SENSING SYSTEM BASED ON AN ELECTRICAL CIRCUIT TO GENERATE AN ANALOGUE SIGNAL FOR A VEHICLE

Abstract

Electrical circuit (22) for generating an analog signal for a vehicle (10), in particular a railway vehicle, the electrical circuit (22) comprising two input terminals (30, 32) configured to receive a predetermined electrical voltage defined between said input terminals (30, 32), the electrical circuit (22) further comprising a main branch (34) connecting said input terminals (30, 32), in which the main branch (34) comprises a plurality of sensing resistors (R1, R2), connected in series between said input terminals (30, 32), each sensing resistor (R1, R2) having a different value with respect to each value of the other sensing resistors (R1, R2), and the main branch comprising for each sensing resistor (R1, R2), two short-circuiting terminals (40) configured to short-circuit the respective sensing resistor (R1, R2).

Description

[0001] The present invention relates to an electrical circuit for generating an analog signal for a vehicle.

[0002] The invention further relates to a system for detecting an associated analog signal.

[0003] In a manner known per se, the status of a plurality of electrical or electronic devices within a vehicle, for example a railway vehicle, must be monitored. To this end, vehicles are equipped with input / output modules for receiving signals from these devices indicating the respective states, and transmitting these states, for example, to a controller of the vehicle. The signals are, for example, logic or binary signals, i.e. signals having two possible states, for example indicating nominal operation or a failure.

[0004] As the number of devices in the vehicle increases, more states must therefore be monitored.

[0005] However, when adding equipment to be monitored in the vehicle, it can be difficult to monitor the status of this additional equipment via the existing input / output modules. Input / output modules include a predetermined number of inputs.

[0006] Also, space within vehicles is limited, which limits the possibility of adding additional input / output modules.

[0007] Furthermore, adding additional input / output modules has disadvantages, since this addition enlarges and weighs down the system configured to transmit equipment statuses.

[0008] One aim of the invention is thus to overcome the aforementioned drawbacks.

[0009] In particular, an aim of the present invention is to obtain an electrical circuit, and in particular a detection system comprising such an electrical circuit, allowing the monitoring of a large number of pieces of equipment of a vehicle, while being compact and lightweight.

[0010] To this end, the subject of the invention is an electrical circuit for generating an analog signal for a vehicle, in particular a railway vehicle, the electrical circuit comprising two input terminals configured to receive a predetermined electrical voltage defined between said input terminals, the electrical circuit further comprising a main branch connecting said input terminals, wherein the main branch comprises a plurality of sense resistors, connected in series between said input terminals, each sense resistor having a different value compared to each value of the other sense resistors, and the main branch further comprising, for each sense resistor, two shorting terminals configured to short-circuit the respective sense resistor when a state of a state contact connecting said shorting terminals is in a closed state, the electrical circuit further comprising at least one output terminal connected to the main branch so as to obtain the analog signal comprising a single voltage depending on the state of each state contact.

[0011] The electrical circuit according to the invention makes it possible to monitor a large number of vehicle equipment items, without adding additional input / output modules. In fact, the electrical circuit makes it possible to generate an analog signal which includes a specific, i.e. unique, voltage, indicative of all the states of the equipment items via their associated status contact.

[0012] By means of the electrical circuit, the analog signal is obtained in particular for transmission to an input / output module, instead of, for example, logic signals indicating the binary status of each equipment separately. The analog signal obtained by the electrical circuit of the invention then comprises information relating to the status of a large number of equipment items in the vehicle. Since each detection resistor has a different value compared to each value of the other detection resistors, the analog signal has a unique voltage, which depends on the status of each status contact of the monitored equipment items.

