Failure of a device to respond to a polling request or to send an expected update due to an open circuit or ground fault results in which type of signal?

Failure of a device to respond to a polling request or to send an expected update due to an open circuit or ground fault results in which type of signal?

• A. Alarm signal
• B. Trouble signal
• C. Supervisory signal
• D. Silence

Answer: (B)

In building automation signaling, different statuses are used to classify conditions. When a device doesn’t respond to polling or misses an expected update because the circuit is open or there’s a ground fault, the system treats this as a fault in the device or its wiring and reports a trouble signal. This indicates a problem that should be investigated, but it isn’t an active alarm event. An alarm would come from an actual process event, a supervisory signal points to a device needing to stay in a safe or controlled state, and silence simply quiets alarms rather than signaling a fault. So, the situation described corresponds to a trouble signal.

In building automation signaling, different statuses are used to classify conditions. When a device doesn’t respond to polling or misses an expected update because the circuit is open or there’s a ground fault, the system treats this as a fault in the device or its wiring and reports a trouble signal. This indicates a problem that should be investigated, but it isn’t an active alarm event. An alarm would come from an actual process event, a supervisory signal points to a device needing to stay in a safe or controlled state, and silence simply quiets alarms rather than signaling a fault. So, the situation described corresponds to a trouble signal.