the instructions from the upper level.
    • The transformation of the lower level devices into actions and commands.
    • The collection of information from the lower levels to pass to the upper level.
    • The arrangement of information for the human supervisor, who may eventually issue commands or set up set-points or thresholds.
  • Level 4—plant supervisory: At this level, the production database collects and stores the main parameters of the production process, and the coordination between the cells is carried out to implement the whole production process.
  • Level 5—plant management level: At this level, the aforementioned integration between the support systems takes place.
  • Level 6—company management: Typically, a company handles several plants, so at this level the information is collected from the lower levels to feed the decision support systems that help managers to plan flows of materials and finance necessary for the maintenance, improvement, and optimization of the production process.

The pyramidal shape used to present the CIM levels is suitable for a hierarchical organization in which the following occurs:

  • Each level communicates directly with the upper one, from which it receives commands and sends information
  • Each level communicates directly with the lower one to send commands and receive information
  • Each level sends to the upper level less information at a lower frequency than that received from the lower level

This strict and mutual interaction between the different systems and sub-systems involved in the production cycle has a number of benefits. Among the most important of these are the following: 

  • More efficient usage of resources through the planning of production processes
  • Greater flexibility in production, as the system can be promptly and easily adjusted to conform to a new process
  • A reduced processing length
  • An improvement of the product design due to digitization, given the need to provide unambiguous information to digital machines and systems
  • The identification, storage, and re-use of information related to the product
  • An improvement in the quality of the product due to more stringent validation checks
  • The reduction of stocks of raw materials and warehouses used to store finished products and any processing waste

It is important to remember that the CIM pyramidal structure is a logical representation of the factory automation world. This means that the canonical six levels can be coalesced into a simpler structure with fewer levels. From an operational perspective, for instance, the CIM pyramid is often represented in five levels:

  • Field: Sensors, actuators, and hardware
  • Control level: Control systems, such as PLCs and DCSes
  • Supervisory level: SCADA systems, time-series databases, recipe management, production reporting, and alarm management
  • Planning level: MESes, plant-wide operations, asset management, and maintenance
  • Management level: ERP systems

In IT companies that provide automation services to factories, the CIM pyramid is typically simplified to a three-level structure:

  • Automation control: All equipment for the automation and control
  • Supervisory: Devices and applications for the supervision of the production process and the maintenance of equipment
  • Production management: Applications for the planning and management of the production

Both coalesced representations of the CIM pyramid are shown in the following diagram:

                                 

 

CIM pyramid architecture – devices and networks

The following simplified schema represents a typical automation architecture with reference to the CIM pyramid. Each level, shown in the center, has been linked on the left-hand side to the related communication networks, and on the right-hand side, to the devices or applications involved: 

Picture courtesy: Rockwell Automation website

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