Single-wire loop alarm system
First Claim
1. An identification module for placement across a normally-closed alarm switch contained in a single-wire loop of an alarm system through which a current normally flows comprising means for representing a module address, means for diverting the loop current from said switch and for powering the module from the diverted current only when said switch is open, means for counting successive momentary interruptions in the loop current, and means responsive to the number of current interruptions corresponding to the module address for momentarily changing characteristics of the module seen by the loop current.
1 Assignment
0 Petitions
Accused Products
Abstract
A single-wire loop alarm system in which an identification module is placed across each alarm switch. Any module which is across an open switch is powered by the loop current and, in response to a pulse count in the loop representing its address, changes the loop impedance in order to report on its status. The loop current may alternate in direction so that oppositely poled modules may be used, thus allowing a larger number of powered modules to accommodated at the same time.
-
Citations
110 Claims
- 1. An identification module for placement across a normally-closed alarm switch contained in a single-wire loop of an alarm system through which a current normally flows comprising means for representing a module address, means for diverting the loop current from said switch and for powering the module from the diverted current only when said switch is open, means for counting successive momentary interruptions in the loop current, and means responsive to the number of current interruptions corresponding to the module address for momentarily changing characteristics of the module seen by the loop current.
- 6. An identification module for placement across a normally-closed alarm switch contained in a single-wire loop of an alarm system through which a current normally flows comprising means for representing a module address, means for diverting the loop current from said switch and for powering the module from the diverted current when said switch is in its open condition, means for counting successive momentary interruptions in the loop current, and means responsive to the number of current interruptions corresponding to the module address for momentarily changing characteristics of the module seen by the loop current.
- 9. An identification module for placement across an alarm switch contained in a single-wire loop of an alarm system through which a current normally flows comprising means for representing a module address, means for diverting the loop current from said switch and for powering the module from the diverted current only when said switch is open, means for counting successive momentary interruptions in the loop current, and means responsive to the number of current interruptions corresponding to the module address for momentarily changing characteristics of the module seen by the loop current.
- 13. An identification module for use in an alarm system by placement across an alarm switch comprising a pair of input terminals for connection across said switch, means responsive to said switch being open and the diversion of current through said input terminals for developing a potential to power the module, means for representing an address, means for counting the number of interruptions in the current flowing through said input terminals each of which is short enough to prevent power-down of the module, and means responsive to the instantaneous count matching the represented address for momentarily changing electrical characteristics of the module as seen looking into said input terminals.
-
16. A combined alarm switch/identification module for use in an alarm system comprising a housing;
- an alarm switch contained in said housing and having a pair of input put terminals; and
circuit means contained in said housing connected across said pair of input terminals;
said circuit means including means responsive to said alarm switch being open and the diversion of current through said circuit means for developing a potential to power the circuit means, means for representing an address, means for counting the number of interruptions in the current flowing through said circuit means each of which is short enough to prevent power-down of the circuit means, and means responsive to the instantaneous count matching the represented address for momentarily changing electrical characteristics of the circuit means as seen looking into said input terminals. - View Dependent Claims (17, 18)
- an alarm switch contained in said housing and having a pair of input put terminals; and
-
19. A combined alarm switch/identification module for use in an alarm system comprising a housing;
- an alarm switch contained in said housing and having a pair of input terminals; and
circuit means contained in said housing connected across said pair of input terminals;
said circuit means including means responsive to said alarm switch being open and the diversion of current through said circuit means for developing a potential to power the circuit means, means for representing an address, means for recognizing an address code represented by the current flowing through said circuit means in a manner such that power-down of the circuit means is prevented, and means responsive to the recognized address code matching the represented address for momentarily changing electrical characteristics of the circuit means as seen looking into said input terminals. - View Dependent Claims (20, 21)
- an alarm switch contained in said housing and having a pair of input terminals; and
- 22. A two-terminal module for use in a single-wire loop alarm system comprising a housing having two terminals, a switch contained in said housing connected between said two terminals, and identification means contained within said housing and connected between said two terminals for responding to an address transmitted over the loop in which the module is connected, said identification means including means for powering itself by quiescent current flowing through said terminals, means for counting current pulses in said loop and for comparing the number with a preassigned address, and means responsive to a match for changing electrical characteristics between the two terminals.
