Everything You Need to Know About ISA-95
In recent years, ISA-95 has become a ubiquitous term in automation. It seems like any system that claims to be capable of enterprise level integrations must include some form of ISA-95 compliance. While we’ve seen a lot of talk about ISA-95, very few resources discuss how it is applicable to the world today. Some even joke that the "95" in "ISA-95" means it was relevant in 1995, but not in 2023. It’s a somewhat fair assessment, given how far technology has come since 1995—many problems are much easier to solve with technology like MQTT and Unified Namespaces. But, the overall concept of modeling a business along with defining the flow of information to speed up integration time and value are timeless concepts.
In this post, we’ll discuss the what and the why of ISA-95 along with where it does and doesn't apply to modern control systems. We’ll outline what you actually need to know to use ISA-95 when designing Enterprise system architectures, and how to think about ISA-95 in the world of Unified Namespaces. Be sure to check out our eBook: Unified Namespaces: The Ultimate Guide.
The 4 Ws of ISA-95
Who Created ISA-95, and When?
The ISA in ISA-95 stands for the International Society of Automation. They are a non-profits standards body for the fields of instrumentation, systems, and automation. ISA develops and maintains standards for all manner of topics in the manufacturing world.
ISA-95 began life in 1995 and has been continually revised and updated to account for modern technological advancements—including changes from the rise of "Industry 4.0".
What Is ISA-95?
ISA-95 is officially titled "Enterprise-Control System Integration". It describes the overall hierarchy of manufacturing businesses including:
Level 4 - Business Planning and Logistics
Level 3 - Manufacturing Operations and Control
Level 2 - Automation
Level 1 - Field devices and functions
This hierarchy concept is also referred to as the “Automation Pyramid.”
Beyond the automation pyramid concept, ISA-95 also details how to describe manufacturing processes in the form of a "production model", how to define and implement integrations between manufacturing operations and the business itself. The more recent parts of the standard discuss how to manage the flow of information and messaging between the various systems in a manufacturing operation.
Why Does ISA-95 Exist?
As manufacturing technology became more complex, computing power was integrated with the plant floor along with network connectivity. Without a framework like ISA-95 to manage everything, it became difficult to understand and manage these increasingly complex interactions.
To be blunt, ISA-95 also exists because non-profit does not mean open source. This also means that ISA is able to sell the ISA-95 standard to many companies for a decent sum.
ISA-95 In Detail
At the time of this writing, the ISA-95 has eight parts plus a supplemental data template. You can read the titles and a brief description of each on the main ISA Standards page. Combined, the ISA-95 is a huge amount of information and could be used in conjunction with technology platforms to build out a great system. But when searching online, you will find that most of the information about ISA-95 you can access is only the first 20% of Part 1!
ISA-95 Part 1: Models and Terminology
Part 1 of the ISA-95 standard outlines the different models and levels of abstraction for fully understanding and mapping out manufacturing operations and business system integrations.
The standard begins with domain level definitions (control systems and enterprise systems). This includes functions in each domain, functions of interest to ISA-95—along with how information flows through the functions, the relevant categories of information, and how the information is defined.
Keep in mind that ISA-95 focuses on the integration between levels 3 and 4 of the pyramid (Manufacturing Operations and Control, and Business Planning and Logistics). It will also define operations at the enterprise level, how they integrate with operations at the manufacturing level, and how we need to structure the model of every business level to effectively communicate between Levels 3 and 4.
Along with the automation pyramid, Part 1 also describes the plant’s production model. The production model is commonly referred to as the "Enterprise->Site->Area->Line" model.
Most online content about ISA-95 focuses on this model—and for good reason. It’s vitally important to understand this part of the standard, because it will inform how you architect your overall system. This is also the simplest way to approach tracking OEE, one of the most common first steps into an MES integration.
Without using the term OEE, ISA-95 Part 1 describes everything you need to capture the data for calculating OEE as part of an overall object model. Equipment Status and Scheduled Production time (Availability), Production Capacity (Throughput), Production Rules (Quality) are concepts layered on top of the production model. They give you the ability to build a representation of your plant, and understand how it is operating from an OEE perspective. These tools allow you to build a process capability model—essentially, the ability to calculate OEE for free while you are building out the model of your operation.
Unfortunately, is where most articles stop when explaining ISA-95, mainly because it makes a solid point when you are looking only at OEE. This is sad because Part 1 also includes a detailed breakdown of the most common business functions in a manufacturing operation using the Functional Enterprise-Control Model.
The Functional Enterprise-Control Model
The Functional Enterprise-Control Model describes how a business operates. If you consider the concept of a Unified Namespace, this encompasses all of the "events" of the business you need to capture for a complete snapshot of your business at any given point in time.
