Sound the alarm: Standards that help you deal with the unexpected
One of the best ways to save energy and minimize waste is to better manage your processes and know what is going on every step of the way. ISA is trying to help manufacturers do this, with three standards committees that are focused on developing documents to improve the way we work with our control systems and their human machine interfaces (HMIs).
The oldest of these standards is the ISA-18 series on “Instrument Signals and Alarms,” which includes the ISA-18.1 standard on annunciators, sequences and specifications. The ISA-18.2 series of documents, however, is presently before the IEC to become a global standard, and this is more relevant to modern alarm systems. (Note that the keywords “alarm systems” are now being used when referring to taking control and managing the data used to inform you of an abnormal situation.) The committee released three documents — “Enhanced and Advanced Alarm Methods,” “Alarm Monitoring, Assessment and Audit,” and “Alarm Design for Batch and Discrete Processes” — in 2012. They plan to complete an additional four documents — “Alarm Philosophy,” “Alarm Identification and Rationalization,” “Basic Alarm Design,” and “Alarm Management for Packaged Equipment” — this year before submitting all seven documents to the IEC.
With an effective alarm design process in place through ISA-18, the resulting information then has to be presented to the operator. This is where the second series of standards, ISA-101, comes into play. ISA-101 documents on “Human Machine Interfaces” are intended for those responsible for designing, implementing, using and/or managing HMIs in manufacturing applications. The documents will include such items as: menu hierarchies; screen navigation conventions; graphics and colour conventions; dynamic elements; alarming conventions; security methods and electronic signature attributes; interfaces with background programming and historical databases; popup conventions, help screens and methods used to work with alarms; program object interfaces; and configuration interfaces to databases, servers and networks.
These two standards are starting to take advantage of networks and device intelligence by incorporating device health information into the associated logic, reports and displays. As part of its recommendations, ISA-101 recommends that a status matrix or status box adjacent be associated with each tag/control loop. The philosophy is to use colour to display an abnormal situation so that an operator can quickly identify that something is happening and start the corrective action process.
It is all well and good to know that something is happening in your facility; however, the important part is how you respond to the situation. This is where the third of the ISA standards, ISA-106 “Procedure Automation for Continuous Process Operations,” helps by automating the response from the control system to either take action directly or provide direction to the operator on how to respond to events that do not occur regularly. To do this, ISA-106 develops standards, recommended practices and technical reports on the design and implementation of procedures for automating continuous process operations. They do this by providing guidance on: models and terminology; modularization of procedural steps to foster re-use and lower total cost of ownership; exception handling for abnormal situations; physical, procedural and application models; process unit orientation with operational perspective; recommended best practices; implementation of startup, shutdown, abnormal situations, hold states and transition logic; recommended target platform (i.e., control system vs. safety system) for different types of procedures; life cycle management best practices; and training and certification best practices for continuous processing applications. Effectively, the tools that ISA-106 provide allow you as an operator to not only capture best practices for your facility from all the knowledge that will soon be retiring, but in doing so will also increase your compliance with regulations while providing a documented procedure in the rare event something out of the ordinary does happen.
We have not yet perfected the HMI and likely never will; however, we are getting better at taking into consideration how we interact with our control systems and the new information now available to us. I may not always know what I am doing, but with the new standards and practices available today, I can now at least quickly see how I am doing, which is certainly a step in the right direction for managing our processes to operate most efficiently, saving energy and minimizing waste in the process.
This column originally appeared in the March/April 2014 issue of Manufacturing AUTOMATION.
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