-
28. A single-wire loop alarm system comprising a central control;
- a wire loop whose ends terminate at said central control;
a plurality of normally-closed alarm switches disposed along said loop;
means in said central control for normally causing a fixed current to flow through said loop and the alarm switches disposed therealong;
a plurality of identification modules each connected in parallel across a respective alarm switch, having means for representing a unique address, and including means responsive to a transmitted code corresponding to said unique address appearing on the loop when the respective alarm switch is open for changing a loop characteristic;
means in said central control responsive to an increase in the loop impedance when an alarm switch is open for polling said modules by applying sequentially on said loop the codes corresponding to the module addresses; and
means in said central control for registering those modules for which the loop characteristic changes responsive to the appearance on the loop of the corresponding transmitted code. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
- a wire loop whose ends terminate at said central control;
-
45. A single-wire loop alarm system comprising a central control;
- a wire loop whose ends terminate at said central control;
a plurality of alarm switches disposed along said loop;
a plurality of two-terminal identification modules each connected in parallel across a respective alarm switch, having means for representing a unique address, and including means responsive to a transmitted code corresponding to said unique address appearing on the loop when the respective alarm switch is open for changing its electrical characteristics;
means in said central control for normally causing a fixed current to flow through said loop, and the alarm switches and identification modules disposed therealong;
means in said central control responsive to a change in the loop impedance when an alarm switch changes state for polling said modules by applying sequentially on said loop the codes corresponding to the module addresses; and
means in said central control for registering those modules for which the loop electrical characteristics change responsive to the appearance on the loop of the corresponding transmitted code. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
- a wire loop whose ends terminate at said central control;
-
61. A single-wire loop alarm system comprising a control unit;
- a wire loop whose two ends terminate at said control unit;
a plurality of alarm switches disposed along said loop;
a plurality of identification modules connected in parallel with respective ones of said alarm switches, some of said modules being responsive to current pulses in a first direction through said loop and others of said modules being responsive to current pulses in a second direction through said loop, all of said modules simply allowing the loop current to be bypassed if the current is in the direction for which the module is not responsive;
means in said control unit for causing a direct current to flow through said loop alternating between the two directions for ascertaining if an alarm condition exists;
means in said control unit responsive to the existence of an alarm condition for generating a series of current pulses in the loop, alternating between the two directions, for addressing individually said identification modules;
each of said identification modules including means responsive to its individual addressing for changing its internal characteristics so as to affect the current flowing in said loop in a manner representative of its status; and
means in said control unit for monitoring the current in said loop to determine the status of an addressed identification module. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76)
- a wire loop whose two ends terminate at said control unit;
-
77. An alarm system comprising a control unit;
- a wire loop whose two ends terminate at said control unit;
a plurality of alarm switches disposed along said loop;
a plurality of identification modules connected in parallel with respective ones of said alarm switches, some of said modules being responsive to currents in a first direction through said loop and others of said modules being responsive to currents in a second direction through said loop, all of said modules simply allowing the loop current to be bypassed if the current is in the direction for which the module is not responsive;
means in said control unit for causing a direct current to flow through said loop alternating between the two directions for ascertaining if an alarm condition exists;
means in said control unit responsive to the existence of an alarm condition for generating a series of address codes in the loop, alternating between the two directions, for addressing individually said identification modules;
each of said identification modules including means responsive to its individual addressing for changing the current flowing in said loop in a manner representative of its status; and
means in said control unit for monitoring the current in said loop to determine the status of an addressed identification module. - View Dependent Claims (78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91)
- a wire loop whose two ends terminate at said control unit;
-
92. A single-wire loop alarm system comprising a control unit;
- a wire loop whose two ends terminate at said control unit;
a plurality of normally-closed alarm switches disposed along said loop;
a resistance in series with each of said normally-closed alarm switches;
an identification module connected in parallel across each of said series connections of an alarm switch and a resistance;
means in said control unit for causing a relatively large current to flow through said loop and for recognizing a change in potential across said loop as indicative of the opening of an alarm switch;
each of said identification modules including means responsive to the diversion of current therethrough responsive to the opening of the associated alarm switch for powering the module; and
means in said control unit responsive to the recognition of the opening of an alarm switch for reducing the magnitude of the current caused to flow through said loop and for coding said current to successively poll said identification modules;
each of said identification modules further including means for recognizing a poll thereof and for responding by selectively changing the impedance presented to the loop current, said control unit means for recognizing a change in loop potential thus being informed of the responses to the poll of said identification modules. - View Dependent Claims (93, 94, 95, 96)
- a wire loop whose two ends terminate at said control unit;
-
97. An alarm system comprising a plurality of alarm switches and paired identification modules connected in a loop;
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
each of said identification modules including means for transmitting the status of its paired alarm switch responsive to the appearance of its address on said loop;
said control unit further including means for cyclically displaying the addresses of all identification modules paired with alarm switches whose statuses represent alarm conditions, and switch means for causing said control unit to subsequently ignore the alarm condition of any alarm switch whose address is displayed while said switch means is momentarily operated.
