Signal transmission device of a signal securing system for securely transmitting an ac signal

Abstract

The invention relates to a signal transmission device (3) of a signal-related safety system (1) for the reliable transmission of signal information from an AC signal to a processing unit (4), comprising: • a first input channel (14a) and a second input channel (14b) for acquiring the AC signal, • a first output channel (10a) and a second output channel (10b), wherein the first output channel (10a) and the second output channel (10b) are galvanically isolated from each other, wherein each input channel (14a, 14b) is connected to each output channel (10a, 10b) via a coupling element (8a, 8b) with galvanic isolation, characterized in that at least two resistors (16a - 16f) connected in series of each input channel (14a, 14b) differ in at least one characteristic value, and that at least two voltage-direction-dependent electronic switching devices (19a - 19f) connected in series of each Input channel (14a,14b) differ in at least one characteristic parameter, wherein the voltage direction-dependent electronic switching devices (19a - 19c) of the first input channel (14a) are electrically connected to the AC signal source (2) with opposite polarity to the voltage direction-dependent electronic switching devices (19d - 19f) of the second input channel (14b).

Description

Subject of the invention

[0001] The invention relates to a signal transmission device of a signaling security system for the secure transmission of signal information of an AC signal to a processing unit, comprising an input circuit for detecting the AC signal, wherein the input circuit comprises a first input channel and a second input channel, and an output circuit for evaluating the AC signal, wherein the output circuit comprises at least one first output channel and at least one second output channel, wherein the first output channel and the second output channel are galvanically isolated from one another, wherein the first input channel is connected to the at least one first output channel via a first coupling element but is galvanically isolated from the at least one first output channel,wherein the second input channel is connected to the at least one second output channel via a second coupling element but is galvanically isolated from the at least one second output channel, wherein each input channel comprises a plurality of resistors connected in series.,

[0002] The invention also relates to a signaling safety system with a signal transmission device according to the invention. Furthermore, the invention relates to the use of a signal transmission device according to the invention. Background of the invention

[0003] Reliable signal transmission of AC signals is important, for example, to provide the processing unit with information regarding the signal aspect of a traffic signal or axle counting information and to reveal errors in the signal transmission. AC signals are picked up by a component of a signaling system, e.g., a signal lamp, and the resulting information is sent back to the interlocking as a command.

[0004] Such a signal transmission device is known from the Vital21 transmission system

[01] , which is used, among other things, for the secure transmission of data for controlling interlocking systems and for fault detection. The Vital21 transmission system has an input / output unit with a two-channel, microcontroller-controlled interface module. The interface module reads input information via optocoupler inputs and forwards output information via output relays. To increase the security of data transmission, the two data channels are designed independently of each other. The signal transmission device comprises two input channels and two output channels, each with a microcontroller for signal evaluation. To meet the safety requirements of CENELEC EN 50129, the electrical resistors are designed in a safety design.

[0005] The signal transmission device disclosed in

[01] requires comparatively complex and expensive electrical components to avoid disruption of the signal transmission due to a failure of these components.

[0006] A circuit for the separate transmission of different half-waves is known from CN 105759204 B

[02] . This is a diagnostic circuit for chargers of electric vehicles.

[0007] DE 33 38 490 A1 also discloses a two-channel signal transmission device of a signaling safety system. Object of the invention

[0008] The object of the invention is to provide a signal transmission device that enables secure signal transmission using simply structured and cost-effective components. It is also an object of the invention to provide a signaling security system with such a signal transmission device. Furthermore, the object of the invention is to specify a use for such a signal transmission device. Description of the invention

[0009] These objects are achieved according to the invention by a signal transmission device according to claim 1, a signaling safety system according to claim 9, and a use of the signal transmission device according to claim 11. Advantageous embodiments emerge from the dependent claims.

