How to upgrade to a high-performance HMI
在开始硬件和软件升级项目时，应考虑实现高性能人机界面(hp - hmi)图形，以便更好地控制制造过程和系统。
A new industrial age is upon us and with it comes a wave of innovative technology such as machine learning, artificial intelligence (AI), virtual reality (VR) and augmented reality (AR). These leading-edge technologies are adding value to businesses and, even more important, are creating safer work environments. The manufacturing sector is beginning to embrace this next level of automation to improve their processes and upgrade or replace their outdated control systems and software. For many, it is a great opportunity to innovate and not replicate their systems and software.
To leverage the latest technology and ensure manufacturing processes continue to run smoothly, attention should be paid to the human-machine interface (HMI), which is a tool operators use on a daily basis. HMI graphics are used in every aspect of a process control system and are key to getting critical data to the right people at the right time. The move to high-performance HMIs will help improve an operator’s ability to manage operations effectively and increase response time to alarms and other abnormal situations.
Depending on its size and scope, a high-performance HMI upgrade can be fraught with challenges and may require a significant investment in time and resources. However, the benefits realized from a high-performance-HMI far outweigh the upfront investment.
Early HMI design issues
One of the greatest challenges in upgrading legacy HMI revolves around the existing design and converting the screens to a new or different format. In the early days, when control systems became sophisticated enough to have real-time process control graphics, personnel were tasked with developing the graphics (see Figure 1). In most cases, they created them using piping and instrumentation diagrams (P&IDs) and came up with their own set of best practices, trying to determine what “good” looked like. It worked for the most part.
Over the years, however, facilities may have had multiple personnel involved in creating their HMI graphics, which introduced inconsistencies in color and alarms. The graphics sported eye-catching colors but tended to cause operator confusion, making it difficult to see at a glance whether a process was running well or poorly. In addition, graphics were organized by pages, like a book with tabs. Some pages had customizable dropdown lists and others had lists with links to the graphics requiring the operator to select a back button to change displays. Some designs tended to be too simplistic while others were very complex. These displays can be overwhelming for someone not familiar with the overall look and process.
In a sense, low-performance HMI (LP-HMI) graphics were established and many are still in use today. Poorly-designed HMIs, along with poorly-configured process alarming, have often been cited as significant contributors to major industrial accidents.
Establishing graphics standards upfront is key to overcoming these design issues. They help guide the entire process and overall company vision. Today’s high-performance HMI software takes a multilayered approach. Its standards guidelines were created to optimize the end user experience and encourage creating a graphics hierarchy to help establish a sensible graphics flow. With high-performance HMI, information (data) is presented in a way that there is no question as to whether conditions are good or bad. Operators can use multilevel hierarchy displays to navigate quickly to a screen or drill down to an even more detailed display. Dashboards contain an overview with buttons or links that open graphics for more detail on specific areas in a facility.
Operator buy-in for high-performance HMIs
Prior to implementing an high-performance HMI upgrade, it is critical to get operator buy-in. Real resistance comes when trying to implement anything that isn’t pulled from existing layouts or piping and instrumentation diagrams (P&IDs). Operators are comfortable with their traditional graphics and tend to follow the old mindset: “Make it look exactly like the screens that are there.” They are familiar with the old-style drawing layout challenges.
The resistance to change is understandable. For many facilities, operators and engineers have invested a lot of time in how their legacy HMI screens are driven from menus or alarms. They want any new screens to fit the same scheme. Some facilities also have extensive database-driven layouts and object locations, which means it’s not always easy bringing the two together.
Overcoming change starts with proper upfront planning, preparation and training. Understanding the process and how the graphics and objects work is key before starting to fully design screens. Take the time needed to train personnel and start slowly to build some small screens and devices simulated with test programmable logic controller (PLC) code. This process should be basic and quick.
It is important, and possibly the difference between success and failure, to remember a few key points when planning and implementing a high-performance HMI. Personnel often struggle with:
- Too many screens
- Input/output (I/O) overload
- Massive amounts of alarms.
Other HMI tools and considerations
Other tools and issues to consider include alarm management, visualization tools and read-only remote access.
Alarm management.HMI software and alarm management go hand in hand. The standards and importance of alarm management have inspired improvements in HMI software. Alarm management standards (e.g., ANSI/ISA-18.2) have been developed to address issues with nuisance alarms, alarm floods, alarm tolerances, stagnant alarms and more. Poor alarm systems can be just as bad as not having an alarm system at all.
Read-only remote access.许多供应商还提供工具集，可用于创建与过程控制系统的HMI图形几乎完全相同的图形显示。这使得过程控制网络之外的决策者能够实时看到作业者正在监测和看到的情况。从本质上讲，这将过程控制图形以“只读”格式扩展到组织内任何人的桌面或笔记本电脑，而不用担心过程受到任何影响。这种只读视图还确保任何使用可视化工具监视进程的人都将始终拥有正确的图形版本。
Eliminating the danger of altering or controlling a process removes all threats of accidental or intentional manipulations within the process control system. With proper security applied to the replicated graphics, remote personnel will not be able to make changes to the graphic files.
With any high-performance HMI or overall system and software upgrade project, manufacturers must weigh their strategic investment options and plan early to avoid incurring significant cost. Hardware and software upgrade projects require a holistic view and careful, upfront planning that includes long-term costs, maintenance and sustaining services as part of the overall strategy. Before getting started, consider the following:
Maverick Technologiesis a certified member of theControl System Integrators Association (CSIA)and a CFE Media content partner.
Original content can be found atControl Engineering.