SACAC Newsletter – December 2016 | Download Newsletter (PDF – 900Kb)
Message from the President – Otis Nyandoro
Typically the year of a SACAC president starts upon election at the annual AGM. As I look back from the AGM at the beginning of the year at Forum Homini at the Cradle of Humankind a lot has happened over the last couple of months. The AGM’s keynote presentation was done by Professor Margret Bauer who reflected on her experiences at ABB in Germany. Her reflections on the recent developments of the Internet of Things for Control Applications and Automation were well received. The occasion was graced by the SAIEE President. As the national member organisation for the International Federation of Automatic Control, SACAC’s goal for more than five decades of its existence has been to maintain a formal association with IFAC.
To this end a number of key IFAC events have been hosted in South Africa. These have included the most memorable 2014 IFAC World Congress. A number of SACAC individuals continue to hold key roles in IFAC in technical committees and other administrative committees. Another key goal has been to continually organise workshops that are relevant to its members. A key addition to the workshops has been to offer workshops to members especially outside of Gauteng. SACAC has also seen more workshops added to its offering list with workshops such as the Observer Design workshop, Modern Techniques and Software for Process Control and the more typical workshops such as Functional Design Specifications Workshop. The postgraduate students continue to annually hold the Control Systems Day, which was hosted in November at the North West University.
The year started off with the AGM and looking to the future we would like to invite our members to the AGM to be held in February 2017. Future events to look forward to are the Control Conference for Africa to be held from the 7th to the 8th of December 2017 and also IFAC’s MMM Symposium to be held in 2019. We would like to encourage our members to take part in the organisation and participation of these major events.
Past SACAC events
Over the past year, SACAC presented three quality workshops:
1. Modern Techniques and Software for Process Control
The first took place at Mintek (Johannesburg) on 21 July 2016 and was titled Modern Techniques and Software for Process Control. The case was made for the ability of model predictive control (MPC) to address the increasingly stringent control demands required by industry, especially in the presence of significant noise and disturbances.
Dr Kevin Brooks from BluESP started by showcasing the ability of modern software to derive accurate multi-variable empirical plant models relatively quickly through the use of appropriate multi-stepping methods. These models are consequently used in a linear-MPC structure once the control aims are encapsulated in an appropriate cost function. Dr Loutjie Coetzee from Mintek continued with the application of nonlinear MPC to a grinding mill circuit by way of an example. By altering the cost function to emphasise different economic goals, attendees were shown the different responses of the manipulated and controlled variables.
The added benefit of the workshop was the opportunity for attendees to experiment with software packages (AspenTech and MillStar on StarCS) to develop and apply their own MPC structures. Although it is desirable to use a detailed fundamental models of a process in for example non-linear MPC, the challenge is often to measure the unknown states and parameters.
2. Observer Design
On 21 October 2016, Mr Derik le Roux from the University of Pretoria presented a workshop titled Observer Design to address this issue. The aim was to equip attendees with the necessary tools to determine which states and parameters of an observer model can be estimated with reasonable accuracy from available measurements. Once observability requirements were established, Extended Kalman Filtering was shown as a means to observe unknown states and parameters. A benefit of the workshop was the detailed notes and code supplied to attendees to develop observers for their own systems. A note of thanks is extended to Opti-Num Solutions for supplying attendees with the necessary software to experiment with different observers.
3. Control Systems Day 2016
The annual Control Systems Day was held at the North-West University (NWU) on 28 October 2016. This was an opportunity for postgraduate students involved with control and automation to present and discuss their research with other students. Themes varied from fault detection and plant performance evaluation using different data analysis techniques, to the investigation of different modelling approaches to describe complex processes. Dr Kenny Uren, lecturer at NWU and organiser of the event, also gave attendees a tour of the comprehensive laboratory facilities available to students at NWU. We thank the postgraduate students from Stellenbosch University, University of Witwatersrand, University of Pretoria, and North-West University for presenting quality research.
