FIRE SYSTEM WITH CURRENT RESPONSE CALIBRATION

Abstract

A fire system 10 for a building is provided, the fire system 10 including a fire panel 12 for monitoring the building and activating an alarm; and a plurality of remote units 14, 16, 18 electrically connected to the fire panel 12 in a circuit 20 having a loop configuration. At least some of the plurality of remote units 14, 16, 18 including an indicating device 14, 18 for modulating a current in the circuit 20. The plurality of remote units 14, 16, 18 are in communication with the fire panel 12 in a master-slave relationship. The fire panel 12 includes a calibration module 22 for polling each indicating device 14, 18 to obtain a current response value and for storing said current response values, the current response value of an indicating device 14, 18 being based on the amplitude of the current when modulated by that indicating device.

Claims

1. A fire system for a building, the fire system comprising: a fire panel for monitoring the building and activating an alarm; and a plurality of remote units electrically connected to the fire panel in a circuit having a loop configuration, at least some of the plurality of remote units comprising an indicating device for modulating a current in the circuit; wherein the plurality of remote units are in communication with the fire panel in a master-slave relationship; and wherein the fire panel comprises a calibration module for polling each indicating device to obtain a current response value and for storing said current response values, the current response value of an indicating device being based on the amplitude of the current when modulated by that indicating device.

2. The fire system as claimed in claim 1, wherein the fire panel comprises a memory device for storing the current response values.

3. The fire system as claimed in claim 2, wherein the fire panel comprises a loop card, and the loop card comprises the memory device.

4. The fire system as claimed in claim 1, wherein the fire panel is configured to trigger a maintenance mode of operation for measuring the current response value of each indicating device and/or a calibration mode of operation for measuring and storing the current response value of each indicating device in the fire system, such as by the calibration module being configured to trigger the maintenance mode and/or calibration mode.

5. The fire system as claimed in claim 4, wherein the maintenance mode is automatically triggered in response to changes to the fire system and/or in response to passage of a time period.

6. The fire system as claimed in claim 4, wherein the maintenance mode and/or the calibration mode is triggered in response to an input from an operator.

7. The fire system as claimed in claim 4, wherein the maintenance mode is triggered as part of a maintenance routine.

8. The fire system as claimed in claim 4, wherein the calibration module is configured to produce a maintenance report in the maintenance mode.

9. The fire system as claimed in claim 1, wherein the calibration module is configured to poll the indicating devices by transmitting a polling signal through the loop.

10. The fire system as claimed in claim 9, wherein the polling signal is a modulation of a voltage in the loop, and/or wherein the indicating devices are configured to respond to the polling signal by modulating the current in the loop.

11. The fire system as claimed in claim 1, wherein the calibration module is configured to indicate a warning if a current response value is within a predetermined margin from a current threshold value, the current threshold value being the current response value at which the fire panel triggers an alarm.

12. The fire system as claimed in claim 1, wherein the calibration module is configured to adjust a current threshold value based on an input from a user and the current response values, the current threshold value being the current response value at which the fire panel triggers an alarm.

13. The fire system as claimed in claim 1 comprising a plurality of isolators for electrically isolating at least some of the remote units from the rest of the loop during calibration.

14. The fire system as claimed in claim 1, wherein the fire panel is configured to determine which indicating device a detected modulation in current has originated from based on the current response values.

15. A method of operating a fire system as claimed in claim 1, wherein the method comprises polling each indicating device for its current response value, and then reporting said current response values to a user and/or storing said current response values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Certain embodiments of the disclosure will now be described by way of example only and with reference to the accompanying drawings in which:

[0075] FIG. 1 is a diagram of a fire system using a master-slave communication system;

[0076] FIG. 2 is a diagram of a fire panel comprising a calibration module;

[0077] FIG. 3 is a diagram of a fire system with a circuit break; and

[0078] FIG. 4 is a diagram of a fire system with isolators operating in a calibration mode.