[0010] The signal transmission device according to the invention is characterized in that at least two of the resistances of each input channel differ in at least one characteristic, and in that each input channel comprises a plurality of series-connected voltage-direction-dependent electronic switching devices, wherein at least two of the voltage-direction-dependent electronic switching devices of each input channel differ in at least one characteristic, and wherein the voltage-direction-dependent electronic switching devices of the first input channel are electrically connected to the AC signal source with opposite polarity than the voltage-direction-dependent electronic switching devices of the second input channel.

[0011] The AC signal from the AC signal source alternately activates the first or second input channel depending on the polarity. The associated coupling elements are also activated with the first and second input channels, so that the first coupling element transmits a first partial signal of the AC signal and the second coupling element transmits a second partial signal of the AC signal from the associated input channel to the output circuit. The first partial signal is the part of the AC signal with a first polarity, while the second partial signal is the part of the AC signal with a second polarity that is opposite to the first polarity. The partial signals follow one another directly and are designed as half-waves, particularly in the case of sinusoidal AC signals. The coupling elements thus each transmit a transmission signal alternately and in a pulsed form.Output signal in the form of one of the two sub-signals of the AC signal from the input circuit to the output circuit. By connecting the input channels with opposite polarity, the two output signals of the coupling elements exhibit a temporal offset that is related to the duration of the polarity of the input signal. In the two input channels, independent signal information is generated from different time intervals (positive half-wave or negative half-wave) of the AC signal of the signal source for the two (or possibly several) independent output channels. This enables reliable detection and evaluation of this signal for its presence at the input.

[0012] In particular, the sub-signals of the AC signal transmitted by the coupling elements can be compared with each other to detect transmission errors and / or recombined into a complete signal. Analysis of the sub-signals can be performed, in particular, using an FPGA (Field Programmable Gate Array) and / or a monostable circuit.

[0013] The resistors and voltage-direction-dependent electronic switching devices exhibit different failure behaviors due to their different characteristics. In particular, this prevents the resistors or voltage-direction-dependent electronic switching devices in one input channel from failing simultaneously. If one of the aforementioned components fails, damage to the signal transmission device is averted by the remaining electrical components in the input channel. A failure of one of the electrical components in one of the input channels leads to a change in the output signal emitted by the coupling element arranged in the respective input channel. Thus, the failure of the respective electrical component can be reliably detected by comparing this output signal with the output signal of the coupling element in the other input channel.Signal reliability during the transmission of the AC signal is thus guaranteed even when using structurally simple, cost-effective electrical components in the signal transmission device.

[0014] The use of resistors and voltage-direction-dependent electronic switching devices with different characteristics is also referred to in the application as "diversification" of these electrical components. The inventive diversification (different types, values, manufacturers) ensures, in particular, that common mode errors cannot occur, since the different components have different robustnesses and manufacturing-related errors do not have the same effect (failure type) and at the same time (failure time).

[0015] The critical situation where all components in an input circuit are defective to the point where the entire AC signal (both polarities) is affected is unlikely due to the use of diverse components and the multiplication of resistors and diodes. If only one polarity of the input signal is affected by defects, the other circuit is still operational, and the different output signals of the two coupling elements are detected as defective.

[0016] Due to the high reliability of the components and the low probability that all components in a circuit will fail together, the input circuit can be used as a safe AC input.

[0017] The coupling elements between the input channels and the output channels enable transmission of the AC signal, whereby the galvanic isolation between the input channels and the output channels prevents interference currents between the input channels and the output channels during signal transmission.

[0018] The galvanic isolation of the output channels achieves signal independence. Signal independence means, in particular, that two or more functionally interacting output channels cannot lead to a dangerous condition due to their joint malfunction. This eliminates systematic multiple failures. This enables the demonstration of the harmlessness of individual failures and thus ensures safe operation. Signal independence is achieved, in particular, by preventing signal distortion in the input channels and / or the output channels due to a faulty current flow between the input channels and the output channels and / or between the output channels, by ensuring that the respective signal transmission takes place without electrical conductors.

