CN111698016A

CN111698016A - Apparatus and method for data transmission

Info

Publication number: CN111698016A
Application number: CN202010177966.8A
Authority: CN
Inventors: 科尼利厄斯·芬克; 康斯坦丁·斯利普安丘克
Original assignee: Liebherr Aerospace Lindenberg GmbH
Current assignee: Liebherr Aerospace Lindenberg GmbH
Priority date: 2019-03-13
Filing date: 2020-03-13
Publication date: 2020-09-22
Anticipated expiration: 2040-03-13
Also published as: DE102019106410A1; FR3093831A1; FR3093831B1; BR102020004852A2

Abstract

The invention relates to a device and a method for data transmission, which are particularly suitable for communication between components of a system group of redundant architecture. In this case, the components of the system group of the redundant configuration are not connected to separate physical connection lines as is usual in the prior art, but rather a common physical connection is provided which connects all the system groups of the redundant configuration. The required transmission security with regard to data integrity is achieved by CRC encoding, wherein temporally successive data packets are provided with increasing counter values, so that the CRC code formed on the basis thereof reliably detects static errors over time.

Description

Apparatus and method for data transmission

Technical Field

The present invention relates to a device and a method for data transmission, in particular for use in an aircraft such as an airplane.

Background

Disclosed herein is an apparatus and method for securely exchanging information between computers, preferably via a digital data bus of an aircraft. The systems required in flight operations typically use different computers and local data buses. Such systems include, for example, flight control systems, landing gear systems, actuation systems or air conditioning systems of the aircraft.

In the exemplary embodiment, the control and monitoring functions relating to the system are carried out in central processing units, which are usually accommodated in so-called "avionics bays" in the aircraft fuselage. These central computers transmit the signals required for control to remote electronic devices, usually by means of a data bus. The remote electronic device, also known as a remote electronic assembly (REU), performs the control functions of the actuators locally, for example in the wing of an aircraft. The transmission of erroneous data relating to the control of the actuators may lead to serious flight conditions and, in the worst case, to the crash of the aircraft.

For this reason, it must be ensured that the information required for regulation, control and monitoring is generated safely, that a safe data transmission takes place between the central computer and the remote electronic device, and that the available data is processed further safely until the actuator is controlled. To this end, the invention describes a device and a method which reduce the complexity of the device and the wiring effort at the aircraft level.

As a prior art, physically separate transmission of signals or data having the same meaning is applied to each system group of redundant structures to ensure integrity. This is therefore also done in such a way that the same tampering does not occur and therefore no detected misinterpretations occur at the receivers of the respective redundant system groups.

Since separate physical data transmissions are provided separately, errors that occur can be detected at the receiver by deviations in the content. In many high safety critical systems, such as in an aircraft system, it is necessary to be able to reliably detect errors.

CRC codes (cyclic redundancy check) are usually introduced to improve the protocol level identifiability of each transmitted packet. In order to be able to distribute the data over time, at least the combined, temporally subsequent data packets are accompanied by a counter value (also referred to as a time stamp), which can be changed according to its chronological order. This occurs at the application level so that deterministic response characteristics can be supported even in an arrangement with multiple receivers.

After a data error cannot be reliably detected by simple calculations and transmission paths, in the prior art the same information is transmitted by at least two separate data generators, data buses and receivers, which differ in hardware and software.

As known to those skilled in the art, a cyclic redundancy check, for example, cannot receive errors if the error polynomial applied by the error can be divided by the generator polynomial of the cyclic redundancy check. If the error polynomial is not equal to zero and can be divided exactly by the generator polynomial, the error cannot be detected by the CRC check.

To be able to detect such errors as well, considerable expenditure is incurred both on the hardware and software of the computer and on the aircraft wiring (more plug connectors, more cabling in the aircraft, and more complex laying due to the double signal routing which increases the cable weight).

Disclosure of Invention

The object of the invention is to reduce the weight of the cables in an aircraft and to reduce the hardware costs on the computer, while ensuring the necessary integrity of the signals to be transmitted. Preferably, this should be done by using a physical transmission path between the communicating computers.