[0013] According to other advantageous aspects, the electrical generation circuit comprises one or more of the following characteristics, taken individually or in all technically possible combinations: the state of each status contact depends on an operating state of a vehicle equipment associated with said status contact, preferably each status contact being in the closed state when the equipment associated with said status contact is in a nominal operating state; the main branch further comprises a service resistor connected in series between one of the sensing resistors and one of the input terminals, the output terminal being connected to a midpoint between said sensing resistor and the service resistor; the single voltage is the voltage between the output terminal and one of the input terminals; the electrical circuit further comprises at least one diode connecting the input terminals, preferably connecting the input terminals by a parallel connection to the main branch, the diode preferably being a Zener diode; the electrical circuit is implemented as a surface-mounted component;the value of the single voltage satisfies the following equation, when the state contact of one of the detection resistors, called active resistance, is in an open state: ; V S = R 0 , t ⋅ V E R 0 , t + R X Or : V S is the value of the single voltage included in the analog signal; R 0, t is the value of the service resistance, preferably adjusted by a predetermined resistance tolerance; V E is the value of the predetermined electrical voltage between the input terminals, and R X is the value of the active resistance.

[0014] The invention also relates to a system for detecting an analog signal, comprising at least one electrical circuit as described above, the detection system further comprising, for each detection resistor, the state contact configured to connect the respective short-circuit terminals in the closed state.

[0015] According to further advantageous aspects, the detection system comprises one or more of the following features, taken individually or in all technically possible combinations: the detection system further comprises an input / output module configured to receive the analog signal, and configured to transmit a detection signal comprising the analog signal to a controller of the vehicle; the detection system comprises several electrical circuits, wherein the input / output module is configured to receive the analog signal from each electrical circuit, the detection signal comprising the analog signal from each electrical circuit.

[0016] These characteristics and advantages of the invention will appear on reading the description which follows, given solely as a non-limiting example, and made with reference to the appended drawing in which: there figure 1 is a schematic representation of a part of a vehicle comprising a system for detecting an analog signal.

[0017] In reference to the figure 1 , a vehicle 10 comprises a plurality of equipment 12, 14, a detection system 16, and a controller 18.

[0018] The vehicle 10 is preferably a railway vehicle. Alternatively, the vehicle 10 is a land vehicle or a ship.

[0019] Preferably, the vehicle 10 comprises a number of equipment items n, where n is an integer greater than or equal to 2, preferably n being at least 20, more preferably n being at least 100.

[0020] Each piece of equipment 12, 14 is in particular equipment having an electrical interface.

[0021] Each equipment 12, 14 has a nominal operating state, and at least one failure state.

[0022] Each piece of equipment 12, 14 is, for example, a circuit breaker, a limit switch or switch, a relay, a contactor, a pressure switch or a solenoid valve.

[0023] The detection system 16 comprises a plurality of state contacts I1 to Ix, designated on the figure 1 for example by I1 and I2, a voltage source 20, at least one electrical circuit 22 and an input / output module 24.

[0024] According to one example, the detection system 16 comprises several electrical circuits 22. In this case, for example, each electrical circuit 22 is connected to an analog input which is specific to it or which is dedicated to it or which is associated with this electrical circuit 22, of the same module or of different input / output modules 24.

[0025] Preferably, the detection system comprises x status contacts, where x is an integer greater than or equal to 2. Preferably, the number x is equal to the number n of equipment of the vehicle 10.

[0026] Each status contact I1 to Ix is associated with a respective equipment 12, 14. In particular, each status contact I1 to Ix is connected to a respective equipment 12, 14. For example, status contact I1 is connected to equipment 14, and status contact I2 is connected to equipment 12.

[0027] Each state contact I1 to Ix has a state selected between the closed state and the open state. This state depends in particular on the operating state of the equipment 12, 14 of the vehicle 10, which is associated with the respective contact I1 to Ix.

[0028] Each state contact I1 to Ix is in particular an electrical contact configured to allow the passage or interrupt the passage of a current between its terminals. According to an exemplary implementation, each state contact I1 to Ix takes the form of a switch having either the closed state or the open state.

