Multi-zone microprocessor fire control apparatus

• US 5,008,840 A
• Filed: 05/27/1988
• Issued: 04/16/1991
• Est. Priority Date: 05/27/1988
• Status: Expired due to Term

• Current Assignee: Napco Security Systems Incorporated
• Original Assignee: Napco Security Systems Incorporated
• Inventors: DePierro, Alfred V.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Cosimano, Edward R.
• Application Number:
  US07/199,772
• Time in Patent Office: 1,054 Days
• Field of Search: 340/525, 340/577, 340/578, 340/579, 364/550
• US Class Current: 340/506
• CPC Class Codes: G08B 29/145 of fire detection circuits

Abstract

There is disclosed a multi-zone microprocessor fire control apparatus. The control apparatus employs a microprocessor which monitors a plurality of zones. Each zone may be associated with a smoke detector and which smoke detector will provide a predetermined condition when smoke is present in a zone. The microprocessor is controlled to monitor each zone by scanning the zones in a predetermined sequence. The microprocessor is associated with the key pad. According to the present invention, the key pad is accessed by a serviceman who inserts a given code into the key pad indicative of a one man test mode. The microprocessor recognizes the selection of this mode and therefore anticipates receiving an alarm condition due to the fact that the serviceman, after accessing the key pad, will enter a selected zone to provide an intentional alarm at that zone. Based on the fact that the microprocessor recognizes the selection of this one man test mode, the microprocessor will expect an alarm from the selected zone and will notify the serviceman by providing an audible alarm after the serviceman has intentionally caused the alarm. In this manner the serviceman can access each of the zones selected to verify proper operation by intentionally causing an alarm at each zone without causing the system to provide a normal output alarm signal which would occur upon the existence of true smoke conditions in a zone. There are other modes of operation during this test mode which enable the microprocessor to selectively inform a serviceman of conditions at selected zones by enabling the serviceman to repair such conditions as necessary.

Claims

1. A fire control system including a plurality of zones, each zone associated with a smoke detector and arranged in at least a two wire loop, with said smoke detector positioned across said two wires to provide a low impedance condition upon detection of smoke indicative of a fire in that zone and to provide a high impedance when smoke is not detected, comprising

biasing means for each loop to allow a current to flow in each loop indicative of a normal condition as distinguished from a low impedance condition across said loop as caused by said smoke detector;

multiplexer means having one input for each loop and having a control input to provide at an ouptut the condition of each loop in a selected sequence as controlled by a signal applied to said control input;

a microprocessor means having output means coupled to said multiplexer control input for controlling the same;

comparator means having inputs coupled to said multiplexer output and outputs coupled to said microprocessor means to enable said microprocessor to store the condition of each loop indicative of each zone and as to whether said loop is in a normal condition or a low impedance condition;

a keyboard coupled to said microprocessor means for causing said microprocessor to recognize selected key depressions indicative of a one man test mode, whereby when said mode is recognized said microprocessor means responds to low impedance conditions of selected loops as being intentionally implemented during a predetermined period to notify a user of said test mode in order to verify an intentional implemented low impedance condition of said loop as caused by an associated smoke detector with said microprocessor coupled to said biasing means to interrupt said current flow in said loop for a given period to allow said intentional condition to clear back to normal indicative of the completion of said one man test mode.

2. The system according to claim 1 further including audible output means coupled to said microprocessor means and responsive to the implementation of said intentional low impedance condition to provide a first audible signal indicative of said intentional low impedance condition during said one man test mode and to provide a second output audible signal when said low impedance condition is cleared.

3. The system according to claim 1 further including display means coupled to said microprocessor means for receiving a display signal from said microprocessor means indicative of said zone which provides said intentional low impedance condition.

4. The system according to claim 1 further including means associated with said microprocessor means and operative to monitor said key pad means to enable a user to select one or more zones in said plurality during said one man test mode.

5. The system according to claim 1 further including a PROM coupled to said microprocessor means and operative to store therein data indicative of said given period as selected according to the type of smoke detection employed with said zone.

6. The system according to claim 1 further including means within said microprocessor means for responding to an high impedance condition of any one of said zones to provide an indication of said high impedance condition during said one man test mode.

7. The system according to claim 6 further including second audible output means coupled to said microprocessor means and operative to provide a different audible signal indicative of said high impedance condition at any one of said zones.

8. A method of operating a fire control system in a one man test mode to enable a sole serviceman to test said system, said system including a plurality of zones, each zone associated with an alarm device whereby activation of said device causes a predetermined condition to appear at a zone output where said zones are monitored by a microprocessor, said microprocessor coupled to a key pad for causing said microprocessor to recognize commands from said key pad as inserted by said keys being depressed, comprising the steps of:

inserting a code in said key pad indicative of said one man test mode;

deciphering said code to inform said microprocessor of the selection of said one man test mode;

accessing a selected zone to cause said device to provide said predetermined condition;

causing said microprocessor to recognize said predetermined condition to verify said condition as implemented by accessing said device;

providing a predetermined signal upon recognition by said microprocessor to enable said serviceman to verify said system operation and removing said predetermined condition from said accessed zone; and

enabling said microprocessor to recognize said removed predetermined condition to provide a second signal upon said removal to inform said serviceman of the same.

9. The system according to claim 8 further including the step of selecting one or more zones to be tested by depressing said key pad according to said selected zones.

10. The system according to claim 9 further including the steps of deciphering said selected zones to inform said microprocesor of the same.

11. The method according to claim 8 wherein said alarm device is a smoke detector with said predetermined condition caused by blowing smoke into said smoke detector when accessing said zone.

12. The method according to claim 11 wherein said predetermined condition is caused by opening a zone during said test mode to cause said microprocessor to recognize said opening as said predetermined condition.

13. The method according to claim 11 wherein the step of removing said predetermined condition includes blowing air into said smoke detector to dispel smoke from said chamber of said detector.

14. The method according to claim 13 wherein the steps of removing said predetermined condition includes removing power from said smoke detector for a given selected period of a time sufficient to enable said smoke detector to revert to a non-alarm condition after blowing said air into said detector.

15. In a fire control system of the type including a plurality of zones to be monitored, each zone associated with a smoke detector and arranged as a two wire loop with said smoke detector positioned across said two wires to provide a short upon detection of smoke, with each zone monitored by processing means operative to scan said zones in a determined sequence to respond to the condition of each loop in each zone in order to determine the presence of an alarm in said zone manifested by said smoke detector activation providing a short across said wires, whereby if said alarm continues said processing means will provide an output indicative of said alarm, the combination therewith of apparatus for testing system operation in a one man test mode, comprising:

first means coupled to said processing means and operative to inform said processing means of said selection of said one ma test mode;

means responsive to said selection to cause said processing means to wait a given period before providing an alarm output during said one man test mode to enable a serviceman to intentionally provide an alarm in a zone by activating said associated smoke detector;

second means coupled to said processing means operative to cause said processing means to provide an output indicative of said intentionally provided alarm to thereby notify said serviceman of the same.

16. The combination according to claim 15 wherein said first means includes a key pad coupled to said processing means for inserting a code via said pad indicative of said one man test mode.

17. The combination according to claim 15 wherein said second means includes an audible output means to enable said serviceman to be notified.

18. The combination according to claim 15 further including display means coupled to said processing means for displaying the zone location upon which said intentional alarm is provided.

19. The combination according to claim 15 further including third means coupled to said processing means to automatically restore said intentional alarm to a non-alarm condition during said test mode and during a predetermined time period.

20. The combination according to claim 19 wherein said third means includes means coupled to said smoke detector means for removing operating potential therefrom during said predetermined period.