[0019] To increase reliability, the basic circuit could be multiplied again to increase the number of channels and thus the independence of signal evaluation. This would create multiple channels for the negative half-wave and / or multiple channels for the positive half-wave, creating redundancy for the corresponding time interval.

[0020] The device according to the invention enables signal information to be input in a signal-technically secure manner.

[0021] The signal source could be, for example, a signal lamp whose signal aspect is to be transmitted to a signal box. For this purpose, the AC current flowing through the lamp's illuminant is tapped. Preferred embodiments of the invention

[0022] Preferably, the voltage-direction-dependent electronic switching devices are diodes. The series-connected diodes are connected in series with the series-connected resistors.

[0023] An advantageous embodiment of the signal transmission device is characterized in that at least one of the resistors, preferably all resistors, has a design that allows a short circuit in the event of a defect. Thus, components with a safety design (inherently safe components) can be dispensed with. This saves costs and time in development.

[0024] A preferred embodiment of the signal transmission device is characterized in that the at least one characteristic is the manufacturer and / or the service life and / or the robustness and / or nominal values ​​and / or component shapes and / or component technologies. Sufficiently different characteristics of the resistors in the respective input channel from one another and / or of the voltage direction-dependent electronic switching devices in the respective input channel from one another ensure that the respective electrical components do not fail in the same way, so that a short circuit does not occur in the first or second input channel during operation of the signal transmission device. Preferably, the characteristics of each two resistors in an input channel differ by at least a factor of 1.1 orthe characteristics of voltage direction-dependent electronic switching devices in an input channel by at least a factor of 1.1.

[0025] The aforementioned parameters, particularly component shapes and / or component technologies, also influence the change behavior of the electrical components of the respective input channels due to use. Thus, individual components that initially exhibit a relatively minor defect due to use can be detected and / or replaced early on, while the remaining components in the respective input channel are still functional. This prevents a critical situation from occurring.

[0026] In a further embodiment of the signal transmission device, the coupling elements are optocouplers. Optocouplers are advantageously compact and transmit the AC signal via light signals with little or no delay. The transmitting parts of the optocouplers are each part of one of the input channels (first optocoupler in the first input channel, second optocoupler in the second input channel), whereas the receiving parts of the optocouplers are each part of one of the output channels. The polarity / forward direction of the optocouplers is preferably selected according to the forward direction of the diodes in the corresponding input channel.

[0027] Alternatively or in addition to an optocoupler, a transformer, a DC / DC transformer or an optical fiber (OFC) with an OFC transmitter and OFC receiver can also be used.

[0028] An embodiment of the signal transmission device is advantageous, which is characterized in that the output circuit is designed to transmit signal information from the first output channel to the second output channel and from the second output channel to the first output channel by means of further coupling elements.

[0029] By coupling the signal information from one output channel to the other, the entire signal information transmitted to the output circuit can be evaluated on a single output channel. This increases the reliability of the transmission of the AC signal components, as the entire signal information can be tapped externally at each of the two output channels.

[0030] Each of the two output channels always has independent information from both channels, which is important for a reliable evaluation of the presence of the signal from the signal source.

[0031] In addition, the signal transmission device can be used more flexibly due to the various options for tapping the partial signals of the AC signal.

[0032] A further development of the aforementioned embodiment is characterized in that a third optocoupler is used to transmit the signal information from the first output channel to the second output channel and a fourth optocoupler is used to transmit the signal information from the second output channel to the first output channel, wherein the first output channel comprises the transmitting part of the third optocoupler and the receiving part of the fourth optocoupler, and wherein the second output channel comprises the transmitting part of the fourth optocoupler and the receiving part of the third optocoupler.

[0033] The third and fourth optocouplers enable fast signal transmission between the output channels in a compact design. They also ensure galvanic isolation of the output channels to prevent interference between the output channels during signal transmission.

[0034] An advantageous embodiment of the signal transmission device with the coupling elements for coupling the output channels is characterized in that the output channels are configured to compare the signal information of the first output channel with the signal information of the second output channel. In particular, an evaluation unit for comparing the signal information from the output channels is located on at least one of the output channels.