DETAILED DESCRIPTION OF THE INVENTION

[0079] As shown in FIG. 1, a fire system 10 comprises a fire panel 12 and a number of remote units 14, 16, 18. The fire system 10 and remote units 14, 16, 18 are electrically connected in a loop configuration, joined by wire 20, with each remote unit positioned at a different location along the loop. This fire panel 12 may be used to additionally provide power to the remote units 14, 16, 18. Alternatively, the remote units 14, 16, 18 may be powered independently of the fire panel 12. The remote units of FIG. 1 comprise indicating devices 14, indicator devices 16, and combined indicating and indicator device 18. Indicating devices 14 are used to detect conditions indicative of an emergency, and may include manual call points, smoke detectors, and/or heat detectors. Indicator devices 16 are used to alert users of an emergency condition and may include audible or visual devices, such as lights and/or bells. The combined indicating and indicator device 18 has a detection capability alongside an alarm, and may comprise a fire and/or smoke alarm. Although not shown in FIG. 1, the fire system may further comprise fire suppression devices.

[0080] The remote units 14, 16, 18 communicate with the fire panel 12 in a master-slave relationship. The remote units 14, 16, 18 send signals to the fire panel 12 through the wire 20 in the form of modulations in the current. These signals inform the fire panel 12 of the status of the remote units 14, 16, 18. The modulations in the current created by the remote units 14, 16, 18 may be increases or decreases in current. In response, the fire panel 12 may issue a command to the remote units 14, 16, 18. For example, if indicating device 14 modulates the current in such a way that is indicative of a possible emergency, the fire panel 12 may send a command to the remaining remote units 14, 16, 18 instructing them to enter an alarm condition. Alternatively, the fire panel 12 may send this command to only some of the remote units 14, 16, 18, depending on the location and nature of the possible emergency. The command may be in the form of a modulation of the voltage.

[0081] The fire panel 12 may also periodically send polling signals to the remote units 14, 16, 18, and the remote units 14, 16, 18 may respond with information regarding their status, their address, and/or their manufacturer code. The fire panel 12 may comprise means for alerting a user of a possible emergency. These means can include, but are not limited to, lights and/or a display.

[0082] The fire panel 12 may determine a current response value from any detected modulations in current caused by the remote units 14, 16, 18. The current response value is based on the amplitude of the current when modulated by a remote device, as detected by the fire panel 12. The fire panel 12 may compare this current response value to a current threshold value in order to determine whether the modulation in current is indicative of a possible emergency. For example, the current response value may be considered to indicate a possible emergency if it exceeds the current threshold value. Alternatively, the current response value may be considered to indicate a possible emergency if it falls below the current threshold value.

[0083] The fire panel 12 is shown in FIG. 2. The fire panel 12 comprises a calibration module 22 for carrying out and controlling the calibration of the fire system 10. As shown in FIG. 2, the fire panel 12 may also comprise a memory device 26. The memory device 26 may store the current response values. A user may be able to view these current response values through a fire panel display, if desired. The memory device 26 may be part of a loop card 24. The loop card 24 may receive information from the remote devices 14, 16, 18 and communicate that information to the calibration module 22, and/or to a loop controller (not shown). Similarly, the loop card 24 may receive signals from the calibration module 22 and/or loop controller and communicate those signals to the remote devices 14, 16, 18. The loop card 24 may therefore electrically connect the calibration module 22 to the loop. The loop card may comprise LED lights for indicating a basic condition of the fire system, such as an alarm condition or a fault condition.

[0084] The operation of the fire panel 12 may be controlled by a loop controller, which may be a central processing unit (CPU). The loop controller may process the information received from the remote units 14, 16, 18 and decide how to respond. For example, the loop controller may decide whether it is necessary to communicate an alarm condition to some or all of the remaining remote units 14, 16, 18, or may cause the remote units 14, 16, 18 to enter an alarm condition at different times in order to aid and manage evacuation of a building. The calibration module 22 may be part of the loop controller, or may work alongside the loop controller in order to carry out maintenance and/or calibration of the fire system 10.

