Compensation method for time delay in data transmission network based on time division multiple access (TDMA) protocol

Abstract

The invention relates to a method for compensating for latency in a time division multiple access (TDMA) protocol-based bidirectional data transmission network between a master device (M1) and at least one slave device (E1), said latency being caused by electronic data transmission means inside the master device and the slave device. The method comprises the following iterative steps:-synchronizing the slave device with the master device by synchronizing according to a synchronization signal (S) transmitted by the master device; measuring the internal delay introduced by the electronic data transmission means of the respective primary device; and compensating for the measured internal delay.

Description

Technical Field

[0001] The present invention relates to data transmission networks, and more particularly to the time synchronization of such data exchanges according to the time division multiple access protocol. Background Art

[0002] Today, avionics systems and aeronautical systems use a very large number of sensors for different purposes. These sensors can be divided into three main application categories:

[0003] - Regulation: These sensors are the most critical sensors because the data measured by these sensors is used to regulate the mechanical and hydraulic systems of the aeronautical equipment during flight. These sensors are used for servo-control of the systems;

[0004] - Monitoring: The data obtained by these sensors is used to monitor the behavior and health status of the systems or structures of the aircraft during flight;

[0005] - Instrumentation: The data measured by these sensors is used for ground test benches and flight test benches to verify and perform the maintenance of the aeronautical equipment. The benches are complex because they use a very large number of sensors.

[0006] Thus, each sensor used in an aircraft is independently connected to a calculator via a cable to ensure the processing of its data. This is called point-to-point topology. In this way, the wiring associated with each of the sensors becomes particularly bulky, which poses problems in terms of mass and overall size. Therefore, adding new sensors is restricted.

[0007] There are configurations that allow multiple sensors to communicate with a single calculator via the same cable, such as Avionics Full-Duplex Switched Ethernet (AFDX).

[0008] For example, as Figure 1 shown, in order to ensure the communication between each sensor and the calculator, a distinction is made between two types of devices, namely a device M1 configured as a "master" and devices E1, E2, ……, EN configured as "slaves". The master device or slave device is defined as a set of electronic components that provides an interface between the sensor and the calculator and jointly ensures the communication between the sensor and the calculator. The "slave" device is capable of connecting to multiple sensors with different applications and receiving the data measured by these sensors. The "master" device M1 connected to the aeronautical calculator triggers the reception of data at each of the "slave" devices to send all the collected data to the aeronautical calculator. Thus, the "master" device manages the communication on the sensor network.

[0009] Therefore, the master device M1 sends the setpoint TR3 to each "slave" node E1, E2, ……, EN in the form of a data sequence.

[0010] In the case of two-way communication, each "slave" device E1, E2, ……, EN has a programmable electronic device, which is configured to send data TR2 to the "master" device M1, for example, to indicate to the "master" device M1 that the task has been actually executed.

[0011] The fact that multiple slave devices E1, E2, ……, EN exchange data with the master device M1 via the same link requires multiplexing of the data. The protocol for this type of link is the so-called time-based multiplexing protocol, such as the Time Division Multiple Access (TDMA) protocol.

[0012] Therefore, as Figure 2 shown, the data sequence TR3 sent by the master device M1 to each slave device E1, E2, ……, EN includes a data frame TR1 and a data frame TR2. In this example, the duration of each sequence TR3 is approximately 1 millisecond (ms).

[0013] The master device M1 includes a master clock, which times the data transmission in each sequence TR3 of the sequences TR3. Similarly, each slave device X1, X2, ……, XN includes a slave clock, which times the data reception in each sequence TR3 of the sequences TR3.

[0014] Each data frame TR1 includes a master signal M, which includes data related to the master device M1, such as a sensor reading command, or a supervision and maintenance command. The frame TR1 also includes an analog synchronization signal S.

[0015] Each data frame TR2 includes a plurality of time slots X1, X2, ……, XN, which are used for data transmission from each slave node E1, E2, ……, EN to the master device M1. In this example, there will be N = 20 slave devices.

[0016] In this way, each slave device E1, E2, ……, EN can transmit data TR2 to the master device M1 within the time slot allocated to it, thus avoiding the risk of data interaction with other slave devices.

[0017] To achieve this, the slave clock of each slave device E1, E2, ……, EN for timing data transmission and data reception must be fully synchronized with the master clock of the master device M1.

