Digital instrumentation comb

Abstract

The present document relates to a digital instrumentation comb (30) for an aircraft engine, comprising: a body (32) of longitudinal axis (X) and provided with a plurality of orifices spaced apart along the longitudinal axis (X); a plurality of nozzles (36); and at least one printed circuit board (38), which comprises: a substrate comprising a base (38a) arranged in the longitudinal cavity and a plurality of tabs (38b), each tab (38b) extending from the base (38a) and through a respective orifice; a plurality of digital sensors, at least one digital sensor (39) being arranged on a respective tab (38b); a switching device (35) arranged on the base (38a) of the printed circuit board (38); and a first electrical signal converter (44) arranged on the base (38a).

Description

Description Title: Digital Instrumentation Comb technical field

[0001] This disclosure falls within the domain of aircraft engine instrumentation combs. Previous technique

[0002] It is known from the prior technique for measuring the internal and ejection flows of aircraft engines in an aerodynamic channel to use measuring "combs" charged with collecting measurements, including measurements such as gas pressures and / or temperatures at different stages of the engine.

[0003] Figures 1 and 2 illustrate such a comb 2 having a central support, called body, 4, on which are arranged a predefined number of nozzles 6 distributed along the length of the body 4, each nozzle having a respective number of recirculation holes 6a.

[0004] Combs 2 are measurement means used in instrumentation to determine the thermodynamic performance of turbomachines via pressure taps 5 and / or temperature taps 7.

[0005] This pressure and / or temperature measurement is carried out by means of sensors 8 arranged in the nozzles 6, said sensors 8 being in contact with the flow to be measured which flows through the holes 6a.

[0006] Regarding pressure, the pressure sensors are too large to be directly integrated into the nozzles 6 or even into the body 4, so they are remote and connected to a plurality of pressure measuring tubes 5. The state of the art is to use capillary tubes with a diameter between 1 mm and 2 mm.

[0007] These pressure measurements are impacted by a response time and a frequency attenuation which are a function of the diameter of the capillary and the length of the pressure measuring tube 5.

[0008] Therefore, there is a need to improve the response time and bandwidth of pressure measurements.

[0009] Regarding temperature, the use of thermocouple probes or electrical resistance probes is known.

[0010] For thermocouple probes or electrical resistance probes, the information is sent in the form of an analog signal which must be conditioned by several electronic components connected to said temperature probes.

[0011] It has been found that electronic components are a major source of temperature uncertainty. In other words, the information transmission chain adds further uncertainty to the measured temperature, in addition to the inherent uncertainty of the temperature probe.

[0012] Another problem related to connectivity was also observed. Although the cables connecting the temperature probes are small (on the order of a millimeter), their integration with the electronic components results in a significant number of connecting cables.

[0013] This is especially true in the case of temperature measurements taken by several probes simultaneously, the number of cables to be routed corresponds to the number of temperature measurement points, multiplying tenfold the volume of the necessary connectors (dimensions of the cabling, cable routing, etc.).

[0014] At the end of the body 4, a base 10 allows the comb 2 to be fixed on the engine casing, and the cables 12 from the various sensors 8 to be brought out to an acquisition unit (not shown), for example located remotely in an engine test bench.

[0015] The environment of the test bench or the aircraft that supports the engine is a confined space which does not allow such bulk and which imposes significant distances (on the order of several tens of meters) between the temperature probes performing the measurements and an acquisition unit to which the data relating to the measurements must be routed.

[0016] On the other hand, the requirements for calculating efficiency (through temperature and pressure measurements, among others) demand high precision and short response times. For example, improved accuracy in temperature measurement translates into a significant improvement in engine efficiency assessment.

[0017] Therefore, there is a need to both reduce the bulk in terms of connectivity and reduce the uncertainty of temperature sensors.

[0018] Combs are a so-called "intrusive" measurement method, because their installation in the aerodynamic duct of an engine causes an obstruction of part of the flow circulating in that duct, and consequently pressure losses.