[0085] The fire panel 12 may trigger a maintenance mode of operation in the fire system 10. The maintenance mode may be a mode in which the current response values of each indicating device 14, 18 are measured, and a maintenance report is produced and communicated to a user, the maintenance report including information based on the measured current response values. The fire system 10 may be placed in the maintenance mode automatically, and the maintenance mode may be triggered by the calibration module 22 and/or loop controller. The maintenance mode may be triggered in response to a change in the fire system 10 being detected by the fire panel 12, such as the addition, removal, or replacement of a remote unit 14, 16, 18, or a change due to a maintenance repair. The maintenance mode may be triggered periodically, for example weekly, monthly, or daily. This may be done automatically or in response to an input from an operator.

[0086] In addition to the above, or as an alternative, the fire panel 12 may trigger a calibration mode of operation in the fire system. In the calibration mode of operation, the current response values may be both measured and stored, for example in the loop card 24. The calibration mode may also include re-calibration of the current threshold value, as will be explained in further detail below.

[0087] The fire panel 12 may trigger the maintenance mode and/or the calibration mode in response to a command from an operator. The maintenance mode and/or calibration mode may be triggered by pressing a button on the fire panel 12, or an option on the fire panel display. The fire panel 12 may comprise means for wirelessly communicating with a mobile device, for example via a Wi-Fi network. Therefore, an operator may be able to trigger the maintenance mode and/or calibration mode remotely through a mobile device. The calibration mode may be triggered by an operator based on the maintenance report. For example, the operator may trigger the calibration mode when the maintenance report indicates that the currently stored current response values are no longer accurate, and/or if the maintenance report has led to maintenance work being done to the fire system 10.

[0088] The calibration mode may be triggered when the fire system 10 is first installed, either automatically or by an operator. This initial calibration may be used to determine the current threshold value of the fire system 10, and to store initial current threshold values of each indicating device 14, 16.

[0089] The calibration module 22 is configured to poll each indicating device 14, 18 for its current response value. The calibration module 22 may therefore transmit a polling signal through the loop. The polling signal may be encoded with an address of the indicating device 14, 18 it is intended for, and the indicating devices 14, 18 may comprise a transceiver for decoding the polling signal. If an indicating device 14, 18 determines that it is the indicating device 14, 18 that the polling signal is intended for, it may respond by modulating a current in the loop. This modulation in the current may be equivalent to that transmitted by the indicating device 14, 18 when it detects conditions indicative of an emergency.

[0090] The fire panel 12 may detect this modulation in the current in the loop through its loop card 24. The loop card 24 may then communicate this information to the calibration module 22. The calibration module 22 may determine the amplitude of the modulation in current, and may determine the current response value based on that amplitude. The calibration module 22 may work together with the loop controller to do this. Alternatively, the loop controller may determine the amplitude of the modulation in current and the current response value itself, and may communicate this information to the calibration module 22. The calibration module 22 may then, if in the calibration mode, store the current response values, for example in the memory device 26.

[0091] This process may be repeated for each indicating device 14, 18 in the loop until the current response value of every indicating device is measured and, if in the calibration mode, stored. The indicating devices 14, 18 may be polled sequentially. For example, the indicating device located closest to the fire panel 12 in the loop may be polled first, and the indicating device located furthest from the fire panel 12 in the loop may be polled last, or vice versa.