In order to save cable weight, which is particularly advantageous on board an aircraft, it is desirable to find a way of transmitting data over only one physical connection, so that the integrity of the data is still guaranteed and tampering can be reliably detected. The CRC check built into the data transmission protocol is not sufficient for reliable detection, especially in cases where functional security is highly required.

The above-mentioned disadvantages are overcome by a device according to claim 1 or a method according to claim 12. Further advantageous embodiments are described in the dependent claims.

Thus, according to claim 1, there is provided an apparatus for data transmission comprising: a first computer unit having a first module and a second module, a second computer unit also having a first module and a second module, a first data transmission connection between the first module and the second module of the first computer unit, a second data transmission connection between the first module and the second module of the second computer unit, and a third data transmission connection between the first module of the first computer unit and the first module of the second computer unit, wherein the device is designed for transmitting a first time sequence of data packets from the first module of the first computer unit to the first module of the second computer unit and additionally for transmitting a second time sequence of data packets from the second module of the first computer unit to the second module of the second computer unit, the first module of the first computer unit being designed for adding a first count value to each data packet of a plurality of data packets (301) of the first sequence, the first counting values differ from packet to packet by an increment, the second module of the first computer unit being designed to add a CRC code to each of a plurality of packets of the second sequence, the CRC code being based on the respective packet and a second counting value appended thereto, the second counting values differing from the packets of the second time sequence by an increment, the second module of the first computer unit being further designed to transmit the packets, extended by the second counting value and the CRC code, respectively, from the second module of the first computer unit to the first module of the first computer unit via a first data transmission connection, the packets, extended by the first counting value and the CRC code, respectively, the first module of the first computer unit being designed to receive the packets, extended by the first counting value and the CRC code, respectively, from the second module in order to append the respective packets, of the extended packets of the second sequence, received, to the time-dependent extended packets of the first sequence, and the combined data packets thus formed are transmitted together to the first module and via the third data transmission connection to the second computer unit, the first module of the second computer unit being designed to split the combined data packets into a first sequence of individual spread data packets and a second sequence of individual spread data packets and to transmit the second sequence of split spread data packets via the second data transmission connection to the second module of the second computer unit, and the first module of the second computer unit being designed to check the CRC code of temporally subsequently arriving second sequence of spread data packets.

It can be seen that the described apparatus is particularly suitable for communication between components of a system group of redundant architecture. In this case, the components of the system group of the redundant architecture are not connected to separate physical connection lines as is customary in the prior art, but rather a common physical connection, i.e. a third data transmission connection, which connects all the system groups of the redundant architecture. The required transmission security with regard to data integrity is achieved by CRC encoding, wherein temporally successive data packets are provided with increasing counter values, so that the CRC code formed on the basis thereof reliably detects static errors over time.

The CRC code added in the application program provided according to the present invention can significantly improve the probability of false detection. A judicious choice of the generator polynomial and a sufficiently high order allow setting the degree of recognizability of the error. In this new data transmission, the combination of mechanisms and inclusion of a count value in the CRC calculation are important. In this way, CRCs with variations in definition are generated even on a temporally constant date (or a plurality of constant dates), i.e., when the time stamps are the same. The receiver performs multiple CRC checks on data arriving sequentially in time ensures that much higher detection security is generated.

Static errors that unexpectedly result in a correct CRC result are likely to be detected by a new CRC calculation at the next date that is biased by a change in the counter value. Thus, the effect of the third test value is enhanced.

According to an alternative embodiment, it is provided that the first data transmission connection, the second data transmission connection and/or the third data transmission connection is a physical data transmission connection, in particular a wired or wireless data transmission connection, and/or that the third data transmission connection is realized by only one physical connection, and that no further physical data transmission connection exists between the first computer unit and the second computer unit.

This excludes that a further data transmission connection exists between the two computer units, via which data exchange is possible.

In addition, adding a CRC code may also mean appending test bits to the data packet to be checked based on a cyclic redundancy check. The concept of creating a CRC code using its generator polynomial is known to those skilled in the art and will not be described in detail herein. The bit sequence provided with the CRC code has here check bits which are usually appended to the bit sequence. These check bits represent the remainder of the check bit division (multiplied by the highest polynomial order that generates the polynomial) considered as a polynomial.