[0019] Thus, the comb, present in the bore, has an impact on the operation of the turbomachine. Therefore, there is a need to reduce (miniaturize) the body of these combs and / or the size of the sensors integrated into the comb. Summary

[0020] To this end, this document proposes a digital instrumentation comb for an aircraft engine comprising: a longitudinally oriented body including a longitudinal cavity and provided with a plurality of orifices spaced along this longitudinal axis; a plurality of nozzles, each nozzle being arranged longitudinally at each orifice; and at least one printed circuit board, which includes: - a substrate comprising a base arranged in the longitudinal cavity and a plurality of legs, each leg extending from said base and through a respective orifice so as to open into a corresponding nozzle; - a plurality of digital sensors for measuring a physical parameter of the aircraft engine, at least one digital sensor being arranged on a respective pin; - a switching device arranged on the printed circuit board, said switching device being electrically connected to said at least one digital sensor on each pin by a first primary communication bus; and - a first electrical signal transformer arranged on the base and electrically connected to the switching device by a first secondary communication bus.

[0021] During operation, physical parameter data, such as temperature, are acquired and then digitized by multiple digital sensors. For each digital sensor, this digital data is then encapsulated in a frame, and an electrical signal carrying this frame is emitted.

[0022] The electrical signal then follows this path: it travels through the first primary communication bus, the switching device, and the first secondary primary communication bus. The electrical signals from the plurality of digital sensors then converge at the first electrical signal transformer.

[0023] For one leg, the digital instrumentation comb allows multiplexing of the electrical signals emitted by said at least one digital sensor arranged on said leg through the switching device and on a single communication bus, the first primary communication bus.

[0024] Using at least one printed circuit board allows for the integration of a large number of components with a significantly reduced number of cables. This results not only in a smaller footprint but also in easier assembly.

[0025] In this way, the space occupied by the connectors remains virtually constant regardless of the number of digital sensors or probes used. Measurement redundancy can then be achieved, or the number of measurement points multiplied, without having to worry about space requirements.

[0026] Furthermore, no additional uncertainty is added to the temperature measurement by the transmission chain, as the physical measurement data is digitized by the plurality of digital sensors.

[0027] The arrangement of the elements of said at least one printed circuit board on the base or a leg of the substrate (surface mount) allows positioning with a tolerance of ±0.025 mm: the use of a printed circuit board therefore offers precise positioning of the digital sensors in the nozzles.

[0028] Furthermore, digital sensors are inexpensive sensors.

[0029] Each leg can have a length, at least one of the digital sensors being arranged at a distance from the end of the head less than 30% of said length, preferably 15%.

[0030] Alternatively, the comb may comprise a plurality of printed circuits arranged end to end in the longitudinal cavity.

[0031] Said at least one printed circuit board may further include a plurality of additional digital sensors for measuring a physical parameter of the aircraft engine, which are arranged on the basis of said at least one printed circuit board.

[0032] The digital instrumentation comb may further include a plurality of pressure tubes connected (i.e. coupled) to a plurality of additional digital pressure sensors arranged on the basis of the printed circuit board.

[0033] In other words, the plurality of additional digital sensors is arranged on the base and at a distance from the pins of the printed circuit board.

[0034] The said plurality of pressure tubes can extend from the plurality of additional digital pressure sensors and through a respective orifice so as to open into a corresponding nozzle.

[0035] More specifically, each pressure tube can open on one side into the nozzle, and on the other side opposite the corresponding additional digital pressure sensor.

[0036] In this way, the design of the digital instrumentation comb avoids the problems associated with the sizing of certain pressure sensors (sometimes very bulky, and unable to be inserted into a nozzle) while ensuring a reliable measurement.

[0037] Alternatively, each pressure tube can extend opposite one leg of said at least one printed circuit board.

[0038] The said at least one printed circuit board may include a coating of tropicalizing varnish. This protects the said at least one printed circuit board from humidity, dust, chemical contaminants, and temperature variations.

[0039] The switching device may include a plurality of address translators, each address translator being associated with a pin and electrically connected to said pin at least one digital sensor arranged on said pin by the first primary communication bus.

[0040] The electrical signal follows this path: it travels through the first primary communication bus, the respective address translator, and the first secondary primary communication bus. The electrical signals from the plurality of digital sensors then converge at the first electrical signal transformer.

[0041] Overall, the digital instrumentation comb allows multiplexing of electrical signals from the plurality of address translators through the first electrical signal transformer.

[0042] In other words, an address translator associated with a pin is shared by the digital sensors arranged on said pin, and the first electrical signal transformer is shared by the plurality of address translators.

[0043] The address translator is an integrated circuit whose role is to assign a different address to each digital sensor. This allows the same digital sensor to be integrated multiple times in the comb or on the same network without being limited by address conflicts.

[0044] In other words, the plurality of address translators allows each digital sensor to have its own unique address.