[0092] FIG. 3 shows the fire system 10 with a circuit break in the loop, shown by the cross between indicating device 14 and indicating device 18. Typically, the indicating devices 14, 18 may modulate the current in the loop in a first direction A and the fire panel 12 may supply both power and communications to the remote units 14, 16, 18 in a second direction B which is opposite to the first direction A. It will be appreciated that, although direction A is shown to be clockwise in FIG. 3 and direction B is shown to be anticlockwise, the inverse is possible and depends on the fire system 10 being used. In FIG. 3, the circuit break is preventing all devices located behind the break (i.e. along the second direction B from the break) from receiving power and/or communications in the second direction B, as well as preventing any indicating devices 14, 18 behind the break from communicating with the fire panel 12 in the first direction A. When the fire panel 12 and/or remote units 14, 16, 18 detect this situation, the direction of communications and/or power will be reversed for the remote units behind the circuit break. That is, the remote units 14, 16, 18 located behind the break will begin modulating the current in the second direction B instead, whilst the fire panel 12 will start supplying power and/or communications to these remote units through the first direction A.

[0093] The current response values of the indicating devices 14, 18 may depend based on how far the modulation in current has had to travel before it reaches the fire panel 12. Hence, if the direction in which the current is modulated is reversed, this may affect the current response values of the indicating devices 14, 18. In view of this, the calibration module 22 may be configured to poll the indicating devices 14, 18 for their current response values in both directions through the loop 20. That is, the polling signals in the maintenance and/or calibration mode may request the indicating devices 14, 18 to modulate the current in both the first direction A and the second direction B. The polling signals transmitted by the calibration module 22 may include a first polling signal requesting a first current response value in the first direction and a second polling signal requesting a second current response value in the second direction. Alternatively, the polling signals may include a single polling signal for each indicating device 14, 18 requesting the first and second current response values at the same time. The indicating devices 14, 18 may respond by modulating the current in each direction sequentially or simultaneously. In the calibration module, the calibration module 22 may store both the first and second current response values of the indicating devices 14, 18 in the loop card 24.

[0094] The calibration module 22 may compare each current response value to the current threshold value. If a current response value is within a predetermined margin from the current threshold value, the calibration module 22 may label it as a warning value and indicate a warning. This may occur in both the calibration mode and the maintenance mode of operation. The calibration module 22 may indicate the warning visually, for example through LED lights. The calibration module 22 may issue a warning notification, which may be displayed on the fire panel display or transmitted wirelessly to a mobile device. The warning notification may inform a user of which indicating device caused the warning value, and where it is located. As such, the fire system 10 can monitor the performance of the indicating devices 14, 18 through the calibration mode, and can notify an operator when the performance of an indicating device 14, 18 has degraded to the point where it might not be able to communicate a fire alarm condition. Hence, potential faults in the fire system 10 can be identified and rectified before any failure actually occurs. For example, any indicating devices 14, 18 responsible for warning values may be replaced in the fire system 10 in order to prevent any faults occurring.

[0095] As mentioned above, the calibration module 22 may be configured to produce a maintenance report in the maintenance mode of operation. This maintenance report may contain information such as the stored current response values of the indicating devices 14, 18, the measured current response values of the indicating devices 14, 18, a difference between the stored and measured current response values, and an indication of which current response values are labelled as warning values. The maintenance report may be communicated to an operator through the fire panel display, or may be transmitted to a mobile device of an operator through a transmitter device of the fire panel 12. An operator may then decide to trigger the calibration mode in the fire system 10 based on the maintenance report.

[0096] The calibration module 22 may be configured to set a new current threshold value based on the current response values. The calibration module 22 may only set a new current threshold value if instructed to by an operator, for example through the triggering of the calibration mode. An operator may decide to set a new current threshold value based on the maintenance report produced during the maintenance mode. For example, an operator may see one or more current response values are labelled as warning values and thus are dangerously close to the current threshold value. The calibration module 22 may set the current threshold value to be equal to the lowest current response value plus or minus a predetermined error margin. Consequently, a dynamic current threshold value may be established that is adaptable to changes in the fire system 10. The calibration module 22 may communicate this new current threshold value to an operator, for example by communicating the new current threshold value to a transmitter device such that it can be transmitted to the operator or by displaying the new current threshold device on the fire panel display. Therefore, if the new current threshold value is set too low, such that it may result in a number of false positives, an operator may be able to see this and recalibrate the fire system 10 accordingly. Alternatively, the calibration module 22 may itself determine that a new current threshold value would be too low and hence would risk improper operation of the fire system 10. In this case, the calibration module 22 may retain the previous current threshold value, and indicate a warning instead.

