• 14 MAR 17

    Everything You Need to Know About PackML Explained by an Expert

    Following the recent announcement that Lee Smith, Lead Software Engineer at Mettler-Toledo, has been appointed Co-Chairman of the OMAC Packaging Workgroup, we’re pleased to welcome Lee for his first guest blog…

    Hi everyone and welcome to my first blog post of 2017. I’m delighted to have been appointed co-chairman of the OMAC Packaging Workgroup as of January this year. For those that don’t know, the Packaging Workgroup is the part of OMAC (the Organization for Machine Automation and Control) which is responsible for PackML and its related initiatives (amongst other things).

    Having represented Mettler-Toledo for the last four years at most of OMAC’s events in Europe and the US, I’m excited about being involved in shaping the future direction of OMAC’s packaging initiatives. In addition, I’m looking forward to meeting more of the OMAC community in my new role and would urge you to introduce yourself if you attend any future OMAC events. In my first post, I’d like to give a short overview of PackML…

    What is PackML?

    PackML, or ISA TR88.00.02 to give it its full name, is a machinery standard produced by OMAC. It’s been around for several years and one of the original objectives was to provide best practice software templates to allow machine builders to produce high-quality code for their machine controllers.

    PackML introduces the concept of machine modes and states. The modes represent the different fundamental operations of the machine, whereas the base state machine provided by PackML can be customised to model the behaviour of the machine for a given operational mode. The result is operating software that adopts a clean and common structure and terminology. Machines designed using PackML from first principles should be easier to maintain compared to non-PackML machines that often suffer from ‘spaghetti code’.

    Machines built upon PackML typically adopt the ‘Make2Pack’ modular coding standard, defined as part of ISA 88.00.05. Although this isn’t actually mandated by the PackML standard, it fits well with PackML by enforcing logically separate software modules known as ‘equipment modules’ and ‘control modules’. Such a structure leads to software modules with lower coupling that are highly cohesive and readily reusable. Numerous examples exist of machine builders that were able to rapidly create new machines by reusing existing PackML and Make2Pack software modules.

    Automation vendors that provide the machine controllers also typically offer ‘PackML templates’ directly within their automation development environments. These templates provide a PackML ‘quick-start’ for programmers, to allow machine builders to quickly and easily adopt PackML within their products. Such PackML templates include the boilerplate coding structure, standard naming conventions and sometimes HMI templates, allowing the development to be focused on the value-added, rather than on the low level technical details.

    From an end user and integrator perspective, the real benefits of PackML are all about common elements between different machines, irrespective of the provider. If the fundamental control platform of each machine is designed using PackML, it’s not too much of a leap for lower-skilled operators to move between multiple different machines without the need for extensive training. Operators familiar with PackML will be aware of the fundamental concept of changing modes on the machine to perform different operations, and the concept of issuing commands to navigating the state model. They will also be aware of the common PackML terminology and definitions.

    If PackML is adopted across an entire line, PackML states can often serve as a diagnostics mechanism to identify the reason for unplanned downtime. Some end users even go to the lengths of having their own internal maintenance teams who have the skills required to modify PLC code in order to troubleshoot machine failures. In such cases, PackML can simplify is process by providing a platform that’s familiar to the maintenance team, leading to quicker and more reliable fixes.

    PackML and Product Inspection Equipment

    PackML offers different benefits to different types of users. As a supplier of product inspection solutions, Mettler-Toledo could reasonably be described as a provider of auxiliary packaging equipment, as opposed to a provider of large primary packaging machinery. So far, the emphasis for us has been on leveraging PackML in combination with a range of industry standard communications protocols to provide a standards-based interface for reporting machine state and performance information e.g. Overall Equipment Effectiveness (OEE), ultimately making our solutions easier to work with for both end users and integrators. Having said that, however, we’re always considering ways we can further realise some of the additional benefits PackML offers as part of our new product developments.

    Lee Smith will be speaking in Copenhagen, Denmark on March 15-16. His OMAC presentation (The Organization for Machine Automation and Control) will cover the implementation of PackML across a range of in-line product inspection solutions, including checkweighing, metal detection, vision and x-ray inspection systems.

    In next week’s blog, I’ll explain how PackML’s evolved over the years and what the future has in store. In the meantime, please add any comments below.

    PackML & OPC UA Seminar – Microsoft Development Center, Copenhagen, Denmark

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