Method for asynchronous data communication in a real-time capable ethernet data network
According to the invention, in order that the asynchronous bandwidth available in a real-time capable Ethernet data network protocol can be better utilized without collision at least one slave (S 1 , . . . , Sn) which wishes to transmit asynchronous data informs the master (M) in a transmission cycle (Z(m)) by means of a request data packet (DPa) how much asynchronous data this slave (S 1 , . . . , Sn) wishes to transmit asynchronously and by means of an invitation data packet (DPe) the master (M) informs the slave (S 1 , . . . , Sn) as to the time (t as ) within a following transmission cycle (Z(m+k+l)) at which the slave (S 1 , . . . , Sn) should transmit the asynchronous data in an asynchronous data packet (DPas).
1. A method for asynchronous data communication in a real-time capable Ethernet data network utilizing at least one master connected, via the Ethernet data network, to a plurality of slaves, the method comprising:
utilizing real-time Ethernet data communication with a transmission cycle having a predetermined cycle time, wherein the transmission cycle is divided into an isochronous section and an asynchronous section;
utilizing the real-time Ethernet data communication in the isochronous section such that the at least one master knows which data packet sizes the slaves will transmit isochronously; and
utilizing the asynchronous section for asynchronous data communication between the at least one master and the plurality of slaves;
when at least one slave wishes to transmit asynchronous data, sending a request data packet to the at least one master from the at least one slave, wherein the sending occurs within a first transmission cycle and the request data packet indicates how much asynchronous data the at least one slave wishes to transmit asynchronously, and
after the sending, transmitting an invitation data packet from the at least one master to the at least one slave, said invitation data packet indicating a time within a second transmission cycle at which the at least one slave is permitted to transmit the asynchronous data in an asynchronous data packet,
wherein the data communication in the isochronous section is planned data communication that occurs cyclically, and
wherein the data communication in the asynchronous section is planned data communication by the master and occurs non-cyclically.
2. The method according to claim 1 , wherein the second transmission cycle is one of multiple transmission cycles that follow the first transmission cycle.
3. The method according to claim 2 , wherein the invitation data packet indicates which of the multiple transmission cycles the at least one slave is permitted to transmit the asynchronous data in the asynchronous data packet.
4. The method according to claim 1 , wherein the asynchronous data packet is transmitted and the invitation data packet is received in a one transmission cycle.
5. The method according to claim 1 , wherein the asynchronous data packet is transmitted in a transmission cycle that immediately follows the second transmission cycle.
6. The method according to claim 1 , wherein the invitation data packet indicates how much asynchronous data the at least slave should transmit.
7. The method according to claim 1 , further comprising detecting an error in the real-time Ethernet data communication when there is a deviation between data quantity of the asynchronous data requested from the at least one slave and data quantity of the asynchronous data communicated by the at least one master.
8. The method according to claim 1 , wherein the request data packet is transmitted in the isochronous section of the first transmission cycle.
9. The method according to claim 1 , wherein the request data packet comprises a plurality of request data packets.
10. The method according to claim 1 , further comprising transmitting a plurality of request data packets by the at least one slave in a transmission cycle that follows the first transmission cycle.
11. The method according to claim 1 , wherein the second transmission cycle immediately follows the first transmission cycle.
12. The method according to claim 1 , wherein the first and second transmission cycles are a same transmission cycle.
13. The method according to claim 1 , wherein the invitation data packet comprises a plurality invitation data packets.
14. The method according to claim 1 , further comprising, during the first transmission cycle, transmitting an asynchronous data packet from the at least one master to at least one slave.
15. The method according to claim 1 , further comprising detecting an error in the real-time Ethernet data communication when, after the sending, the at least one slave does not receive an invitation data packet.
16. A method for asynchronous data communication in a real-time capable Ethernet data network, the method comprising:
connecting at least one master, via the Ethernet data network, to a plurality of slaves;
utilizing real-time Ethernet data communication with a transmission cycle having a predetermined cycle time, wherein the transmission cycle is divided into an isochronous section and an asynchronous section;
utilizing the real-time Ethernet data communication in the isochronous section such that the at least one master knows which data packet sizes the slaves will transmit isochronously; and
utilizing the asynchronous section for asynchronous data communication between the at least one master and the plurality of slaves;
when at least one slave wishes to transmit asynchronous data, sending at least one request data packet to the at least one master from the at least one slave, wherein the request data packet indicates to the at least one master how much asynchronous data the at least one slave wishes to transmit asynchronously, and
after the sending, transmitting an invitation data packet from the at least one master to the at least one slave, said invitation data packet indicating a time within the transmission cycle at which the at least one slave is permitted to transmit the asynchronous data in an asynchronous data packet,
wherein the data communication in the isochronous section is planned data communication that occurs cyclically, and
wherein the data communication in the asynchronous section is planned data communication by the master and occurs non-cyclically.
17. A method for asynchronous data communication in a real-time capable Ethernet data network, the method comprising:
connecting at least one master, via the Ethernet data network, to a plurality of slaves;
utilizing real-time Ethernet data communication with a transmission cycle having a predetermined cycle time, wherein the transmission cycle is divided into an isochronous section and an asynchronous section;
utilizing the real-time Ethernet data communication in the isochronous section such that the at least one master knows which data packet sizes the slaves will transmit isochronously; and
utilizing the asynchronous section for asynchronous data communication between the at least one master and the plurality of slaves;
when at least one slave wishes to transmit asynchronous data, sending, within a first transmission cycle, at least one request data packet to the at least one master from the at least one slave, wherein the request data packet indicates to the at least one master how much asynchronous data the at least one slave wishes to transmit asynchronously, and
transmitting, within a following transmission cycle, an invitation data packet from the at least one master to the at least one slave, said invitation data packet indicating a time within the second transmission cycle at which the at least one slave is permitted to transmit the asynchronous data in an asynchronous data packet,
wherein the data communication in the isochronous section is planned data communication that occurs cyclically, and
wherein the data communication in the asynchronous section is planned data communication by the master and occurs non-cyclically.