EP0130307A2

EP0130307A2 - Fire detector equipped with sensor

Info

Publication number: EP0130307A2
Application number: EP84104862A
Authority: EP
Inventors: Yoshiaki C/O Nohmi Bosai Kogyo Co. Ltd. Okayama
Original assignee: Nohmi Bosai Kogyo Co Ltd
Current assignee: Nohmi Bosai Ltd
Priority date: 1983-06-03
Filing date: 1984-04-30
Publication date: 1985-01-09
Anticipated expiration: 2004-04-30
Also published as: DK166109B; FI842160A0; DK166109C; DK274284D0; DK274284A; DE3485713D1; FI842160A; EP0130307A3; ES533356A0; JPS59223896A; ES8504398A1; NO842183L; ATE76211T1; EP0130307B1

Abstract

This invention relates to a fire detector equipped with a sensor which detects physical quantity of heat, light or smoke and which, in particular, stores time when the fire detector has operated and output of the sensor at this time and indicates these stored data whenever necessary.

Description

This invention relates to a fire detector which is equipped with a sensor detecting physical quantity of heat, light or smoke and which, in particular, stores the time when the fire detector has operated and the output of the sensor at that time so that these stored data may be indicated whenever required later.
The conventional fire detector of this kind continuously supervises changes in output level of the above sensor and operates when the predetermined basic level is exceeded. Therefore, even though one can know by operation of the fire detector that the output level has exceeded the basic level, it is not possible to know later the actual output level at that time or the operating time of the detector. Therefore, it has been impossible to clear up the cause of the false alarm if produced by the fire detector.
In view of the above, this invention offers a fire detector which is equipped means to store the time when the fire detector has operated and the output level of the sensor at that time, and to indicate the stored time and output level at any time so that these stored data may be confirmed later whenever necessary.
The following describes an embodiment of this invention with reference to the accompanying drawings. Shown in Figure 1 are as follows:

a sensor 1 which detects physical quantity of heat, light or smoke. an amplifier 2 which amplifies output of the sensor 1. an A - D converter 3 which converts an analogue signal showing an output level of the sensor 1 to a digital signal. a clock part 4. a first indicating part 5 which indicates a present time or a present output level of the sensor 1 whenever necessary. a second indicating part 6 which indicates the time when the fire detector operated and an output level of the sensor 1 at that time. a memory 7 (hereafter referred to as ROM) which stores a predetermined basic level as a basis to determine whether the output level of the sensor 1 should be taken as fire. a memory 8 (hereafter referred to as RAM) which stores the time when the fire detector operated and an output level of the sensor 1 at that time. These parts 1 through 8 are connected to a central processing unit 9 (hereafter referred to as CPU) for their centralized control. Connected further to the CPU9 are an operating means comprising a power supply E, switches SW₁ ~ SW₄ and resistors R₁ ~ R₄, input terminals IN₁ ~ IN4 to which external apparatus corresponding to the individual switches SW₁ ~ SW4 are connected, and output terminals OUT₁ ~ OUT₄ to which external apparatus corresponding to the indicating parts 5 and 6 are connected.

