Patent Application
20220017127
The present disclosure concerns in general the field of controlling wayside devices and equipment of railway systems. More in particular, the present disclosure relates to a system for controlling operations of vital wayside devices, which are devised to perform determined tasks in a fail-safe manner within a railway network where they are installed, and to a vital switch suitable to be used in connections with such vital devices.
As known, in present railway systems, wayside locations are stationed along the roadway to house the equipment and cabling interconnections. Based on the complexity of the section of train tracks being controlled by a given location, these wayside locations can be quite large and complex, with hundreds to thousands of connection points and wires. In particular, interconnections and control of the various pieces of equipment are realized by means of copper cables, according to solutions, which entail some drawbacks. For example, copper wires require lightning protections or some form of transient protection, they produce and are susceptible to electromagnetic interferences since copper cablings act like antennas and may transmit/receive noise; further, these cables require a large physical footprint and are rather expensive.
These drawbacks are further amplified and result in additional issues when vital equipment is involved. Indeed, a vital or fail safe equipment is a device aimed at performing very important functionalities within a system architecture and for this reason such devices are properly conceived and operated in such a way that any malfunctioning affecting safety will cause the faulty equipment to revert to a state that is generally known to be safe. Examples of such vital or fails safe equipment used in railway systems are interlocking devices, level crossings, lights; for instance, in case or a fault involving a light, an assumed red signal is a type of safe status.
In view of their special characteristics, vital devices require additional and ad hoc measures; for example, proper vital trace spacing/creepage and clearance are required between sets of copper vital inputs and outputs to ensure that a short circuit will not occur between two pieces of equipment. What is more, each piece of vital equipment is usually controlled by an associated electromechanical vital suppliers relay, and wayside control locations can encompass a large number of vital relays, e.g. from tens to hundreds of vital relays. These relays are usually physically large and require DIN/rack mounting, they are rather expensive, they vary in impedance as well as in thresholds for turn on/turn off, they have analog thresholds and compatibility issues between different suppliers and, since they are based on mechanical components, they are subject to wear and hence require maintenance and/or replacement.
Hence, it is evident that there is room and desire for improvements in the way devices, and in particular vital devices are controlled in a railway system.
The present disclosure is aimed at providing a solution to this end and, in one aspect, it provides a system for controlling one or more vital wayside devices of a railway network, comprising:
In another aspect, the present disclosure provides a vital switch for a device of a railway control system, comprising an optical receiver adapted to receive at least one light command signal emitted by a controller, and a solid state switch which is configured to switch from an open status to a closed status to provide power and ground to said device upon receiving the at least one light command signal outputted by the controller.
Detailed characteristics and advantages will become apparent from the description of some preferred but not exclusive exemplary embodiments a system according to the present disclosure, illustrated only by way of non-limitative examples with the accompanying drawings, wherein:
It should be noted that in the detailed description that follows, identical or similar components, either from a structural and/or functional point of view, may have the same reference numerals, regardless of whether they are shown in different embodiments of the present disclosure. It should be also noted that in order to clearly and concisely describe the present disclosure, the drawings may not necessarily be to scale and certain features of the disclosure may be shown in somewhat schematic form.
Further, when the term “adapted” or “arranged” or “configured” or “shaped”, is used herein while referring to any component as a whole, or to any part of a component, or to a combination of components, it has to be understood that it means and encompasses correspondingly either the structure, and/or configuration and/or form and/or positioning. In particular, for electronic and/or software means, each of the above listed terms means and encompasses electronic circuits or parts thereof, as well as stored, embedded or running software codes and/or routines, algorithms, or complete programs, suitably designed for achieving the technical result and/or the functional performances for which such means are devised.
In addition, when the term “substantial” or “substantially” is used herein, it has to be understood as encompassing an actual variation of plus or minus 5% with respect to an indicated reference value, time or position.
Finally, in the following description and claims, the numeral cardinals first, second, third, etc . . . , will be used only for the sake of clarity of description and in no way they should be understood as limiting for whatsoever reason; in particular, the indication of a component referred to for instance as the “third . . . ” does not imply necessarily the presence or strict need of the preceding “first” or “second” ones, unless such presence is clearly evident for the correct functioning of the subject switch machine, nor that the order should be the one described in the illustrated exemplary embodiment(s).
A system for controlling one or more wayside devices, in particular vital devices, which are installed in a railway network, is illustrated in
The control system 100 comprises or more vital switches, each vital switch being comprised in or operatively connected to an associated vital wayside device; in particular, in the exemplary embodiment illustrated in
The control system 100 further comprises a controller 50 which is configured to control each of the one or more wayside vital devices 10, 11, 12.
Conveniently, in the system 100 the controller 50 is connected to each of the one or more vital switches 20, 21 and 22, by means of at least one optical fiber cable and is configured to output one or more light command signals over the at least one optical fiber cable; correspondingly, each vital switch 20, 21 and 22 is configured to switch from an open to a closed operative status to provide power and ground to the associated device 10, 11, 12 upon receiving at least one corresponding light command signal which has been outputted by the controller 50 for the specific vital switch 20 or 21 or 22. In this way, the vital wayside device 10 or 11 or 12 associated to the vital switch which received the light command signal performs a needed function, for example switching from green to red, or closing a crossing level.