Future SACAC events
Control Conference Africa 2017
SACAC is proud to host The Control Conference Africa (CCA 2017) from 7 to 8 December 2017 at the historical Liliesleaf Farm (Johannesburg). CCA 2017 promotes the exchange of ideas and developments in control engineering in Africa and builds on previous South African events in control engineering. The conference specifically addresses control engineers from African countries, African control engineers based abroad who wish to reconnect to their roots, and all control engineers who want to connect with Africa. Both academic and industrial control engineering practitioners have the opportunity to present their work and exchange research ideas with colleagues from across the globe.
One of the keynote addresses will be done by Prof David Limebeer (University of Oxford). David received his Ph.D from the University of Kwazulu-Natal, South Africa, in 1980, and became Professor of Control Engineering at the University of Oxford in 2009. His research interests include applied and theoretical problems in robust, optimal, and process control, as well as the control of aeroelastic phenomena in large structures. Another keynote address will be given by Prof Babatunde Ogunnaike. He was born and bred in Nigeria, received his Ph.D from the University of Wisconsin-Madison, and is now the Dean of the College of Engineering at the University of Delaware. In 2012 he was elected to fellowship of the Nigerian Academy of Engineering and to the US National Academy of Engineering. Prof Bozenna Pasik-Duncan, Professor of Mathematics at University of Kansas (KU), will also give a keynote address. She is a Fellow of IEEE, a Fellow of IFAC, and recipient of the IEEE Third Millennium Medal, and the IEEE CSS Distinguished Member Award. She is founder of IEEE Women in Control. Her research interests are primarily in stochastic systems and adaptive control, and STEM education.
The keynote addresses above are only three of six prestigious addresses planned for the event. Articles or posters to be presented at the conference can be submitted until 2 May 2017, and registration for the event opens on 31 July 2017. Further information can be found on the SACAC website.
For more information, see the First Call for Papers at: http://sacac.org.za/pages/cca/
2019 MMM Symposium
The South African Council of Automation and Control is pleased to announce that it has been awarded the right to host the 2019 Metals, Mining and Minerals MMM Symposium In South Africa. This prestigious symposium is hosted under the auspices of the International Federation of Automatic Control (IFAC), and is only held every three years.
While 2019 may seem far away, the IFAC cycle is a long one, and SACAC had to present its proposal at the recent 2016 Symposium held in Vienna. Dr Lidia Auret, co-chair of the national organising committee, presented our proposal, which sets down the beautiful town of Stellenbosch as the venue. Lidia will co-chair with Dr Kevin Brooks of BluESP, immediate past-president of SACAC. We are fortunate in having the agreement of Professor Chris Aldrich, once of Stellenbosch but now at Curtin University in Perth, to act as chair of the International Programme Committee.
Symposium on Control, Optimisation and Automation in Mining, Mineral and Metal Processing
The 17th IFAC Symposium on Control, Optimisation and Automation in Mining, Mineral and Metal Processing took place from 31 August to 2 September 2016 in the beautiful city of Vienna (Austria). SACAC and South African institutions/companies were well-represented, with ten authors and eight papers. These papers covered aspects of grinding mill modelling, control and optimisation; model predictive control of a coal dense medium drum separator; computer vision based monitoring of spiral concentrators; and seat suspension control for mining dump trucks. (All papers from the conference are available on IFAC-PapersOnLine at www.sciencedirect.com/science/journal/24058963/49/20).
The conference featured new Future Perspective sessions, where industry experts discussed future challenges in control, optimisation and automation in mining, mineral, and metal processing. Industry 4.0 and process data analytics were also discussed in plenary sessions. The hosts of future IFAC MMM events were finalised at a technical committee meeting, with Shangai (China) awarded the MMM 2018 Workshop, and Stellenbosch (South Africa) awarded the MMM 2019 Symposium.
SACAC would like to thank each and every SACAC EXCO member for their valuable contribution to the success of SACAC during the course of this year.