[0045] Each address translator can be arranged on the printed circuit board basis in greater proximity to said at least one associated pin digital sensor than the first electrical signal transformer.

[0046] The substrate of at least one printed circuit board can have a thickness between 0.2 mm and 2 mm, for example 0.8 mm. Such a thickness allows for reduced response times of the various sensors arranged on the printed circuit board.

[0047] Indeed, the thinner the printed circuit board, the better the response time of the temperature sensors arranged on the printed circuit board.

[0048] The substrate of said at least one printed circuit board may comprise a material from among epoxy, polyimide, aluminium and copper.

[0049] The comb may further include a base forming a proximal end of the body and intended to be fixed to a part of the aircraft engine casing.

[0050] The switching device may include a multiplexer, the multiplexer being electrically connected to the plurality of digital sensors by the first primary communication bus.

[0051] According to this aspect, the electrical signals circulating in the first primary communication buses of each leg are combined into a single electrical signal circulating in the first secondary communication bus.

[0052] The multiplexer allows communication with several peripherals (the plurality of digital sensors) via a single bus (first secondary communication bus) even if the peripherals have identical addresses.

[0053] In addition, the multiplexer makes it possible to reduce the number of components mounted on the printed circuit board: a single component (the multiplexer) is common to all of the plurality of digital sensors.

[0054] In other words, the multiplexer is shared by the plurality of digital sensors arranged on the plurality of pins of the printed circuit board and in the plurality of nozzles of the comb.

[0055] Additionally, the multiplexer ensures measurement reliability at any operating temperature specific to the environmental conditions of an aircraft engine (including above 85°C).

[0056] The first electrical signal transformer may be capable of converting an electrical signal using an I2C communication protocol (“Inter-Integrated Circuit” in English or inter-integrated circuit in French) into an electrical signal using a CANI2C layer.

[0057] The first primary communication bus and the first secondary communication bus can use an I2C communication protocol.

[0058] The first electrical signal transformer may be capable of converting an electrical signal using an I2C communication protocol and circulating in the first secondary communication bus into an electrical signal using a CANI2C layer.

[0059] In this particular configuration, the electrical signal emitted by at least one digital sensor and routed through the first communication bus uses an I2C communication protocol. This I2C communication protocol allows the sending of frames specific to the needs of the physical measurement being performed.

[0060] For example, it allows, through the sending of said frames, the emission of an average value, a setting of the confidence interval, a setting of the sampling frequency, an average of the acquired data, etc.

[0061] The I2C communication protocol includes an SCL signal ('Serial Clock' in English or serial clock in French) and an SDA signal ('Serial Data line' in English or serial data line in French).

[0062] This I2C communication protocol is particularly suited to a printed circuit board (simplicity of wiring, space saving, ease of integration...).

[0063] However, the physical layer of this I2C protocol is not suitable for distances between devices on the order of several meters or tens of meters, unlike a physical layer of the CAN protocol.

[0064] The CAN (Controller Area Network) protocol is a serial communication protocol: bits are sent one after the other over a single link. Unlike parallel communication, for example, where bits are sent simultaneously over multiple wires, the CAN serial communication protocol uses a single pair of wires to send data bits sequentially.

[0065] The CAN physical layer allows the electrical signal to be routed over long distances (several tens of meters) between the digital instrumentation comb and a possible acquisition unit.

[0066] It also offers the advantage of being robust and able to operate in the temperature and vibration conditions specific to an aircraft engine environment.

[0067] According to this embodiment, the first electrical signal transformer receives the SDA and SCL signals routed by the first secondary communication bus using the I2C communication protocol.

[0068] Then, to carry each of the SDA and SCL signals over significant distances (on the order of several meters, to several tens of meters), the first electrical signal transformer can convert (transform) said signals into signals using a CANI2C layer.

[0069] By CANI2C layer, we mean a layer comprising a physical layer of the CAN protocol as well as a link layer and higher layers of the I2C protocol.

[0070] More specifically, the CANI2C layer refers to a dual CAN communication bus, in the form of a twisted pair. In other words, it consists of a first CAN communication bus carrying the SDA signal, and a second CAN communication bus carrying the SCL signal.

[0071] In other words, by CANI2C layer, we mean a CANI2C physical layer.

[0072] The first electrical signal transformer thus makes it possible to extend the I2C communication bus of the received SDA and SCL signals (I2C protocol) into a first and second CAN communication bus, each CAN communication bus being associated with a signal.

