EP2105898A2 - Transfer path check method for a danger notification assembly - Google Patents

Abstract

A method for testing a line-bound transmission path (6,8,9) of a hazard alarm system to unacceptably high resistance (Rx) by generating a current on the final with an end module (10) completed transmission path, measuring the voltage, comparing with a setpoint and generating an error message falls below this setpoint allows a test under normal load conditions, when using the Endmoduls (10) the current on the transmission time-dependent up to a predetermined value is generated increasing, measured simultaneously the voltage at the end of the transmission path (9) and this measured voltage with a Setpoint is compared.

Description

The invention relates to a method for testing a line-bound transmission path of a security alarm system to unacceptably high resistance by measuring the current on the completed with an end module transmission path and comparison with a setpoint.

The invention further relates to a hazard detection system that performs this test method, preferably a system with a central office, to which via a communication bus at least one coupler is connected.

Alarm systems have long been designed so that to the alarm panel, in the following "Central", connected or controlled by the control center, line-bound transmission paths can be monitored for interruption and short circuit, both the lines, the sensors, and in particular detectors, connect to the control center, as well as the lines through which the central actuators, ie z. As signalers and / or electromechanical closing and opening devices controls or triggers. Common practice is the quiescent current monitoring, in which the respective spur line is terminated with a resistance of eg 10 kiloohms. In the case of sensor lines, in a test mode, the control panel measures the quiescent current on the line in question and compares it with a tolerance field in which the measured current is taking into account the line resistance, the connected sensors and the terminating resistor got to. An excessively low current is interpreted as an inadmissibly high series resistance, in an extreme case as an interruption, an excessively high current as an unacceptably high parallel resistance, in extreme cases as a short circuit.

In order to be able to apply the same test method to actuators despite their substantially lower internal resistance compared to sensors, it is known to connect each actuator to the line via a diode and to feed the line in test mode with a DC voltage which is poled such that the diodes of the actuators are in the locked state. In the alarm state, i. to trigger the actuators, the DC supply voltage is reversed. For this purpose, a control circuit, which is usually referred to as a bus coupler or simply as a coupler, is connected via a communication bus with the center and can be connected to the more than one monitored line.

From the EP-A-1 777 671 It is known to terminate the line instead of a fixed resistor with an element with current-dependent resistance, such as a thermistor, a diode or a voltage-controlled transistor in series with a resistor. To test the line for interruption or short circuit, the coupler of the line in each case imprinted a predetermined current, measures the voltage which is set at the beginning of the line and compares this with a setpoint range. As a result, the comparison provides whether the line is in a proper or faulty state. Like the test method working with a fixed resistor as line termination, the method according to the EP-A-1 777 671 on a resistance measurement from the coupler, ie at the beginning of the line.

By DIN EN 54 Part 13, the requirements for the functionality of a cable-bound transmission path of a security alarm system have been significantly increased. In particular, a standard-compliant system must ensure that each transmission path under normal load conditions to the relevant component (eg sensor, coupler, actuator) supplies the minimum voltage required for the function of this component. Unlike in the case of the known systems and their test methods, it is therefore necessary to check for an excessively high resistance of the line in the case of one of the above-mentioned systems, that is, a so-called creeping interruption, as described, for example. due to poor clamping or corrosion can be carried out under load.

The invention has for its object to provide a method and a hazard detection system available to perform such a test.

In a method having the features of the preamble of claim 1, this object is achieved in that by means of the end module on the transmission a time-dependent up to a predetermined value increasing current is generated. The predetermined value is equal to the load current flowing in normal operation, that is to say for actuators connected to the transmission path in the event of an alarm.

In order to test the transmission path, ie the line, the end module thus simulates a load which increases in time from a small initial value to a value corresponding to the actual conditions, wherein at the beginning of the line the actual operating voltage, ie a voltage greater than a predetermined one Minimum value is applied. At the same time, the voltage at the end of the over measured transmission path, compared with a setpoint for the end module and generates the error message below this setpoint. The method is suitable not only for spur lines but also for ring lines. The end module is then located at the end of the loop remote from the feed port.

