Time based subscription framework for Source and Channel coding in SCADA Clients

The need for industry has always been to collect continuous data and provide accurate monitoring locally and through servers remotely in Supervisory control and data acquisition – SCADA. If the SCADA system is not able to archive data at required high rate then the underlying manufacturer has the ability to store the values with a time stamp associated with process time and will be independent of the polled SCADA time basis making archiving assumption realistic.

By Control Engineering Staff January 10, 2005

The need for industry has always been to collect continuous data and provide accurate monitoring locally and through servers remotely in Supervisory control and data acquisition– SCADA. If the SCADA system is not able to archive data at required high rate then the underlying manufacturer has the ability to store the values with a time stamp associated with process time and will be independent of the polled SCADA time basis making archiving assumption realistic. In this paper we discuss a programmable rate compression encoder which is driver of larger SCADA system. The SCADA framework has offline parameters which are available to the driver interface through pre-processing and source coding. Once the numbers of client requests are monitored the driver negotiates with the channel’s bandwidth requirements and network cost factors to come up with an optimized logging encoder(OLE) bi-directional code which works well for the subscription time window(active trend time) & browsing of tags in compressed archives by only decompressing the required tagvalues for specified time window.

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