[0029] Preferably, each status contact I1 to Ix is in the closed state when the equipment 12, 14 associated with this status contact is in the nominal operating state. For example, each status contact I1 to Ix is in the open state when the equipment 12, 14 associated with this status contact is in a faulty state. For example, with reference to the figure 1 , the status contact I1 is in the closed state, thus indicating that the equipment 14 is in the nominal operating state. The contact I2 is, in this example, in the open state, thus indicating that the equipment 12 is in the fault state.

[0030] For example, the state of each state contact I1 to Ix forms a logic input for the electrical circuit 22.

[0031] By "logical input" is meant an input with two possible values, also called a binary input, for example either the value "0" or the value "1".

[0032] The voltage source 20 is configured to provide a predetermined electrical voltage. For example, the voltage source 20 is a direct voltage source.

[0033] For example, the voltage source 20 is configured to provide a voltage substantially equal to 24 V, in particular in direct voltage.

[0034] The electrical circuit 22 is described in more detail in the following.

[0035] When the detection system 16 comprises several electrical circuits 22, each electrical circuit 22 is preferably identical.

[0036] Preferably, in particular to save space, the electrical circuit 22 is produced in the form of a surface-mounted component, the acronym of which is CMS, also called in English “Surface Mounted Device”.

[0037] Alternatively, the electrical circuit 22 is produced with components conventionally used for electrical circuits.

[0038] Alternatively, in particular to save space, the electrical circuit 22 is produced in the form of a plug configured to be connected to an input of the input / output module 24, as well as to outputs of the status contacts I1 to lx.

[0039] Alternatively, the electrical circuit 22 is produced in the form of an electronic card or an equipped terminal block.

[0040] The electrical circuit 22 comprises two input terminals 30, 32, a main branch 34 connecting the input terminals 30, 32, at least one output terminal 36 and a diode 38, in particular a Zener diode 38 for adapting the voltage to the input / output module 24.

[0041] The input terminals 30, 32 are configured to receive the predetermined electrical voltage from the voltage source 20. In particular, the input terminals 30, 32 are electrically connected to the voltage source 20.

[0042] The main branch 34, which connects the input terminals 30, 32, comprises a plurality of sense resistors R1 to Rx of single values.

[0043] By "unique value" it is meant that the value of each resistor is different from each value of the other sense resistors R1 to Rx.

[0044] In the example of the figure 1 , the main branch 34 comprises the sense resistor R1 and the sense resistor R2. The sense resistors R1 to Rx are connected in series between said input terminals 30, 32.

[0045] The main branch 34 further comprises, for example, at least one service resistor R0. The service resistor R0 is connected in series between one of the detection resistors R1 to Rx and one of the input terminals 30, 32. For example, the service resistor R0 is connected between the detection resistor R2 and the output terminal 32.

[0046] The main branch 34 further comprises, for each detection resistor R1 to Rx, two shorting terminals 40 configured to short-circuit the respective detection resistor R1 to Rx when the state contact I1 to Ix connecting these shorting terminals is in the closed state. Preferably, the shorting terminals 40 are, for a specific resistor R1 to Rx, positioned on either side of this resistor, or at opposite ends of this resistor.

[0047] For example, when the state contact I1 is in the closed state, the resistor R1 is short-circuited by these short-circuiting terminals 40 which connect ends of this resistor together via the state contact I1. According to the example of the figure 1 , when the state contact I2 is in the open state, the short-circuiting terminals 40 positioned on either side of the resistor R2 do not short-circuit this resistor, since the state contact I2 is open.

[0048] Each detection resistor R1 to Rx is associated with the corresponding status contact I1 to Ix, and in particular connected to this status contact by the respective short-circuit terminals 40.