The Functional Enterprise-Control Model includes:
Order Processing
Production Scheduling
Production Control
Maintenance Management
Quality Assurance and Control
Operations Planning
Inventory Management
Shipping and Receiving
R&D
Marketing and Sales
The model describes how these operations act as the glue between different departments and parts of manufacturing goods, along with how to manage the data definitions and flow between each of the areas. It even has plenty of examples of how to use the ISA-95 mindset for building vendor-agnostic systems (with receipts for how they arrived at the standard).
Seriously, if you haven't read ISA-95 Part 1, it is worth the time! It has a TON of great information for how to architect systems—even if some of the specifics of HOW to get data from point A to point B have been improved with technological advancements like MQTT.
ISA-95 Part 2: Object Model Attributes
If we think of ISA-95 Part 1 as an outline of everything we will learn in ISA-95 101, the following parts will detail specific topics. Applying the concepts in Part 2 will give you a standardized set of definitions and terminology for clear communication across all elements of your business—for automated data exchanges, as well as person to person communication.
ISA-95 Part 2 focuses on the the interface between manufacturing business hierarchy levels 3 and 4 for the models we have in ISA-95, including:
Production capability (useful for OEE)
Process segments (useful for how products are actually produced/flow of materials)
Personnel and equipment models
Materials
Production scheduling and performance
Production routing and material dependencies
These models are described again (similarly as in Part 1), but this time Part 2 describes each model’s many potential attributes you may want to use when architecting your own models. These attributes are represented on tables including descriptions, dependencies, values, with examples of typical scenarios, and how to link models together for gaining a full understanding of your operation from a data perspective.
To be fair, it is slightly disingenuous to say people DON'T talk about parts 2-8 and the supplemental template. Often, it’s not necessary to talk about them in detail to understand the major concepts.
Part 2 and beyond describe the bulk of the work for architecting an ISA-95 compliant solution on a project.
ISA-95 Part 3: Activity Models of Manufacturing Operations Management
Where Part 2 focuses on how to model your equipment, process segments, and materials, Part 3 helps you define and standardize your business processes. These processes include:
Production
Quality control
Maintenance
Inventory management
Reporting and data collection
Scheduling and performance analysis
Maintenance
Now, you can build a standard set of operations activities to integrate with your object model for describing how your operation is structured, and how work is done within the hierarchy of your business. This enables integration between level 4 logistics and planning functions and level 2 manual and automated process control functions.
These concepts encourage adopting best practices across the company, and help you integrate your manufacturing operations with other enterprise systems.
The benefits to Part 3 are enhanced integration between systems, better communication across your company, and improved understanding of manufacturing operations. Ultimately, this will result in increased operational efficiency, reduced costs, and improved competitiveness in the manufacturing industry.
ISA-95 Part 4: Objects and Attributes for Manufacturing Operations Management Integration
Part 4 builds on Part 3 to define and standardize how object and activity models can be used and integrated with other systems. It shows how to omprove communication across the organization by clearly spelling out how to get data from one system to another—and how people can use that data to do their jobs more efficiently.
The concepts detailed in ISA-95 Part 4 produce benefits such as reducing the time and cost to reach optimal production levels. This is accomplished by:
Enabling vendors to supply the appropriate tools and technology to integrate with your existing systems
Helping your users and stakeholders determine their needs for new tools
Reducing the overall cost of integrating and automating manufacturing processes
Optimizing your supply chain and movement of goods through your facility
Reducing overall engineering lifecycle costs for integration work
ISA-95 Part 5: Business-to-Manufacturing Transactions
Part 5 takes the concepts from Parts 3 and 4 and defines the "verbs" which actually integrate different systems. This is similar to thinking about how a web server uses PUT, GET, and POST requests to get data from point A to point B.
Similar to Parts 3 and 4, ISA-95 Part 5 focuses on the same models for objects and activities, and utilizes the data models from Part 2 to define which data will be sent where, when integrating systems.
Overall, Part 5 outlines the structure, content, and format of the information related to work performance and quality that needs to be exchanged between manufacturing operations management systems and other enterprise systems. Part 5 provides a standardized model for passing data between systems.
Now, you can easily spec out integrations by defining which data will be integrated and how it will be integrated between systems.
The benefit to the approach described in part 5 is a decoupling of vendor specific implementations so you can use standard protocols and approaches to data integrations instead. It also streamlines how you will describe integration requirements for anyone involved with your manufacturing operations systems as a whole.
ISA-95 Part 6: Messaging Service Model
If you are looking at ISA-95 through the lens of a Unified Namespace Part 6 is for you!
It could be argued that Part 6 is less relevant in 2023 after the wide adoption of technologies like MQTT and Sparkplug B. Although, ISA-95 Part 6 still has some great concepts and best practices.
Part 6 defines the concept of a Messaging Service Model (MSM) as a way to specify how data is transformed when communicating between disparate systems.
Overall, Part 6 is a layer on top of Parts 2, 4, and 5 when considering different applications with different data structures. Essentially, each application collects "local" data, converts it into the "global" format, converts "local" names to "global" names where applicable, and sends data to the exchange service. Then, the other system ingests the data, uses it, and then sends any required responses.
