Alarms are a critical and essential part of any SCADA system. However, the design, implementation and management of these alarms are usually given little thought or no attention at all. Poorly designed SCADA alarms can create several problems.
Operator Apathy
Alarms should only be utilised for scenarios that require the operator’s corrective action. When designing alarm systems, it is important to understand the difference between alarms and events. For example, an operator can’t do anything if the ambient temperature of an air handling unit is >40°C, so why classify this as an alarm? It’s better to log this as an event. Examples of alarms are motor tripped, battery low, tank level low, tank pressure high.
On the other hand, events are any other piece of data you might want to know that doesn’t have a required action associated with it. This data can be used as a report for maintenance purposes. Examples of these events are motor started, ambient air humidity high, circuit breaker open.
The problem with confusing events and alarms is that it leads to too many nuisance alarms, which could cause operator apathy. Imagine if all of these events are utilised as alarms, and every day, hundreds of these events occur. Eventually, a mission-critical alarm will get buried, and you don’t want this to happen!
Waste of Resource / Inefficient System
Alarm grouping and priorities are commonly underutilised. These alarm tools effectively direct required actions to the right group of people needed for that alarm so that it can be handled in the most direct manner and the shortest possible time.
For example, if you have a critical alarm related to your boiler plant, you wouldn’t want to alert technicians from the electrical department (or anyone else who is not directly responsible for the boiler). In that case, most likely, the alarm would be a nuisance to them, and they would just ignore it. If this happens in the middle of the night, and everyone is alerted to come down to the plant, it would be a waste of everyone’s time, and they are better off using this time resource elsewhere. The alarm needs only to alert the people who have responsibility for the area, or those who can rectify the issue.
Not all alarms carry the same weight. This is where alarm priorities become useful. 
To efficiently manage alarms, your SCADA system needs an alarm priority scheme. Priority should first be given to alarms related to safety and then on potential economic impact. It is important as well that the HMI keeps the higher priority alarms as the most visible. By properly developing an alarm priority scheme, operators are not required to decide what is most important because the system will do it for them.
Our Recommendations
These are some of the recommended practices in order to have efficient SCADA alarm management:
- Stop alerting events
- Stop sending alarms to everyone
- Stop treating all alarms the same
- Stop alarming on obvious issues
- Stop alarming when you’re doing maintenance
- Stop using “Acknowledge All”
- Enforce user logins for each operator
Here at Mescon, our engineers can help you achieve SCADA alarm management that promotes operator empathy, safety and efficiency. Talk to us today to know more.
