(Editor’s note: This is the second article of two articles.)
Pipeline controllers work in an environment with continuous interruptions and distractions. With every new SCADA upgrade there is the potential to increase the amount of information presented on the displays, causing the amount of distraction to grow side by side with industry innovation.
Such distractions can become “noise,” confusing or distracting a pipeline controller from making timely decisions that affect the safe operation of the pipeline.
To help operators cut down on such noise while ensuring they provide adequate information to better manage processes and controls in both normal and abnormal situations, this article will identify areas to consider when implementing a human machine interface (HMI) on a SCADA system.
Whenever a SCADA system is added, expanded or replaced, API RP 1165 now requires evidence that Sections 1, 4, 8, 9, 11.1 and 11.3 have been properly implemented.
As part of formulating programs for new control room management requirements, many pipeline companies have reviewed SCADA displays to determine if best practices have been followed – even if the company was not in the process of changing its SCADA systems.
API RP 1165 provides guidance with specific examples on navigation, colors, fonts, symbols, data entry and control/selection methodologies. However, much is to be gained in the quality of information presented. For example, focusing on the fundamentals of good graphic presentations ensures that pipeline information is presented in the clearest way possible, providing good situational awareness and mitigating eye strain and fatigue.
Good Display Design
The Gestalt principles as stated in Section 4 of API RP 1165 provide extremely useful guidelines that, if followed, will ensure an orderly and clutter-free appearance with obvious indications of important interrelationships. The following principles should be used to evaluate pipeline SCADA displays relative to fundamental good display design:
Human perception wants to organize objects into groups, if they are near each other. Therefore, group-related information in close proximity to the source of the data, paying close attention to ensure the location is in the correct position in relation to hydraulic values, for example.
Make sure objects perceived as groups share common properties such as size, color, orientation in space or brightness.
• Effective use of white (blank) space can improve group identification.
• Ensure dynamic information is easily identified by including static labels, but avoid using static text colors that could represent abnormal operating conditions.
Stability; presentation of information at right angles in a vertical or horizontal group is easier to perceive than curved or angled visual images.
• Ensure proper alignment of all information whenever possible to reduce eye strain and organize related data.
• Use of white space improves readability and reduces data density.
Signal to Noise
Information overload must be carefully avoided. If information is not useful it should be considered noise.
• If units are well-known and understood, then including units on every level of displays may be considered noise.
• Colons (:) are noise. Periods (.) are noise. Fuzzy or overly detailed symbols are noise.
• Pipeline specific tabulars have a good signal to noise ratio. The tabulars can be a pipeline dashboard complete with navigational links and should not be discounted due to lack of visual pipeline context.
• Pipeline controllers should provide feedback regarding information that does not provide value.
HMI Factors to Consider
When addressing the specific best practices mentioned in API RP 1165, these general factors should be assessed:
• Appropriateness in level of detail for the hierarchy level of a display.
• Difficulty in navigation, such as too many clicks required to complete a task.
• Avoidance of inadvertent distractions, such as animations.
• Consistency across the console, including integration of third-party applications within the SCADA environment, including leak detection.
• Depiction of flow paths consistently among displays in which flow direction is important
• The use of coding that provides visual cues including color, shape and labeling for shapes and symbols
Use of Maps
Many companies like to use a geographic map as a navigational tool, overlaying it to provide high-level information, such as real-time values or alarm indication. Careful selection of an image or vector map is needed to avoid potential background noise that distracts from the value of the data in its spatial context.
The Abnormal Situation Management (ASM) Consortium guideline for effective operator display design is referenced in the API 1165 recommended practice and is gaining momentum in the SCADA industry.
Before a pipeline organization adopts the ASM display guidelines for its controller consoles, it is important to keep in mind that their SCADA is different from the process industries that ASM is rooted in. In pipeline SCADA not only are values displayed indicating the current condition of a device such as if the data is current and updating, but displays also show if it’s off-scan, or manually overwritten.
As pipelines span long distances with multiple communication channels that are subject to intermittent failures, information can be stale or temporarily unavailable for part of the process, while still providing adequate information for the remainder of the process.
The other consideration is the supervisory nature of SCADA. If there is a situation developing upstream on a pipeline, there is more time to take action and alter the outcome than there would be in a typical plant environment in which all equipment is in close proximity. It is this latency in the supervisory information that makes SCADA unique.
As the ASM Consortium guidelines for planning, designing and implementing effective operator displays are applied to pipeline SCADA, these unique considerations should be addressed and become part of the evolving guidelines.
High Performance Training
One of the outcomes of the CRM regulations has been the need to hire many more pipeline controllers to ensure that operators can meet the “hours of service” requirements relative to fatigue mitigation. An operator’s program must provide training for controllers who carry out the roles and responsibilities defined by the operator, including responding to abnormal operating conditions. Computerized simulation is recognized as a best practice for training controllers.
In order to reduce training time and allow new controllers to experience realistic pipeline behavior – using the tools they’ll use to run the pipeline – a pipeline simulator with the same HMI as the SCADA system provides a great advantage. Pipeline simulation technology can provide realistic, repeatable and unbiased assessments of each controller’s skills and abilities in a neutral setting.
Some vendors provide both full scope and generic pipeline training simulators integrated with its SCADA systems. A “full scope” trainer provides an exact representation of a pipeline. Complete with the logic for key control elements of the pipelines, it gives the best possible training simulation experience for controllers.
Generic trainers provide simulated operating scenarios based on real pipelines, but the pipelines used are not the actual ones a controller would operate. This key differentiator addresses the maintenance requirement to continually update the model to match the changes made to the pipeline assets, while providing a representative pipeline with common equipment and operational tasks.
The incorporation of API RP 1165 into pipeline safety regulations is intended to ensure that pipeline operator’s SCADA system HMI graphics are an effective tool for the safe and efficient control of the processes, in both normal and abnormal situations.
By complementing its recommendations along with the basics of good graphic presentations combined with a comprehensive training program, pipeline operators should be confident they are meeting the regulatory requirements for pipeline SCADA displays and providing adequate information.
Authors: Lars Larsson is a senior product manager at Schneider Electric with over 22 years of oil and gas pipeline industry experience from system design to commissioning and support. He earned bachelor’s degrees in process automation from Telemark Technical College in Norway and in control engineering from the University of Sheffield, UK.
Kelly Doran is an industry solution architect at Schneider Electric and works with the liquids suite, which includes several leak detection applications. He has trained hundreds of pipeline controllers on new or upgraded SCADA systems.