A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A unique digital code address is assigned to sensor where inputs of the sensors are connected to a single power and signaling cable system using a daisy chain. The serial bus controller is to interrogate each of the sensor devices using the address to identify zones where moisture is detected. A transmitting antenna is provided at each sensor which is switched on when moisture is detected for detecting of the sensor from above the membrane by a utility locate device to confirm the location of the sensor.

An automatic addressing system for a fire loop and a method for automatically addressing a plurality of remote units electrically connected to a fire panel in a fire loop, the method including: (1) requesting an initial identifier from each remote unit; (2) for each remote unit which responds with a unique initial identifier: (a) assigning a unique address to the remote unit; and (b) silencing the response of the configured remote unit to further identifier requests; (3) for each remote unit which responds with an initial identifier matching the initial identifier of at least one other remote unit: (a) initialising an identifier array with the initial identifier for the remote unit in question; (b) requesting a further identifier and adding it to the identifier array for the remote unit; (c) for each remote unit which responds with a unique identifier array: (i) assigning a unique address to the remote unit.

A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A unique digital code address is assigned to sensor where inputs of the sensors are connected to a single power and signaling cable system using a daisy chain. The serial bus controller is to interrogate each of the sensor devices using the address to identify zones where moisture is detected. A transmitting antenna is provided at each sensor which is switched on when moisture is detected for detecting of the sensor from above the membrane by a utility locate device to confirm the location of the sensor.

A communication unit and a safety system, through which an increase in initial cost is minimized in constructing a safety system, are provided. In a communication unit of the invention, two input and output portions are configured to be directly connected to each other when a plurality of unit main bodies are connected to each other in series, and a notched portion forming a disposition space for a connection portion-side terminal of at least a cable is provided at an end of the unit main body.

An automatic addressing system for a fire loop and a method for automatically addressing a plurality of remote units electrically connected to a fire panel in a fire loop, the method including: (1) requesting an initial identifier from each remote unit; (2) for each remote unit which responds with a unique initial identifier: (a) assigning a unique address to the remote unit; and (b) silencing the response of the configured remote unit to further identifier requests; (3) for each remote unit which responds with an initial identifier matching the initial identifier of at least one other remote unit: (a) initialising an identifier array with the initial identifier for the remote unit in question; (b) requesting a further identifier and adding it to the identifier array for the remote unit; (c) for each remote unit which responds with a unique identifier array: (i) assigning a unique address to the remote unit.

A bus node is capable of performing a method for the assigning of bus node addresses to bus nodes of a serial data bus. The method is performed with the aid of bus shunt resistors in the individual bus nodes of the data bus system in an assignment time period. After the assigning of bus node addresses to the bus nodes in the assignment time period, there follows an operating time period. For this purpose, the bus node comprises such a bus shunt resistor. The bus node is characterized by a bus shunt bypass switch which, prior to assigning a bus node address to the bus node in the assignment time period is opened and which after the assignment of bus node address to the bus node in the assignment time period is closed, and which is closed in the operating time period.

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.

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 method and apparatus relating to providing a remote device for a fire alarm control system are, in turn, provided. The aspects include configuring each at least two replaceable sub-devices to provide at least one of a notification and a detection of a fire event. The aspects include configuring a housing to receive and connect to the at least two replaceable sub-devices.