In a fire alert system energy is harvested from a wire line pair (408) used to provide primary electrical power from a fire panel central monitoring station to a plurality of remote devices (406). The fire panel central monitoring station begins communications with a remote device by modulating the voltage on the wire line pair so as to communicate a first message (502) to one of the plurality of remote devices. Thereafter, one of the remote devices will respond to the first message with a second message (504) by modulating the voltage on the line pair. Energy is selectively harvested from the wire line pair at one or more of the remote devices in accordance with the remote device address specified in the first message.

A notification appliance circuit includes at least one notification appliance. The at least one notification appliance includes a charge controller including a single stage current controller, the charge controller being configured to output a charge current, an energy store configured to receive the charge current, and provide a discharge current, and a notification component configured to receive the discharge current and emit a notification.

The present application relates to a detection circuit for detecting a detector removal fault. The detection circuit comprises: a switching circuit. The switching circuit comprises one or more switching elements; an energy storage element; and a control circuit for controlling the energy storage element to discharge by controlling the one or more switching elements to perform an opening or closing action. The control circuit is configured to cause the energy storage element to discharge based on a first loop if the detector is removed from the diode bases, and to cause the energy storage element to discharge based on the first loop and a second loop including the terminal resistor if the detector is not removed from the diode bases. The control circuit is further configured to detect the detector removal fault based on an output voltage of the area monitoring module during discharge process.

An isolator circuit (25) for a unit of a safety system (10) includes a power control line (14) connectable to a first loop of a safety system and a power connection (16) connectable to a second loop of the safety system. A switch (26) is connected to the power control line (14), and the switch has a closed configuration and an open configuration. A controller (28) controls the configuration of the switch (26). If a voltage across the circuit (10) from the power connection (16) to the power control line (14) falls below a predetermined level, the controller (28) opens the switch (26), thereby causing a disconnection to occur in the first loop.

A fault sensing circuit is provided in a remote device configured to be connected to an end of line resistor (EOLR) that is used to detect wiring faults. The fault sensing circuit includes a current monitoring subcircuit configured to detect when an input current of the remote device has crossed a fault threshold corresponding to a fault in the remote device. The fault sensing circuit further includes a switching subcircuit connected to the current monitoring subcircuit and the EOLR. The switching subcircuit is configured to electrically connect a fault resistor in parallel with the EOLR to change a value of an end of line resistance for a fault indication when the input current of the remote devices has crossed the fault threshold.

In one aspect, an integrated circuit (IC) includes a sensor. The sensor includes a processor configured to provide speed and/or direction of a target object based on the speed of the target object; monitor for a diagnostic fault; provide information if the diagnostic fault is detected; monitor for critical faults; and provide information if a critical fault is detected and the sensor recovers from the critical fault.

An apparatus and method for detection and adaption to an end-of-line resistor in a notification appliance circuit (NAC) of a control panel or power booster of, for example, an alarm system, and for ground fault localization in the alarm system are provided. The apparatus can include the NAC where the NAC includes first and second analog input terminals, where the NAC includes first and second external output terminals, and where the NAC includes an end-of-line resistor. Current can be driven through the NAC via the first and second analog input terminals, and voltage can be measured at each of the first and second external output terminals. The measured voltage can be indicative of one of a value of the end-of-line resistor or that a state of the NAC is one of open, shorted, ground faulted, or normal.

A tethered device for prevention and recovery of a vehicle component (e.g., a catalytic converter) is provided herein. The tethered device comprises a housing having an exterior surface and defining an interior cavity. The tethered device further comprises an electronic component disposed within the interior cavity. The tethered device further comprises a plurality of spacers extending from the exterior surface and configured to be adjacent to the vehicle component. The plurality of spacers defines a channel configured to promote airflow between the tethered device and the vehicle component thereby minimizing heat transfer between the tethered device and the vehicle component.

An isolator circuit (25) for a unit of a safety system (10) includes a power control line (14) connectable to a first loop of a safety system and a power connection (16) connectable to a second loop of the safety system. A switch (26) is connected to the power control line (14), and the switch has a closed configuration and an open configuration. A controller (28) controls the configuration of the switch (26). If a voltage across the circuit (10) from the power connection (16) to the power control line (14) falls below a predetermined level, the controller (28) opens the switch (26), thereby causing a disconnection to occur in the first loop.

Devices, systems, and methods for command transmission based on an electrical measurement in an event system. In some examples, one or more embodiments include a controller comprising a memory and a processor to execute instructions stored in the memory to determine an electrical measurement in an event device loop including a number of event devices connected to an event device panel, compare the electrical measurement to a threshold value, and determine, based on the comparison of the electrical measurement to the threshold value, a plurality of commands to be transmitted to the event devices in the event device loop.