Dr Lidia Auret obtained BEng (2007) and PhD (2010) degrees from the Department of Process Engineering at Stellenbosch University. The topic of her PhD dissertation was “Unsupervised process monitoring with random forests”. Employed as a lecturer at Process Engineering (Stellenbosch University) since 2012, her undergraduate responsibilities include lecturing dynamic modelling and process control, while postgraduate research projects under her supervision in process monitoring, modelling and control topics with extractive metallurgy applications have been funded by various industrial sponsors. Dr Auret also serves on the executive committee of the Western Cape branch of the Southern African Institute of Mining and Metallurgy ..
Margret Bauer is an Associate Professor in the School of Electrical and Information Engineering at the University of the Witwatersrand, Johannesburg, South Africa, since 2014. Prior to her current engagement Margret worked for ABB Corporate Research, Germany, focusing on operational technology topics in chemicals, petrochemicals, pulp & paper, minerals and metals since 2005. She has worked and published in the areas of process control, integration of industrial software systems and operations management.
Margret received her PhD from University College London, UK, in 2002 and her Master’s degree in electrical engineering from the University of Erlangen-Nuremberg, Germany. From 2005-2006 she was a postdoctoral fellow and recipient of the Claude-Leon-Fellowship, as well as the fellowship of the National Research Foundation at the University of Pretoria, South Africa. She was appointed as associate professor at the University of Johannesburg, South Africa. Margret’s research interest is on data analytics and big data for process control, recently focusing on the sensor’s lifecycle. She is currently involved in organising the Control Conference Africa 2017.
Prof Samuel John (PhD) is an Associate Professor of Mechanical Engineering at the Namibia University of Science and Technology (NUST). He obtained his BEng and MSc degrees from the Ahmadu Bello University, Zaria, Nigeria in 1978 and 1992 respectively, and a PhD from the University of the Witwatersrand, Johannesburg, South Africa in 2012. Prof John’s research interest is largely in the field of linear, non-linear and artificial intelligent control systems and renewable energy. Prof John is currently the Dean of the Faculty of Engineering of the Namibia University of Science and Technology (NUST). His university teaching and research career spans over 25 years. Of this, he has over 10 years experience in academic administration and leadership. He serves as a reviewer of several high-impact journals. He is a visiting professor at the University of Applied Science, RheinMain, Germany and holds an academic title of Research Associate Professor of the University of New Mexico, USA. Samuel is also an integral part of the Local Organising Committee for the Control Conference Africa 2017.
Sponsorships to attend IFAC events
The triennial IFAC World Congress is one of the most prestigious events for control engineers across the globe. SACAC’s IFAC 2017 World Congress Author Sponsorship aims to enable employees and students of SACAC’s industrial and institutional members to participate in this international event. The next congress will be held in Toulouse (France) from 9 to 14 July 2017, and expects to draw more than 2500 delegates from across the globe. Sponsorship will be provided to two delegates from SACAC’s industrial members and two delegates from SACAC’s institutional members to present articles at the congress. Application for the sponsorship closes on 3 March 2017, and the sponsorship will be awarded by 17 March 2017.
SACAC is pleased to announce that Mr Ernst Nienaber from Stellenbosch University is the winner of the SACAC Conference Author Sponsorship for 2016. This yearly sponsorship launched in 2016 aims to enable a delegate of one of SACAC’s members to participate in an international IFAC conference. Mr Nienaber received this sponsorship for his paper titled: “Spiral Concentrator Interface Monitoring through Image Processing” as presented at the 17th IFAC Symposium on Control, Optimisation and Automation in Mining, Mineral and Metal Processing in Vienna (Austria) held from 31 August to 2 September.
I EC 61131, 61850, 61499 and the Future of Automation
The Industrial revolution and the computer age gave birth to the Automation Industry which in turn has given rise to ever more complex machines ranging from the simple repetitive boolean logic state machines to very complex expert systems and machine learning type controllers now making up the vast array of automation equipment available in the market place. Many vendors have come to market offering their versions of the most suitable and powerful controllers to address the manufacturing, processing or materials handling industry needs, some of which were originally completely proprietary and others that claimed openness and interoperability with equipment from other vendors. So, as has been necessary with most technologies in the world, standardisation of the technologies and machines became paramount in order to protect and future proof the user’s installations, businesses and investments.