[0035] If one of the two input channels is faulty, the optocoupler outputs of the first and second optocouplers will display different signals. Accordingly, the optocoupler outputs of the third and fourth optocouplers will display different signals, and the fault can be immediately identified by comparison.

[0036] Preferably, the comparison takes place in the signal transmission device, i.e., before transmission to the processing unit. By directly tapping and evaluating the signal information at the relevant output channel, longer transmission paths for evaluation are avoided, which can cause a time delay during evaluation and corrupt the signal information. Alternatively, it is also possible to perform the comparison outside the signal transmission device.

[0037] A further embodiment of the signal transmission device is characterized in that the signal transmission device is part of a signal box, a vehicle device, a field element, in particular an axle counter, or an operating element. The signal transmission device ensures reliable signal transmission from the element of which it is designed to a processing unit, whereby comparatively cost-effective, simply structured electrical components can be used in the signal transmission device.

[0038] A signaling safety system according to the invention comprises a processing unit, an AC signal source for providing an AC signal, and a signal transmission device according to the invention as described above. In the signaling safety system, secure communication between modules of the control and safety technology of the signaling safety system can take place with a material-saving design of the components of the signal transmission device.

[0039] An advantageous embodiment of the signaling safety system is characterized in that the AC signal source is a field element, in particular a traffic signal, and that the AC signal indicates the state of the field element, whereby the state of the field element is a prerequisite, for example, for the output of an associated signal image. Traffic signals are among the critical components of a signaling safety system, so secure data transmission between a traffic signal and a processing unit of the signaling safety system is particularly important. In particular, the signal transmission device can reliably transmit signal information indicating whether the traffic signal, through its switching state, indicates that a train line is open or closed.

[0040] The signal transmission device according to the invention can be used for fault detection in a safety-critical system. The use of the signal transmission device reliably detects faulty signals in the safety-critical system, particularly in a signaling security system. The components in the signal transmission device are comparatively simple in structure and inexpensive to manufacture.

[0041] Further advantages of the invention will become apparent from the description and the drawings. Likewise, the features mentioned above and those further detailed below can be used individually or in combination. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention, the scope of which is defined by the claims. Short description of the drawings

[0042] Fig. 1 schematically shows a signaling safety system according to the invention with a signal transmission device according to the invention; Fig. 2 schematically shows a circuit diagram of the signal transmission device according to the invention. Detailed description of the drawings

[0043] Fig. 1 shows a schematic of a signaling safety system 1, in which an AC signal source 2 transmits an AC signal through lines 13a, 13b, 13c, 13d, via a signal transmission device 3 to a processing unit 4, e.g., a signal box. The AC signal source 2 can be, for example, a field element of the signaling system 1, for example, a traffic signal or an axle counting point, from which the AC signal is to be transmitted to the processing unit 4. The AC signal is fed from the AC signal source 2 to an input circuit via two input lines 13a, 13b. 6the signal transmission device 3. The input circuit 6 has two transmitting parts 7a, 7b a first and a second coupling element 8a, 8b wherein the coupling elements 8a, 8b supply the AC signal to an output circuit 9 To avoid interference signals during transmission, the input circuit 6 and the output circuit 9 are galvanically isolated from each other, which is indicated by a dashed line GT1 between the input circuit 6 and the output circuit 9. The input circuit 6 is designed in such a way (cf. Fig. 2 ) that the first coupling element 8a transmits a first partial signal of the AC signal, while the second coupling element 8b transmits a second partial signal of the AC signal.

[0044] The output circuit 9 is provided with a first output channel 10a and a second output channel 10b trained, the receiving parts 11a, 11bof the first and second coupling elements 8a, 8b. Each partial signal of the AC signal is transmitted for processing and output from the signal transmission device 3 through the coupling elements 8a, 8b into one of the output channels 10a, 10b. To avoid mutual distortion of the partial signals due to the build-up of interference potentials between the output channels 10a, 10b, the output channels 10a, 10b are galvanically isolated from each other, which is indicated by a further dashed line GT2 The partial signals are transmitted from the output channels 10a, 10b via output lines 13c, 13d to the processing unit 4, wherein the partial signals are evaluated by an evaluation unit 23 (here: within the processing unit (4)) can be compared with each other to detect possible errors in the transmission of the AC signal. Furthermore, the partial signals can be recombined into a complete signal.