The system 100 comprises also one or more power sources, in particular DC power sources, for providing the needed power; in the embodiments illustrated in
According to the exemplary embodiment illustrated in
According to the exemplary embodiment illustrated in
The controller 50 can comprise or be constituted by any processor-based device, e.g. a microprocessor, microcontroller, a microcomputer, a programmable logic controller, an application specific integrated circuit, or any other programmable circuit, of a type commercially available, suitably programmed and provided to the extent necessary with circuitry, in order to perform the innovative functionalities devised for the system 100 according to the present disclosure.
The system 100 according to the present disclosure comprises at least one optical transmitter, indicated in
Usefully, in the system 100 according to the present disclosure the optical transmitter 60 and each optical receiver 80 are arranged according to a two-out of-two (2oo2) architecture and the communication between them is realized using a vital protocol, which can be of any suitable type of available vital communication protocol, such as RP2000 and RP2009. In practice, in exchanging vital signals, two channels are used and both must agree in order to send/receive a signal vitally.
In particular, the optical transmitter 60 is adapted to generate, for each command to be outputted towards a corresponding vital switch, a first or reference light command signal and a safety signal; in turn, the optical transmitter is adapted to check consistency between the safety signal and a feedback signal. The optical receiver 80 of each vital switch 20, 21 and 22 is adapted to receive the first light command signal and to switch from an open to a closed status to provide power and ground to the associated wayside vital device.
More in details, the optical transmitter 60 comprises two independent processors/FPGA's that are each responsible for a portion of the signal being transmitted. According to the exemplary embodiment of
In turn, in the exemplary embodiment illustrated in
According to a possible embodiment, the vital switches 20, 21, 22 comprise or are constituted each by a solid state switch which is associated to an external optical receiver, like the optical receiver 80 previously described; alternatively a vital switch, which can constitute the vital switches 20, 21, 22 used in the system 100, or which can be applied in any other suitable application, includes an optical receiver adapted to receive at least one light command signal emitted by a controller, like the controller 50, and a solid state switch which is configured to switch from an open status to a closed status to provide power and ground to an associated vital wayside device 10, 11, 12 upon receiving the at least one light command signal outputted by the controller 50.
A first possible embodiment of a solid state switch which can be used as or is comprised in a vital switch 10, 11, 12 is illustrated in
In a second possible embodiment illustrated in
According to this exemplary embodiment, a first clock signal and a second clock signal are sent by the controller 50 over the relevant fiber optical cable. These clock signals have a proper frequency suitable to switch the charge pump, have for example a 50% duty cycle and are 180° out of phase. Pulse signals A_pulse (delivered to 27 and 29) and B_pulse (delivered to 28 and 30) are derived from the clock signals via two corresponding PLDs not illustrated in the figures, which are for example part of the vital switch or alternatively they can be part the controller 50. For the proper working of the solid state vital switch, these two PLDs can be of any suitable type available in the market properly arranged to the extent necessary not to contain any logic that could generate a pulse signal in absence of a corresponding clock signal. Further, they have to be completely independent with respect to their corresponding clock and pulse signals related operations, and no direct communication or synchronization should exist since the only source of synchronization is represented by the clock signals properly generated by the controller 50 and suitably transmitted over the optical fiber cable. In this case, the vital switch is activated when the current flows in the correct polarity, and in particular in the example illustrated only if the positive (+) is connected to ground and a negative voltage is generated, which condition can occur if the A_pulse and the B_pulse are both dynamic with a frequency and a difference which are in the correct range. A feedback is sent back to the controller 50 if a negative voltage is not generated when should be, then the controller 50 negates the clock signals and reveals the failure triggering maintenance. If a clock is used for the PLDs, for example for filtering out and discriminating signals received from the fiber optical cable, its frequency should be preferably orders of magnitude greater than the frequency of the pulse signals. In turn, the resistence Rsafety is sized in such a way that the capacitor Cfly is unable to charge when switched at a too high frequency; the capacitor Cfly is properly sized to be unable to transfer sufficient energy when switched too slowly.
In a third possible embodiment illustrated in
Hence, it is evident that the system 100 according to the present disclosure, compared with prior art solutions, allows to reduce drastically the presence of copper wires used for cabling the various I/O between a controller and the vital wayside devices controlled by it. In this way, issues related to electromagnetic interferences and compatibilities, as well as threshold incompatibilities, are also substantially mitigated if not completely eliminated. The use of small optically controlled vital switches 20, 21, 22, and in particular of vital solid state switches allows to remove or substantially reduce the need for large and costly electro-mechanical relays and the presence of isolation transformers.
The system 100 and vital switch 20, 21 and 22 thus conceived are susceptible of modifications and variations, all of which are within the scope of the inventive concept as defined in particular by the appended claims; for example, some parts of the controller 50 may reside on the same electronic unit, or they can be realized as subparts of a same component or circuit of an electronic unit, or they can be placed remotely from each other and in operative communication there between; the transmitter 60 and receiver 80 can be realized according to many other suitable solutions; the vital switches used in the system 100 can be all of the same type, or it is possible to use different types of vital switches among those described in the exemplary embodiment of
