System for generating unsolicited messages on high-tier communication link in response to changed states at station-level computers
First Claim
1. A database cache computer for connection in a factory automation system for improving communication between a user interface computer and a plurality of station-level computers located at a corresponding plurality of stations, the database cache computer comprising:
- database means for storing a database of data items collected from the plurality of station-level computers;
first communication means coupled to the database means for communicating the data items through a first communication link to and from the user interface computer via a message including data items from a plurality of station level computers;
second communication means coupled to the database means for collecting the data items through a second communication link from the station-level computers; and
wherein an improvement comprises;
means in the database cache computer responsive to a first message from the user interface computer to designate data items as being subject to change-of-state monitoring;
means in the database cache computer for detecting changes in states of the designated data items collected through the second communication link from the plurality of station-level computers; and
means in the database cache computer responsive to changes in the states of the designated data items collected through the second communication link from the plurality of station-level computers for assembling and transmitting an unsolicited message to the user interface computer, wherein the unsolicited message includes the changed states originating at a plurality of station-level computers for a plurality of the designated data items.
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Accused Products
Abstract
In a method for monitoring and collecting data in a multi-tier computer system, a database operation message, referred to as an "open" message is transmitted to a database cache computer with a list of data items in the database cache computer to be monitored on a change-of-state basis. The database cache computer responds by monitoring the data items and returning unsolicited "change data" messages containing only states for data items which have changed over the monitoring period. The change data messages are sent back periodically without the need for polling by a higher-level computer. The monitoring process is terminated by closing data records in the higher-level computer which generates a "close" message to the database computer to terminate the transmission of the change data messages. Also disclosed is a database cache computer and a user interface computer for carrying out the method.
119 Citations
11 Claims
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1. A database cache computer for connection in a factory automation system for improving communication between a user interface computer and a plurality of station-level computers located at a corresponding plurality of stations, the database cache computer comprising:
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database means for storing a database of data items collected from the plurality of station-level computers; first communication means coupled to the database means for communicating the data items through a first communication link to and from the user interface computer via a message including data items from a plurality of station level computers; second communication means coupled to the database means for collecting the data items through a second communication link from the station-level computers; and wherein an improvement comprises; means in the database cache computer responsive to a first message from the user interface computer to designate data items as being subject to change-of-state monitoring; means in the database cache computer for detecting changes in states of the designated data items collected through the second communication link from the plurality of station-level computers; and means in the database cache computer responsive to changes in the states of the designated data items collected through the second communication link from the plurality of station-level computers for assembling and transmitting an unsolicited message to the user interface computer, wherein the unsolicited message includes the changed states originating at a plurality of station-level computers for a plurality of the designated data items. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for collecting and monitoring data in a multi-tier computer system while reducing message traffic, the method comprising:
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opening a data record by executing an application program in a supervisory computer, wherein the data record includes data items to e monitored at one or more station-level computers that are remote from the supervisory computer; in response to the opening of a data record in the supervisory computer, generating an "open" message from the supervisory computer to a database cache computer that stores a database of data items to be monitored at the one or more station-level computers that are remote form the supervisory computer, wherein the "open" message includes a list of data items to be monitored, and wherein the "open" message identified the data items as being subject to change-of-state monitoring in which only states that have changed for data items within the database within a monitoring period are transmitted back to the supervisory computer; in response to receiving the "open" message at the database cache computer, monitoring those data items which have been identified in the "open" message as being subject to change-of-state monitoring by receiving update messages from the station-level computers and detecting those states which have changed from last states stored in the database; and transmitting a change data message from the database cache computer to the supervisory computer, wherein the change data message includes only states of data items that have changed since the beginning of the monitoring period. - View Dependent Claims (8, 9, 10, 11)
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Specification