[0049] Each sense resistor R1 to Rx has a different resistance value compared to each resistance value of the other sense resistors I1 to Ix. In particular, each sense resistor R1 to Rx has a unique resistance value, or single value. Preferably, each sense resistor R1 to Rx has its unique resistance value with a tolerance less than or equal to 1% of the resistance value. This makes it possible to obtain a very large number of different voltages depending on the states of the state contacts I1 to Ix, and thus makes it possible, from a single voltage value, to obtain information on the state of each state contact I1 to Ix.

[0050] The output terminal 36 is connected to the main branch 34 so as to obtain an analog signal comprising a single voltage depending on the state of each state contact I1 to Ix.

[0051] By "single voltage" is meant a voltage value only obtained for a specific combination of the states of the state contacts I1 to Ix. For example, when closing and / or opening one or more of the state contacts I1 to Ix, due to the different value of each resistor R1 to Rx, the single voltage varies.

[0052] For example, output terminal 36 is connected to a midpoint between one of the sense resistors R1 to Rx and the service resistor R0.

[0053] Preferably, the single voltage is the voltage between the output terminal 36 and one of the input terminals 30, 32. For example, with reference to the figure 1 , the single voltage is the voltage between output terminal 36 and input terminal 32. In the example of the figure 1 , the single voltage is designated by an arrow 42.

[0054] Preferably, the electrical circuit 22 forms a voltage divider, providing as output the single voltage measured on the service resistance R0.

[0055] Diode 38 of electrical circuit 22 connects input terminals 32 and 30, in particular by a parallel connection to the main branch 34. In particular, diode 38 is a Zener diode.

[0056] The diode 38 is in particular configured to decree a specific voltage value from the predetermined electrical voltage received from the voltage source 20. In particular, the diode 38 makes it possible to obtain a voltage value having a low tolerance. For example, the diode 38 is configured to decree a voltage equal to 20 V between the input terminals 30, 32.

[0057] Preferably, the value of the single voltage satisfies the following equation, when the state contact Ix of the detection resistor Rx, called active resistance, is in the open state: V S = R 0 , t ⋅ V E R 0 , t + R X Or : V S is the value of the single voltage included in the analog signal, in particular between the output terminal 36 and the input terminal 32; R 0, t is the value of the service resistance R0, preferably adjusted by a predetermined resistance tolerance; V E is the value of the predetermined electrical voltage between the input terminals 30, 32, and R X is the value of the active resistance.

[0058] The value R 0, t is for example determined as a function of the value of the resistor R0 and as a function of the value of an internal resistor 46 (described below) of the input / output module 24. In particular, the combination of the resistance values ​​gives an equivalent resistance value.

[0059] Preferably, the value of the resistor R0 is at least one order of magnitude lower than the value of the internal resistor 46.

[0060] The resistance R 0, t imposes in particular an available voltage range, and is for example modifiable according to the internal resistance 46.

[0061] The usable number of sense resistors R1 to Rx depends for example on the resistance R 0, t , taking into account in particular a minimum value of each detection resistor.

[0062] According to the example, the electrical circuit 22 has a resistor 44 linked to the diode 38, in particular the Zener diode. This resistor 44 is configured to limit the current passing through the diode 38. This thus makes it possible, for example, to limit the voltage of the analog input to the input / output module 24.

[0063] The input / output module 24 is configured to receive as input the analog signal of the or each electrical circuit 22, comprising the single voltage, which depends on the state of each state contact I1 to Ix of the respective electrical circuit 22.

[0064] The input / output module 24 is configured to transmit a detection signal comprising the or each analog signal to the controller 18.

[0065] Preferably, the input / output module 24 is positioned remotely from the controller 18, for example in a different compartment or a different car from the vehicle 10 than the controller 18.

[0066] Preferably, the input / output module 24 is a COTS (Commercial Off-The-Shelf) computer product.

[0067] Preferably, the input / output module 24 comprises, for example, an internal resistor 46 making it possible to measure the single voltage by an internal circuit, not shown, of the input / output module 24.

[0068] The 24 input / output module is for example a BRIO module (from the English “Basic Remote Input / Output” module for basic remote input / output module).

