Rosemount Inc.

Digi International Inc.

Fisher-rosemount Systems, Inc

Gene H Olson

Dennis A Quy

Jon Dale Westbrock

Craig R Tielens

Richard R Sharpe, Jr

Robert Bruck

Ralph E Richardson

A computer-based database management method permits management of a configuration database associated with one of a plurality of devices. Each device has a variable configuration which includes at least one adjustable parameter. The method includes the steps of selecting a particular device, selecting a particular parameter of the particular device, assigning a particular value for the particular parameter at a particular time, communicating the particular value for the particular parameter to the particular device at the particular time, creating a transaction record, and storing the transaction record in a configuration database. The transaction record includes an identifier uniquely identifying the particular device and further specifies the particular parameter of the particular device, the particular value for the particular parameter, and the particular time at which the particular value is to be applied to the particular parameter.

System and method for managing a transaction database of records of

A terminal server for providing communication between a host computer and a synchronous, asychronous or parallel communications port across a general purpose network is provided utilizing a unique device driver interface and multiplexing communication protocol. The server communicates data and control commands for multiple ports on a single connection, thereby reducing demands on the network. In addition, genuine TTY devices are made available across the general purpose network which have all the characteristics of local communication ports. The present invention also makes possible access to the ports on the server to multiple host computers located on the network, allowing fair access to shared resources such as modems and printers. Finally, the invention can also be implemented in hardware, further increasing compatibility with existing host computer software and further reducing host computer overhead.

Network terminal server with full API implementation

An apparatus for handling data at two or more ports is described. In one embodiment, the apparatus comprises an apparatus for receiving data at multiple ports, each port having a buffer capable of holding B units of received data and being serviced by a processor resource. The apparatus has software causing the processor resource to have a polling session with each port and to read unread units of data from the buffer in each port during its polling session. It also has a counter for determining the number of units of data that have been read from the buffer and circuitry responsive to said counter to assert flow control from said port based on the number of units of data read.

Apparatus and method for input data loss prevention with a buffered UART

This invention is an improved method for transmit polling of buffered UARTs. For each polling interval, the method predicts the minimum number of characters needed to keep the transmitter from going idle before the next polling interval and places exactly that many characters in the transmit fifo.

Method for supplying data to a buffered UART

A plurality of message packets are individually acknowledged in a communications network. The acknowledgement includes multiple types of status information including ACK, NAK and BUSY. Each message packet is assigned a sequence number. Acknowledgements are sent in response to receiving a message packet and include status information for the last message packet received along with status information for the seven message packets previously received. If after a timeout period expires and no message packets have been received, a status inquiry message is transmitted.

Technique for acknowledging packets

A method of dynamically reconfiguring a UART polling loop with a jump table.

Dynamic reconfiguration of UART polling loop with a jump table

A distributed computer network is synchronized as to time provided to each peerway and its associated stations or nodes. Highway interface adapters (HIAs) serve as time references for each node on a peerway and as communication links between peerways. At periodic intervals, each HIA transmits a Time Interval Control packet (TIC) including the time of day and an ordinal number denoting the HIA priority in the network and a distance factor. By comparing ordinal numbers, an HIA will adjust its clock to the TIC packet being transmitted from the HIA with the highest priority and the smallest distance. This ensures that a synchronized time is provided to each node on the network from a single source over an optimal distance.

Time synchronization of control networks

A data communication system allocates use of a common data communication medium shared by a plurality of stations. During each transmission cycle, the communication medium carries data packets of varying priority which each station receives. The stations are allocated use of the communication medium during one or more priority intervals as a function of the priority of the packet which the station is ready to transmit. Each station is synchronized to a transmission cycle period which is divided into subperiods. Certain types of packets are relegated to transmission and reception within predetermined subperiods.

Communication system with subdivided transmission cycles

A redundant common communication system for a distributed process control or data processing system has multiple stations which are coupled to at least two redundant communication channels (such as communication busses). Each station includes a transmitter for transmitting data packets and a receiver for receiving data packets. Each data packet includes a channel selection field which identifies a selected channel to be used by all station during a succeeding transmission of a data packet. Each station makes an assessment of quality of each channel based upon the occurrence of errors when that channel is in use. The station computes a margin value based upon assessed quality factors. When the station gets an opportunity to transmit, the channel selection field of the transmitted packet identifies a channel which is selected based upon the margin value and the frequency of previous use of each of the channels. As a result, frequent switching among the channels occurs, with the percentage of use of each channel being dependent upon the assessed quality of that channel by the various stations.

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Minneapolis, MN, United States of America

Gene H Olson