Network distributor

1. A method for transferring data telegrams each with at least one payload field in a data network with network users and a network distributor that has a master interface, a first user interface and a second user interface,

wherein the master interface is connected to a master over a master data path, the first user interface is connected to at least one first network user over a first user data path, and

the second user interface is connected to at least one second network user over a second user data path, and

wherein the method comprises the following steps:

receiving a first master data telegram sent by the master through the network distributor via the master interface connected to the master data path,

compiling a first transmission data telegram and a second transmission data telegram through the network distributor,

transferring the first transmission data telegram to the first network user via the first user interface connected to the first user data path and the second transmission data telegram to the second network user through the network distributor via the second user interface connected to the second user data path,

receiving a first reception data telegram sent by the first network user over the first user data path via the first user interface and a second reception data telegram sent by the second network user over the first user data path via the second user interface through the network distributor,

compiling a second master data telegram through the network distributor, and

transferring the second master data telegram via the master interface to the master through the network distributor,

wherein the first master data telegram, the second master data telegram, the first and second transmission data telegrams and the first and second reception data telegrams each have a counter field with an access indicator that indicates an access to the payload field through one of the network users, and

wherein the access indicator of the second master data telegram is compiled in order to represent accesses to payload fields of the first master data telegram, of the first transmission data telegram, of the second transmission data telegram, of the first reception data telegram and of the second reception data telegram.

2. The method as claimed in claim 1 , wherein the access indicator of the second master data telegram corresponds to at least the sum of the access indicator of the first master data telegram, of the access indicator of the first reception data telegram minus the access indicator of the first transmission data telegram, and of the access indicator of the second reception data telegram minus the access indicator of the second transmission data telegram.

3. The method as claimed in claim 2 , wherein the access indicator of one of the transmission data telegrams is zero.

4. The method as claimed in claim 1 ,

wherein the payload fields include payload,

wherein the payload of the first transmission data telegram and the payload of the second transmission data telegram each comprise, after compilation by the network distributor, at least part of the payload of the first master data telegram, and

wherein the payload of the second master data telegram comprises, after compilation by the network distributor, part of the payload of the first reception data telegram and part of the payload of the second reception data telegram.

5. The method as claimed in claim 1 , wherein the payload field of the first transmission data telegram and/or the payload field of the second transmission data telegram are compiled as a copy of the payload field of the first master telegram.

6. The method as claimed in claim 1 , wherein the network distributor compiles one of the transmission data telegrams by transmitting the first master data telegram as a first or second transmission data telegram via the first and second user interface, respectively.

7. The method as claimed in claim 1 ,

wherein the payload field of the first master data telegram, of the second master data telegram, of the first and second transmission data telegrams and of the first and second reception data telegrams each have the same size,

wherein the payload field of the second master data telegram contains payload from a first sub-area of the payload field of the first reception data telegram and payload from a second sub-area of the payload field of the second reception data telegram, and

wherein the first sub-area and the second sub-area do not overlap.

8. The method as claimed in claim 1 , wherein the network distributor, during the compilation of the payload field of the second master data telegram, subjects the payload field of the first reception data telegram to an OR operation with the payload field of the second reception data telegram.

9. The method as claimed in claim 8 , wherein the network distributor multiplies, during the compilation of the second master data telegram, the payload field of the first reception data telegram by a first data mask and the payload field of the second reception data telegram by a second data mask.

10. The method as claimed in claim 8 , wherein the network distributor multiplies, during the compilation of the first transmission data telegram, the payload field of the first master data telegram by a third data mask and, during the compilation of the second transmission data telegram, multiplies the payload field of the first master data telegram by a fourth data mask.

11. The method as claimed in claim 8 ,

wherein the network users of one of the user data paths are arranged in a line,

wherein a last network user in the line converts one of the transmission data telegrams of the network distributor into one of the reception data telegrams,

wherein at least part of the payload field of the one of the reception data telegrams is set to zero and returns the one of the reception data telegrams to the network distributor,

wherein the one of the transmission data telegrams and the one of the reception data telegrams pass through all the network distributors of the one of the user data paths, and the network users only carry out read accesses to the payload field of the one of the transmission data telegrams and only carry out write accesses to the payload field of the one of the reception data telegrams.

