System and Method for Signal Failure Detection in a Ring Bus System
AssigneeSMSC Europe GmbH
InventorsStefan Kerber, Robert Wilhelm
Life of this patent
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Abstract
A communication system, network node, and communication port architecture are provided for transporting data across a ring network. If a network node detects a signal failure, the communication port of the network node configures itself as timing master and communicates a shutdown command to the other network nodes. In addition, the communication port sets an internal flag signaling this “signal off” event. All other network nodes, which receive the shutdown flag, do not set this internal status, and instead, save a status of “no fault saved.” Accordingly, it can be easily determined where the loss of signal occurred.
Claims12
A communication port for a node in a communication network having a plurality of nodes coupled together via a bus, wherein each node comprises a communication port having an input for receiving data, an output for transmitting data and means for detecting a signal off condition at the input, and wherein the communication port is configured for:
- detecting a signal off condition;
- after a signal off condition has been detected, checking whether a shutdown flag has been received, wherein if:
- a shutdown flag is not received, the communication port is further configured for performing the steps of:
- saving its internal status “signal off”;
- configuring itself as timing master for the bus;
- setting a shutdown flag, which is forwarded over the bus to the communication port of a subsequent node;
- waiting a predetermined amount of time;
- and
- switching an output signal associated with the communication port off;
- and
- a shutdown flag is received, the communication port is further configured for performing the steps of:
- saving its internal status “no fault saved;” and
- the output signal associated with the communication port off.
A method for shutting down a communication port of a network node, wherein the method is performed by the communication port and comprises:
- A0) detecting a “signal off” event;
- A1) checking whether a shutdown flag is present, wherein:
- if a shutdown flag is not present, the method performed by the communication port further comprises:
- A2) configuring the communication port as timing master;
- A3) setting a shutdown flag and forwarding the shutdown flag over a network to a subsequent network node;
- A4) waiting a predetermined amount of time;
- A5) switching an output signal associated with the communication port off;
- and
- A6) at any time after step Al, saving an internal status of the communication port as “signal off;” and
- if a shutdown flag is present, the method performed by the communication port further comprises:
- A7) saving the internal status of the communication port as “no fault saved;” and
- A8) switching the output signal associated with the communication port off.
A communication system having a plurality of nodes coupled together via a bus, wherein each node comprises a communication port having an input for receiving data, an output for transmitting data and means for detecting a signal off condition at the input, and wherein the communication port is configured for:
- detecting a signal off condition;
- after a signal off condition has been detected, checking whether a shutdown flag has been received, wherein:
- if a shutdown flag is not received, the communication port is further configured for:
- saving an internal status as “signal off”;
- configuring itself as timing master for the bus;
- setting a shutdown flag, which is forwarded over the bus to a communication port of a subsequent node;
- waiting a predetermined amount of time;
- and
- switching an output signal associated with the communication port off;
- and
- is a shutdown flag is received, the communication port is further configured for:
- saving an internal status as “no fault saved;” and
- switching an output signal associated with the communication port off.
Dependencies are inferred from the claim text.