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
-
98. An alarm system comprising a plurality of alarm switches and paired identification modules connected in a loop;
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
each of said identification modules including means for transmitting the status of its paired alarm switch responsive to the appearance of its address on said loop;
said control unit further including manually operated means for triggering the display of the history of the alarm system subsequent to the preceding display, and means responsive to the operation of said manually operated means for cyclically displaying the addresses of all identification modules paired with alarm switches whose statuses represented alarm conditions during preceding polling sequences. - View Dependent Claims (99)
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
-
100. An address programmer for an alarm system, said alarm system having a plurality of alarm switches and paired identification modules connected in a single-wire loop;
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
each of said identification modules including means responsive to receipt of programming current pulses for setting its address, and means for transmitting on said loop the status of its paired alarm switch responsive to the appearance of its address on said loop during a polling sequence;
said address programmer comprising means for representing an address, means connectable across said loop, and means for applying to said loop programming current pulses for setting the address of a selected identification module to be that represented in the programmer. - View Dependent Claims (101, 102)
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
-
103. An alarm system comprising a plurality of alarm switches and paired identification modules connected in a single-wire loop;
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
each of said identification modules including means for transmitting on said loop the status of its paired alarm switch responsive to the appearance of its address on said loop during a polling sequence, and means responsive to the appearance of a control code on said loop for setting the address of the module in accordance with the control code. - View Dependent Claims (104)
- and a control unit, said control unit including means for transmitting addresses over said loop to all of said identification modules in a polling sequence, for ascertaining status information transmitted back along said loop, and for taking appropriate action in response to such status information;
- 105. An identification module comprising means for responding to an assigned address transmitted over a line in which the module is connected, the module including means for powering itself by current flowing in said line, means for counting current pulses in said line and for comparing the number with said assigned address, and means responsive to a predetermined condition on said line following the counting of current pulses for assigning an address to the module which is equal to the pulse count number.
-
109. A single-wire loop alarm system comprising a central control;
- a wire loop whose ends terminate at said central control;
a plurality of normally-closed alarm switches disposed along said loop;
means in said central control for normally causing a fixed current to flow through said loop and the alarm switches disposed therealong;
means for registering an alarm condition responsive to the opening of one of said alarm switches;
a plurality of identification modules each connected in parallel across a respective alarm switch, having means for representing a unique address, and including means responsive to a transmitted code corresponding to said unique address appearing on the loop when the respective alarm switch is open for responding with an indication of its status; and
means in said central control responsive to a change in the loop impedance when an alarm switch is open for polling said modules by applying seqentially on said loop the codes corresponding the the module addresses;
each of said modules allowing an alarm condition to be registered in the normal manner even if the module malfunctions and does not respond with an indication of its status when its address appears on the loop.
- a wire loop whose ends terminate at said central control;
-
110. A single-wire loop alarm system comprising a central control;
- a wire loop whose ends terminate at said central control;
a plurality of alarm switches disposed along said loop;
means in said central control for normally causing a fixed current to flow through said loop and for measuring the potential drop across said loop;
a plurality of identification modules each connected in association with a respective alarm switch, having means for representing a unique address, and including means responsive to a code transmitted from said central control corresponding to said unique address appearing on the loop for responding with an indication of its status; and
means in said central control for sensing changes in the loop potential for ascertaining changes in the statuses of said alarm switches and for polling said modules by applying sequentially on said loop the codes corresponding to the module addresses;
said means for causing changes in the loop potential including programmable comparator means, means for setting a threshold level in said programmable comparator means, means for determining whether the loop potential is above or below said threshold level, and means for changing said threshold level as a function of small changes in said loop potential which are not large enough to be indicative of a change in status of an alarm switch.
- a wire loop whose ends terminate at said central control;
Specification