12. The method as claimed claim 1 ,

wherein the data telegrams are autoinc data telegrams which have at least one address value and which address the network users via a position within the data network, and

wherein an address value of the second transmission data telegram corresponds to an address value of the first master data telegram plus a number of network users connected to the first user data path.

13. The method as claimed in claim 12 , wherein an address value of the second master data telegram corresponds at least to the sum of an address value of the first master data telegram plus the number of network users connected to the first user data path and plus a number of network users connected to the second user data path.

14. The method as claimed in claim 1 , wherein the network distributor compiles the second master data telegram, after receiving the first reception data telegram via the first user interface or after receiving the second reception data telegram via the second user interface, if no error occurs during the reception of the respectively other reception data telegram via the respectively other user interface.

15. The method as claimed in claim 14 , wherein the error consists in that the network distributor does not receive within a specified waiting time after having received the first or second reception data telegram via the first and second user interface, respectively, a reception data telegram via the respectively other user interface.

16. The method as claimed in claim 14 ,

wherein the first reception data telegram and the second reception data telegram include identifiers, and

wherein the error consists in that the identifier of the reception data telegram received via the respectively other user interface does not match an expected identifier.

17. The method as claimed in claim 1 , wherein the data network is an Ethernet network, in particular an EtherCAT network.

18. The method as claimed in claim 1 , wherein the first and second transmission data telegrams are simultaneously transmitted by the network distributor.

19. The method as claimed claim 1 ,

wherein the network distributor has a memory area, and

wherein the first reception data telegram received via the first user interface is stored in the memory area by the network distributor, if the reception of the first reception data telegram takes place prior to the reception of the second reception data telegram via the second user interface, and

wherein the second reception data telegram received via the second user interface is stored by the network distributor in the memory area, if the reception of the second reception data telegram takes place prior to the reception of the first reception data telegram via the first user interface.

20. The method as claimed in claim 1 , wherein the network distributor is integrated into a network user that carries out read and/or write accesses to the payload field of one or more of the first or second master data telegrams, of the first or second transmission data telegrams or of the first or second reception data telegrams.

21. A network distributor having a master interface, a first user interface and a second user interface, designed for transferring data telegrams each with at least one payload field in a data network with network users and a network distributor that has a first user interface and a second user interface,

wherein the master interface is connected to a master over a master data path, the first user interface is connected to at least one first network user over a first user data path, and the second user interface is connected to at least one second network user over a second user data path, and

wherein the network distributor comprises a memory area coupled to a data processor configured for:

receiving a first master data telegram sent by the master through the network distributor via the master interface connected to the master data path,

compiling a first transmission data telegram and a second transmission data telegram through the network distributor,

transferring the first transmission data telegram to the first network user via the first user interface connected to the first user data path and the second transmission data telegram to the second network user through the network distributor via the second user interface connected to the second user data path,

receiving a first reception data telegram sent by the first network user over the first user data path via the first user interface and a second reception data telegram sent by the second network user over the first user data path via the second user interface through the network distributor,

compiling a second master data telegram through the network distributor, and

transferring the second master data telegram via the master interface to the master through the network distributor,

wherein the first master data telegram, the second master data telegram, the first and second transmission data telegrams and the first and second reception data telegrams each have a counter field with an access indicator that indicates an access to the payload field through one of the network users, and

wherein the access indicator of the second master data telegram is compiled in order to represent accesses to payload fields of the first master data telegram, of the first transmission data telegram, of the second transmission data telegram, of the first reception data telegram and of the second reception data telegram.

22. A data network having a master, at least one first and one second network user and a network distributor according to claim 21 ,

wherein the master is connected to a master data path, the first network user is connected to a first user data path and the second network user is connected to a second user data path, and

wherein the network distributor is connected to the master data path via the master interface, to the first user data path via the first user interface and to the second user data path via the second user interface.