[0018] In other words, the slave clocks of each slave device E1, E2, ……, EN must be timed with the same reference clock.

[0019] Patent FR 3,108,817 describes the emission of an analog synchronization signal S in each data sequence TR1.

[0020] The synchronization signal S includes an amplitude adjustment part S1 and an optimized synchronization part S2. The amplitude adjustment part is in the form of a sine wave with a constant amplitude during a predetermined number of pulses, and the optimized synchronization part is in the form of a triangular amplitude modulation of the sine wave. The optimized synchronization part S2 does not have a constant amplitude but has a variable amplitude, so the transition between the rising phase and the falling phase can be detected quickly and accurately, thereby determining a very accurate reference moment TOP. Therefore, the master clock and the slave clocks can be synchronized, and the time slots of each sequence TR3 can be timestamped very accurately. Therefore, the reference moment TOP can define the start of the period during which each of the slave devices E1, E2, ……, EN sends data X1, X2, ……, XN to the master device M1 respectively.

[0021] However, for both the master device and the slave devices, the transmission circuits and reception circuits of each device may introduce time delays in propagating the synchronization signal S or the data TR2 due to their electronic components.

[0022] This time delay also varies with the temperature at the master device and the slave devices, which may become a problem in an environment with high thermal stress.

[0023] This time delay may also vary according to the transmission time, especially due to the long distance between the master device and the slave devices.

[0024] To compensate for these time lags, very "advanced" signal processing techniques are used. Although these techniques are effective, they also increase the complexity of the communication system, both in terms of the required computing power / electronic processing and because the measured data is transmitted between devices or on a specific channel, increasing the amount of information to be transmitted. For example, when the length of the transmission line is 30 meters, the resulting time delay is approximately 200 nanoseconds.

[0025] In addition, this time delay can be suppressed by frequency compensation, for example, by using compensation techniques such as "Least Squares (LS)" or "Minimum Mean Square Error (MMSE)".

[0026] Therefore, the challenge lies in overcoming the problems mentioned above. Summary of the Invention

[0027] In view of the foregoing, the present invention allows each of the master / slave nodes to perform synchronization independently.

[0028] To this end, the present invention relates to a method for compensating for the time delay in a two-way data transmission network based on the TDMA protocol between a master device (M1) and at least one slave device (E1), the time delay being caused by the electronic data transmission devices inside the master device and the slave devices, the method comprising the following iterative steps:

[0029] - Synchronizing the slave device with the master device by synchronizing according to a synchronization signal (S) sent by the master device;

[0030] - Measuring the internal time delay introduced by the electronic data transmission devices of each master device and slave device; and

[0031] - Compensating for the measured internal time delay.

[0032] These steps are repeated cyclically.

[0033] Therefore, each node can measure its own electronic devices through "loopback" without affecting other nodes on the cable. Then, each node uses the measurement result to change the moment when it will send on the cable and centers its received signal listening window.

[0034] In this way, each device autonomously measures the time delay generated by the propagation of the signal within its electronic transmission (i.e., data transmission and data reception) electronic circuit.

[0035] In other words, the slave device does not need to know the time delay generated by the master device.

[0036] Similarly, when the master device or the slave device is in a communication group, it does not have to obtain the value of the time delay generated by other devices.

[0037] This releases the bandwidth, thereby increasing the data exchange speed between the master device and the slave device. In fact, the synchronization between devices does not use learning frames, thus releasing the bandwidth.

[0038] Advantageously, in the step of synchronizing the master device with the slave device, the slave device synchronizes according to an analog synchronization signal sent by the master device.

[0039] In addition, in the step of synchronizing the slave device with the master device, a reference time is extracted from the data sent by the master device, and the reference time defines the start of the time period for sending data to each slave device.

[0040] According to the characteristics of the present invention, the internal delay is measured by the following operations: looping back the loopback signal between the outputs and inputs of each master device and slave device, and measuring the propagation duration of the signal looped back between the outputs and inputs of each master device and slave device.

[0041] Advantageously, the loopback signal is generated in regular time slots.

[0042] Data is transmitted in the form of data sequences. For each data sequence, the duration of the reception delay is substantially equal to a first delay value associated with the master device, and the duration of the data transmission advance is substantially equal to a second delay value associated with the slave device.

