Fire alarming system

• US 6,195,003 B1
• Filed: 05/14/1999
• Issued: 02/27/2001
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Nohmi Bosai Limited (Secom Company Limited)
• Original Assignee: Nohmi Bosai Limited (Secom Company Limited)
• Inventors: Takahashi, Keiichi, Takeyoshi, Kenji, Ichikawa, Nobuyuki, Hirooka, Eiji
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US09/311,637
• Time in Patent Office: 655 Days
• Field of Search: 340/501, 340/505, 340/506, 340/517, 340/519, 340/520, 340/521, 340/525, 340/530, 340/825.07, 340/825.08, 340/825.09, 340/825.1, 340/825.11, 340/825.12, 340/825.13, 340/825.2, 340/825.21, 340/825.47, 340/825.52
• US Class Current: 340/506
• CPC Class Codes: G08B 26/001 with individual interrogation of substations connected in parallel

Abstract

A fire alarming system includes a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other devices to be controlled; and a receiving device to which the plurality of terminal devices are connected. A great number of terminal devices with a manual box are connected to the receiving device. When a plurality of manual boxes are activated at the same time, the terminal devices corresponding to the activated manual boxes can be called at the same time without encountering a collision among returning-back signals transmitted from these terminal devices. That is, when a plurality of manual boxes are activated at the same time, the signal of only one of the plurality of activated manual boxes can arrive at the receiving device.

Claims

1. A fire alarm system comprising:

a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other controlled devices; and

a receiving device to which said plurality of terminal devices are connected;

wherein said plurality of terminal devices are divided into a plurality of groups;

said receiving device includes;

means for transmitting common return-back instructions to the terminal devices belonging to said divided groups,

means for generating a time period between the transmission of common return-back instructions to one group and the transmission of common return-back instructions to other group,

means for generating a time slot allocated to each terminal device in said time period, state information of each of the terminal devices belonging to said one group is necessarily returned to said receiving device in said time slot,

said terminal devices include;

means for returning state information and sum check data necessarily in said time slot allocated to each terminal device when said receiving device receives common return-back instructions from said transmitting common return-back instructions.

2. A fire alarm system according to claim 1, wherein:

a transmitter slot which receives only a transmitter address from said transmitter is provided after each of the time slots.

3. A fire alarm system according to claim 1, said fire alarm system further comprising:

transmission error detecting means for detecting a transmission error when any of said plurality of terminal devices has a transmission error;

storage means for storing the number of times that the transmission error occurs; and

transmission error indicating means for indicating that a transmission error has occurred when the number of times that the transmission error occurs stored in said storage means exceeds a predetermined number.

4. A fire alarm system according to claim 1, wherein said receiving device conducts a polling operation which is continued even when a terminal device has a transmission error.

5. A fire alarm system according to claim 1, wherein each of said manual boxes includes:

address transmission means for transmitting their own device address from the least significant bit;

bit comparison means for comparing a bit on a signal line with their own bit to be tried to transmit;

bit transmission prohibition means for prohibiting bit transmission when said bit on the signal line is active and the own bit to be tried to transmit is inactive.

6. A fire alarm system according to claim 1, wherein each of said manual boxes includes:

address transmission means for transmitting their own device address from the most significant bit;

bit comparison means for comparing a bit on a signal line with their own bit to be tried to transmit;

bit transmission prohibition means for prohibiting bit transmission when said bit on the signal line is inactive and the own bit to be tried to transmit is active.

7. A fire alarm system in which a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other controlled devices are connected via a signal line to a receiving device, and said fire alarm signal receiving device polls said plurality of terminal devices thereby acquiring terminal device information from said terminal devices, making decisions, displaying information, and/or controlling said terminal devices, said fire alarm system comprises:

first signal inverting means disposed at a node between said fire alarm signal receiving device and a signal line; and

second signal inverting means disposed at a node between each of said terminal devices and said signal line;

wherein an active bit on said signal line indicates fire information, an inactive bit on said signal line indicates false information, when the active bit and the inactive bit overlie, a bit on said signal line become the inactive bit.

8. A fire alarm system comprising:

a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other controlled devices; and

a receiving device connected;

wherein each of said manual boxes includes;

address transmission means for transmitting their own device address from the most significant bit;

bit comparison means for comparing a bit on a signal line with their own bit to be tried to transmit;

bit transmission prohibition means for prohibiting bit transmission when said bit on the signal line is inactive and the own bit to be tried to transmit is active.

9. A fire alarm system comprising:

a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other controlled devices; and

a receiving device connected;

wherein each of said manual boxes includes;

address transmission means for transmitting their own device address from the least significant bit;

bit comparison means for comparing a bit on a signal line with their own bit to be tried to transmit;

bit transmission prohibition means for prohibiting bit transmission when said bit on the signal line is active and the own bit to be tried to transmit is inactive.

10. A fire alarm system comprising:

a plurality of terminal devices including fire sensors, transmitters, manual boxes, and/or other controlled devices; and

a receiving device to which said plurality of terminal devices are connected;

wherein said plurality of terminal devices are divided into a group;

said receiving device includes;

means for transmitting common return-back instructions to the terminal devices belonging to said group,

means for generating a time period between the transmission of common return-back instructions to said group and the transmission of common return-back instructions to the group,

means for generating a time slot allocated to each terminal device in said time period, state information of each of the terminal devices belonging to said group is necessarily returned to said receiving device in said time slot,

said terminal devices include;

means for returning state information and sum check data necessarily in said time slot allocated to each terminal device when said receiving device receives common return-back instructions from said transmitting common return-back instructions.

11. A fire alarm system according to claim 10, wherein:

the width of each of said time slots is set such that said time slot width increases with the delay of the start time of said time slots.

12. A fire alarm system according to claim 10, wherein:

a transmitter slot which receives only a transmitter address from said transmitter is provided after each of the time slots.

13. A fire alarm system according to claim 10, said fire alarm system further comprising:

transmission error detecting means for detecting a transmission error when any of said plurality of terminal devices has a transmission error;

storage means for storing the number of times that the transmission error occurs; and

transmission error indicating means for indicating that a transmission error has occurred when the number of times that the transmission error occurs stored in said storage means exceeds a predetermined number.

14. A fire alarm system according to claim 10, wherein said receiving device conducts a polling operation which is continued even when a terminal device has a transmission error.