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Friday, May 10, 2024

OK, lets talk ISA-95!

ISA-95 - How does it fit and what is its impact in the new digital manufacturing paradigm? No need for introductions and summaries of both topics, there is more than enough written on this to cover that. 

Let's start with a reminder that ISA-95 was developed and became a standard a long time ago and both technology and manufacturing has changed since then. It is based on the Purdue Model that dates to 1990s and relies on functional decomposition in general. Therefore at a minimum we should be critical and understand what has changed in order to reflect on the standard - specifically what is still valid and what is not, or needs to be changed. 

ISA-95 attempt to provide a holistic representation of how manufacturing operations should be supported with information systems. Being a standard it offers a double-edged sword. On the positive side it promotes efficient implementation, reduced risk, ease of integration and fosters trust in solution scope. However, standards can also stifle innovation by limiting creative design approaches, and adherence can be costly for manufacturers, especially companies with limited budgets. 

ISA-95 functional model pyramid where lifecycles intersect at operations (from "Beyond the Pyramid: Using ISA95 for Industry 4.0 and Smart Manufacturing", Dennis Brandl)

We have been using the standard for decades and it has helped many companies to clearly define and solve the shop floor control challenge. As such it was mostly used as a reference to define the solution architecture. For solution suppliers it was used mostly to show completeness of their products, i.e. in level of compliance to the standard which helped companies understand what they are getting and what no. The very structured approach that the standard brings certainly helped in effective integration and information exchange. However in the digital manufacturing realm where IIoT and composability is gaining acceptance this presents new challenges:
  • Rigidity: The new paradigm emphasizes adaptability and real-time decision-making. The hierarchical structure of ISA-95 might seem somewhat rigid for these needs. Modern systems favor a composable approach for better scalability and networked IIoT architectures with edge and cloud components.

  • Data Deluge: The explosion of data from the IIoT network of devices, apps, machines, etc. puts a strain on the traditional ISA-95 framework. We need to allow for real-time data processing and analytics at the "edge" (closer to devices) alongside centralized enterprise systems and cloud services. The standard dictates a central Manufacturing Operations Management (MOM) system for data routing. In an IIoT solution nodes communicate at multiple levels in a dynamic networked architecture with edge and cloud components.

  • Gaining Insights: Extracting insights from data is crucial in digital systems and ISA-95 doesn't explicitly address advanced analytics needed to support both the volume and variety of data. It also sets a very rigid structure for data that doesn't lend itself to advanced analytics and AI/ML technologies. 

So Does this mean ISA-95 is obsolete? Not entirely. The core principles of data hierarchy and information flow remain valuable. One of the main thing that I find valuable are some of the patterns in the data models. The core hierarchy concept of organizing data flow into different levels (field devices, automation, operations, and business planning) remains a valuable framework for understanding information flow in a manufacturing setting.  It is not surprising, a lot of experience and time has been put into generalizing how to model production and process and these can be valuable when contextualizing content in next generation digital system. B2MML also provides some valuable insights in to ERP information sharing. But at the same time be warned, use the patterns to add context to data at the source, don't fall into the pit of rigidity and global one size fits all data models.  

So where does ISA-95 go from here (see Walker Reynolds interview Dennis Brandl)? Some advocate evolving the standard but I question the value. Not because of its relevancy but I fundamentally questions if we really need such an overarching holistic standard in the manufacturing operations space. In other words is it even worth the effort? As it stands we can leverage what we need from the standard, as mentioned above, and use these to accelerate adoption of the new paradigm. Let's not reinvent what already works but spend time to build out the principles of flexibility, data management, and openness into specific standards that provide targeted value. There is already plenty of effort and initiatives in this space such Sparkplug B, OPC UA, CESMIIs SM Profiles, Asset Administration Shell (AAS), UNS, etc.

We should also take into account that we are not done transforming. We are in the thick of the shift to the new paradigm and as such technologies are still being developed and some have not yet even emerged. Trying to standardize in a world that is still changing does not yield much. We can however be aware of the standard's relevancy and where if falls short. Focus on the need for agility, the data rich digital systems that are being adopted, and most of all on composability. We have to ask the hard question of the value of a holistic standard when we have citizen developers chatting with no-code systems to create content. So use what is relevant and evolve into the digital realm where it makes sense. Even a Tesla uses standard wheels and tires as a core component, no need to reinvent the wheel there! 


Anonymous said...

Having just implemented a composable innovative, 100% fit to requirement MES for a 7-site rollout that is 100% compliant with ISA95 in less than 4 months, there is undeniable proof that your conclusions about ISA95 are invalid.

Gilad Langer said...

Can you clarify what "implemented a composable innovative" means?