According to a further alternative variant of the invention, the first computer unit can be designed to generate a first sequence of data packets in its first module and/or the first computer unit can be designed to generate a second sequence of data packets in its second module. The module of the first computer unit, whose bits to be transmitted are generated and transmitted according to the described procedure, has the task of generating and transmitting redundant information with respect to one another.

In this case, it can advantageously be provided that the first module of the first computer unit, the second module of the first computer unit, the first module of the second computer unit and/or the second module of the second computer unit are separate computers, which preferably comprise a CPU and a working memory. By structurally separating the individual computer units from one another, a hardware error may not result in a complete failure of multiple modules. In general, even if the modules are structurally separate from one another, the structural organization of the modules is carried out in a different manner in order to also exclude the resulting simultaneous errors.

Preferably, the first module of the first computer unit and the second module of the first computer unit are redundant systems with respect to one another, which preferably transmit the same information in their data packets in their error-free control operation. Alternatively or additionally, it can be provided that the first module of the second computer unit and the second module of the second computer unit are redundant systems with respect to one another, which preferably process the same information in their data packets in error-free control operations.

Thus, the first and second modules of the first computer unit and the first and second modules of the second computer unit may each perform functions that are redundant of each other. For this purpose, the same information can be transmitted via the first module and the second module of the first computer unit, which information is to be received reliably and without tampering by means of the first and second modules of the second computer unit.

According to a further development of the invention, it can be provided that the first module of the first computer unit and the first module of the second computer unit form a system group, the second module of the first computer unit and the second module of the second computer unit form a system group, and the two system groups are redundant system groups with respect to one another and preferably process identical information in transmitted data packets in their error-free control operation.

Preferably, in the combined data packets, temporally combined data packets from a first time series of data packets and a second time series of data packets, respectively, are combined, which carry the same information in an error-free control operation. The first sequence is usually derived from a first module of the first computer unit, and the second sequence is usually derived from a second module of the first computer unit.

According to a further development of the invention, it can be provided that the first module of the first computer unit is designed to provide the combined data packet with a CRC code based on the combined data packet before it is sent to the first module of the second computer unit, and that the first module of the second computer unit is designed to carry out a check of the CRC code based on the combined data packet. Thus, there is a further CRC code which is now formed by the first module of the first computer unit and checked by the first module of the second computer unit.

Preferably, the first module of the first computer unit is also designed to be identical to the first module of the second computer unit and vice versa, and the second module of the first computer unit is also designed to be identical to the second module of the second computer unit and vice versa, so that it is possible to carry out two-way communication between the first computer unit and the second computer unit in the same way and two-way communication can be carried out between the first computer unit and the second computer unit in the same way.

Furthermore, it can be provided that the first module of the first computer unit, the second module of the first computer unit, the first module of the second computer unit and/or the second module of the second computer unit are implemented by a microcontroller and/or an FPGA, preferably in such a way that one of the modules of the computer units is implemented by a microcontroller and the other module of the same computer unit is implemented by an FPGA.

The invention also describes a method for data transmission with a device, comprising a first computer unit having a first module and a second module, a second computer unit also having a first module and a second module, a first data transmission connection between the first module and the second module of the first computer unit, a second data transmission connection between the first module and the second module of the second computer unit, and a third data transmission connection between the first module of the first computer unit and the first module of the second computer unit, wherein in the method a first time sequence of data packets is transmitted from the first module of the first computer unit to the first module of the second computer unit and in addition a second time sequence of data packets is transmitted from the second module of the first computer unit to the second module of the second computer unit, adding a first counter value to each of a plurality of data packets of a first sequence, the first counter values differing from data packet to data packet by an increment, adding a CRC code to each of a plurality of data packets of a second sequence, the CRC code being based on the corresponding data packet and a second counter value appended thereto, the second counter values differing from data packets of a second time sequence by an increment, respectively, transmitting the data packets to which the second counter values and the CRC code have been respectively extended from a second module of the first computer unit to a first module of the first computer unit via a first data transmission connection, receiving the data packets to which the first counter values and the CRC code have been respectively extended from the second module, so as to append the corresponding data packets of the received second sequence of extended data packets to the time-dependent extended data packets of the first sequence, respectively, and the combined data packets thus formed are transmitted together to the first module and over the third data transmission connection to the second computer unit, the combined data packets are separated into the individual extension data packets of the first sequence and the individual extension data packets of the second sequence, and the separated extension data packets of the second sequence are transmitted via the second data transmission connection to the second module of the second computer unit, and the CRC code of the temporally subsequently arriving extension data packets of the second sequence is checked.