[0073] The physical parameter can be any one or a combination of the following parameters (for example and without limitation): pressure, temperature, humidity, fluid acceleration, vibration, or gas composition.

[0074] The plurality of digital sensors can be any one or an association of the following: a pressure tube, a digital temperature probe or temperature sensor, a digital sensor of the type microelectromechanical system, MEMS (“Micro Electro Mechanical System” in English), an accelerometer, a pressure sensor, a combined pressure and temperature sensor and a gauge.

[0075] A digital sensor of the microelectromechanical system (MEMS) type helps to reduce the intrusive nature of the sensor.

[0076] At least one digital sensor can be a digital temperature sensor and may include conductive beads, a diode, a voltage measuring device, and a computer. In operation, the heat from the fluid is first absorbed by the conductive beads, which transfer it to the diode. As the diode's temperature increases, the voltage across its terminals decreases. The voltage measuring device then measures this voltage across the diode, and the measured voltage is subsequently processed by the computer for digitization.

[0077] This document may also relate to a system for collecting measurements of a physical parameter of an aircraft engine, including: - at least one digital instrumentation comb of the aforementioned type; and - an acquisition unit comprising: - a second electrical signal transformer electrically connected to the first electrical signal transformer by a second communication bus, the second communication bus enabling the transmission of information between the first electrical signal transformer and the second electrical signal transformer; and - an acquisition device electrically connected to said second electrical signal transformer by a third communication bus.

[0078] The collection system offers multiplexing of electrical signals from the plurality of address translators through the first electrical signal transformer onto a single communication bus, the second communication bus.

[0079] When considering the transmission chain as a whole (from the plurality of digital sensors to the acquisition device), the collection system makes it possible to reduce the bulk of the connectors.

[0080] Within the link between the comb and the bench system, using two pairs of twisted wires (wire pair as defined by the physical layer of the CANI2C layer (CAN physical layer)), a third pair of wires can provide power to said at least one digital instrumentation comb.

[0081] The acquisition unit can be electrically connected to a test bench via a fourth communication bus.

[0082] In the case of a switching device incorporating a multiplexer, at the request of the acquisition system, the multiplexer activates only the desired input (i.e., at least one digital sensor associated with a comb nozzle, and therefore a printed circuit board pin), thus avoiding any address conflicts across the plurality of digital sensors arranged on the plurality of pins of the plurality of nozzles. In other words, the multiplexer allows the plurality of digital sensors on the nozzle pins to be activated sequentially as needed.

[0083] In operation, I2C data is selectively routed to the output and the system, thus allowing the number of I2C devices with the same addresses to be increased without the need for additional components.

[0084] The first electrical signal transformer may be capable of converting an electrical signal using an I2C communication protocol and circulating in the first secondary communication bus into an electrical signal using a CANI2C layer and circulating in the second communication bus.

[0085] The first electrical signal transformer may be capable of converting an electrical signal using an I2C communication protocol and circulating in the first secondary communication bus into an electrical signal using a CANI2C layer and circulating in the second communication bus; the second electrical signal transformer is capable of converting an electrical signal using a CANI2C layer and circulating in the second communication bus as an electrical signal using an I2C communication protocol and circulating in the third communication bus.

[0086] In this particular configuration, the electrical signal carried in the second communication bus (from the first electrical signal transformer to the second electrical signal transformer) uses a link as defined in the CAN physical layer of the CANI2C layer.

[0087] As mentioned previously, the CAN physical layer allows the electrical signal to be carried over long distances (on the order of several meters to several tens of meters).

[0088] In this particular configuration, the electrical signal carried in the third communication bus (from the second electrical signal transformer to the acquisition device) uses an I2C communication protocol.

[0089] The second electrical signal transformer performs the inverse operation of the first: the electrical signal returns to its initial state as emitted by at least one digital sensor. In this way, it can be used by the acquisition device. Thus, the CAN physical layer becomes transparent, as the digital frame resulting from the multiple sensors is reconstructed according to the I2C protocol.

[0090] In other words, the second electrical signal transformer allows the first primary communication bus to be recreated using the I2C communication protocol for each digital sensor.

[0091] The first primary communication bus enables the transmission of information between the plurality of digital sensors and the first electrical signal transformer.

[0092] The first secondary communication bus enables the transmission of information between the first electrical signal transformer and the switching device.

[0093] The second communication bus allows the transmission of information between the first electrical signal transformer and the second electrical signal transformer.

[0094] The third communication bus enables the transmission of information between the second electrical signal transformer and the acquisition device.

