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Serial bus communication method in a refrigeration system

  • US 5,323,385 A
  • Filed: 01/27/1993
  • Issued: 06/21/1994
  • Est. Priority Date: 01/27/1993
  • Status: Expired due to Fees
First Claim
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1. A method of two-way communication in a refrigeration system between a central communication node and remote nodes via serial data bus using a modified Controller Area Network protocol having a fixed message frame format which includes a combined identification and arbitration field and a data field, comprising the steps of:

  • converting a predetermined portion of the data field of each message frame to a permanent data descriptor expansion byte (DEB),setting a predetermined bit of said DEB to a first logic level in at least the first frame of a message, to indicate a control frame,loading information descriptive of the message in the remaining bits of said DEB, and in the remaining data field, of said control frame,said message descriptive information in the data field of the control frame including an algorithm and algorithm block number associated with the data being transmitted, when the data is being transmitted from and to the central communication node,setting said predetermined bit of said DEB to a second logic level in at least one subsequent frame of the message, to indicate a data frame,loading a block of data in the data field of each data frame,and loading index information in the remaining bits of the DEB in each data frame which is specific to the data of the associated data frame.

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