The danger alarm system with the features of the preamble of claim 2 is characterized according to the invention in that the end module in the test mode generates a time dependent on a rest value to a predetermined value increasing current on the line, while measuring the input voltage and transmits the measurement result to the coupler.

The end module is preferably located at the end of each stub, but may also be in the coupler when the stub has a two-wire return, so is a total of four wires or if the line is designed as a two-core loop.

Preferably, the end module generates a current ramp, that is, a linear time-dependent rising current.

In principle, the end module can transmit the input voltages measured during the current increase as data telegrams, for example to the coupler, which carries out the evaluation. Preferably, however, the end module continuously compares the input voltage itself with a stored setpoint value and only transmits a first current response when the setpoint value is exceeded, and a second, second current response that differs from the setpoint value via the line to the coupler.

The end module preferably generates the time-dependent rising current in a predetermined time interval and transmits the result of the voltage measurement to the coupler after the end of this time interval.

The control panel can put all couplers in test mode at the same time. If more than one line (stub or loop) is connected to a coupler, each of which is terminated with an end module, it is recommended that each of these couplers puts all end modules in test mode at the same time, to ensure that both at the input of the module Kopplers as well as at its outputs, ie the inputs of the connected lines, respectively the same load condition as in normal operation, ie z. B. exists in case of alarm.

Likewise, it is recommended that an end module, upon detection of a line fault, ie a voltage dropping below the stored setpoint at its input, maintains the relevant current, ie does not abort the current ramp prematurely upon detection of the line fault. As a result, an inadmissibly high line resistance of the connecting line between an external supply voltage source and the coupler can be detected, even if this line resistance does not lead to a drop in the input voltage of the coupler below the minimum value when loaded with the current only of the other end modules or.

The end module can generate the time-dependent rising current in particular by means of a controlled transistor as an adjustable resistor in series with a further resistor.

The end module preferably comprises a microprocessor for controlling the current slew rate and / or the current end value and / or for measuring the voltage setpoint, which must not be lower than the end of the time interval.

The microprocessor of the end module can have an individual address and be programmable by current pulses after addressing by the control center. As a result, in particular the current end value and the voltage setpoint, which is to be reached at least at the end of the time interval, can be conveniently adapted to the individual load conditions on the line in question in the event of an alarm.

For testing for short circuit (including "creeping short circuit"), which is basically much simpler than the test for an inadmissibly high line resistance ("creeping interruption"), the control center can generate a time window immediately preceding the said time interval, in which the coupler conducts , if applicable, check all lines connected to this coupler for a short circuit.

A simple possibility is that the coupler microcontroller switches a series resistor into the line, measures a voltage proportional to the current through the line, compares this with a setpoint value, transmits the data telegram "Error" when the setpoint is exceeded at the control center and if it falls below of the setpoint at the end of the first time window bridges the inserted resistance.

Preferably, the coupler for generating the current-proportional voltage comprises a current measuring resistor with a diode is bridged. As a result, the coupler or its microcontroller thus measures the currents through the current measuring resistor, which lead to a voltage drop across the current measuring resistor, which is less than the forward voltage of the diode of z. B. 0.6V is. When the current responses of the end module (or at least the lower current response) are placed within the range that produces a voltage drop of less than the diode forward voltage across the current sense resistor, the coupler can easily distinguish the current responses. At the same time, the coupler remains backwards compatible with existing alarm systems with an end module in the form of a fixed resistor of z. B. 10 kiloohms, because the caused by this terminating resistor current of eg 1 mA at 10 V produces a lower than the diode forward voltage across the current measuring resistor.

