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New concentration parameter...

Sep 23, 2010 at 12:18 PM
Edited Sep 23, 2010 at 12:20 PM

FYI, in the latest release a new parameter has been added to simplify concentration, the parameter is called "performTimestampReasonabilityCheck". This parameter defines a flag that determines if timestamp reasonability checks should be performed on incoming measurements (i.e., measurement timestamps are compared to system clock for reasonability using leadTime tolerance). Setting this value to false will make the concentrator use the latest value received as "real-time" without validation; this is not recommended in production since time reported by source devices may be grossly incorrect. For non-production configurations, setting this value to false will allow concentration of historical data.

Basically this turns off the processing that trys to determine if a timestamp is reasonable. When you turn off the feature the "LeadTime" will have no meaning and you will need to turn off "UseLocalClockAsRealtime". Just so you know, this is the normal mode of operation for most concentrators - they just assume that the most recently received timestamp from a remote device is real-time.

The timestamp reasonability chcek is there for a good reason, some remote field device tend to lie about the current time - you don't want your production system thinking the current time is 20 years in the future because one device is sending a bad timestamp. This would make all other data look 20 years old!

Even so, the concept of "LeadTime" is complex (see ActionAdapterBase Documentation) especially for new users and it is often misconfigured, so for simple setups and testing environments, you may want to set this flag to false to simplfy your configuration.

I haven't added this as a database field and/or on screen check box yet, so to use this parameter you need to manually enter "performTimestampReasonabilityCheck = false" into the "Connection String" field for your Output Stream or Calculated Measurement.