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US 2003/0145120 A1Published application
Noninvasive testing of network interface error codes for safety network
AssigneeRockwell Automation Technologies, Inc.
InventorsDavid A. Vasko, Joseph A. Lenner
Life of this patent
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Abstract
Error detection codes implemented in standard network interface circuits are enlisted in obtaining high reliability necessary for safety systems by virtual testing of the network interface circuits using background levels of network errors. The frequency of the testing matches the frequency of the network errors.
Claims28
A safety communications system comprising:
- (a) a network for transmitting messages, the messages having data and error detection codes derived from the data;
- (b) a network interface connectable to the network to receive the messages, the network interface including a network error testing means reading the error detection codes of the messages to detect errors in the data of messages;
- and
- (c) a supplemental error testing means communicating with the network interface to receive the data of received messages, the supplemental error testing means independently detecting errors in at least a portion of the message;
- whereby operation of the network error testing means may be tested in the presence of a background level of network errors.
2 more elements
A safety communications system meeting a standard of detecting communication errors in the transmission of data on a network to at least a predetermined required total statistical probability, the safety communications system comprising:
- (a) a standard communications network;
- (b) a standard network interface operating to:
- (i) receive data and applying an error detection code to the data and transmit the combined data and error detection code as a message on the network;
- (ii) receive a message of combined data and error detection codes from the network and using a network error testing means to read the error detection code to detect errors in the data at a first statistical probability;
- (c) a supplemental error testing means for detecting errors in the data at a second statistical probability;
- whereby the required total statistical probability is greater than either of the first and second statistical probabilities alone and no greater than the combined first and second statistical probabilities.
3 more elements
Dependencies are inferred from the claim text.