[0043] Another object of the present invention is a bidirectional data transmission system, which includes a master device and at least one slave device, and the system is capable of realizing bidirectional data communication between the master device and the slave device. The master device and the slave device include electronic data transmission devices according to the time division multiple access protocol. The data transmission system includes: means for synchronizing the slave device with the master device by synchronizing according to a synchronization signal sent by the master device; means for measuring the internal delay introduced by the electronic data transmission devices of each master device and slave device; and means for compensating the measured internal delay.

[0044] Based on another characteristic of the transmission system according to the present invention, the means for measuring the internal delay includes: means for looping back a signal between the outputs and inputs of each master device and slave device, and means for measuring the propagation duration of the signal looped back between the outputs and inputs of each master device and slave device.

[0045] Another object of the present invention is a turbine, which includes at least one system as defined above.

[0046] Another object of the present invention is a sensor for aviation applications, which is particularly used for regulation, monitoring and / or instrumentation measurement, and the sensor includes a system as defined above.

[0047] Another object of the present invention is an aircraft, which includes a turbine as defined above.

[0048] Another object of the present invention is an aircraft, which includes at least one system capable of realizing the bidirectional data communication as described above. Description of the Drawings

[0049] Other objects, characteristics and advantages of the present invention will become apparent when reading the following description, which is provided only as a non-limiting example and with reference to the accompanying drawings, in which:

[0050] Figure 1 ​(previously mentioned) schematically illustrates the communication between a master device and a group of slave devices;

[0051] Figure 2 (previously mentioned) schematically shows a data frame transmitted from a master device to a slave device according to the present invention;

[0052] Figure 3 shows a data communication system including a master device and a slave device according to the prior art;

[0053] [Figure 4a] and

[0054] [Figure 4b] show a device for measuring the time delay by means of a feedback between a data transmission device and a data acquisition device in a master device and a slave device respectively according to an embodiment of the present invention;

[0055] [Figure 5a] and

[0056] [Figure 5b] show the principle of time delay compensation implemented by the method and device according to the present invention, and show the transmission of data sequences without time delay compensation and with time delay compensation respectively; and

[0057] Figure 6 shows a flowchart of a compensation method according to an embodiment of the present invention. Detailed Embodiment

[0058] In Figure 3 , an electronic system 1 is shown, which includes an electronic master device M1 and an electronic slave device E1.

[0059] For clarity, slave devices E2,..., EN are not shown in the figure. Next, a single slave device E1 will be referred to, but this does not exclude the master device M1 being coupled to multiple slave devices having an electronic architecture similar to that of the slave device E1.

[0060] To achieve two-way data communication between the master device M1 and the slave device E1 according to the time division multiple access (TDMA) protocol, the electronic system 1 includes a transmission line 2 capable of propagating analog electrical signals.

[0061] Then, the transmission line 2 is coupled on the one hand to the transmitting device 4 and the acquiring device 5 of the master device 1, and on the other hand to the transmitting device 6 and the receiving device 7 of the slave device E1.

[0062] More specifically, the transmitting device 4 includes a series of electronic components that can convert a digital signal into an analog signal and then transmit the analog signal to the slave device E1 via the transmission line 2.

[0063] As previously referred to Figure 2 ​​​As described, each data sequence TR3 includes a header frame TR1 and a data frame TR2. Frame TR1 includes a main signal M, which includes data of the master device M1 transmitted by the master device M1 for the slave devices E1, E2, ……, EN; and an analog synchronization signal S transmitted by the master device M1 for the slave devices E1, E2, ……, EN. In particular, signal S enables the time slots of the frames of data sequence TR3 to be timestamped very accurately. Each frame TR2 also includes time slots X1 to X20, which are used to send data from each slave device to the master device M1.

[0064] According to patent FR 3,108,817, the analog synchronization signal S includes an amplitude adjustment part S1 and a synchronization part. The amplitude adjustment part is in the form of a sine wave with a constant amplitude during a predetermined number of pulses, and the synchronization part is optimized to determine the reference time TOP. The reference time TOP allows defining the start of the period during which data X1, X2, ……, XN are respectively sent from each of the slave devices to the master device. It is known that the reference time TOP is very accurate. In addition, this allows accurately determining the time period (about 1 ms) between two reference times TOP, so as to infer the frequency of the master clock and possibly correct the frequency of the slave clock.