The method can be further developed in an advantageous manner in that the third data transmission connection is realized by only one physical connection and no further physical data transmission connection exists between the first computer unit and the second computer unit.

The invention further relates to a local data bus in an aircraft, in particular in an aircraft, wherein the local data bus comprises a device for data transmission according to one of the device variants described above or uses a method according to one of the above variants.

The invention also relates to an aircraft, in particular an airplane, in which a data bus or a method according to one of the above-described variants of the device is used for communication between a central computer and remote electronic devices, for example for controlling a flight control system, a landing gear system, an actuation system or an air conditioning system.

Drawings

Other details, features, and advantages of the invention will become apparent from the following description of the drawings. The figure shows that:

fig. 1 is a schematic diagram of an apparatus for data transmission according to the prior art.

Fig. 2 is a schematic diagram of an apparatus for data transmission according to the present invention.

Fig. 3 is a schematic illustration of a combined data packet sent over the data transmission connections of the various computer units.

Detailed Description

Fig. 1 shows a device 100 for data transmission according to the prior art, which is used, for example, in an aircraft. A first computer unit 101 and a separate computer unit 102 can be seen, between which data is to be transmitted. In order to ensure the integrity of data transmission, it is known to provide physically separate transmissions of signals or data having the same meaning. This ensures that no identical tampering, and thus misunderstanding, occurs. Thus, errors occurring can be identified in the receiving computer unit 102 by deviations in the redundantly transmitted information content.

A first module 121 and a second module 122 are provided in the sending computer unit 101 in order to create information that acts redundantly with each other. Here, each

module

121, 122 of the first computer unit 101 is connected to the

relevant module

131, 132 of the second computer unit 102 by its own physical

data transmission connection

141, 142. In this case, the logical connection 151 between the first module 121 of the first computer unit 101 and the first module 131 of the second computer unit 102 and the logical connection 152 between the second module 122 of the first computer unit 101 and the second module 132 of the second computer unit 102 are made by means of the

connections

141, 142 which are physically separated from one another. Here, the

logical connections

151, 152 do not share a common physical transport platform at any time.

In order to temporarily allocate the transmission data of the individual redundant systems, they may be provided with a count value (also called a time stamp) respectively. This may also occur at the application level or also at the protocol level. Deterministic response characteristics may be supported in this way even in an arrangement with multiple receivers.

A disadvantage of the embodiment shown in the system according to fig. 1 is that the expenditure in terms of hardware and software is excessive, in particular there is a repeated wiring, which requires an increase in the weight of the cable, additional complex wiring and a large number of plug connectors.

Fig. 2 shows a schematic structure of a device 200 for transmitting data according to the invention, which reduces the cable weight and the number of required plug connections while maintaining the required integrity of the signal to be transmitted.

Here, the structure of the first computer unit 201 and the second computer unit 202 is similar to that of fig. 1. Thus, the first computer unit 201 has a first module 221 and a second module 222. The second computer unit 202 also has a first module 231 and a second module 232.

In contrast to the prior art, a data transmission connection exists between the first module 221 of the first computer unit 201 and the second module 222 of the first computer unit 201. A data transmission connection is also provided between the first module 231 of the second computer unit 202 and the second module 232 of the second computer unit 202. Furthermore, the two

computer units

201, 202 are connected to each other by only one single physical data transmission connection 241. Which extends from the first module 221 of the first computer unit 201 to the first module 231 of the second computer unit 231.

Thus, the logical connection 261 established between the

second modules

222, 232 extends via the

first modules

221, 231 and shares a common physical data transfer connection 241 with the logical connection 251 between the

first modules

221, 231. Although not shown in fig. 2, it is of course possible to carry out a two-way communication between the two

computer units

201, 202 or the individual modules instead of a one-way communication.