[0095] This document may also relate to an assembly method for obtaining a digital instrumentation comb (30) of the type described above, the method comprising the steps of: (a) provide a body (32) with longitudinal axis (X), the body (32) having a plurality of orifices (34) and a longitudinal slot (56), (b) to bring a plurality of nozzles (36) to the right of a respective orifice (34), (c) provide a printed circuit board (38) comprising: - a substrate comprising a base (38a) arranged in the longitudinal cavity and a plurality of legs (38b), each leg (38b) extending from said base (38a) and being able to pass through a respective orifice so as to open into a corresponding nozzle; - a plurality of digital sensors for measuring a physical parameter of the aircraft engine, each digital sensor being arranged on a respective pin (38b); - a switching device (35) arranged on the base (38a) of the printed circuit board (38), said switching device being electrically connected to said at least one digital sensor (39) of each leg (38b) by a first primary communication bus (41-1a); and -- a first electrical signal transformer (44) arranged on the base (38a) and electrically connected to the switching device (35) by a first secondary communication bus (41-1b), (d) insert the printed circuit board (38) into the body (32) through the slot (56) so that the pins (38b) extend through a respective orifice, and (e) close the slot (56) using a resin.

[0096] The longitudinal slot can be arranged opposite the plurality of orifices, and the central tube can be introduced at step (d) by a translational movement in a direction orthogonal to the longitudinal axis.

[0097] This method allows for easy mounting of the printed circuit board in the central tube with a simple translational movement. This prevents damage to the printed circuit board or any surface-mounted components.

[0098] The longitudinal slot can be arranged at an angle to the plurality of orifices, and the central tube can be introduced at step (d) by a pivoting movement around the longitudinal axis.

[0099] This document may also relate to a digital instrumentation comb array comprising several digital instrumentation combs of the aforementioned type, in which the digital instrumentation combs are appropriately distributed (e.g., regularly) around the periphery and over several planes of the aircraft engine, the comb array further comprising: - a shared acquisition unit for all digital instrumentation combs, comprising: - a second electrical signal transformer electrically connected to the first electrical signal transformers of all the digital instrumentation combs by a second communication bus, the second communication bus enabling the transmission of information between the first electrical signal transformers and the second electrical signal transformer; and - an acquisition device electrically connected to said second electrical signal transformer by a third communication bus.

[0100] The digital instrumentation combs of the same plane can be linked together one by one to form a loop network, the single communication link with the acquisition unit being made from at most one digital instrumentation comb of each plane of the comb network.

[0101] The comb network can be characterized in that a given instrumentation comb of a given plane is connected to another given instrumentation comb of a different plane.

[0102] This document may also relate to an aircraft engine comprising at least one instrumentation comb of the aforementioned type or a network of combs of the aforementioned type.

[0103] This document may also apply to an aircraft with an engine of the aforementioned type. Brief description of the drawings

[0104] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which:

[0105] [Fig. 1] illustrates a perspective view of an instrumentation comb according to the previous technique,

[0106] [Fig. 2] is an axial cross-sectional view of the instrumentation comb in Figure 1,

[0107] [Fig. 3] is an axial cross-sectional view of a digital instrumentation comb according to a first embodiment of this document,

[0108] [Fig. 4] illustrates the architecture of a system for collecting measurements of a physical parameter of an aircraft engine comprising a digital instrumentation comb according to the first embodiment of Figure 3,

[0109] [Fig. 5] is an axial cross-sectional view of a digital instrumentation comb according to a second embodiment of this document,

[0110] [Fig. 6] illustrates the architecture of a system for collecting measurements of a physical parameter of an aircraft engine comprising a digital instrumentation comb according to the second embodiment of Figure 5,

[0111] [Fig. 7] illustrates a step in an assembly process to obtain a digital instrumentation comb, according to a first embodiment of the process,

[0112] [Fig. 8] illustrates a step in an assembly process to obtain a digital instrumentation comb, according to a second embodiment of the process, Description of the implementation methods

[0113] Figure 3 is an axial cross-sectional view of a digital instrumentation comb according to a first embodiment of this document and Figure 4 illustrates the architecture of a measurement collection system for a physical parameter of an aircraft engine comprising said digital instrumentation comb.

[0114] The digital instrumentation comb 30 includes a central tube (called "comb body") 32 with longitudinal axis X provided with a plurality of orifices 34 distributed along the length of the central tube 32.