[0065] Thus, the receiving device 7 includes a series of electronic components, which are used to filter the analog signal TR3 received by the transmitting device 4 and convert it into a digital signal to be processed.

[0066] As for the transmitting device 6 of the slave device E1, its function is to transmit an analog signal to the acquisition device 5, and the acquisition device can filter the analog signal and then convert it into a digital signal. Ideally, the analog signal is transmitted by the transmitting device 6 during the time slot allocated to the slave device E1, and the analog signal includes the data TR2 sent to the master device.

[0067] However, the electronic components of the transmitting device 4 and the acquisition device 5 of the master device M1, as well as the electronic components of the transmitting device 6 and the receiving device 7 of the slave device E1, may introduce time delays when propagating the synchronization signal S or the data TR1 and TR2.

[0068] This time delay also changes according to the temperature at the master device M1 and the slave device E1, and / or according to the transmission time, especially due to the long link distance between the master device and the slave device.

[0069] Therefore, at the first observation point N1 located between the transmission line 2 and the transmitting device 4, the propagation time delay D1 of the analog signal TR1 transmitted to the slave device E1 is observed.

[0070] At a second observation point N2 located between the transmission line 2 and the receiving device 7, the time delay remains substantially equal to D1, since the time delay associated with the propagation of the signal through the transmission line 2 remains negligible.

[0071] For example, when the length of the transmission line 2 is 30 meters, the resulting time delay is at most approximately 200 nanoseconds.

[0072] For example, the time delay can also be suppressed by minimum mean square error (“MMSE”) frequency compensation.

[0073] When the signal TR1 is received by the receiving device 7 and converted into a digital signal, a time delay D2 is introduced.

[0074] Similarly, converting the digital signal into an analog signal TR2 that can be transmitted by the transmitting device 6 results in a time delay D3 measured at a third observation point N3.

[0075] Finally, receiving the analog signal TR2 by the acquisition device 5 and converting it into a digital signal may extend the time delay by a duration D4, which is measured at a fourth observation point N4.

[0076] Therefore, when implementing data communication between the master device M1 and the slave device E1 according to the TDMA protocol, it is important to compensate for the propagation time delays D1, D2, D3, and D4.

[0077] Knowledge of the time delays D1, D2, D3, and D4 enables synchronization of the transmission windows and the listening windows of the signals X1 to XN during such data exchange.

[0078] For this purpose, FIG. 4a shows the master device M1, which also includes a measuring device 8a coupled to the transmitting device 4 and the acquisition device 5.

[0079] Such a measuring device 8a is capable of generating an analog loopback signal that propagates only between the data transmitting device 4 and the acquisition device 5 and undergoes a propagation period due to the electronic transmission device of the master device.

[0080] To this end, the master device M1 includes a first switch 9a that can couple and decouple the transmitting device 4 and the acquisition device 5.

[0081] The master device M1 also includes a second switch 10a that can couple and decouple the transmitting device 4 and the transmission line 2.

[0082] A third switch 11a is also provided between the acquisition device 5 and the transmission line 2 to couple and decouple the receiving device 5 and the transmission line 2.

[0083] Thus, the measuring device 8a can close the first switch 9a and open the switches 10a and 1a1 to loop back the signal only between the data transmitting device 4 and the acquisition device 5.

[0084] Thus, the propagation period of the looped-back signal corresponds to a first delay value T1, which is substantially equal to the sum of the delay D1 and the delay D4.

[0085] For the slave device E1, referring to FIG. 4b, the slave device also includes an electronic architecture similar to that of the master device M1, and in addition includes a measuring device 8b coupled to the transmitting device 6 and the receiving device 7, and switches 9b, 10b, and 11b to generate such a looped-back signal: the looped-back signal propagates only between the receiving device 7 and the transmitting device 6 and experiences a propagation period due to the electronic transmission device of the slave device.

[0086] Thus, a second delay value T2 is measured, which is substantially corresponding to the sum of the delay D2 and the delay D3.

[0087] In other words, each device M1, E1 autonomously measures the delay generated by the propagation of data in its transmitting circuit and in its data receiving circuit.

[0088] As previously described, a delay is introduced at each viewing point. Therefore, the delays are accumulated and added at each point, which results in the lag becoming obvious, especially at the viewing point N4. Therefore, the listening window of the master device M1 for the signals X1, X2, ……, XN must be data-centered to avoid these lags. Therefore, the delay of the electronic device can be predicted via the previously described developed circuit and the data transmission can be adjusted because the induced delay (especially the delay caused by the electronic device) is known.