[0097] FIG. 4 shows fire system 10 comprising a plurality of isolators 28. In FIG. 4, an isolator 28 is positioned between each remote unit 14, 16, 18. However, it will be appreciated that the isolators 28 may be embedded in the remote units 14, 16, 18 instead, or in addition to the isolators 28 located on the loop. The isolators 28 allow selected remote units 14, 16, 18 to be electrically isolated from the rest of the loop. At least some of the isolators 28 may be activated in the maintenance mode and/or the calibration mode in order to electrically isolate at least some of the remote units 14, 16, 18 from the loop. Different isolators 28 may be activated at different times depending on which indicating device 16, 18 is being polled. The calibration unit 22 and/or the loop controller may automatically control the operation of the isolators, or an operator may manually control the operation of the isolators.

[0098] For example, the calibration module 22 may activate the isolators 28 such that only remote unit 18 is electrically connected to the fire panel 12, with the other remote units 14, 16 being electrically isolated from the loop by the isolators 28. As such, noise in the loop may be reduced when determining the current response value of the remote unit 18.

[0099] However, during normal operation of the fire system 10, the remote units 14, 16, 18 are all electrically connected to the fire panel 12. Therefore, any modulations in current travelling through the loop will be affected by the remote units 14, 16, 18 it passes by. It is therefore important for the fire panel 12 to take account of this when using isolators 28 in the maintenance mode and/or the calibration mode. Hence, when isolators 28 are utilised in the maintenance mode and/or calibration mode, the current consumption of any remote devices 14, 16, 18 that the modulation in current passes will be taken into account when determining the current response values.

[0100] As shown in FIG. 4, the remote unit 18 modulates the current in a direction A along the loop. When the fire panel 12 is determining the current response value of this remote unit, it may therefore factor in the current consumption of all the remote units located along the loop in the direction A from the remote unit 18.

[0101] The current response values may be used during normal operation of the fire system 10 in order to distinguish between responses from the indicating devices 14, 18. For example, the current response values may be considered to be characteristic of each indicating device 14, 18 if each indicating device 14, 18 has a different current response value. As such, the fire panel 12 may be able to determine which indicating device 14, 18 a modulation in current has originated from based on the current response value of the modulation in current. Further, the fire panel 12 may be able to determine if a detected modulation is a result of multiple responses from a single indicating device or multiple responses from different indicating devices through the current response values. For example, if a first indicating device has a current response value of 20 mA and a second indicating device has a current response value of 25 mA, then a current modulation with a value of 45 mA may be determined to have come from both the first and second indicating devices. Alternatively, a current modulation with a value of 40 mA may be determined to be a result of multiple responses from the first device.

[0102] As mentioned above, the remote units 14, 16, 18 may comprise indicating devices 14, indicator devices 16, or combined indicator and indicating devices 18. These can include manual call points; smoke detectors; heat detectors; other building sensors used for fire or heat detection, such as room thermostats; sensors for supervised doors; sensors for supervised fire extinguishers; water flow sensors; sirens; bells; lights; transmitter devices and so on. The fire system 10 may include input-output modules for handling information from some types of indicating devices 14 that may lie outside of the fire system 10, such as thermostats or water flow sensors. Additionally or alternatively, input-output modules may be provided for activating automatic door opening and/or closure systems, or door locking systems.

[0103] The calibration module 22 therefore allows the condition of the fire system 10 to be monitored. By measuring the current response values of each indicating device 16, 18, the performance of the fire system 10 can be observed and the fire system 10 can be adapted accordingly. This may be achieved by establishing an appropriate current threshold value for the specific fire system 10 being used, and/or identifying and remedying any degradations in performance before a fault occurs. A fire system 10 with improved reliability and safety is therefore provided by the use of such a calibration module 22.