[0115] At each orifice 34 is arranged a nozzle 36 extending from the central tube 32 and in a direction orthogonal to the longitudinal axis X.

[0116] The central tube 32 delimits a longitudinal cavity in which is arranged a base 38a of the substrate of a printed circuit 38.

[0117] The printed circuit board 38 further comprises a plurality of pins 38b extending from the base 38a and in the direction orthogonal to the longitudinal axis X, each pin 38b extending through an orifice 34 so as to open into a respective nozzle 36.

[0118] On each end 38b-1 of a leg 38b are mounted a plurality of digital sensors 39.

[0119] A switching device 35 comprises a plurality of address translators 40 mounted on the base 38a so that each address translator 40 is arranged adjacent to a respective pin 38b.

[0120] For example, the plurality of address translators 40 may be of the brand ANALOG DEVICES® and reference LT4316.

[0121] Each address translator 40 is electrically connected to a plurality of digital sensors 39 of a respective pin 38b by a first primary communication bus 41-1a.

[0122] For example, the digital sensors may be from the Texas Instruments® brand and reference TMP117.

[0123] The comb 30 includes a base 42 directly connected to one end 32a of the central tube 32. The base 42 is intended to fix the comb 30 on a motor housing, and to bring out cables connecting the printed circuit board 38 to an acquisition unit 50.

[0124] A first electrical signal transformer 44 is arranged at one end 38a-1 of the proximal base 38a of the base 42.

[0125] For example, the first electrical signal transformer 44 may be of the brand ANALOG DEVICES® and reference LT3960.

[0126] The first electrical signal transformer 44 is electrically connected to all address translators 40 by a first secondary communication bus 41-1b.

[0127] The collection system 49 includes the digital instrumentation comb 30 and the acquisition unit 50.

[0128] The acquisition unit 50 includes an acquisition device 52 and a second electrical signal transformer 54.

[0129] For example, the second electrical signal transformer 54 may be of the brand ANALOG DEVICES® and reference LT3960.

[0130] The first electrical signal transformer 44 is connected to the second electrical signal transformer 54 by a second communication bus 41-2.

[0131] In operation, the digital sensors 39 perform physical measurements of a fluid in an aerodynamic vein with which the digital sensors 39 are in contact.

[0132] The digital data relating to the measurements are encapsulated in frames which are transported by an initial electrical signal emitted using an I2C communication protocol.

[0133] For sensors on the same pin 38b, the initial electrical signal travels in the first primary communication bus 41-1a and arrives at the corresponding address translator 40.

[0134] The address translator 40 associates each digital sensor 39 with its own unique address.

[0135] The address translator 40 makes it possible to avoid an address conflict between the different digital sensors 39. In this way, it is possible to distinguish the digital sensors 39 from each other, in particular at the level of the acquisition unit 50.

[0136] The initial electrical signal then travels in the first secondary communication bus 41-1b and arrives at the first electrical signal transformer 44.

[0137] The first electrical signal transformer 44 converts the initial electrical signal into an intermediate electrical signal, the latter using a CANI2C layer, i.e. an electrical link as defined by the physical layer of the CAN protocol, but a link layer and upper layers remaining those defined by the I2C protocol.

[0138] In this way, the intermediate electrical signal is able to travel over the distance separating the first electrical signal transformer 44 from the second electrical signal transformer 54 through a second communication bus 41-2. In other words, the intermediate electrical signal is able to travel from the digital comb 30 to the acquisition unit 50.

[0139] The second electrical signal transformer 54 then converts the intermediate electrical signal into a final electrical signal using an I2C communication protocol. In other words, the second electrical signal transformer 54 performs the reverse conversion (the inverse operation) of the first electrical signal transformer 44.

[0140] In this way, the final electrical signal can be used by the acquisition device 52, which is in the same acquisition unit 50 as the second electrical signal transformer 54 (and therefore adjacent to it). The final electrical signal travels in the third communication bus 41-3 from the second electrical signal transformer 4b to the acquisition device 4a.

[0141] The first primary communication bus 41-1a, the first secondary communication bus 41-1b and the third communication bus 41-3 use the I2C communication protocol, and the second communication bus, arranged between the first secondary communication bus 41-1b and the third communication bus 41-3, uses the CANI2C layer.

[0142] Figure 5 is an axial cross-sectional view of a digital instrumentation comb according to a second embodiment of this document and Figure 6 illustrates the architecture of a measurement collection system for a physical parameter of an aircraft engine comprising said digital instrumentation comb.