[0045] Fig. 2shows schematically a circuit diagram of the signal transmission device 3. For detecting the AC signal from the AC signal source, the signal transmission device 3 is designed with the input circuit 6, wherein the input circuit 6 has a first input channel 14a and a second input channel 14b The input channels 14a, 14b both run from a first signal input 15a to a second signal input 15b the signal transmission device 3, to which the poles of the AC signal source 2 are connected (see Fig. 1). The first input channel 14a is used to receive the first partial signal of the AC signal, whereas the second input channel 14b is designed to receive the second partial signal of the AC signal. The first partial signal of the alternating current signal is a part of the AC signal with a first polarity, whereas the second partial signal is a part of the AC signal with a second polarity that is opposite to the first polarity. The two partial signals follow one another alternately when the AC signal is transmitted and are designed in particular as half-waves. The coupling elements 8a, 8b are alternately activated in the sequence of partial signals of the AC signal in order to feed the respective partial signal of the AC signal from the input circuit 6 into the output circuit 9. For external transmission of the AC signal, for example to the processing unit 4 (see Fig. 1), the signal transmission device 3 has the output circuit 9, wherein the input circuit 6 and the output circuit 9 are galvanically isolated, which is indicated by the dashed line GT1.

[0046] The first input channel 14a has three series-connected electrical resistors in the direction from the first signal input 15a to the second signal input 15b to avoid short circuits and to regulate the voltage 16a, 16b, 16c wherein at least two of the resistors 16a, 16b, 16c of the first input channel 14a differ in at least one characteristic, in particular in their service life. The different characteristics prevent several or all of the resistors 16a, 16b, 16c from failing simultaneously, which could lead to damage to the signal transmission device 3 and distortion of the AC signal to be transmitted due to the change in the current flow through the first input channel 14a.

[0047] For the transmission of the first partial signal flowing through the first input channel 14a, the three resistors 16a, 16b, 16c are followed by the transmitting part 7a of the first coupling element 8a, connected in series with the resistors 16a, 16b, 16c, here in the form of a first optocoupler, wherein the transmitting part 7a is designed here as a light-emitting diode or laser diode and the associated receiving part 11a of the first optocoupler 8a is designed here in the form of a phototransistor. The receiving part 11a is part of the first output channel 10a of the output circuit 9. In the embodiment shown, the receiving part 11a of the first optocoupler 8a is connected to a reference potential (here: ground). In addition, a resistor 16gA first collector voltage is applied to the receiving section 11a of the first optocoupler 8a. The first optocoupler 8a enables transmission of the first partial signal of the AC signal to the first output channel 10a, wherein the first input channel 14a and the first output channel 10a are galvanically isolated from each other. A protective diode is provided to protect against overvoltages. 18a connected in parallel to the transmitting part 7a of the first optocoupler 8a.

[0048] As electrical blocking elements, in the first input channel 14a in the direction from the first signal input 15a to the second signal input 15b after the transmitting part 7a of the first optocoupler 8a, voltage direction-dependent electronic switching devices 19a, 19b, 19cconnected in series. These voltage-direction-dependent electronic switching devices 19a, 19b, 19c are designed as rectifier diodes, wherein at least two of the rectifier diodes 19a, 19b, 19c differ in at least one characteristic, in particular in their service life. The rectifier diodes 19a, 19b, 19c are aligned with their forward direction towards the second signal input 15b and ensure that only the first partial signal of the AC signal flows through the first input channel 14a, while the second partial signal of the AC signal is blocked. The first input channel 14a is therefore only active with one of the two polarities of the AC signal source 2 (see Fig. 1) is activated. The different characteristics of the rectifier diodes 19a, 19b, 19c prevent the rectifier diodes 19a, 19b, 19c from failing simultaneously. In particular, this prevents current from flowing through the first input channel 14a for both polarities of the AC signal source 2, thus preventing the AC signal to be transmitted from being distorted.