Despite the common physical transport connection, the CRC method provided from the prior art is now insufficient in order to ensure the integrity of the data. A further CRC, which is preferably inserted at the application level, can therefore increase the probability of error detection in such a way that very high functional requirements imposed on the safety of the function can also be achieved. In this case, the count value is advantageously included in the CRC calculation. Thus, a temporally constant date may result in a CRC that deviates in definition.

The receiver performs multiple CRC checks on data arriving sequentially in time to ensure that there are multiple higher detected errors. Static errors that unexpectedly result in a correct CRC are likely to be detected by a new CRC calculation at the next date that is biased by a change in the count value. Therefore, the effect is improved at the third value.

The function of the device 200 shown in fig. 2 is explained below with the aid of fig. 3. In this way, the information present in the second module 222 of the first computer unit 201 and in error-free operation-equivalent to the information present in the first module 221 of the first computer unit 201-are converted into a binary data sequence and summarized as a data packet 302. Thus, user data is located in this packet 302 and may also be referred to as user data packet 302.

Due to the constant or continuous accumulation of information in the module 222, there is a time series of several data packets 302 so that they can be identified by a value 303. The temporally successive data packets 302 are provided with a counter value 303, which differs by an increment in each case. The count 303 precedes (not shown) or is appended to the data packet 302 as a binary sequence.

In this case, next, the common bit sequence of the packet 302 and the count value 303 is subjected to CRC algorithm processing, and the remainder produced when the common bit sequence is divided by the generator polynomial is placed before (not shown) or attached to the common bit sequence in the CRC bit sequence 304. The length of the CRC bit sequence 304 to be added here corresponds to the order of the generator polynomial. The CRC bit sequence 304 added here is therefore based not only on the (useful) data packet 302 but also on the count value 303.

After the second module 222 of the first computer unit 201 has processed the data packet 302 accordingly, the

data packets

302, 303, 304 extended in this way are passed on to the first module 221 via the data transmission connection existing between the

modules

221, 222.

In the first module 221 of the first computer unit 201, the (useful) data packets 301 originating there are then provided with a counter value 305, so that the sequence of the data packets 301 exiting from the first module can also be understood here. Of course, the count value may be placed before or appended to the packet 301 of the first module 221.

The packet 301 of the first module 221, extended by the count value 305, is combined with the

extended packets

302, 303, 304 of the second module 222 by appending or prepending the packet. The combined

data packets

301, 305, 302, 303, 304 thus obtained are then transmitted from the first module 221 of the first computer unit 201 via the data transmission connection 241 to the first module 231 of the second computer unit 202, where they are received and divided.

In this case, the (useful) data packet 301 of the first module 221 of the first computer unit 201, which is expanded by the counter value 305, is separated from the combined

data packets

301, 305, 302, 303, 304 and processed in the first module 231 of the second computer unit 202.

The (useful) data packet 302 of the second module 231 of the first computer unit 201, which is expanded by the counter value 303 and the CRC code 304, is then transferred from the first module 231 of the second computer unit 202 to its second module 232 and is passed on to the second module 232 via the data transfer connection between these two

modules

231, 232 of the second computer unit 231.

A CRC check is then performed there to detect the transmission error that occurred. Particularly in the case of temporally subsequent checks, the probability of detecting a static error is greater due to changing count values or CRC calculations that differ in time and are biased by changes in the count values. Thus, according to one possibility, for example, the generator polynomial used for the CRC calculation may vary according to the count value.

By learning the counter reading from the previously received data block, the count value of the now received data block must differ by exactly one increment. If this is not the case, there is a transmission error that is not detected by the CRC, and therefore corresponding measures can be taken.

In this case, the modules of the different computer units may be identical in their structural organization, but may also differ from one another in terms of an increased probability of failure.

Thus, for example, the modules of the

computer units

201, 202 may be implemented by microcontrollers or FPGAs. It is also possible to arrange that the two modules of the

computer units

201, 202 are different, that is to say that the first module is for example a microcontroller and the second module is an FPGA, or vice versa.

