Take a closer look at your alarm management system
When was the last time you really looked at your facility’s alarm management system? Is it doing the job it is supposed to do? Is it doing the job it could be doing?
Good alarm management practices can benefit any facility: They promote better use of resources, allow the plant to operate more efficiently, and, perhaps most critically, help it achieve the competitive edge needed to survive in an uncertain and volatile economy. In addition, advanced technologies such as smart sensing and I/O devices, controllers and Web-enabled HMI/SCADA systems, give facilities the power to build state-of-the-art alarm systems with unprecedented capabilities.
An alarm system is a basic component in nearly every plant, whether process or discrete. Many operations, however, address alarm functionality only from a worst-case scenario. This approach too often ignores low-level, non-critical alarms, allowing them to trigger unnecessarily, wasting time and resources. Further, the effect of these circumstances is exacerbated by an economy that is forcing manufacturers to operate with fewer personnel and constrained budgets, leaving many alarm system issues unresolved and unaddressed.
They do not need to be. With a small investment in time, effort and equipment, any facility can turn an underperforming alarm management system into a well-equipped, optimally configured one, the benefits of which extend beyond improved maintenance and operations to the better performance of the entire facility. Improving a system can be as simple as examining what is already in place and making a few small modifications. Consider these actions:
Evaluate %%MDASSML%% Review all existing alarm management equipment and determine if it is being used optimally. Are alarms properly classified? Are operators responding to alarms appropriately?
Analyze %%MDASSML%% Consider when and where alarms are occurring. Determine trends and response rates. Have patterns been studied? Are recording and reporting features being used?
Enhance %%MDASSML%% Review existing equipment. Would simple upgrades add higher-technology features that could easily pay for themselves? Would a small investment yield a large payback?
Let’s take a look at these areas in a bit more detail, and see what benefits attention to each might bring.
Make your system work for you
First, look closely at the system in place. Reviewing the existing system involves examining both personnel and equipment related issues. In some cases, looking at what is alarmed, and why, might yield some surprises. If operations have changed and alarming has not, it might be time to walk through the operation and revise accordingly.
How operators respond to alarms can make a difference as well. Consider whether a change in procedures might also be needed. Operators need to be able to identify the most important alarms if they are to address them first. Displays need to be configured %%MDASSML%% or reconfigured %%MDASSML%% to present information in a way that enables them to do this. Often, clearing one alarm resolves multiple issues and returns a series of alarming operations to normal conditions.
Specifically, be sure to:
Determine alarm hit rates %%MDASSML%% How often do alarms occur? Examine the operation to determine if a change will keep an alarm from tripping as frequently.
Measure the mean time between alarms %%MDASSML%% Does an alarm occur on the same piece of equipment at the same time each day? If so, why?
Ascertain the cause of an alarm %%MDASSML%% Is the equipment malfunctioning? Is something in the process causing an alarm condition? Determining causes of alarms leads to better equipment performance and better product quality.
Alarm classification should be an important focus of the review. When was the last time the alarms were grouped or classified? Accurate classification makes it easier to discern patterns, set priorities and identify and resolve problems. Alarms may have multiple classifications, signaling one kind of issue if an alarm goes off alone and another if it triggers in conjunction with other alarms. Classifying and reporting all alarms, along with recording, reporting and analyzing them, addresses the status of the entire process, not just alarming for and alerting to major events. Time spent investigating and addressing low-level alarms can alert the plant to potentially deteriorating conditions and allow intervention before more serious, catastrophic problems arise.
The impact of data
Once the existing alarm system configuration has been evaluated, review the reports it is generating. No 21st century company operates autonomously. Data are critical to top level management today, who are constantly scrutinizing the bottom line. Reports reveal which areas of the facility experience the most alarms and at what frequency, and reveal the trends that, if addressed, could lead to greater profitability.
Recording alarms and reporting results lets plants perform the analytics that uncover problems and lead to solutions. Typical report options show hit rates, the times alarms come in, how long it took to acknowledge an alarm and/or clear a condition, and flag recurring alarms. An alarm triggered by an abnormality in the same piece of equipment or same operation on the same day every week needs to be addressed and analyzed to determine why that alarm is recurring. Is this alarm being ignored? Does it need to be re-classified? Alarm analysis uncovers patterns and problems and provides information for improving the overall operation.
