Alarm management strategies need to be re-evaluated as many legacy systems from 15+ years ago do not have adequate alarm functionality. While control loops are regularly updated, alarm settings often remain static. This can lead to alarm showers where many alarms are triggered by a single event. Condition-based alarm management through additional software can help minimize unnecessary alarms and direct operators to the root cause. Process manufacturers should establish alarm strategies with periodic review and upgrade older systems or add third-party alarm management software when needed.

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ARC estimates that $65 billion of process automation systems (PAS) installed and operat-
ing throughout the world are 15 years or older and rapidly approaching the end of their
useful life. Most of these legacy systems and the majority of all systems do not have the
current PAS functionality. While nearly all are doing an adequate
8QOLNH FRQWURO ORRSV PDQ DFWLYH job of regulatory control, many are inadequate for the “first line of
DODUPV DUH VHW H[DFWO DV WKH ZHUH defense” against abnormal situations – alarm management.
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ILUP ILUVW FRPPLVVLRQHG WKH SODQW When control strategies are not operating properly, plant personnel
generally have time to respond while the plant is still in a normal
operating range. Furthermore, most companies are organized to constantly improve
control strategies and deal with malfunctioning control immediately. When an alarm
strategy is not working, often the time to respond is compressed since the plant may al-
ready be in an abnormal range. Alarm strategies need to be reviewed and adjusted as
process conditions change throughout the operating life just as control strategies need to
be.
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Almost since the beginning of the concept of automatic control, there have been process
alarms. For most manufacturing plants, automatic control has progressed far beyond
early control devices that operated independently. Control loops today are commonly
linked, cascaded and melded into coordinated control strategies to ensure that they work
together in concert. If one measurement changes, the control loops affected will respond
correctly in a cooperative way. Controller strategies are developed to drive toward the
common goal of maintaining the equilibrium and status quo. When the status quo is
interrupted many put their faith in the fact that alarms will warn operators of malfunc-
tions and allow him to calmly return to normal.
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Maybe it is fitting that so much time, energy, and technology has been put into advanc-
ing the state of control. After all, thanks in part to the advances over the years,
automated control has been a significant contributor to manufacturers approaching 6
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sigma levels of operation. Actually in the process industries it is closer to 4 Sigma, but
this still represents 99.4 percent of the time the plant is operating correctly.
A lot of attention is paid to improving control strategies to squeeze the last 0.6 percent
out and eliminate failures all together. Very few active control loops are tuned or con-
figured exactly as they were when the plant was first commissioned by the engineering
contractor firm. Most manufacturers’ control departments devote a significant amount
of time to maintain and improve control functions. This cannot be said for alarm set-
tings.
In order to squeeze the last 0.6 percent out and eliminate failures all together, traditional
alarming approaches are just not good enough. Ideally, alarms should never happen, if
the control strategies, production equipment and processes all work together, but when
they don’t this is when alarms need to be at their best. Alarms are often set independ-
ently and remain static until someone discovers that they are set incorrectly for the
current operating conditions. Discovering this when a problem arises is the worst time.
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The advances in control over the years to the pervasive use of digital control, has cer-
tainly helped make interactive, coordinated control strategies possible and
commonplace. It has also allowed the “loop count” that modern operators can handle to
increase into the hundreds.
In the days of hardwired controls and alarms, engineers were
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very stingy with alarms partly due to the fact that each alarm
o 0LQLPL]H DODUP FODVVHV point had a cost. Since each alarm today is virtually free
with the measurement and control loop, the conventional
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wisdom is often “when in doubt - put an alarm on it”. With
o RQVLGHU FRQGLWLRQEDVHG PDQDJHPHQW the potential for every measured point to have a “high”,
“low” and other variations often there are more alarm points
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process variable they are connected to, they are not aware of
other alarms. This can result in a phenomenon called alarm showers. Alarm showers
occur when one failure causes many process variables to trip their preset alarms. The
result can be catastrophic when the quantity of alarms masks the real source of the prob-
lem and causes delays in operator corrective actions.
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Alarms and controls have another thing in common; they must be configured specifically
to meet the process application and operation philosophy. Just as all process control
strategies are developed with the same basic building blocks but configured differently
for each application, alarm strategies are built using a common set of alarm tools. Just
like control, the best alarm strategy for one process is not necessarily the same for an-
other. Each process requires its alarms to be configured and tuned to meet the specific
process requirements.
For example, processes that tend to have a large number of controlled and measured
variables under the operational control of a single operator require strategies to prevent
overwhelming the operator. These type of processes not only need to have a well-
established process for setting alarms in the first place, but they also need to have a con-
tinuous review process. Even processes that have few control points may need a unique
alarm strategy, if process dynamics, operating ranges or equipment status are constantly
changing.
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Alarms should only be used to cause an operator to take action. It makes no sense for an
operator to have to respond to an alarm for low flow when the pump controlling the
flow is shut down for maintenance. Having the system manage these situations can take
place in many ways. Most modern PASs contains alarm management software that al-
lows for grouping of alarms. Not all suppliers offer equally comprehensive alarm
management functions. Furthermore, some alarm management strategies while com-
prehensive may be extremely complex to use. The user should make sure that alarm
management functionality is on the checklist for their next PAS purchase.
If you have an older, legacy control system with inadequate alarm management, you
have other options. Most of the Process Automation System suppliers have HMI or PIM
software that can be added to your legacy control systems to provide additional alarm
capability. These include software such as Wonderware’s Intouch, Intellution’s iFix,
Rockwell’s RSView, GE Fanuc’s CIMPLICITY, Honeywell Hi-Spec’s PHD, Yokogawa’s
IT
Exaquantum, and ABB’s Inform .
Plant Automation Services is headquartered in Houston and has specialized in the alarm
management software business for many years. Their AMO Suite is designed specifi-
cally to optimize alarm management. Other third party software systems such as
AspenTech’s InfoPlus.21, OSI’s PI, eMation’s WizFactory, and Wellspring’s OA2alarms
offer alarm management as an integral part of their HIM or PIM systems.
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Yes there is considerable help available both in terms of services as well as software ap-
plications. ARC has previously written about software specifically designed to address
Abnormal Situation Management (ASM). This software tends to be more predictive and
aimed at providing operators with intelligent guidance beyond the simple act of alarm
notification. Additional discussion of ASM will be provided in subsequent Insights. The
purpose of this Insight is to help focus attention to the “first line of defense” against ab-
normal situations – alarm management.
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• Process Industry manufacturers should establish an Alarm Strategy with guidelines
and procedures for periodic review and evaluation of alarms.
• Manufacturers with older legacy systems with inadequate alarm functionality,
should either look to automation system suppliers to replace or upgrade their sys-
tems or look for third party software suppliers that can provide add-on alarm
management functions to meet their alarm management strategies
• Suppliers need to provide their users with alternatives that fit their specific alarm
management requirements. Above all, alarm management should be made as easy
as control strategy management is.
For further information, contact your account manager or the author at crhill@arcweb.com.
Recommended circulation: All MAS-H and MAS-P clients.
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