Fig. 1

ein vereinfachtes Blockschaltbild einer Gefahrenmeldeanlage,

Fig. 2

ein Blockschaltbild eines der Buskoppler in Fig. 1,

Fig. 3

ein Blockschaltbild eines Endmoduls,

Fig. 4a, 4b

ein Spannungs/Strom-Diagramm während eines Prüfzyklus,

Die im Blockschaltbild in Fig. 1 dargestellte Gefahrenmeldeanlage umfasst eine Zentrale 1, an die mehrer Meldelinien 2.1 bis 2.n sowie über einen Kommunikationsbus 3 Buskoppler 4, 4.1 seriell angeschlossen sind. Die Meldelinien 2.1 bis 2.n umfassen Sensoren wie Brandmelder, Gasmelder oder Bewegungsmelder (nicht dargestellt). Jeder Koppler 4, 4.1 hat neben dem Kommunikationsanschluss einen Eingang E, an dem eine von einem externen Netzteil 5 über eine Leitung 6, einen Sicherungsverteiler 7 und eine weitere Leitung 8, 8.1 gelieferte Versorgungsgleichspannung mit einem Nennwert von z. B. 15 V anliegt. Jeder Koppler 4 hat (nur beispielhaft) zwei Ausgänge A1 und A2. An jeden Ausgang ist über eine Stichleitung 9.1, 9.2 eine Anzahl von Aktoren 11, z. B. akustische Signalgeber, optische Signalgeber, Magnetventile usw. über je eine Diode D angeschlossen. Jede Stichleitung ist mit einem Endmodul 10, 10.1 abgeschlossen. Alle Leitungen 8, 8.1 und 9.1, 9.2 haben einen insbesondere von ihrer Länge abhängigen Leitungswiderstand, der durch die Serienwiderstände Rx symbolisiert ist.The method and the alarm system according to the invention are explained below with reference to the schematically simplified drawing of an embodiment. It shows:

Fig. 1

a simplified block diagram of a hazard alarm system,

Fig. 2

a block diagram of one of the bus coupler in Fig. 1 .

Fig. 3

a block diagram of an end module,

Fig. 4a, 4b

a voltage / current diagram during a test cycle,

The block diagram in Fig. 1 The hazard alarm system shown comprises a control center 1, to which several signaling lines 2.1 to 2.n and via a communication bus 3 bus couplers 4, 4.1 are connected in series. The detection lines 2.1 to 2.n include sensors such as fire detectors, gas detectors or motion detectors (not shown). Each coupler 4, 4.1 has in addition to the communication port an input E, to which a supplied from an external power supply 5 via a line 6, a fuse distributor 7 and a further line 8, 8.1 DC supply voltage with a nominal value of z. B. 15 V is applied. Each coupler 4 has (only by way of example) two outputs A1 and A2. At each output is a stub 9.1, 9.2 a number of actuators 11, z. As acoustic signalers, optical signal transmitters, solenoid valves, etc. connected via a respective diode D. Each stub is terminated with an end module 10, 10.1. All lines 8, 8.1 and 9.1, 9.2 have a particular depending on their length line resistance, which is symbolized by the series resistors Rx.

Each coupler such as 4 comprises according to FIG Fig. 2 a voltage supplied via the input E microcontroller MK, which can exchange data telegrams 1 via the communication port K of the bus 3 with the center 1. The microcontroller MK measures the DC supply voltage at the input E and reports to the control center 1 in Fig. 1 an error if this input DC voltage below a predetermined minimum value of z. B. 10.5 V drops. Upon receipt of this message, the center z. B. generate a Strörungsmeldung and / or the coupler or supplying this supply voltage source 5 in Fig. 1 switch off.

In the following, the wiring and testing of the output A1 of the coupler will now be explained in detail. The output A2 and any other outputs are fed and tested in an analogous manner.

A relay Rel has a two-pole changeover contact for each output A1 or A2, such as r1, r2 for output A1. In the rest position of the relay Rel the contacts r1, r2 have the drawn position. On a sent from the center 1 via the Kommuniationsbus 3 and the port K command to the microcontroller MK begins a first, z. Time window of e.g. 150 ms duration. In this time window, the coupler checks the stub 9.1 for a short circuit, more precisely to an inadmissibly low parallel resistance Ry. For this purpose, the microcontroller MK includes a switch S1 and thereby loosens a resistor R1 in the power supply of the output A1, d. H. the stub 9.1, which is now fed in relation to the alarm state according to the operating position of the relay Rel reversed polarity, so that all diodes D lock. About R1, the line resistance Rx, the end module 10 in the idle state and R2 flows a certain quiescent current. The voltage dropping across R2 is fed via an operational amplifier OP1, which amplifies this voltage in a manner known per se, to an input of the microcontroller MK, which checks whether the measured voltage lies within a desired value range. If the measured voltage and thus the current on the stub 9.1 is unacceptably high, the microcontroller MK opens the switch S1 and sends to the central station 1 a data telegram "error" or a specific data telegram "short circuit". In the event of a short circuit, R1 limits the short-circuit current and a diode D1 parallel to R2 limits the voltage drop across R2. If the measured voltage and thus the current during this time window within the allowable range, the microcontroller MK closes a switch S2 and thus bridges the resistor R1.