Claims

1. Device (200) for data transmission, in particular in an aircraft, comprising:

a first computer unit (201) having a first module (221) and a second module (222),

a second computer unit (202) also having a first module (231) and a second module (232),

a first data transmission connection between a first module (221) and a second module (222) of the first computer unit (201),

a second data transmission connection between the first module (231) and the second module (232) of the second computer unit (202), an

A third data transmission connection (241) between the first module (221) of the first computer unit (201) and the first module (231) of the second computer unit (202), wherein

The device is designed to transmit a first time sequence (251) of data packets (301) from a first module (221) of a first computer unit (201) to a first module (231) of a second computer unit (202) and additionally to transmit a second time sequence (261) of data packets (302) from a second module (222) of the first computer unit (201) to a second module (232) of the second computer unit (202),

the first module (221) of the first computer unit (201) is designed to add a first counter value (305) to each data packet of a first sequence (251) of a plurality of data packets (301), the first counter value (305) differing from data packet to data packet by an increment,

the second module (222) of the first computer unit (201) is designed to add a CRC code (304) to each of a plurality of data packets (302) of the second time series (261), the CRC code being based on the respective data packet (302) and an accompanying second counter value (303), the second counter value (303) differing for the data packets of the second time series (261) by an increment,

furthermore, the second module (222) of the first computer unit (201) is designed to transmit data packets (302, 303, 304) which have been respectively extended by a second counter value (303) and a CRC code (304) from the second module (222) of the first computer unit (201) to the first module (221) of the first computer unit (201) via the first data transmission connection,

the first module (221) of the first computer unit (201) is designed to receive data packets (302, 303, 304) from the second module (222) which have been extended by a first counter value (303) and a CRC code (304), respectively, to append corresponding data packets (302, 303, 304) of the received second sequence (261) of extended data packets (302, 303, 304) to the time-dependent extended data packets (301, 305) of the first sequence (251), respectively, and to transmit the combined data packets (301, 305, 302, 303, 304) thus formed together to the first module (231) and via a third data transmission connection (241) to the second computer unit (202),

the first module (231) of the second computer unit (202) is designed to split the combined data packet (301, 305, 302, 303, 304) into a first sequence (251) of individual spread data packets (301, 305) and a second sequence (261) of individual spread data packets (302, 303, 304), and to transmit the second sequence (261) of individual spread data packets (302, 303, 304) to the second module (232) of the second computer unit (202) via a second data transmission connection, and

the first module (231) of the second computer unit (202) is designed to check the CRC code (304) of a second sequence (261) of expansion data packets (302, 303, 304) arriving later in time.

2. The apparatus (200) of claim 1, wherein

The first, second and/or third data transmission connection (241) is a physical data transmission connection, in particular a wired or wireless data transmission connection, and/or

The third data transfer connection (241) is realized by only one physical connection and no other physical data transfer connection exists between said first computer unit (201) and the second computer unit (202).

3. The apparatus (200) of any of the preceding claims, wherein adding a CRC code indicates appending test bits to the data packet to be checked based on a cyclic redundancy check.

4. The apparatus (200) according to any one of the preceding claims, wherein

The first computer unit (201) is designed to generate a first sequence (251) and/or a first sequence (251) of data packets (301) in a first module (221) of the first computer unit

The first computer unit (201) is designed to generate a second sequence (261) of data packets (302) in a second module (222) thereof.

5. The apparatus (200) according to any one of the preceding claims, wherein

The first module (221) of the first computer unit (201), the second module (222) of the first computer unit (201), the first module (231) of the second computer unit (202) and/or the second module (232) of the second computer unit (202) are separate computers, which preferably comprise a CPU and a working memory.

6. The apparatus (200) according to any one of the preceding claims, wherein

The first module (221) of the first computer unit (201) and the second module (222) of the first computer unit (201) are redundant systems which preferably transmit the same information in their data packets in their error-free control operation and/or

The first module (231) of the second computer unit (202) and the second module (232) of the second computer unit (202) are redundant systems, which preferably process the same information in their data packets in error-free control operations.

7. The apparatus (200) according to any one of the preceding claims, wherein

The first module (221) of the first computer unit (202) and the first module (231) of the second computer unit (202) form a system group,

the second module (222) of the first computer unit (201) and the second module (232) of the second computer unit (202) form a system group, and

both said system groups are redundant system groups with respect to each other and preferably process the same information in transmitted data packets in their error-free control operation.