[0049] The second input channel 14b has, corresponding to the first input channel 14a, three series-connected resistors in the direction from the second signal input 15b to the first signal input 15a 16d, 16e, 16f to which the transmitting part 7b of the second coupling element 8b in the form of a second optocoupler 8bThe second optocoupler 8b serves to couple the second partial signal, whose polarity is opposite to the first partial signal of the AC signal, via the receiving part 11b of the second optocoupler 8b into the second output channel 10b of the output circuit 9. In the embodiment shown, the receiving part 11b of the second optocoupler 8b is connected to a reference potential (here: ground), whereby the reference potential of the receiving part 11b of the second optocoupler 8b can differ from the reference potential of the receiving part 11a of the first optocoupler 8a. In addition, the resistor 16hat the receiving part 11b of the second optocoupler 8b, a second collector voltage is applied, which can in particular be identical to the first collector voltage. The second partial signal is coupled in through the second optocoupler 8b with galvanic isolation of the second input channel 14b from the second output channel 10b. The transmitting part 7b of the second optocoupler 8b is protected by a second protective diode connected in parallel. 18b protected against overvoltages.

[0050] The transmitting part 7b of the second optocoupler 8b is followed in the direction from the second signal input 15b to the first signal input 15a by three series-connected voltage-direction-dependent electronic switching devices 19d, 19e, 19fin the form of rectifier diodes, which are aligned with the forward direction towards the first signal input 15a. The rectifier diodes 19a, 19b, 19c of the first input channel 14a on the one hand and the rectifier diodes 19d, 19e, 19f of the second input channel 14b on the other hand are connected with opposite polarity to the AC signal source 2 (see Fig. 1 ) are electrically connected. As a result, only the second sub-signal of the AC signal flows through the second input channel 14b, whereas the first sub-signal of the AC signal is blocked.

[0051] At least two of the resistors 16d, 16e, 16f of the second input channel 14b differ in at least one characteristic, in particular their service life. Likewise, at least two of the rectifier diodes 19d, 19e, 19f of the second input channel 14b differ in at least one characteristic. This prevents the resistors 16d, 16e, 16f or the rectifier diodes 19d, 19e, 19f from failing simultaneously, which would distort the AC signal to be transmitted.

[0052] Preferably, the characteristics of each electrical resistor 16a, 16b, 16c of the first input channel 14a correspond to the characteristics of each electrical resistor 16d, 16e, 16f of the second input channel 14b. Accordingly, the characteristics of each voltage-direction-dependent electronic switching device 19a, 19b, 19c, here in the form of the rectifier diodes 19a, 19b, 19c, of the first input channel 14a preferably correspond to the characteristics of each voltage-direction-dependent electronic switching device 19d, 19e, 19f of the second input channel 14b. Furthermore, the characteristics of the first and second optocouplers 8a, 8b also preferably correspond. By selecting similar components in the input channels 14a, 14b, it is possible for identical input signals in the input channels 14a, 14b to lead to identical transmission signals, which are transmitted by the optocouplers 14a, 14b.

[0053] The transmitting part 7a of the first optocoupler 8a emits a light signal whose path follows the first partial signal of the AC signal. In the first output channel 10a, the receiving part 11a of the first optocoupler 8a converts the light signal emitted by the transmitting part 7a of the first optocoupler 8a back into a voltage whose path maps the first partial signal of the AC signal. The voltage generated in the transmitting part 7a of the first optocoupler 8a can be applied to a first output 21a of the first output channel 10a can be tapped from the outside in order to transmit the first partial signal of the AC signal to an external system, in particular to a processing unit.