[0089] It should be noted that the delay values T1 and T2 are measured periodically to update these delay values according to the temperature changes at the master device M1 and the slave device E1. Periodicity means that the master device and the slave device are available (i.e., they are not monopolized by sending data at a specific moment). This measurement is performed once per cycle, and preferably, the duration of each cycle is 1 ms.

[0090] Thus, the looped-back signal is generated during the guard time slot between two consecutive data sequences TR3. The guard time slot refers to the time slot when the master device or the slave device is idle (i.e., they neither send nor receive).

[0091] Referring to FIGS. 5a and 5b, FIGS. 5a and 5b respectively show the electronic system 1 before and after compensation, where the delays T1 and T2 before the transmission data sequence TR3 are measured.

[0092] In these figures, the observation points N1 and N6 are the observation points of the master device M1, the observation points N2 and N5 are the observation points of the transmission line 2, and the observation points N3 and N4 are the observation points of the slave device.

[0093] Similarly, in these figures:

[0094] - The time period D1 represents the time delay of the transmit chain (Tx) of the master device: Δt Tx_M = D1;

[0095] - The time period D2 represents the time delay of the receive chain (Rx) of the slave device: Δt Tx_Xn = D2;

[0096] - The time period D3 represents the time delay Δt of the transmit-receive chain (Tx) of the slave device Rx_Xn = D3;

[0097] - The time period D4 represents the time delay of the receive chain (Rx) of the master device: Δt Rx_M = D4.

[0098] It will also be noted that the channel time delay Dc represents the propagation time between the master device and the slave device, which is shorter than the time period compensated by the time delay compensation method according to the present invention due to electronic devices, and this propagation time will be compensated by channel compensation.

[0099] Therefore, the time delay caused by the transmit chain (Tx) of the master device and the receive chain (Rx) of the slave device is: D1 + D2.

[0100] The time delay caused by the transmit chain (Tx) of the slave device and the receive chain (Rx) of the device is: D3 + D4.

[0101] Referring to Figure 5a, in the case of no compensation, the balance of the time delays at the observation nodes N1 to N6 is written as:

[0102] N1 = 0

[0103] N2 = D1:

[0104] N3 = D1 + D2

[0105] N4 = D1 + D2

[0106] N5 = D1 + D2 + D3

[0107] N6 = (D1 + D4) + (D2 + D3).

[0108] For the receiver of the slave device (node N3), the time delay applies to both the synchronization pulse TOP and the data, so that the time window is aligned with the allocated interval without time lag.

[0109] Therefore, the synchronization problem especially occurs in the return direction, i.e., when a signal is sent from the slave node to the master device.

[0110] Therefore, referring to FIG. 5b, the delay caused by the slave device E1 is compensated by the displacement of the time listening window of the slave device E1.

[0111] As for the acquisition device 5 of the master device M1, it can start receiving the data TR2 according to the first delay value T1.

[0112] For this purpose, the acquisition device 5 is configured to delay the activation of the time listening window of the master device M1 by a duration that is approximately equal to the measured first delay value T1.

[0113] Therefore, at the fourth observation point N4, the receiver of the slave node sends its signal in advance. Therefore, the balance of the delay is D1 + D2 - (D2 + D3), i.e., D1 - D3.

[0114] Similarly, the period from the transmitter to the device N5 is also compensated in advance. At the node N5, the balance of the delay is D1 - D3 + D3, i.e., D1. It should be noted that this delay can be compensated by another method (such as MMSE).

[0115] At the node N6, the balance of the delay caused by the compensation is written as D1 + D4, and the latter delay is compensated by the master device by delaying its listening window and the period measured by itself.

[0116] Now referring to Figure 6 , Figure 6 FIG. shows a flowchart of the delay compensation method according to the present invention, which is implemented by the electronic system 1 during the two-way data communication between the master device M1 and the slave device E1. It should be noted that each method step is iteratively implemented and in a permanent loop.

[0117] The method starts from step 100, during which the transmitting device 4 sends the data sequence TR3 to the slave device E1.

[0118] Since the data communication is based on the TDMA protocol, the data sequence TR3 includes the data frames TR1 and TR2. During this first step 100, the reference TOP is extracted from the synchronization signal S transmitted by the master device (more specifically, from the optimized synchronization part S2).

