Understanding PACE alarms and thresholds
Learn how PACE presents warnings, alerts and alarms, and how thresholds and hysteresis affect their behaviour.
How do PACE alarms work?
PACE alarms notify operators when a monitored parameter crosses a configured threshold. Three levels — Warning, Alert, and Alarm — are displayed in yellow, amber, and red respectively. Thresholds are set centrally and distributed to all connected displays.
PACE can apply warning, alert and alarm thresholds to configured parameters. These thresholds help draw the operator’s attention to values that have moved outside defined operating limits.
Thresholds can normally be configured for both high and low values. The exact limits depend on the installation, monitored parameter and operational requirements.
What are the PACE alarm levels?
A typical PACE configuration uses three levels:
| Level | Typical display | General purpose |
|---|---|---|
| Warning | Yellow | Early advisory that a value is approaching an operational limit |
| Alert | Amber | Increased operational attention may be required |
| Alarm | Red | A defined operational limit has been reached or exceeded |
The terminology, colours and responses may differ between installations. Operators should always follow the procedures established for their facility, vessel or helideck.
PACE presents the configured state. It does not replace the customer’s operational procedures or decision-making responsibilities.
How do PACE alarm thresholds behave?
High and low thresholds
A parameter may have thresholds above or below its normal operating range.
Examples can include:
- Wind speed above a defined limit
- Atmospheric pressure outside an expected range
- Motion exceeding an operational criterion
- Temperature below or above a configured threshold
Not every parameter uses all three alarm levels.
Hysteresis
PACE can use hysteresis to prevent an alarm from repeatedly activating and clearing when a measured value fluctuates close to a threshold.
For example, an alarm may activate when a value exceeds its configured limit but remain active until the value returns sufficiently inside the acceptable range.
The hysteresis value forms part of the approved parameter configuration and should not be changed without understanding its effect on system behaviour.
How are alarm messages distributed to remote displays?
Alarm states are configured centrally on the PACE Weather Monitoring System computer and are distributed to connected displays.
Depending on the installation, pop-up messages may be enabled or disabled locally on individual display clients. The absence of a pop-up does not necessarily mean that the central alarm state is inactive.
Responding to an unexpected indication
Operational alarm or system fault?
An operational alarm indicates that a valid measurement has crossed a configured threshold.
A sensor or communication fault is different. It may result in an invalid, unavailable or stale value rather than a normal threshold alarm.
Operators should follow the procedures established for the installation when responding to any warning, alert, alarm or system fault.
Information to record
When investigating an unexpected indication, record:
- The affected parameter
- The displayed value
- The alarm colour or message
- The time of the event
- Whether the value was changing
- Whether other displays showed the same condition
- Any associated sensor or communication message
Screenshots can help WISE Group support identify the type and source of the indication.
Who can change PACE alarm thresholds?
Threshold changes can affect operational decisions and system compliance. They should only be made by authorised personnel following the applicable customer procedures.
Contact WISE Group support before changing thresholds, hysteresis values, calculations or parameter configuration on an operational PACE system.