[0054] Accordingly, the transmitting part 7b of the second optocoupler 8b emits a light signal whose path follows the second partial signal of the AC signal. In the second output channel 10b, the receiving part 11b of the second optocoupler 8b converts the light signal emitted by the transmitting part 7b of the second optocoupler 8b back into a voltage whose path maps the second partial signal of the AC signal. The voltage generated in the transmitting part 7b of the second optocoupler 8b can be applied to a first output 22a of the second output channel 10b can be tapped from the outside in order to transmit the second partial signal of the AC signal to an external system.

[0055] The two partial signals of the AC signal transmitted in this way can be reassembled into an overall signal after transmission or compared with each other with regard to errors during transmission (in particular due to defective components of the signal transmission device 3).

[0056] Near the second output channel 10b, in the first output channel 10a, a transmitting part 7c a third coupling element 8c in the form of a third optocoupler 8c which emits a light signal whose course follows the voltage applied to the receiving part 11a of the first optocoupler 8a. This signal is received by a receiving part 11c of the third optocoupler 8c, which is arranged in the second output channel 10b. Since the voltage at the receiving part 11a of the first optocoupler 8a follows the first partial signal of the AC signal, the signal transmitted by the third optocoupler 8c represents the first partial signal of the AC signal. Thus, the first partial signal of the AC signal is also transmitted to the second output channel 10b and can be output there at a second output. 22b of the second output channel 10b. At a resistor 16jThe second collector voltage is preferably applied to the third optocoupler 8c.

[0057] Accordingly, in the second output channel 10b near the first output channel 10a, a transmitting part 7d a fourth coupling element 8d in the form of a fourth optocoupler 8d arranged, wherein the transmitting part 7d emits a light signal whose course follows the voltage applied to the receiving part 11b of the second optocoupler 8b. This signal is received by a receiving part 11dof the fourth optocoupler 8d, wherein the receiving part 11d is arranged in the first output channel 10a. Since the voltage at the receiving part 11b of the second optocoupler 8b follows the second partial signal of the AC signal, the signal transmitted through the fourth optocoupler 8d represents the second partial signal of the AC signal. Thus, the second partial signal of the AC signal is also transmitted to the first output channel 10a and can be output there at a second output. 21b of the first output channel 10a. At a resistor 16i The first collector voltage is preferably applied to the fourth optocoupler 8d.

[0058] The partial signals tapped at the outputs 21a, 21b of the first output channel 10a can be compared with each other using an evaluation unit (not shown). Likewise, the partial signals tapped at the outputs 22a, 22b of the second output channel 10b can be compared with each other using the evaluation unit.

[0059] The first output channel 10a and the second output channel 10b are grounded between the receiving sections 11c, 11d and the transmitting sections 7c, 7d of the third and fourth optocouplers 8c, 8d so that the signals transmitted in the third and fourth optocouplers 8c, 8d do not influence each other. The coupling of the first and second partial signals from one output channel 10a, 10b into the other output channel 10a, 10b is carried out by the third and fourth optocouplers 8c, 8d with galvanic isolation of the output channels 10a, 10b (represented by the dashed line). GT2 ) to avoid interference potentials between the output channels 10a, 10b. List of reference symbols

[0060] 1 Signaling security system 2 AC signal source 3 Signal transmission device 4 Processing unit 6 Input circuit 7a, 7b Transmitting parts of the coupling elements 8a, 8b Coupling elements between the input circuit and output circuit (here: optocouplers) 8c, 8d Coupling elements between the output channels of the output circuit (here: optocouplers) 9 Output circuit 10a, 10b Output channels 11a, 11b Receiving parts of the coupling elements 13a, 13b Input lines 13c, 13d Output lines 14a, 14b Input channels 15a, 15b Signal inputs of the signal transmission device 16a-c Resistors of the first input channel 16d-f Resistors of the second input channel 16g-j Resistors of the output circuit 18a, 18bProtection diodes 19a-cVoltage direction-dependent electronic switching devices, (here: diodes) 21a, 21bOutputs of the first output channel 22a,22bOutputs of the second output channel 23Evaluation unit GT1galvanic isolation between input circuit and output circuit GT2galvanic isolation of the output channels, List of cited documents