[0069] According to another example, the input / output module 24 is a RIOM module (from the English “Remote Input / Output Module”).

[0070] It is understood that the invention presents a certain number of advantages.

[0071] In fact, the electrical circuit 22 makes it possible to transform a plurality of logic inputs received at the short-circuiting terminals 40 into an analog signal which includes the information of the states of the state contacts I1 to Ix, in the form of the single voltage.

[0072] In particular, the electrical circuit 22 makes it possible to dispense with the need to add an additional input / output module 24 to detect a greater number of equipment states 12, 14.

Claims

1. An electrical circuit (22) for generating an analog signal for a vehicle (10), in particular a railway vehicle, the electrical circuit (22) comprising two input terminals (30, 32) configured to receive a predetermined electrical voltage defined between said input terminals (30, 32), the electrical circuit (22) further comprising a main branch (34) connecting said input terminals (30, 32), wherein the main branch (34) comprises a plurality of sense resistors (R1, R2), connected in series between said input terminals (30, 32), each sense resistor (R1, R2) having a different value compared to each value of the other sense resistors (R1, R2), and the main branch further comprising, for each sense resistor (R1, R2), two short-circuit terminals (40) configured to short-circuit the respective sense resistor (R1, R2) when a state of a state contact (I1,I2) connecting said short-circuiting terminals (40) is in a closed state, the electrical circuit (22) further comprising at least one output terminal (36) connected to the main branch (34) so ​​as to obtain the analog signal comprising a single voltage depending on the state of each state contact (I1, I2)., 2. Electrical circuit (22) according to claim 1, wherein the state of each status contact (I1, I2) depends on an operating state of an equipment (12, 14) of the vehicle (10) associated with said status contact (I1, I2), preferably, each status contact (I1, I2) being in the closed state when the equipment (12, 14) associated with said status contact (I1, I2) is in a nominal operating state.

3. Electrical circuit (22) according to claim 1 or according to claim 2, wherein the main branch (34) further comprises a service resistor (R0) connected in series between one of the detection resistors (R1, R2) and one of the input terminals (30, 32), the output terminal (36) being connected to a midpoint between said detection resistor (R1, R2) and the service resistor (R0).

4. An electrical circuit (22) according to any preceding claim, wherein the single voltage is the voltage between the output terminal (36) and one of the input terminals (30, 32).

5. Electrical circuit (22) according to any one of the preceding claims, further comprising at least one diode (38) connecting the input terminals (30, 32), preferably connecting the input terminals (30, 32) by a parallel connection to the main branch (34), the diode preferably being a Zener diode.

6. Electrical circuit (22) according to any one of the preceding claims, produced in the form of a surface-mounted component.

7. Electrical circuit (22) according to any one of the preceding claims, in which the value of the single voltage satisfies the following equation, when the state contact of one of the detection resistors (R1, R2), called active resistance, is in an open state: V S = R 0 , t ⋅ V E R 0 , t + R X Or : V S is the value of the single voltage included in the analog signal; R 0,t is the value of the service resistance, preferably adjusted by a predetermined resistance tolerance; V E is the value of the predetermined electrical voltage between the input terminals (30, 32), and R X is the value of the active resistance.

8. Detection system (16) of an analog signal, comprising at least one electrical circuit (22) according to any one of the preceding claims, the detection system (16) further comprising, for each detection resistor (R1, R2), the state contact (I1, I2) configured to connect the respective short-circuit terminals (40) in the closed state.

9. The detection system (16) of claim 8, further comprising an input / output module (24) configured to receive the analog signal, and configured to transmit a detection signal comprising the analog signal to a controller (18) of the vehicle (10).

10. A detection system (16) according to claim 9, comprising a plurality of electrical circuits (22), wherein the input / output module (24) is configured to receive the analog signal from each electrical circuit (22), the detection signal comprising the analog signal from each electrical circuit (22).