Discarding a partially received message from a data queue
AssigneeFisher-Rosemount Systems, Inc.
InventorsBrian Franchuk, Roger Benson
Life of this patent
Estimating the term…
Abstract
Devices in a process control system communicate by data messages over a communication medium segment. Each device includes a communication controller that includes a received data memory and a plurality of received message objects. When a message is received, a received message object is activated, and the initial position of a write pointer in the received data memory is stored in the received message object. During message reception, if a hardware device determines that the message is to be ignored, the received message object is deactivated, thereby preventing further writing of the message to the received data memory. The write pointer is then preferably returned to its initial position as stored in the received message object.
Claims13
A device for communicating over a communication medium, the device comprising:
- a medium attachment unit (MAU) for receiving and transmitting messages on the communication medium;
- a central processing unit (CPU) for processing data contained in messages received and creating data to be contained in messages to be transmitted;
- a communication controller for interfacing between the MAU and the CPU, the communication controller including a data queue and a queue of received message objects, the data queue for storing a plurality of messages received on the communication medium, each received message object corresponding to a message stored in the data queue;
- wherein upon receipt of a message on the communication medium, a first received message object is activated and stores an initial position of a write pointer in the data queue;
- and
- wherein the first received message object is deactivated if the message is to be ignored.
A method of filtering a message in a communication device before the entire message is received, the method comprising:
- enabling a first received message object;
- storing in the first received message object an initial position of a write pointer in a received data memory;
- writing the message to the received data memory starting at the initial position of the write pointer;
- incrementing a position of the write pointer as the message is written to the received data memory;
- and
- disabling the first received message object during message reception when the communication device determines that the message is to be ignored.
A method of removing a received message from a data queue in a communication device, the data queue for storing a plurality of messages received on the communication medium, the method comprising:
- storing an initial position of a write pointer in the data queue;
- writing the received message to the data queue starting at the initial position of the write pointer;
- incrementing a position of the write pointer as the received message is written to the data queue;
- and
- returning the write pointer to the initial position if the message is to be removed such that a next message received by the communication device overwrites the received message.
Dependencies are inferred from the claim text.