Testing of communication on loop of a fire alarm system

Abstract

Testing communication on a 2-wire addressable loop of a fire alarm system is done using a portable test tool comprising: connecting the portable test tool to the two wires of the loop using a pair of leads; pairing the portable test tool with a remote device using a wireless protocol; detecting and decoding communications which are put on the addressable loop; download the communications from the portable test tool to the remote device using the wireless protocol; and analysing the communications.

Description

[0001] Testing of Communication on Loop of a Fire Alarm System

[0002] Field of Invention

[0003] The present invention relates to the testing of communication on the loop of a fire alarm systems installed on a premises.

[0004] Backg round

[0005] Fire alarm systems are installed in many premises, such as office buildings, factories, homes, and the like, and typically include a fire alarm control panel (often known as control and indicating equipment, CIE), a number of detectors and sounders, and wiring connecting the detectors and sounders to the fire alarm control panel. The system might also include call points and a range of other ancillary modules. In many cases, the wiring which is installed is a 2 wire addressable loop, and the detectors, sounders, call points and other ancillary modules (hereafter called "the devices") are arranged on the loop connected across its 2 wires. Multiple loops are generally installed from the control panel, with each loop typically carrying the devices to a different part of the premises. The loops typically provide power to the devices on the loop, and convey instructions and data from the control panel to the individual devices, such as configuration data to all devices or an alarm signal to the sounders, and convey data from the devices to the control panel, such as an indication that a fire has been detected. The looped arrangement means that there is some resilience to a break in an individual loop occurring during operation and that the voltage level between the wires in the loop are maintained sufficiently high to sustain all of the devices around the complete loop. In one known fire alarm system, a fire alarm control panel can support up to 16 loops, and each loop can support up to 250 devices. In it, communication on the loop uses frequency shift keying (FSK)) with sinusoidal signals on a DC pedestal of 37.6V. The general structure of a data packet under this encoding method comprises: a header; a byte comprising an 8 bit data packet; and a stop bit. The data is encoded such that the frequency of a "0" is much higher than the frequency of a "1". In this case, the frequency of a "0" is 6667Hz, and that of a "1" is 3030Hz, and when converted to a pulse width modulated signal, a "0" is represented with a much narrower pulse width than a "1". Of course, it is to be understood that FSK encoding could use different frequencies, and could use a different pedestal voltage. Indeed, different encoding systems altogether could be used.

[0006] Once the system has been installed, it must be commissioned, which involves testing that everything is operating correctly and configuring all of the devices. To test the loops, a portable commissioning tool is often used which is connected to the ends of the wires that will form a loop. The portable commissioning tool, such as the MX TrueStart tool, tests the loop by ensuring that each wire has continuity, and by applying a DC voltage across one end of the loop and testing that the voltage at the opposite end of the loop is maintained at a sufficiently high voltage that it is able to operate all of the devices around the loop. The portable commissioning tool also communicates with each device on the loop once they have been installed in order to configure them, as appropriate.

[0007] Once installed, faults can arise which must be identified and resolved, which involves testing the integrity of the loops, and the correct operation of the devices and the control panel.

[0008] In this specification, references to testing refers to testing during commissioning and to testing after installation has been completed, typically where a fault has arisen.

[0009] Faults can arise in communication between the fire alarm control panel and the devices on the loop, for example, by errors in installation, or by noise. Communication faults can be difficult to diagnose because they are often intermittent, sometimes a result of the fact that a faulty device or incorrectly installed device communicates infrequently with the control panel, and sometimes for other reasons. In this scenario, engineers typically rely on event logs which are stored in the fire alarm control panel, but event logs contain a limited amount of information, and don't give the exact cause for communication failure.

[0010] An aim of the present invention is to improve the logging of data communication on a loop between the fire alarm control panel and the devices on the loop.

[0011] Summary of Invention

[0012] According to a first aspect of the invention, a method of testing communication between a control panel and a number of addressable networked devices on a 2-wire addressable loop of a fire alarm system using a portable test tool comprises: connecting the portable test tool to the two wires of the loop using a pair of leads; pairing the portable test tool with a remote device using a wireless protocol; detecting and decoding communications between the control panel and the addressable networked devices which are put on the addressable loop; downloading the communications from the portable test tool to the remote device using the wireless protocol; and analysing the communications. By connecting the portable tool wirelessly, the decoding and downloading of communications can be achieved without interfering with the communication on the loop as the portable tool has no connection to earth, which tends to cause communication interference on the loop and to trigger earth faults in the control panel. Preferably, the step of downloading includes streaming the communications to the remote device.