[0119] In step 200, the internal delays introduced by the electronic devices of each master device and slave device are measured using the internal loopback system described previously.

[0120] The transmitting device 7 of the slave device advances the transmission of the data TR2 by a duration equal to the second delay value T2. When transmitting from the slave device to the master device, the slave device must compensate for its delay time. Each slave device will transmit in advance during its time slot Xn and advance its transmission window by T2.

[0121] Finally, in step 300, as previously described with reference to FIGS. 5a and 5b, the acquisition device 5 receives the data TR2 and delays its time listening window by a duration equal to the known first delay value T1.

[0122] When the period of the internal electronic device is known, the system compensates for the delay in two stages using the measured period:

[0123] - Advance the transmission (send) of the signal to the master device;

[0124] - Delay the listening window for receiving the signal on the master device side.

[0125] Therefore, during step 300, the measurement results obtained in step 200 are used to compensate for the delay.

[0126] Therefore, during each transmission sequence TR3, the propagation delays T1 and T2 are compensated.

[0127] Of course, the present invention is not limited to the embodiments and implementations provided only as examples previously described.

[0128] Specifically, the TDMA protocol can be combined with a method of encoding digital signals by multi-subcarrier orthogonal frequency division multiplexing (OFDM).

[0129] Therefore, the integration of these technologies allows optimizing the availability of the spectrum. Then the total bandwidth is divided into multiple sub-bands for a specified number of slave devices.

[0130] Alternatively, single-carrier modulation can be performed by phase-shift keying (“Phase-Shift Keying, PSK”).

Claims

1. A method for compensating for time delays in a bidirectional data transmission network based on the TDMA protocol between a master device (M1) and at least one slave device (E1), said time delays being caused by electronic data transmission means within said master device and said slave device, said method comprising the following iterative steps: - Synchronizing the slave device with the master device by synchronizing according to a synchronization signal (S) transmitted by the master device; - Measuring the internal time delays introduced by the electronic data transmission means of each master device and slave device; and - Compensating for the measured internal time delays, And wherein, wherein the internal time delays are measured by the following operations: loopback of a loopback signal between the outputs and inputs of each master device and slave device, and measurement of the propagation duration of the signal looped back between the outputs and inputs of each master device and slave device.

2. The compensation method according to claim 1, wherein, In the step of synchronizing the slave device with the master device, a time slot including a synchronization signal (S) is extracted from the data transmitted by the master device, the synchronization signal (S) includes an amplitude adjustment part (S1) and a synchronization part (S2) in the form of amplitude modulation, and the synchronization signal (S) can determine a reference time (TOP), and the reference time defines the start of a period for transmitting data to each slave device.

3. The compensation method according to any one of claims 1 and 2, wherein, The loopback signal is generated in regular time slots.

4. The compensation method according to any one of claims 1 to 3, wherein, Data is transmitted in the form of a data sequence (TR3), and wherein, for each data sequence (TR3), the duration of the delay in receiving the data (300) is substantially equal to a first time delay value (T1) associated with the master device, and the duration of the advance in transmitting the data (TR2) is substantially equal to a second time delay value (T2) associated with the slave device.

5. A bidirectional data transmission system (1), said system comprising: - A master device (M1), and - At least one slave device (E1), wherein the system is capable of realizing bidirectional data communication between the master device (M1) and the slave device (E1), the master device (M1) and the slave device (E1) include electronic data transmission means according to the time division multiple access protocol, and the data transmission system includes: means for synchronizing the slave device with the master device by synchronizing according to a synchronization signal (S) transmitted by the master device; means for measuring the internal time delays introduced by the electronic data transmission means of each master device and slave device; and means for compensating for the measured internal time delays, and wherein the means for measuring the internal time delays includes: means for loopback of a signal between the outputs and inputs of each master device and slave device, and means for measuring the propagation duration of the signal looped back between the outputs and inputs of each master device and slave device.

6. A turbine, said turbine comprising at least one system (1) according to claim 5.

7. A sensor for aviation applications, said sensor being particularly used for regulation, monitoring and / or instrumentation measurement, said sensor comprising a bidirectional data transmission system (1) according to claim 5.

8. An aircraft, the aircraft comprising the bidirectional data transmission system (1) according to claim 5.

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