During a subsequent, z. B. from the central generated time interval of z. B. also generates 150 ms Now the end module 10 is a current ramp, which is a quiescent current value of z. B. 1 mA to a predetermined final value of z. B. 1 A increases linearly. For this purpose, the end module 10 according to Fig. 3 a microprocessor MP, which receives a supply voltage derived from the DC supply voltage Vdd, via a port a and a voltage divider R6, R4 measures the DC supply voltage of the end module 10 as samples during the current increase and to generate the current ramp at an output port b a pulse width modulated signal with increasing pulse duration supplies that via a low pass TP in a correspondingly changing, z. B. linearly increasing DC voltage is converted via a differential amplifier OP2 at the control electrode of a transistor T, z. B. an N-MOSFET is applied, which is in series with a resistor R5 between the input terminals of the end module 10.

If during this time interval as a result of the increase in current, the DC supply voltage at the input E of the coupler 4 in Fig. 1 because of too high a resistance in the train of lines 6, 8 drops from the supply voltage source 5 to the coupler 4 below the setpoint, the microcontroller MK of the coupler 4 sends the same error signal to the center 1, he in an inadmissible lowering of the DC supply voltage at input E during the first time window to the center 1 sends. The center 1 will accordingly report a fault in the same way and / or initiate a suitable measure, for. B. the coupler 4 or the power supply 5 off.

If the end module 10 in the time interval during which the current increases linearly via the voltage divider R6, R4 determines that the DC supply voltage at the input of the end module 10 below a predetermined setpoint of z. B. 10 V drops, it stores this result, but drives continue to durchzusteuern the transistor T, so that for the connected to the other outputs A2, etc. of the coupler 4 stub lines whose end modules generate a corresponding current ramp, the same load conditions exist.

If the microprocessor MP of the end module 10 at the end of the time interval determines that even at the highest, set via the transistor T load current, the voltage at the input of the end module 10 is equal to or greater than the voltage set as a minimum value of z. B. 10 V, provides the microprocessor MP at port b during a second time window, a constant pulse train with a pulse width corresponding to a first defined current value through the transistor T corresponding to a first current response of the end module 10 via the stub 9.1. If, on the other hand, the microprocessor MP has detected a voltage before or at the end of the time interval which is smaller than the nominal value of the DC input voltage, it furnishes at its output b a different, constant pulse sequence which correspondingly generates a different current response of the end module 10. Via the current measuring resistor R2, the microcontroller MK of the coupler 4 detects these current responses during the second time window. At the end of the second time window and thus the test cycle, the microcontroller MK opens the switches S1, S2. In an alarm command of the control panel 1, the microcontroller MK controls the relay Rel, so that the contacts r1, r2 switch, the DC supply voltage is switched to all outputs A of the coupler 4 with reverse polarity and thus the actuators 11 in Fig. 1 speak to.

The microprocessor MP of the end module 10 is programmable via R6, R4 from the control center 1 by means of data telegrams which the microcontroller MK of the coupler 4 converts into voltage pulses on the relevant spur line.

The diagrams in Fig. 4a and Fig. 4b illustrate the time-dependent profile of the voltage at the input of the end module 10 and the current on the stub 9.1 during the first time window from t0 to t1, the subsequent time interval from t1 to t2 and the subsequent second time window from t2 to t3. Fig. 4a illustrates the just allowable case, the sinking of the input voltage to 9 V at the end of the time interval, ie at time t2. Fig. 4b shows a possible error case.
At time t0, the coupler 4 starts the short circuit check by closing the switch S1. If the short circuit test does not give an error, the normal operating voltage of 14 V is applied here. About the stub only flows a low quiescent current of z. 1 mA. At the end of the first time window of 150 ms, ie at t1, the end module 10 begins to generate a current ramp, in this example to 1 A after the expiration of a further 150 ms to t2. As a result of the line resistance, the microprocessor MP of the end module 10 measures a linear and in the case of Fig. 4a down to the minimum value of 9 V voltage drop at its input. Therefore, the end module generates at the end of this time interval during the second time window of again 150 ms to t3, the first current response with eg 50 mA, corresponding to "okay".