[0013] It is advantageous if the method further comprises storing the communications in a memory of the portable test tool. In this case, the downloading step may include downloading the communications after the test is complete and / or periodically during the test.

[0014] The wireless protocol used may be Bluetooth (R.TM).

[0015] The method may further comprise converting the communications into log files in the portable test tool and wherein the communications are downloaded as the log files. In this case, the conversion of communications might include adding at least one of a timestamp and metadata collected at the time of the test into the log files.

[0016] The method might further comprise loading software on the remote device whereby the remote device can analyse the communications.

[0017] The method optionally comprising configuring the portable test tool to select the length of the test.

[0018] According to a second aspect of the invention, a portable test tool for testing communication between a control panel and a number of addressable networked devices on a 2-wire addressable loop of a fire alarm system, comprises: leads for connecting the portable test tool to the two wires of the loop; a wireless port by which the tool can be paired to a remote device using a wireless protocol; and a processor for decoding the communications between the control panel and the addressable networked devices detected on the addressable loop and for downloading the communications to the remote device via the wireless port.

[0019] The portable test tool preferably includes a memory for storing the communications in the portable test tool.

[0020] In one embodiment, the wireless port is a Bluetooth (RTM) port.

[0021] The portable test tool optionally comprises a user input by which the tool can be configured to select the length of the test. Brief Description of the Drawings

[0022] The present disclosure will now be described by way of example only with reference to the accompanying drawings in which:

[0023] Figure 1 is a drawing showing a fire alarm system and a test tool according to the present invention;

[0024] Figure 2 is a drawing showing the architecture of the test tool of Figure 1; and

[0025] Figure 3 is a flow diagram showing the steps of testing the communication using the test tool of Figures 1 & 2.

[0026] Detailed Description

[0027] Figure 1 shows a fire alarm system 1 having 2-wire addressable network wiring in the arrangement of a closed loop 2 with two ends terminating at a control panel 3 (often referred to as control & indicating equipment CIE), a number of addressable networked devices 4 attached to the addressable network loop 2, and a portable test tool 5.

[0028] The addressable networked devices 4 can be any of a range of different fire alarm system devices, including : sensors 4a such as smoke detectors, heat detectors, fire detectors and the like; notification devices 4b such as sounders and strobes; and other ancillary modules such as call points 4c which are typically found on the loop of a fire alarm system. The devices 4 are connected across the wires of the loop such that they are powered from the loop and are able to transmit and receive data to and from the control panel 3. Base units are often connected directly to the wires of the loop, and the devices may then be attached to the base units for easy connection to the network loop at a location defined by the position of the base unit (not shown).

[0029] When faults arise in communication between the fire alarm control panel and the devices on the loop, for example, by errors in installation, or by noise, the cause can be difficult to diagnose because they are often intermittent, and because a faulty device or incorrectly installed device communicates infrequently with the control panel. In this scenario, engineers typically rely on event logs which are stored in the fire alarm control panel, but event logs contain a limited amount of information, and don't give the exact cause for communication failure. It has been determined that diagnosis of the cause can be aided by analysing the actual data communicated between the control panel and the devices. Communication on the loop in this embodiment uses frequency shift keying (FSK)) with sinusoidal signals on a DC pedestal of 37.6V. The general structure of a data packet under this encoding method comprises: a header; a byte comprising an 8 bit data packet; and a stop bit. The data is encoded such that the frequency of a "0" is much higher than the frequency of a "1". In this case, the frequency of a "0" is 6667Hz, and that of a "1" is 3030Hz, and when converted to a pulse width modulated signal, a "0" is represented with a much narrower pulse width than a "1". Of course, it is to be understood that FSK encoding could use different frequencies, and could use a different pedestal voltage. Indeed, different encoding systems altogether could be used.

[0030] Communication takes place using a Command / Response protocol where the control panel 3 polls each of the devices 4 with an addressed command, and when a device receives a command addressed for it, the device 4 carries out the instruction and sends a response on the loop for the control panel 3 to receive. The command from the control panel to a device could, for example, instruct it to enter data into its memory, such as configuration data, it could instruct it to send some data to the control panel over the loop, it could request an alarm status, or it could request a value from a detector, if the device is a detector, or it could instruct the device to sound an alarm if the device is a notification appliance. Every device is polled about every 5 seconds.

[0031] The control panel includes a log which stores significant pieces of information, such as when a device notifies an alarm, or when a notification appliance is instructed to sound an alarm, but because the amount of communication data is so large, this is not stored at all, or if it is, not for very long. This makes diagnosis of some problems difficult.

[0032] In the present invention, the portable test tool 5 is used to detect and store the communication data : the commands sent by the control panel; and the responses from the devices, by connecting it to the loop.