The switch SW₁, resistor R₂ and input terminal TN₁ are provided to clear the RAM8 by operation of the switch or external apparatus. The switch SW₂, resistor R_z and input terminal IN₂, the switch SW₃, resistor R₃ and input terminal IN₃, and the switch SW₄, resistor R4 and input terminal IN₄ are provided to switch the indication of the first indicating part 5 from the time to the output level of the sensor 1 by operation of the respective switch or external apparatus, and to cause the second indicating part 6 to indicate the time when the fire detector operated and the output level of the sensor 1 at that time. The output terminals OUT₁ ~ OUT₄ are used for transmitting the time and output level signal to the external apparatus corresponding to the first indicating part 5 and second indicating part 6.
Operation of the embodiment is described below with reference to the flow chart of the CPU9 shown in Figure 2. The output of the sensor 1 is always amplified by the amplifier 2, and the analogue signal indicating the output level is converted to a digital signal by the A - D converter, which is then sent to the CFU9. A signal from the clock part 4 indicating the present time, too, is sent to the CPU9. The ROM7 stores the basic level for comparison with the output level of the sensor 1. As the CPU9 starts operating (step 1), the RAMS in which past data have been stored is cleared (step 3) if the switch SW₁ for clearing the RAM8 is set in the ON position (step 2). In case the switch SW₁ is set in the OFF position (step 2), it is judged that there is no need of clearing the RAM8, and with the signals from the clock part 4 and A - D converter 3 the present time and output level of the sensor 1 are read in (stops 4 and 5) respectively. Then, a discrimination is made as to whether the switch SW₂ used for indicating the output level of the sensor 1 on the first indicating part 5 is set in the ON position (step 6). Nevertheless, since the switch SW₂ is normally set in the OFF position, the first indicating part 5 indicates the present time (step 7). And the output level of the sensor 1 which has been read in at the above step 5 is compared with the basic level stored in the ROM7 (step 9). However, as the output level of the sensor 1 does not reach the basic level before a fire breaks out, a discrimination is made as to whether the second indicating part 6 is giving the past indication (indication given at the time of the previous operation) (step 10). If yes, the second indicating part 6 is cleared (step 11). In the both cases a discrimination is made as to whether the switches SW3 and SW₄ which cause the second indicating part 6 to indicate the operating time and the output level of the sensor 1 at that time are set in the ON position (step 12). Nevertheless, as the switches SW3 and SW₄ are normally set in the OFF position, the operation goes back to the above step 2 and repeatedly follows the above steps.
Now, if the output level exceeds the basic level (step 9), the fire detector produces a fire alarm (step 13), which is transmitted to a control panel which is not shown in the figure. And the time and the output level of the sensor 1 at this time is written in and stored in the RAM8 (step 14), and the operations after the step 2 are repeated. By switching on the switch SW₂ for output level indication (step 6) it is possible to cause the first indicating part 5 to indicate the present output in place of the indicated time (step 8) so that changes in output level of the sensor 1 may be checked whenever necessary.
If it is desirous to know the operating time of the fire detector and the output level of the sensor 1 at that time later, the switches SW₃ and SW₄ should be set in the ON position (step 12). Then, the operating time stored in the RAMS is read out (step 15) and indicated on the second indicating part 6 (step 16). Furthermore the output level of the sensor 1 at the above operating time is read out (step 17) and indicated on the second indicating part 6 together with the above operating time (step 18).
The above has described the operating procedure by means of the switches SW₁ ~ SW₄. It is also possible to remotely cause the above operation to be performed by operating external apparatus which constitute operating means and are connected to the input terminals IN₁ ~ IN4. Furthermore it is possible to connect external apparatus which constitute indicating means to the output terminals OUT₁ ~ OUT₄ so that the above mentioned various indications may be given on these indicating means together with or in place of the indications given by the first and second indication means. Although the first indicating part 5 is so devised that time alone is indicated at all times and the output level can be indicated whenever necessary by operation of the switch SW₂, other indicating methods may also be adopted, e.g. simultaneous indication of both time and the output level, a choise of which should be made properly.
As can be seen from the above description the fire detector according to this invention is equipped with a sensor which detects physical quantity of heat, light or smoke, and means to store the time and output level of the sensor when the fire detector operated and to indicate the stored time and output level at any time. Therefore it is possible to confirm the time when the fire detector operated and the above mentioned physical quantity at that time whenever necessity arises later. This feature is particularly advantageous in case the fire detector falsely operated, and makes possible to clear up the cause. As described above, this invention offers a fire detector having such advantages that have never been realized in the conventional detectors.

Brief description of drawings

Figure 1 is a block diagram of an embodiment according to this invention. Figure 2 is a flow chart to illustrate operation of CPU9.

Claims

A fire detector which is equipped with a sensor detecting physical quantity of heat, light or smoke, which always supervises changes an output level of the sensor and operates when a predetermined basis level is exceeded, and which is equipped with a means to store the time when the fire detector has operated and the output level of the sensor at that time and a means to indicate the stored time and the output level at any time.