The first of such standards, IEC 61131 was drawn up and published by the International Electro-technical Commission to bring about some uniformity in the programming of automation controllers. This proved adequate for most industrial needs but soon thereafter the Power Utility Industry initiated the development and publication of IEC 61850 for utilities and electrical substation automation. Besides these, the proliferation of integrated controllers in consumer products besides those for mining, manufacturing, materials handling or Electricity distribution, also brought about the development and publication of IEC 61499 for embedded control systems. But is there a common thread between all these standards and technologies that have been developed for the different industries that each of the industries should sit up and take note of? It can be expected that this is very much the case and so, besides the ongoing development of each industry’s’ approaches, it may be prudent for each of the Technical Committees to examine the other’s approach and solutions and consider adopting (or adapting) some of those aspects in their own space. A summary is given below of each standard and its particular approach and solution and then some suggestions are made for assimilation of the good practices in one industry to that of the other.
IEC 61131-3 is the international standard for programmable controller (PLC) programming languages. As such, it specifies the syntax, semantics and display for the following suite of PLC programming languages:
· Ladder diagram (LD)
· Sequential Function Charts (SFC)
· Function Block Diagram (FBD)
· Structured Text (ST)
· Instruction List (IL)
IEC 61131-3 is the third component (Part 3) of IEC 61131 family that consists of:
· Part 1 General Overview
· Part 2 Hardware
· Part 3 Programming Languages
· Part 4 User Guidelines
· Part 5 Communication
The easiest way to view the standard is to split it into two parts, Common Elements and Programming Languages, where the common elements cover issues such as data types, syntax, tasks and program organization. This standard is therefore focused mainly on common structure and uniformity of the hardware and software of a controller but is very lean on interfacing or interoperability between hardware and software components or other systems. IEC 61850 is a standard for vendor-agnostic engineering and the configuration of Intelligent Electronic Devices (IED) for electrical substation automation systems to be able to communicate with each other. IEC 61850 is a part of the International Electrotechnical Commission’s (IEC) Technical Committee 57 (TC57) reference architecture for electric power systems. The abstract data models defined in IEC 61850 can be mapped to a number of protocols. Current mappings in the standard are to MMS (Manufacturing Message Specification), GOOSE (Generic Object Oriented Substation Event), SMV (Sampled Measured Values) and soon to Web Services.
These protocols can run over TCP/IP networks or substation LANs using high speed switched Ethernet to obtain the necessary response times below four milliseconds for protective relaying. This standard is therefore focused mainly on interfacing and interoperability as opposed to the programming of the IEDs; although there is some developed in progress by the technical committee to bring in boolean logic functionality such as those defined in IEC 61131 into the 61850 standards suite.
Some TC members have even suggested simply adopting and referring to 61131 in 61850 so that vendors can provide an already well established programming platform for any logic functions, such as master trip logic or auto reclose logic that may be required in an IED type protection relay. What is however extremely important to note in this standard is that the interface and messaging configuration and programming of the IED according to IEC 61850 follows a typical commercial software developed approach, right down to use cases, objects, classes and UML modelling thereby bringing it much closer to the software industry than traditional boolean logic, and exposing standard interfaces for interoperability that are simply not available in STL, LAD, CSF, etc. In fact, the interoperability framework from IEC 61850 would be ideal to be adopted in IEC 61131 to improve interoperability between programming in separate PLC’s and even between the PLC and it’s HMI/SCADA system rather than using the widespread OPC solution at present. Furthermore the high level of accuracy in date and time stamping of control events would also be hugely beneficial in the PLC world.