The key takeaway of ISA-95 Part 6 is that you must define your object and activity models as well as define how your data will be translated to the various systems which will be using it. The work defined in Part 6 cannot be replaced by using Sparkplug B for every definition. Instead, Sparkplug B can handle the task of sending data to the “Information Exchange Service” portion of the system. Use Part 6 to help define how to translate between local and global scopes.
To poke a little fun, Part 6 was released in 2014, and was much more relevant back then than it is in 2023. In today's world, we can simply replace all of Part 6 with: "Use a Unified Namespace and MQTT, and agree on your naming convention before you integrate anything."
ISA-95 Part 7: Alias Service Model
Tell me to use a Unified Namespace without telling me...
ISA-95 Part 7 is basically Part 6, except it adds more detail to the "convert local names to global names" task of exchanging data between systems. Given the advent of technology since ISA-95 was originally implemented, this means that Part 7 is now much more important to consider.
While MQTT and Sparkplug B can easily handle sending data to the Information Exchange Service, with the number of potential integrations across a manufacturing organization you will need to spend more time and energy than ever on the naming convention side.
You will need to convert data from a global namespace to a local namespace for every integration with your system and you can use the concepts outlined in ISA-95 to help.
ISA-95 Part 8: Information Exchange Profiles
Let's be honest. Part 8 seems like the guy in Office Space who deals with the engineers so the people don't have to!
ISA-95 Part 8 defines the framework for standardized information profiles you can use to integrate different technology together in an "ISA-95 way". It is more geared towards software vendors which build software with ISA-95 integrations out of the box. For example: My software package, built with a Part 8 Information Exchange Profile, can send data in an "ISA-95 way" to any other software package that requires it—through a Part 6/7 process—and then it can ingest my data and do something with it.
The fact that everyone does their ISA-95 implementations differently (if at all in today's world) makes Part 8 feel like “too little too late”.
Even if different software companies implement Information Exchange Profiles, you will still need to make the effort to ensure that your naming conventions match across the board—as in Parts 6 and 7. Thankfully, you can easily accomplish all of this in a Unified Namespace without worrying about implementing Information Exchange Profiles.
Maybe it is good to still have Part 8? It is not very applicable in 2023, other than ISA needs to put it out there as an attempt to stay relevant despite technological advancements making parts of ISA-95 obsolete.
ISA-95 TR01: Master Data Profile Template
This is geared towards people who want to develop ISA-95 compliant software. Our assessment of Part 8 also applies here.
Where Does ISA-95 Fall Short?
ISA-95 Parts 1-5 were pretty powerful when they came out. The overall concept of modeling a manufacturing organization, defining the data structures, defining how various tools and systems would be integrated, and utilizing valuable data and information across the company are still powerful concepts today.
But, ISA-95 feels like it has missed the ball in today's world of Unified Namespaces, MQTT, Sparkplug B, cloud-based analytics packages, and more standardized platforms in general.
You could argue that the concepts in parts 6-8 are still highly relevant today, however they assume too much standardization will be done across different companies and business units to be valuable on their own. Now, we have great alternatives for building out standardized naming conventions and sending data to a centralized Information Exchange. You get it almost for free when using MQTT and Sparkplug B.
Another place where ISA-95 runs into roadblocks—modern communication protocols or not—is with complex processes. ISA-95 essentially follows a tree model approach. It does really well with the Enterprise->Site->Area->Line types of manufacturing processes. "Take raw materials, feed them into a linear production line, and stuff comes out the other end" works really well for this approach.
ISA-95 breaks down when there are branching production lines, parallel processes, or even machines with complex operational requirements. These can be difficult to model in the standard equipment hierarchy and lead to some interesting workarounds when you need to calculate OEE.
Since ISA-95 is a layer of abstraction, and isn't necessarily focused on the most granular details at the production line level, some hand-waving arguments and simplifying a complex machine into a work cell isn't the end of the world. After all, ISA-95 is an abstraction for easier communication within an organization to understand how a process is operating at any given point in time. If you can get an idea of a complex process’s health even if it isn't 100% accurate in full HD quality, you will still get about 95% of the value without having to do the last 95% of the work for that last 5% level of detail.
Wrapping Up
Overall, ISA-95 is a solid framework and still has a lot of applicability in 2023—even for complex manufacturing processes.
Though much of today’s available technology gives us many of the benefits of ISA-95 (structure in naming, and parts 6-7 to send data to other systems) essentially for free with modern tools like MQTT, Sparkplug B, and Unified Namespaces, we also live in a world informed by ISA-95. None of these newer technologies were built in a bubble.
In a way, it sort of feels like introducing Gen Z to The Beatles. They might not be amazed by The Beatles because all the music post-Beatles existed in a world where The Beatles came first. If you were around when The Beatles came about (or you look at their legacy and influence on all of music that came after), you can see how powerful they are, and still appreciate their greatness today.
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