8. The device (200) according to any of the preceding claims, wherein in the combined data packets (301, 305, 302, 303, 304), temporally combined data packets (301, 305) from the first sequence (251) and the second sequence (261), respectively, are combined, which carry the same information in an error-free control operation.

9. The device (200) according to any of the preceding claims, wherein the first module (221) of the first computer unit (201) is designed to provide a CRC code based on the combined data packet (301, 305, 302, 303, 304) to the combined data packet (301, 305, 302, 303, 304) before being sent to the first module (231) of the second computer unit (202), and

the first module (231) of the second computer unit (202) is designed to perform a check based on the CRC code of the combined data packet (301, 305, 302, 303, 304).

10. The apparatus (200) according to any one of the preceding claims, wherein

The first module (221) of the first computer unit (201) is also designed to be identical to the first module (232) of the second computer unit (202) and vice versa,

the second module (222) of the first computer unit (201) is also designed to be identical to the second module (232) of the second computer unit (202) and vice versa, and

in the same way, a bidirectional communication is realized between the first computer unit (201) and the second computer unit (202).

11. The device (200) according to any one of the preceding claims, wherein the first module (221) of the first computer unit (201), the second module (222) of the first computer unit (201), the first module (231) of the second computer unit (202) and/or the second module (232) of the second computer unit (202) are implemented by a microcontroller and/or an FPGA, preferably in such a way that one of the modules (221, 231; 222, 232) of a computer unit (201, 202) is implemented by a microcontroller and the other module (221, 231; 222, 232) of the same computer unit (201, 202) is implemented by an FPGA.

12. A method for data transmission with a device, in particular a device (200) according to any of the preceding claims, comprising:

a first data transmission connection between a first module (221) and a second module (222) of a first computer unit (201),

A third data transmission connection (241) between the first module (221) of the first computer unit (201) and the first module (231) of the second computer unit (202), wherein in the method:

the first time sequence (251) of the data packets (301) is transmitted from the first module (221) of the first computer unit (201) to the first module (231) of the second computer unit (202), and the second time sequence (261) of the further data packets (302) is transmitted from the second module (222) of the first computer unit (201) to the second module (232) of the second computer unit (202),

-adding a first count value (305) to each data packet (301) of a first sequence (251) of a plurality of data packets, said first count values (305) differing from data packet to data packet by an increment each,

-adding a CRC code (304) to each of a plurality of data packets (302) of the second sequence (261), the CRC code being based on the respective data packet (302) and an accompanying second count value (303) which differs for the data packets of the second time sequence (261), by an increment respectively,

transmitting the data packets (302, 303, 304) respectively extended by the second counter value (303) and the CRC code (304) from the second module (222) of the first computer unit (201) to the first module (221) of the first computer unit (201) via a first data transmission connection,

receiving data packets (302, 303, 304) from the second module (222) each extended by the first counter value (303) and the CRC code (304), in order to append respective data packets (302, 303, 304) of the received extended data packets (302, 303, 304) of the second sequence (261) to the time-dependent extended data packets (301, 305) of the first sequence (251), and to transmit the combined data packets (301, 305, 302, 303, 304) thus formed together to the first module (231) and via the third data transmission connection (241) to the second computer unit (202),

the combined data packet (301, 305, 302, 303, 304) is split into a first sequence (251) of individual spread data packets (301, 305) and a second sequence (261) of individual spread data packets (302, 303, 304), and the second sequence (261) of individual spread data packets (302, 303, 304) is transmitted via a second data transmission connection to a second module (232) of a second computer unit (202), and

the CRC code (304) of a second sequence (261) of extension packets (302, 303, 304) arriving later in time is checked.

13. The method according to claim 12, wherein the third data transfer connection (241) is realized by only one physical connection and no other physical data transfer connection exists between the first computer unit (201) and the second computer unit (202).

14. Local data bus in an aircraft, in particular in an aircraft, wherein the local data bus comprises a device (200) for data transmission according to any of the preceding claims 1 to 11 or uses a method according to claim 12 or 13.

15. An aircraft, in particular an airplane, in which a data bus according to any one of claims 1 to 11 or a method according to claim 13 or 14 is used in order to enable communication between a central computer and remote electronic devices, for example for controlling a flight control system, a landing gear system, an actuation system or an air conditioning system.