[0033] In the present embodiment, the portable test tool is a portable commissioning tool which is able to carry out a range of tests on the addressable network loop 2 and the devices 4 which are positioned on the loop 2 connected to the tool in any one of a number of different ways. The portable test tool could equally well be a single function tool which can be used only for this invention. The test tool has four terminals with two of those terminals being temporarily connectable using a pair of leads 11 to different wires of the loop 2. It has a display 6 and a user input 7 in the form of buttons. These allow a technician to interact with it, selecting and configuring a test, and displaying the configuration of the test and / or the results from that test. It also includes a processor and storage (not shown) The portable test tool 5 further includes a Bluetooth port 8 to enable it to communicate wirelessly through Bluetooth protocol with other devices. The Bluetooth port 8 could be a wireless data interface of a different kind, such as a Wi-Fi (R.TM) interface. The Bluetooth port 8 enables wireless data communication with another device, in this case, a smartphone 9. The smartphone 9 has a screen 10, a camera 12, and a Bluetooth port 13. The Bluetooth port 13 is able to connect to the Bluetooth port 8 of the test tool 5 via Bluetooth connection 14. Alternatively, or additionally, the other device is a computer 19. The computer 19 has a computer screen 20, a keyboard 21, and a Bluetooth port (not shown). The Bluetooth port of the computer 19 is able to connect wirelessly to the Bluetooth port 8 of the test tool 5 via a Bluetooth connection 23.

[0034] In this invention, "portable" means that the test tool 5 is wireless, so it includes a battery to power it, and that, during testing, it must not be connected to a mains power supply nor to a wired data connection. The only wired connection is to the loop 2. This is because the test tool 5 must not interfere with or affect the communication on the loop 2. If the test tool 5 were connected to a mains power supply or by wire to separate mains powered equipment for exporting communication data, the earth connection from that connection would affect the communication on the loop and trigger an earth fault in the control panel 3.

[0035] Figure 2 shows the architecture of the test tool 5 showing the user input 7 in the form of a keypad of buttons, a display 6, in the form of an array of four LCD devices, a user interface microcontroller 30 to which the user input 7 and the display 6 are connected for controlling operation of those components. The interface microcontroller 30 is also connected to flash memory 31.

[0036] Operation of the test tool 5 is controlled by a microcontroller 32 which is connected to the user interface microcontroller 30, and to its own flash memory 33. The microcontroller 32 generates output signals to a loop driver circuit 34 and a modulator 35, and receives input signals from a first discriminator 36 and a second discriminator 37. The microcontroller 32 is also connected to send output signals to a loop splitter 45, and the loop splitter 45 also receives data from the loop driver circuit 34, the modulator 35 and the first discriminator 36 via a common mode choke 38 which is present to give EMC protection to the system. The loop splitter 45 is further connected to an output switching and monitoring unit 46 which controls communication via the terminals 11.

[0037] Ancillary modules 41 can also be communicated with. The test tool 5 is powered by a battery 48, which in this case, is a lithium ion battery, and can be powered by an A / C adapter 49, although, in operation, this would be disconnected for the tests described in this invention. The battery 48 and A / C adapter 49 are connected to a switching circuit and battery charger whereby the battery is charged from the A / C adapter, when plugged in, and power from the battery 48 and A / C adapter 49 is also used to power the device via a 40V boost converter 51 which powers the MX loop 54, a 5V buck converter 52 which powers a USB port 55, and a 3.3 V buck converter 53.

[0038] The operation of the device will now be described by way of example with reference to Figure 3.

[0039] When the need arises to analyse the data communicated between the control panel 3 and the devices 4, for example when a fault arises within the system, a technician begins with step 81 by preparing the test tool 5 described in Figures 1 and 2. Since it is battery powered, the technician will ensure that it is charged, and will charge it if its battery does not contain sufficient charge. The technician will attach the pair of leads 11 to two of the terminals of the test tool 5. The technician will also disconnect any wired connections to the test tool, such as the A / C adapter 49. In the test, the loop driver circuit 34, the modulator 35 and second discriminator 37 are switched off so that all signals will pass through the first discriminator 36.

[0040] In step 82, the technician connects the test tool 5 to the loop 2 using the pair of leads 11, as shown in Figure 1.

[0041] In step 83, the technician configures the test tool 5 using the user input 7 and display 6. This configuration might include actions such as selecting the type of test which is to be carried out, selecting the model of control panel 3, selecting the version of the MX protocol which is used by the fire alarm system 1 in this installation, the duration of the test, the identity of the testing technician, the location of the fire alarm system 1, and the like.

