Photoelectric smoke sensor and fire detecting system, and sensitivity testing method therefor

A photoelectric smoke sensor comprising:

• first light emitting means for emitting light to detect scattered light due to smoke;
• first light receiving means for receiving the scattered light due to smoke;
• first comparison means for comparing a threshold with said quantity of light received by said light emitting means;
• second light emitting means for lighting continuously when a quantity of light received by said light receiving means is equal to or more than a threshold;
• alarm signal output means for outputting an alarm signal during said second light emitting means lighting continuously;
• sensitivity test starting means for starting a sensitivity test of said photoelectric smoke sensor;
• blinking starting means for starting to blink said second light emitting means when said test is started;
• reference voltage changing means for changing a reference voltage in steps during the sensitivity test;
• second comparison means for comparing said reference voltage with a 0-point level voltage of said light receiving means during the sensitivity test;
• and
• lighting continuing means for stopping the blinking of said second light emitting means to continue the lighting of said second light emitting means when the reference voltage is greater than or equal to the 0-point level voltage.

A sensitivity testing method for a photoelectric smoke sensor of a fire detecting system, said system having a plurality of photoelectric smoke sensors each of which includes a light emitting device and light receiving device for detecting scattered light due to smoke and a test light emitting device for emitting light to said light receiving device during the sensitivity test, and a control panel for controlling said plurality of sensors, said method comprising the steps of:

• selecting one sensor to which a sensitivity test is conducted from said plurality of sensors;
• transmitting a test command from said control panel to said selected one sensor;
• increasing in steps a quantity of light emitted by said light emitting device when said test command is received by said sensor;
• transmitting an alarm signal from said sensor to said control panel when a quantity of light received by said light receiving device is greater than or equal to a threshold;
• measuring a time duration from the transmission of the test command by said control panel until the reception of the alarm signal by said control panel;
• and
• conducting the sensitivity test of said sensor based on the measured time in said control panel.

A sensitivity testing method for a photoelectric smoke sensor of a fire detecting system, said system having a plurality of photoelectric smoke sensors each of which includes a light emitting device and light receiving device for detecting scattered light due to smoke and a test light emitting device for emitting light to said light receiving device during the sensitivity test, and a control panel for controlling said plurality of sensors, said method comprising the steps of:

• transmitting a test command from said control panel to each of said sensors;
• increasing in steps a quantity of light emitted by said light emitting device when said test command is received by said sensor;
• transmitting an emitting light quantity data of said test light emitting device at a point of time when the receiving quantity of said light receiving device is greater than or equal to a threshold from said sensor to said control panel;
• and
• conducting the sensitivity test of said sensor based on the emitting light quantity data in said control panel.

A sensitivity testing method for a photoelectric smoke sensor of a fire detecting system, said system having a plurality of photoelectric smoke sensors each of which includes a light emitting device and light receiving device for detecting scattered light due to smoke and comparison means for comparing a 0-point level voltage of said light receiving device with a reference voltage, and a control panel for controlling said plurality of sensors, said method comprising the steps of:

• selecting one sensor to which a sensitivity test is conducted from said plurality of sensors;
• transmitting a test command from said control panel to said selected one sensor;
• changing in steps the reference voltage when said test command is received by said sensor;
• transmitting an alarm signal from said sensor to said control panel based on a result of the comparison of said comparison means;
• measuring a time duration from the transmission of the test command by said control panel until the reception of the alarm signal by said control panel;
• and
• conducting the sensitivity test of said sensor based on the measured time in said control panel.