Indicating and describing alarms without overloading an operator

Panel of experts discusses how to keep an operator informed without being overwhelmed

By Mike Bacidore, editor in chief

Why are we still using stack lights, annunciators and push buttons? Are machine designers going for a retro look with these antiquated analog components? Or maybe it’s the hipster in them, wanting to show that they were building machines with interface devices before interface was cool. “That annunciator sounded way better on vinyl.”

Human-machine interface (HMI) can offer a digital version of almost any button, knob or light, but analog still has its place on machines, whether it’s for its ruggedness, for no-look interaction or for situations in which touchscreen operation isn’t an option.

We posed several questions regarding these time-tested components to a panel of industry veterans to see what light their experience and expertise might shed on the subject.

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How do I indicate and describe alarms without overloading an operator with too much information?


Zach Tinkler thumbZach Tinkler, Schneider Electric: This is also tricky as the industrial environment plays a major role in how you would need to ensure operators are notified. This may take a combination of lights, sounds and even strobes, depending on the type and number of notifications a machine may have. In some cases, adding other types of notifications to gain attention, such as voice notifications, which can give additional instructions, or maybe even smells or aromas that can be more effective than a sound in a loud industrial plant, may be needed.

Zach Tinkler is U.S. product manager, control and signaling at Schneider Electric.

Alicia Bowers thumbAlicia Bowers, GE DigitalIn the Industrial Internet world, OEMs can use today’s HMI/SCADA to filter alarms better for operators to increase efficiency. Now, we can use machine learning to look at the raw alarms in underlying systems, determine a root cause and guide operators through the right corrective actions. This can take place in a control room or in the field, with instructions going to a mobile device of choice, and deriving intelligence from the raw data.

Machine learning puts traditional alarm rationalization on steroids. HMI/SCADA today, based on the IIoT-connected enterprise, can provide full-scope alarm management and optimization, facilitating alarm rationalization by providing visibility to all alarms, their respective alarm priority/tier and frequency of occurrence for a specified period of time, delivering on an alarm philosophy that improves efficiency, reduces unscheduled downtime and decreases risk.

By 2020, 20% of IIoT technology in plants will be through OEMs, and this presents an opportunity for control designers to modernize how alarms are handled and improve operator efficiency.

Alicia Bowers is product marketing manager, automation software, at GE Digital.

Robb Weidemann thumbRobb Weidemann, Banner Engineering: Visual alarms can include symbols or basic text explaining the status or necessary action. Programmable audible alarms can literally speak to operators, even in multiple languages. Following standards—for example, green light for a run condition—is another way to give the operator consistent information across machines.

Robb Weidemann is senior business development manager at Banner Engineering.


Sopan Khurana thumbSopan Khurana, Patlite: Typically, system designers account for the fact that operators can comfortably remember and respond to a limited number of alarms without becoming overwhelmed or tuning them out and becoming prone to mistakes. One can write an entire paper on just this topic, but typically the key ideas are that every alarm should be relevant and useful to the operator, that there should be no alarm without a predefined operator response and that there should be a defined alarm rate and a manageable quantity of alarms in total.

Sopan Khurana is applications engineer at Patlite. 

Michael Day thumbMichael Day, Siemens: Alarms, by their very nature, cause confusion, so a complex alarming system can only add more confusion to the operator at a time when stress levels are already high. The keys are keeping alarms as simple as possible and making it a systematic approach to minimize information overload. A macro-to-micro approach to step the operator through a process to pinpoint the issue typically works best, especially if the machine or process they are working with is large and complex. This is when stack lights can indicate a general area as to where the issue is. Pilot devices can provide indication as to what has the issue, and an HMI alarm summary can pinpoint the exact issue and corrective steps. By combining alarm indication this way, the operator is informed in a way that minimizes confusion and establishes an operating rhythm that is repeatable and easily trained to new operators.

Michael Day is industrial control products market development manager at Siemens.

Michael ONeill thumbMichael O’Neill, Werma-USA: With the advancement of sophistication of a stack light’s capabilities, it is imperative to simplify the information being shared while keeping solutions flexible to cover a variety of applications at many different end-user applications. The simpler the alarm system is, the better for the operator. Keep-it-simple-and-significant (KISS) is the guide to follow in order not to inundate the machine operator.

Michael O’Neill is president at Werma-USA.

thomas putz bw thumbThomas Putz, Auer Signal: Use standard colors that are common to everyone. Green means find. Orange means attention. Red means alarm. These need almost no explanation. Reinforcing critical operations can be underpinned by acoustic alarms incorporated into the stack light. A cue-card accessory can assist operators in identifying what each beacon on the stack light means.

Thomas Putz is sales manager at Auer Signal. 

Alvaro Sanchez thumbAlvaro Sanchez,Rockwell Automation: Although the amount of information will always depend on the number of alarms that customers want to monitor, there are different ways to inform the operator when an action needs to be taken. If the indication is merely visual, a different color with the same pattern, say, steady light, could represent the best way to display the alarm. It also could be the easiest way for the operator to remember its meaning and the subsequent action to take. On the other hand, if the conditions cannot be represented with established light patterns, the combination with an audible indication—tone or voice—could assist the operator to properly identify the alarm while providing specific instructions on what action to perform.

Alvaro Sanchez is product manager at Rockwell Automation.

Will Healy III thumbWill Healy III, Balluff: Centralized screens with every possible piece of information available can overwhelm users. Users still have to relate the information on the digital screen to the real-world work cell nearby. By using distributed indication lights, you can help the operator to identify where the exact issue is located physically. This speeds maintenance troubleshooting and increases productivity of the equipment. Distributed indication lights can be an effective method of localizing a problem and giving maintenance a head start on fixing a problem.

With manufacturers now embracing Industry 4.0 and the Industrial Internet of Things (IIoT), there will be some significant changes to how we indicate and utilize stack lights for indication in the plant. There will be new opportunities to have a stack light report the results of factory big-data analytics. Analytics data will be indicating how are we performing to quota or meeting quality metrics. Predictive analytics will allow for predictive-maintenance warnings to be communicated visually, so the next time we have a planned shutdown, such as lunch, we can have maintenance ready to investigate the warning. New forms of indication, such as text messages, apps and emails, are appearing already; however, I see big opportunity for augmented reality to provide individualized indication and alarms only to the people that require the information. It will be harder to ignore a machine's material-shortage warning as it shines in the middle of your personal heads-up display (HUD).

Will Healy III is marketing management director at Balluff.