Method for data transmission

• US 8,015,324 B2
• Filed: 08/21/2008
• Issued: 09/06/2011
• Est. Priority Date: 08/23/2007
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Tretter, Albert, Klotz, Dieter
• Primary Examiner(s): Dang; Khanh
• Application Number:
  US12/229,333
• Publication Number:
  US 20090055564A1
• Time in Patent Office: 1,111 Days
• Field of Search: 710 8- 10, 710/29, 710/30, 710/31, 710 33- 35, 710/110, 710/307, 370/235
• US Class Current: 710/33
• CPC Class Codes: H04L 12/4015 by scheduling the transmission of messages at the communication node
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/4026 Bus for use in automation systems

Abstract

The invention relates to a method for data transmission in a serial bus system comprising a control unit and bus users. The method comprises steps: receiving a first data telegram by a bus user from the control unit, wherein the data telegram has a data field containing output data; reading out the data field intended for the bus user from the first data telegram; preparing input data as a response to the read out data field; checking whether a predefined criterion is met, wherein if the criterion is met a second data telegram is newly generated and the input data is attached to the second data telegram and if the criterion is not met, the input data is attached to a data telegram previously received from another bus user; and transmitting the input data to the control unit by the second data telegram.

Claims

1. A method for transmitting data in a serial bus system, comprising:

providing a network comprising a serial data bus, and further comprising a controller and a plurality of users connected to the bus, each user comprising a processor, a memory, a receive unit, and a transmit unit, and each user connected to an automation device for data input therefrom;

transmitting a first telegram from the controller onto the bus, wherein the first telegram comprises a plurality of data fields, each said data field identified within the telegram for one of the users;

each of the users sequentially becoming a receiving user of the first telegram via the bus, and each receiving user sequentially performing the steps of

receiving the first telegram;

forwarding the first telegram onto the bus toward a subsequent receiving user;

determining if one of the data fields is identified in the first telegram for the receiving user, and, if so,

reading said one of the data fields identified for the receiving user;

preparing a receiving user response; and

if the automation device attached to the receiving user provides input data needed for the receiving user response within a predetermined time limit, and if a response telegram of a subsequent receiving user is received by the receiving user within the predetermined time limit,

then

appending the receiving user response to the response telegram of the subsequent receiving user; and

forwarding the response telegram of the subsequent receiving user toward the controller;

else

forwarding the response telegram received from the subsequent receiving user unchanged toward the controller;

forming a new response telegram containing the receiving user response; and

transmitting the new response telegram toward the controller;

wherein a designated last one of the receiving users jumps from the preparing step to the forming step.

2. The method of claim 1, further comprising:

if the receiving user response is one that indicates a malfunction, then jumping from the preparing step to the forming step.