Do not overlook auditing functions. Any system is capable of verifying which alarms have triggered and when. Some systems allow operators to add comments to verification records. The result is a traceable path showing what happened and what was done to correct it. Such information benefits engineering, maintenance, quality control and more as they attempt to discern problems and heighten efficiencies. Comment fields typically appear as pop-up forms on the HMI screen after alarm reconciliation. In some plants %%MDASSML%% especially in regulated industries %%MDASSML%% reasons and remarks must be added before the operator is allowed to clear the alarm and proceed. If a system does not have this feature, look into the cost and feasibility of adding it.
The future is now
Finally, determine if retrofits can add functionality to the system economically and easily. Alarm systems have advanced dramatically from the annunciator panels and stack lights of a few decades ago. Current sophisticated smart device and I/O based alarms and HMI/SCADA systems report incidents, describe what is happening where, provide customized displays of information and connect it all together to reveal operating flaws and impending equipment failures.
The standard functionality in most state-of-the-art HMIs significantly surpasses displays of only a few years ago. Newer units are capable of sophisticated notification, responding to alarm signals with automated responses in the form of cellular text messages, emails or autodial phone calls. Software in modern SCADA systems can be programmed to autodial, text or e-mail a designated call list in a predetermined order until a response is received. Such features reduce the number of personnel required on site and simplify remote location monitoring.
Such capabilities let limited personnel use their time more efficiently. Technicians do not have to respond to every call. They can easily prioritize work orders. Lower priority alarms can be cleared and addressed when convenient, or a technician can group his work, resolving several non-critical items in one area of the plant at a time. Critical alarms, of course, can be cleared and addressed immediately to get equipment back up and running %%MDASSML%% and producing income %%MDASSML%% as quickly as possible.
Alarm functionality once achievable only in upper-end SCADA systems has been pushed down into low-end HMIs. Modern units are more capable, smaller, thinner and more durable than their predecessors. They are applicable in areas for which they never would have been considered a decade ago, allowing more extensive alarming. Smart HMI panels can be retrofit into nearly any existing alarm system, adding comprehensive data acquisition, for example, to a single machine on the plant floor at a cost of about $700. Maintenance managers who once felt it unnecessary to add an HMI in locations rarely frequented by mechanics may now find it advantageous to do so. A unit capable of gathering and transmitting alarm data back to a central control room can be the extra pair of eyes the plant needs. Should an alarm trigger, the HMI can call for help and tell the technician what is wrong.
Using compatible equipment such as PLCs and HMIs from the same vendor can further enhance system performance, transmitting basic messaging data from the PLC automatically into the HMI with only a few simple changes %%MDASSML%% and without reprogramming. Should an I/O point on a PLC fail, for example, the PLC can detect the failure and alert the HMI that I/O point “XYZ” is no longer functioning. It can also provide the number of the failed part and indicate its location. Problems can be diagnosed and corrected without a field visit. Thanks to modern technology, most Web-enabled HMIs can be used to correct, control and operate equipment. With appropriate access, most computers can be used to manipulate a Web-enabled HMI from anywhere simply, quickly and easily.
Once the purview of process and automotive industries alone, alarm management now transcends all industries, spreading rapidly and widely %%MDASSML%% even as far as small and stand-alone equipment. Problematic alarms can slow down %%MDASSML%% even stop %%MDASSML%% an operation, impeding a facility’s ability to operate efficiently and optimally. The investment to fine-tune and upgrade it to state-of-the-art performance is small; the pay-off in efficiency and profitability immeasurable.
Author Information Alan Cone works in HMI product marketing at Siemens Industries Inc., Alpharetta, GA. He has worked at Siemens since 1995, and has been involved with HMI technology since 2000. Cone’s current HMI product responsibilities include SIMATIC HMI Panels, WinCC and WinCC flexible HMI software. He has a BSME form Georgia Tech.