[0143] In this second embodiment, the switching device 35 includes a multiplexer 37 mounted on the base 38a of the printed circuit board 38, so that the multiplexer 37 is arranged adjacent to the first electrical signal transformer 44.

[0144] On the one hand, the multiplexer 37 is electrically connected to the plurality of sensors 39 on each pin 38b by the first primary communication bus 41-1a.

[0145] On the other hand, the multiplexer 37 is electrically connected to the first electrical signal transformer 44 by the first secondary communication bus 41-1b.

[0146] For example, the multiplexer 37 may be of the Texas Instruments® brand and reference TCA9548APWR, which allows to be electrically connected up to eight sets of sensors 39 of eight pins 38b.

[0147] In operation, the acquisition unit 50 commands the multiplexer to activate only one input (the sensors 39 of the same pin 38b, or only one sensor among the sensors 39 of the same pin 38b) in order to avoid an address conflict.

[0148] Figure 5 shows that the use of a 37-channel multiplexer reduces the number of components required for the operation of the comb, and therefore the associated connectors.

[0149] A third embodiment (not shown) is based on the use of the I3C standard. This standard, backward compatible with the I2C standard, adds, among other things, the functionality of on-the-fly reprogramming of the addresses of next generation digital sensors (especially MEMS), such as for example the reference LPS22DF MEMS nanopressure sensors from STMicroelectronics®.

[0150] This further simplifies the architecture by eliminating the need to use the address translator 40. Indeed, each sensor 39 present on the same I2C / I3C bus can be dynamically reprogrammed with a different address, which eliminates any conflict.

[0151] In this third embodiment, the plurality of digital sensors 39 is electrically connected to the first electrical signal transformer 44 (without the intermediary of an address translator 40) by a common communication bus (the first primary communication bus 41-1a and the first secondary communication bus form said common communication bus).

[0152] Reference is now made to figures 7 and 8.

[0153] Figure 7 represents a step in an assembly process to obtain a digital instrumentation comb, according to a first embodiment of the process.

[0154] In a step (a), a central tube 32 with longitudinal axis X is provided, the central tube 32 having a plurality of orifices 34 and a longitudinal slot 56 arranged opposite the plurality of orifices 34.

[0155] In a step (b), a plurality of nozzles 36 are brought to the right of a respective orifice 34.

[0156] In step (c), a printed circuit board 38 is provided comprising: - a substrate comprising a base 38a arranged in the longitudinal cavity and a plurality of legs 38b, each leg 38b extending from said base 38a and being able to pass through a respective orifice 34 so as to open into a corresponding nozzle 36; - a plurality of digital sensors 39 for measuring a physical parameter of the aircraft engine, each measuring sensor 39 being arranged on a respective pin 38b; - a plurality of address translators 40 arranged on the base 38a of the printed circuit board 38, each address translator 40 being electrically connected to a respective digital sensor 39 by a first primary communication bus; and - a first electrical signal transformer 44 arranged on the base 38a electrically connected to the plurality of address translators 40 by a first secondary communication bus,

[0157] In a step (d), the printed circuit board 38 is introduced into the central tube 32 through the slot 56 by a translational movement along a direction F1 orthogonal to the longitudinal axis X so that the pins 38b extend through a respective orifice 34.

[0158] In a step (e), the slot 56 is closed using a resin.

[0159] Figure 8 represents an assembly method for obtaining a digital instrumentation comb, according to a second embodiment of the method.

[0160] In this second embodiment of the process, the longitudinal slot 56 is arranged at an angle to the plurality of orifices 34, more particularly on a face 58 adjacent to the face on which the nozzles 36 are located.

[0161] In addition, the central tube 32 is introduced in step (d) by a pivoting movement around the longitudinal axis.

[0162] Pivoting movement around the longitudinal axis is understood to mean a "turning" movement consisting of a rotation around the longitudinal axis and a displacement along a direction of movement F2 which is oriented by said rotation. In other words, pivoting movement is understood to mean a curved trajectory.

