Alarms
An alarm is a defined condition for a source in PME. The software or the device monitors this condition and records when the condition is met and when not. For example, you can define an Over Voltage alarm for a certain monitoring device in the system. When the voltage threshold is exceeded on this device, the alarm goes active. When the voltage drops below the threshold, the alarm goes inactive. The next time the voltage on this device goes above the threshold again, the same alarm goes active again. An alarm is always associated with a single source and a single measurement.
Some alarms are based on instantaneous events such as a voltage transient, others are based on a condition that lasts a certain period of time such as an over voltage condition. For lasting conditions, the alarm goes from an inactive state to an active state while the condition lasts and then back to an inactive state when the condition is over. Instantaneous alarms are always shown in an inactive state.
The following diagram shows an alarm that is based on a lasting condition. The alarm goes active at the time T1 and inactive at T2. The time interval between T1 and T2 can be short or long.
0 = inactive alarm state; 1 = active alarm state; T = time
T1 = Alarm goes active
T2 = Alarm goes inactive
The following diagram shows an instantaneous alarm. For this alarm, the start time T1 and end time T2 are identical.
0 = inactive alarm state, 1 = active alarm state; T = time
T1/2 = Alarm goes active and immediately inactive again
After an alarm has gone active, it can be acknowledged in the alarm viewer. When you acknowledge an alarm, the date and time of the acknowledgment is recorded together with an optional note that you can enter in the acknowledge window.
An alarm stays unacknowledged until you acknowledge it. After you have acknowledged an alarm, it stays acknowledged until the next time it goes active. At that point it is reset to unacknowledged and is waiting for you to acknowledge it again.
PME counts the number of times an alarm goes through an inactive to active state transition. The number of these transitions is displayed as Occurrences in the alarm viewer in the alarm status view. There are two counters for each alarm. One counter for the total number of occurrences, and one for occurrences since the alarm was last acknowledged.
The time period during which an alarm is active, starting when it goes active, ending when it goes inactive, is called an alarm instance.
Alarm conditions are defined either as software alarms in the Software Alarms tool, or as device-based alarms in the monitoring devices, using the appropriate device configuration tool.
To make it easier to analyze alarms, PME categorizes them into types and combines alarms of similar types into incidents, based on the alarm start times.
The following table shows the different alarm categories and types in PME:
| Category | Type |
|---|---|
| Power Quality |
Flicker |
| Asset Monitoring | Arc Flash Backup Power Over Current Protection Sag (Current) Swell (Current) Thermal Monitor Under Current |
| Energy Management | Air Demand Electricity Gas Power Factor Steam Water |
| General | General Event General Setpoint Unassociated Dropout |
| Diagnostics | Clock / Time Communication Status Device Settings Device Status System Status |
Related topics:
- Viewing incidents
- Viewing alarms
- Viewing events
- Viewing Disturbance Direction
- Viewing Load Impact
- Viewing a timeline analysis
- Viewing Voltage Tolerance
- Viewing waveforms
- Acknowledging alarms
For reference information see:
- Alarm Operation
- Incidents
- Alarms
- Events
- Disturbance Direction
- Load Impact
- Timeline analysis
- Voltage Tolerance
- Waveforms
- Waveform analytics
- Alarms terminology
- Alarms UI
- Timeline analysis UI
- Waveforms UI
For information on how to configure Alarms, see Alarms configuration.