[0042] In step 84, the technician pairs the test tool 5 with the Bluetooth enabled device with which the technician is downloading the test data, in this case, a smartphone 9.

[0043] In step 85, the technician initiates the test. The test itself involves detecting and decoding the communications which are placed on the loop by the control panel 3 and the devices 4. As described above, in this embodiment, communication uses FSK, and the protocol involves the control panel 3 polling each of the devices 4 with an addressed command, and when a device receives the command addressed to it, the device carries out the instruction and sends a response on the loop 2 to the control panel 3. Both the command and response communications are detected and decoded by the test tool 5. The decoding is carried out by the first discriminator 36 and the microcontroller 32. The decoded communications are stored in the flash memory 33 with a timestamp identifying when the communication was received. This received communication, together with the timestamp and any other metadata which is collected at the time constitutes communication data which might be in the form of a log file.

[0044] In step 86, part or all of the stored communication data in the flash memory 33 is downloaded using Bluetooth to the smartphone 9. This downloading might be continuously streamed to the smartphone 9 during the test, but this requires the technician to remain in place close to the test tool 5, which will be wasteful, or for the technician to leave the smartphone in the vicinity of the test tool 5, which is a security risk. Therefore, it is preferred that the communication data is downloaded either once the test is complete, or periodically during the test period, depending on what is convenient.

[0045] In step 87, the test is terminated. This might be done automatically at the end of the test, perhaps after the expiry of the pre-set duration of the test, or might be terminated automatically in some other eventuality, such as after a fault has been identified. Furthermore, the test could be terminated by the technician using the user input 7.

[0046] In step 88, the technician disconnects the test tool from the loop by disconnecting the pair of leads 11 from the loop 2.

[0047] In step 89, the communication data is analysed using the smartphone, or the smartphone transmits the communication data to a separate computing device for analysis. In the case of a smartphone, since the smartphone is likely to be connected to a mobile phone network, the communication data can be sent via the mobile phone network to a server at a different location for analysis of the communication data. Alternatively, if the other Bluetooth enabled device is a computer 19 instead of a smartphone 9, the computer 19 may be loaded with software which will carry out the analysis required on the communication data. It should be noted that step 89 can be carried out while the test is still underway. It does not need to be delayed until after the test has been carried out and the test tool 5 is disconnected from the loop 3.

[0048] If the analysis of the communication data identifies a problem, this will enable the technician to resolve the problem and return the fire alarm system 1 into a fully operational state.

[0049] Various further modifications to the above-described example, whether by way of addition, deletion or substitution, will be apparent to the skilled person to provide additional examples, any and all of which are intended to be encompassed by the appended claims.

Claims

Claims1. A method of testing communication between a control panel and a number of addressable networked devices on a 2-wire addressable loop of a fire alarm system using a portable test tool comprising : connecting the portable test tool to the two wires of the loop using a pair of leads; pairing the portable test tool with a remote device using a wireless protocol; detecting and decoding communications between the control panel and the addressable networked devices which are put on the addressable loop; download the communications from the portable test tool to the remote device using the wireless protocol; and analysing the communications.

2. The method of claim 1, wherein the step of downloading includes streaming the communications to the remote device.

3. The method of claim 1 or claim 2, further comprising storing the communications in a memory of the portable test tool.

4. The method of claim 3, wherein the step of downloading includes downloading the communications after the test is complete and / or periodically during the test.

5. The method of any one of the preceding claims, wherein the wireless protocol is Bluetooth (TM).

6. The method of any one of the preceding claims, further comprising converting the communications into log files in the portable test tool and wherein the communications are downloaded as the log files.

7. The method of claim 6, wherein the conversion of communications includes adding at least one of a timestamp and metadata collected at the time of the test into the log files.

8. The method of any one of the preceding claims further comprising loading software on the remote device whereby the remote device can analyse the communications.

9. The method of any one of the preceding claims, further comprising configuring the portable test tool to select the length of the test.

10. A portable test tool for testing communication between a control panel and a number of addressable networked devices on a 2-wire addressable loop of a fire alarm system, comprising : leads for connecting the portable test tool to the two wires of the loop; a wireless port by which the tool can be paired to a remote device using a wireless protocol; a processor for decoding communications between the control panel and the addressable networked devices detected on the addressable loop and for downloading the communications to the remote device via the wireless port.

11. The portable test tool according to claim 10, further comprising a memory for storing the communications in the portable test tool.

12. The portable test tool according to claim 10 or 11, wherein the wireless port is a Bluetooth ™ port.

13. The portable test tool according to any one of claims 10 to 12, further comprising a user input by which the tool can be configured to select the length of the test.

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