The complete standard consists of the following parts detailed in separate IEC documents:
● IEC 61850-1: Introduction and overview
● IEC 61850-2: Glossary
● IEC 61850-3: General requirements
● IEC 61850-4: System and project management – Ed.2
● IEC 61850-5: Communication requirements for functions and device models
● IEC 61850-6: Configuration language for communication in electrical substations related to IEDs – Ed.2
● IEC 61850-7: Basic communication structure for substation and feeder equipment IEC 61850-7-1: Principles and models – Ed.2
● IEC 61850-7-2: Abstract communication service interface (ACSI) – Ed.2
● IEC 61850-7-3: Common Data Classes – Ed.2
● IEC 61850-7-4: Compatible logical node classes and data classes – Ed.2
● IEC 61850-7-10: Communication networks and systems in power utility automation – Requirements for web-based and structured access to the IEC 61850 information models [Approved new work]
● IEC 61850-8: Specific communication service mapping (SCSM) IEC 61850-8-1: Mappings to MMS (ISO/IEC 9506-1 and ISO/IEC 9506-2) – Ed.2
● IEC 61850-9: Specific communication service mapping (SCSM) IEC 61850-9-1: Sampled values over serial unidirectional multidrop point to point link
● IEC 61850-9-2: Sampled values over ISO/IEC 802-3 – Ed.2
● IEC 61850-9-3: Precision Time Protocol Profile for Power Utility Automation (IEEE C37.238-2011)
● IEC 61850-10: Conformance testing
Most recently, the international standard IEC 61499 , addressing the topic of function blocks for industrial process measurement and control systems, was initially published in 2005. The specification of IEC 61499 defines a generic model for distributed control systems and is based on the IEC 61131 standard. Where IEC 61131 aims to define the hardware and software of a standalone/ single PLC in isolation, IEC 61499-1 defines the architecture for distributed systems of controllers. In IEC 61499 the cyclic execution model of IEC 61131 is replaced by an event driven execution model. The event driven execution model allows an explicit specification of the execution order of function blocks. If necessary, periodically executed applications can be implemented by using the E_CYCLE function block for the generation of periodic events as described in Annex A of IEC 61499-1. IEC 61499 enables an application-centric design, in which one or more applications, defined by networks of interconnected functional blocks, are created for the whole system and subsequently distributed to the available devices. All devices within a system are described within a device model. The topology of the system is reflected by the system model. The distribution of an application is described within the mapping model. Therefore, applications of a system are distributable but maintained together.
Application and device model of IEC 61499 ; Like IEC 61131-3 function blocks, IEC 61499 function block types specify both an interface and an implementation. In contrast to IEC 61131-3, an IEC 61499 interface contains event inputs and outputs in addition to data inputs and outputs. Events can be associated with data inputs and outputs by WITH constraints. IEC 61499 defines several function block types, all of which can contain a behaviour description in terms of service sequences:
● Service interface function block – SIFB: The source code is hidden and its functionality is only described by service sequences.
● Basic function block – BFB: Its functionality is described in terms of an Execution Control Chart (ECC), which is similar to a state diagram (UML). Every state can have several actions. Each action references one or zero algorithms and one or zero events. Algorithms can be implemented as defined in compliant standards.
● Composite function block – CFB: Its functionality is defined by a function block network.
● Adapter interfaces: An adapter interface is not a real function block. It combines several events and data connections within one connection and provides an interface concept to separate specification and implementation.
● Sub Application: Its functionality is also defined as a function block network. In contrast to CFBs, sub applications can be distributed.
To maintain the applications on a device, IEC 61499 provides a management model. The device manager maintains the lifecycle of any resource and manages the communication with the software tools (e.g., configuration tool, agent) via management commands. Through the interface of the software tool and the management commands, online reconfiguration of IEC 61499 applications can be realized. It therefore appears to be a standard that uses aspects of both IEC 61131 and IEC 61850 in its fundamental thinking, however industry uptake, vendor products capable of 61499 and relevant software development tools have been slow to market and it is suspected that this is due to the already large installed base and familiarity of PLC, DCS and substation automation equipment historically deployed in the market place.
Nevertheless, IEC 61499 is touted as the New Standard in Automation and it is expected that as the industry and controller vendors become more familiar with it, realise its benefits and potential, and the market demands products with 61499 capability, this standard will eventual roll out to the various industries. For the moment the biggest uptake is in embedded controllers in consumer products and systems as opposed to industrial and/ or utility automation.
his article was provided by Alfred K Schroder, Senior Automation, Control and Instrumentation Engineer, Aurecon Consulting Engineers South Africa