What type of signal indicates that a monitored system or device is in an abnormal state?

A supervisory signal is used to indicate that a monitored system or device is in an abnormal state. This type of signal does not imply a fire alarm condition but rather signifies that something is not functioning as expected. It serves as an alert to personnel that there may be issues such as a supervisory condition that requires attention, maintenance, or verification of system integrity.

In a fire alarm system, supervisory signals can indicate problems with components like valves being closed, tampering with devices, or other situations that could potentially impact the overall system performance. By distinguishing these signals, the fire alarm system can ensure not only the alerting function during emergencies but also the overall reliability and readiness of the system by alerting operators to non-critical but important conditions.

Other types of signals, such as warning signals or malfunction signals, may indicate different aspects of system operation but are not specifically focused on monitoring the operational status of devices in the same way as supervisory signals. Fire alarm signals are explicitly related to the detection of fire or smoke, so they do not fit the context of indicating an abnormal state of a monitored system.