In contrast, the line resistance as in the case of Fig. 4b too high, then drops the voltage at the input of the end module 10 after about 220 ms to the limit of 9 V. The current remains until t2 to a value of here 500 mA and the input voltage to 9 V. The microprocessor MP of the end module detects this condition as an error and therefore sends in the second time window to the coupler the second current response of eg 2 mA, corresponding to "line resistance too high".

Claims (14)

Method for testing a line-bound transmission path (6, 8, 9) of an alarm system to impermissibly high resistance (Rx) by generating a current on the transmission path terminated with an end module (10), measuring the voltage, comparing with a setpoint and generating an error message Below this target value, characterized in that by means of the end module (10) the current on the transmission path is generated time-increasing up to a predetermined value, and that the voltage measured simultaneously at the end of the transmission path (9) and compared this measured voltage with a target value becomes. Security alarm system with a control center (1) to which via a communication bus (3) at least one coupler (4) is connected, having an input (E) for an external DC voltage, a microcontroller (MK) for communication with the control center (1), for switching through the DC voltage present at the input (E) to at least one output (A1) and for controlling a relay (Rel) which has a two-pole changeover contact (r1, r2) for reversing the polarity of the DC voltage at the output (A1), to which at least one consumer (11) is connected in series with a diode (D) via a line (9.1) terminated with a line end module (10) to connect the line in a test mode initiated by command from the center (1) to check for errors due to short circuit (Ry) or impermissibly high resistance (Rx) and, in the case of an error, to send a data telegram "Fault" to the central (1), characterized in that the end module (10) in the test mode s generates a time dependent on a rest value to a predetermined maximum value increasing current on the line (9.1), during which the input voltage measures and transmits the measurement result to the coupler (4). Installation according to claim 2, characterized in that the end module (10) generates a current ramp. Installation according to claim 2 or 3, characterized in that the end module (10) compares the input voltage with a stored setpoint value and when the setpoint exceeds a first current response, falls below the setpoint one of them different, second current response to the coupler (4) sends. Installation according to one of claims 2 to 4, characterized in that the end module (10) generates the time-dependent rising current in a predetermined time interval (t1 to t2) and transmits the result of the voltage measurement after the end of this time interval to the coupler (4). Installation according to one of claims 2 to 5, characterized in that each coupler (4) puts all connected end modules simultaneously in the test mode. Plant according to claim 6, characterized in that the end module (10) remains in the test mode even in the event of a fault until the end of the time interval (t1 to t2), but keeps the current constant at the last reached ramp value. Installation according to one of claims 2 to 7, characterized in that the end module (10) the time-dependent rising current by means of a voltage or current controlled transistor (T) as adjustable resistor in series with a resistor (R5) generated. Installation according to one of claims 2 to 8, characterized in that the end module (10) comprises a microprocessor (MP) for controlling the current slew rate and / or the current end value and / or the setpoint value of the input voltage. Plant according to claim 9, characterized in that the microprocessor (MP) of the end module is programmable by means of data telegrams transmitted as voltage pulses over the line. Plant according to claim 9 or 10, characterized in that the microprocessor (MP) of the end module (10) has an individual address. Installation according to one of Claims 2 to 11, characterized in that the control center (1) generates a time window (t0 to t1) preceding the time interval in which the coupler (4) checks the line for a short circuit. Installation according to claim 12, characterized in that the microcontroller (MK) of the coupler (4) switches a series resistance (R1) into the line (9.1) for short-circuit testing, measures a voltage proportional to the current through the line, compares this with a desired value, If the setpoint is exceeded, the data telegram "Error" is sent to the control panel (1) and, if the setpoint is undershot, at the end of the first time window, bypasses the inserted resistor (R1). Plant according to claim 12 or 13, characterized in that the coupler (4) for generating the current-proportional voltage comprises a current measuring resistor (R2) which is bridged by a diode (D1).

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