The digital age has thrust us into a new paradigm regarding how we manage our assets and operations. We are fortunate that it is driving more affordable sensing, storage and processing, but the seemingly myriad opportunities may leave one feeling paralysed. Thus, it is important to continue to ask oneself fundamental questions along the way and be analytical.
Another by-product of our digital age is the increased desire to digitally connect production elements within the value chains from CAD model information including production data and continuing through reuse-recycle-disposal. This concept has been referred to as the ‘digital thread’ or ‘tapestry’ whereby the analogy conveys the inter-related role that digitisation plays in collecting, connecting, storing, analysing, and utilising data.
Next-generation manufacturing solutions
In this context, the MTConnect standard is a tool, which is helping enable the next generation manufacturing by allowing communication between different types and brands of devices on the factory floor. Getting started with MTConnect requires little more than a survey of a facility’s capabilities, an assessment of needs and an evaluation of current and near-future vendor solutions available.
As a data standard, application areas for MTConnect are primarily limited by customer needs and vendor implementations. Making data available in a non-proprietary, open format is simply a pre-requisite for next generation manufacturing solutions. The most exciting applications of MTConnect are not the ones that have already been invented, but those that have yet to be imagined.
Data communication standard
The MTConnect Standard is an open, royalty-free data communication standard that defines and structures data collected from devices, such as, manufacturing technology equipment. The standard specifies unique identifiers such as data tags, along with unambiguous meaning. The standard also specifies a hierarchical structure and provides a reference schema for storing and transporting the data to requesting software applications for other devices.
Common uses of the tool
Machine tool builders and distributors are increasingly fielding customer requests for digital manufacturing applications like factory monitoring, predictive or condition-based maintenance, remote access or control and more. Some customers specifically request MTConnect, after gaining a basic understanding of the standard, its capabilities and limitations, how it works with other technologies, and development requirements, which makes for higher customer satisfaction and better sales performance.
Factory or machine monitoring is the most common use case for MTConnect today. Machines that support the standard enable a wide range of software applications for realtime or historic status reporting. The most common function is automatically reporting utilisation. Utilisation refers to the ‘green light’ time, or a measure of machine uptime. More sophisticated applications offer down time analysis. Using MTConnect data on its own, or using it in combination with operator input, downtime analysis adds a layer of explanation for different categories of down time. The categories of downtime vary from company to company, but generally include things like scheduled maintenance, unscheduled maintenance, waiting for material, waiting for tooling, etc.
Overall equipment effectiveness (OEE)
Most factory monitoring suites show a calculation for Overall Equipment Effectiveness or OEE. This is a statistical process control measure that takes into account availability, performance, and quality. MTConnect data from a machine control can provide availability by automatically logging utilisation. Performance uses a combination of data from a control and from engineering on how fast a process runs versus how fast it could run. Quality depends on defect data that usually comes from a source other than the machine control.
MTConnect is also an enabling technology for machine or system control and integration. Applications for controlling a machine, robot, part loader or automated system can use the standard tool to simplify communication between components. For e.g., MTConnect is able to pass information about current states and statuses between machines. This functionality, known as interfaces within the standard, has been implemented in a test environment with robots and is commercially available today for some bar feeders. Development is underway on bringing interfaces to other common machine accessories like probes and on-machine gaging.
Creating order from chaos
There are a few semantic dictionaries in the world of IIoT, where context is key. Regarding structured data, tagging and defining are the essential steps to create order from chaos. Other communication protocols have only recently begun to develop such dictionaries. For example, BACnet for building and controls networks are developing a concept for applying data tags from various dictionaries to BACnet objects and their abstract data model, BACnet XD.
MTConnect is that semantic dictionary for the manufacturing technology world. Where elements have already been defined, such as tooling under ISO 13399, then MTConnect creates a Reference Specification to use the pre-existing ISO 13399 data items. The same is true for when a semantic dictionary is missing but is necessary for other transport protocols such as OPC-binary transport, which is included within OPC’s Unified Architecture (infrastructure layer). OPC UA provides this transport protocol that defines the rules of transport between OPC servers and devices; analogous to defining the ‘piping system’ but does not fully define the fluid moving through the pipe.
Staying true to this analogy, MTConnect, as an Industry Standard Information Model, identifies and defines that ‘fluid’directly and unambiguously. For such cases, the tool generally co-develops a companion specification to those complimentary protocols/standards. It is complimentary to OPC UA and as such, has a Companion Specification for OPC UA, which is currently being updated for the latest MTConnect v1.4 release, similar to the BACnet, which also has a companion specification with OPC UA. All of these fundamental technologies are necessary to realise Industry 4.0-based strategies.
Future application areas for MTConnect data include process optimisation and, eventually, fully autonomous operation. Applying machine learning and algorithms to manufacturing processes holds promise for the near future, but most applications are still in the R&D phase. One particularly promising application area is predictive or condition-based maintenance. Most equipment undergoes preventative maintenance on a predetermined schedule. By applying machine learning, requests for maintenance can be triggered based on actual conditions rather than a pre-ordained schedule. This will save time and money by avoiding unnecessary maintenance and premature breakdowns prior to a scheduled maintenance interval.
Finally, MTConnect data has been experimentally used for optimisation, tuning, and real-time feedback. Fine tuning a manufacturing process on the fly requires input from sources including a machine or control, sensors, tooling, etc. For example, a vibration sensor may be able to detect damaging harmonics in a metal cutting process and automatically adjust or pulse cutting speeds to overcome the harmonic resonance. Thus, MTConnect-enabled devices have more data available as inputs to real-time optimisation software and control systems. Real-world, commercial applications are just starting to see the light of day but are expected to proliferate rapidly in the next 5-10 years.
The article is authored by Tim Shinbara, VP - Technology, AMT and Russell Waddell, Managing Director, MTConnect Institute