US 12,244,436 B2
Method for data communication between subscribers of an automation system
Holger Büttner, Berlin (DE); and Hans Beckhoff, Verl (DE)
Assigned to Beckhoff Automation GmbH, Verl (DE)
Filed by Beckhoff Automation GmbH, Verl (DE)
Filed on Jul. 5, 2022, as Appl. No. 17/857,684.
Application 17/857,684 is a continuation of application No. PCT/EP2021/050467, filed on Jan. 12, 2021.
Claims priority of application No. 10 2020 100 987.9 (DE), filed on Jan. 16, 2020.
Prior Publication US 2022/0337451 A1, Oct. 20, 2022
Int. Cl. H04L 12/40 (2006.01)
CPC H04L 12/40182 (2013.01) [H04L 2012/4026 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for data communication between subscribers of an automation system having an active subscriber and at least two passive subscribers, which comprise at least a first passive subscriber and a second passive subscriber, the active subscriber and the passive subscribers being connected to one another via a bus system, the active subscriber being set up to initiate data communication by transmitting communication requests and the passive subscribers being set up to send out corresponding reply messages in response to the communication requests, wherein the first passive subscriber comprises a first switch-on unit for determining a first transmission time for transmitting a first reply message via the first passive subscriber, and wherein the second passive subscriber comprises a second switch-on unit for determining a second transmission time for transmitting a second reply message via the second subscriber, the method comprising:
receiving a write request sent by the active subscriber to send reply messages by the first passive subscriber and the second passive subscriber in a first receiving step;
counting data units received after receipt of the write request by the first passive subscriber until a first number is reached by the first switch-on unit in a first counting step and determining the first transmission time point for transmitting the first reply message via the first switch-on unit of the first passive subscriber in a first determining step, wherein the first transmission time corresponds to a point in time at which a number of data units received by the first passive subscriber according to a predefined data transmission rate after receiving of the write request equals the first number;
sending out the first reply message at the first transmission time by the first passive subscriber in a first reply step;
receiving the first reply message by the active subscriber and the second passive subscriber in a second receiving step;
counting data units received after receipt of the write request via the second passive subscriber until a second number is reached by the second switch-on unit in a second counting step and determining the second transmission time for transmitting the second reply message by the second switch-on unit in a second determining step, wherein the second transmission time corresponds to a point in time at which a number of data units received by the second passive subscriber according to the predefined data transmission rate after receiving the write request equals the second number;
sending out the second reply message at the second transmission time by the second passive subscriber in a second reply step;
receiving the second reply message by the active subscriber and the first passive subscriber in a third receiving step; and
interpreting the first reply message and the second reply message as a first data segment and a second data segment of a data packet by the active subscriber in an interpreting step.