Claims

Demands

1. A digital instrumentation comb (30) for an aircraft engine comprising: a body (32) with longitudinal axis (X) including a longitudinal cavity and having a plurality of orifices spaced along this longitudinal axis (X); a plurality of nozzles (36), each nozzle being arranged longitudinally at each orifice; and at least one printed circuit board (38), which comprises: - a substrate comprising a base (38a) arranged in the longitudinal cavity and a plurality of legs (38b), each leg (38b) extending from said base (38a) and through a respective orifice so as to open into a corresponding nozzle; - a plurality of digital sensors (39) for measuring a physical parameter of the aircraft engine, at least one digital sensor (39) being arranged on a respective pin (38b); - a switching device (35) arranged on the base (38a) of the printed circuit board (38), said switching device being electrically connected to said at least one digital sensor (39) of each pin (38b) by a first primary communication bus (41-1a); and - a first electrical signal transformer (44) arranged on the base (38a) and electrically connected to the switching device (35) by a first secondary communication bus (41 -1 b).

2. Digital instrumentation comb (30) according to claim 1, wherein the switching device (35) comprises a plurality of address translators (40), each address translator (40) being associated with a pin (38b) and electrically connected to said at least one digital sensor (39) arranged on said pin (38b) by the first primary communication bus (41-1a).

3. Digital instrumentation comb (30) according to claim 1, wherein the switching device (35) comprises a multiplexer (37), the multiplexer (37) being electrically connected to the plurality of digital sensors (39) by the first primary communication bus (41-1a).

4. Digital instrumentation comb (30) according to any one of the preceding claims, wherein the first electrical signal transformer (44) is capable of converting an electrical signal using an I2C communication protocol into an electrical signal using a CANI2C layer corresponding to a layer which includes a physical layer of the CAN protocol as well as a link layer and upper layers of the I2C protocol.

5. Digital instrumentation comb (30) according to any one of the preceding claims, wherein the physical parameter is any one or a combination of the following parameters: pressure, temperature, humidity, fluid acceleration, vibration, or gas composition.

6. A system (49) for collecting measurements of a physical parameter of an aircraft engine comprising: - at least one digital instrumentation comb (30) according to any one of the preceding claims; and - an acquisition unit (50) comprising: - a second electrical signal transformer (54) electrically connected to the first electrical signal transformer (44) by a second communication bus (41-2), the second communication bus (41-2) enabling the transmission of information between the first electrical signal transformer (44) and the second electrical signal transformer (54); and - an acquisition device (52) electrically connected with said second electrical signal transformer (54) by a third communication bus (41-3).

7. Collection system (49) according to the preceding claim, wherein the first electrical signal transformer (44) is capable of converting an electrical signal using an I2C communication protocol and circulating in the first secondary communication bus (41-1b) into an electrical signal using a CANI2C layer, which CANI2C layer corresponds to a layer comprising a physical layer of the CAN protocol as well as a link layer and upper layers of the I2C protocol, and circulating in the second communication bus (41-2), the second electrical signal transformer (54) is capable of converting an electrical signal using a CANI2C layer and circulating in the second communication bus (41-2) into an electrical signal using an I2C communication protocol and circulating in the third communication bus (41-3).

8. A method for assembling a digital instrumentation comb (30) according to any one of claims 1 to 5, the method comprising the steps of: (a) provide a body (32) with longitudinal axis (X) comprising a longitudinal cavity, the body (32) having a plurality of orifices (34) and a longitudinal slot (56) opening onto said longitudinal cavity, (b) to bring a plurality of nozzles (36) to the right of a respective orifice (34), (c) provide a printed circuit board (38) comprising: - a substrate comprising a base (38a) intended to be arranged in the longitudinal cavity and a plurality of legs (38b), each leg (38b) extending from said base (38a) and being able to pass through a respective orifice so as to open into a corresponding nozzle; - a plurality of digital sensors for measuring a physical parameter of the aircraft engine, each digital sensor being arranged on a respective pin (38b); - a switching device (35) arranged on the base (38a) of the printed circuit board (38), said switching device being electrically connected to said at least one digital sensor (39) of each pin (38b) by a first primary communication bus (41-1a); and - a first electrical signal transformer (44) arranged on the base (38a) and electrically connected to the switching device (35) by a first secondary communication bus (41-1b), (d) insert the printed circuit board (38) into the body (32) through the slot (56) so that the pins (38b) extend through a respective orifice, and (e) close the slot (56) using a resin.

9. A method according to claim 8, wherein the longitudinal slot (56) is arranged opposite the plurality of orifices (34), and the body (32) is introduced at step (d) by a translational movement in a direction orthogonal to the longitudinal axis (X).

10. Method according to claim 8, wherein the longitudinal slot (56) is arranged at an angle to the plurality of orifices (34), and the body (32) is introduced in step (d) by a pivoting movement about the longitudinal axis (X).

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