[0061]

[01] Thales Deutschland GmbH: Product description Vital21, part number: 3JA-05000-ACAA-104DE

[02] CN 105759204 B

Claims

1. Signal transmission device (3) of a signaling security system (1) for the secure transmission of signal information of an AC signal to a processing unit (4), which device has: • an input circuit (6) for detecting the AC signal, the input circuit (6) comprising a first input channel (14a) and a second input channel (14b), • an output circuit (9) for evaluating the AC signal, the output circuit (9) comprising at least one first output channel (10a) and at least one second output channel (10b), the first output channel (10a) and the second output channel (10b) being galvanically isolated from one another, the first input channel (14a) being connected to the at least one first output channel (10a) via a first coupling element (8a), but galvanically isolated from the at least one first output channel (10a), the second input channel (14b) being connected to the at least one second output channel (10b) via a second coupling element (8b), but galvanically isolated from the at least one second output channel (10b), each input channel (14a, 14b) comprising a plurality of resistors (16a - 16f) connected in series, characterized in that at least two of the resistors (16a - 16f) of each input channel (14a, 14b) differ in at least one characteristic variable, and in that each input channel (14a, 14b) comprises a plurality of voltage direction-dependent electronic switching devices (19a - 19f) connected in series, at least two of the voltage direction-dependent electronic switching devices (19a - 19f) of each input channel (14a, 14b) differing in at least one characteristic variable, the voltage direction-dependent electronic switching devices (19a - 19c) of the first input channel (14a) being electrically connected to the AC signal source (2) with opposite polarity to the voltage direction-dependent electronic switching devices (19d - 19f) of the second input channel (14b).

2. Signal transmission device according to claim 1, characterized in that at least one of the resistors (16a - 16f), preferably all of the resistors (16a - 16f), are designed to allow a short circuit in the event of a defect.

3. Signal transmission device according to any of the preceding claims, characterized in that the at least one characteristic variable is the manufacturer and / or the service life and / or the robustness and / or nominal values and / or component shapes and / or component technologies.

4. Signal transmission device according to any of the preceding claims, characterized in that the coupling elements (8a, 8b) are opto-couplers.

5. Signal transmission device according to any of the preceding claims, characterized in that the output circuit (9) is configured to transmit signal information from the first output channel (10a) to the second output channel (10b) and from the second output channel (10b) to the first output channel (10a) by means of further coupling elements (8c, 8d).

6. Signal transmission device according to claim 5, characterized in that a third opto-coupler (8c) is used to transmit signal information from the first output channel (10a) to the second output channel (10b), and a fourth opto-coupler (8d) is used to transmit signal information from the second output channel (10b) to the first output channel (10a), the first output channel (10a) comprising the transmitting part (7c) of the third opto-coupler (8c) and the receiving part (11d) of the fourth opto-coupler (8d), and the second output channel (10b) comprising the transmitting part (7d) of the fourth opto-coupler (8d) and the receiving part (11c) of the third opto-coupler (8c).

7. Signal transmission device according to claim 5 or claim 6, characterized in that the output channels (10a, 10b) are configured to compare the signal information of the first output channel (10a) with the signal information of the second output channel (10b).

8. Signal transmission device according to any of the preceding claims, characterized in that the signal transmission device (3) is part of a controlling unit, a vehicle apparatus, a field element, in particular an axle counter, or an operating element.

9. Signaling security system (1) which has a processing unit (4), an AC signal source (2) for providing an AC signal, and a signal transmission device (3) according to any of the preceding claims.

10. Signaling security system according to claim 9, characterized in that the AC signal source (2) is a field element, in particular a traffic signal, and in that the AC signal indicates the switching state of the field element.

11. Use of a signal transmission device (3) according to any of claims 1 to 8 for error identification in a safety-critical system.

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