eDrive is capable of recording and presenting historic values of any Point Objects having the Point Value History option enabled. The historic values can then be obtained via simple web service requests from a consumer.
See the section on eDrive Web Services for more detail on how to request historic values.
To enable Point Value History, set the following options for the subject Point Object:
History Recording Type
[Optional] eDrive is capable of recording and storing historic values of any points. Recording types of None, Simple, TimeScale and Geometric are available. Values are stored on a 'First In - First Out' basis and the total number of entries will vary based on the recording type selected.
None: No history values will be recorded
Simple: Point values are entered at the Recording Interval and purged on a first-in/first-out basis to retain only the Maximum Entries number of records.
Timescale: Point values are entered at the Recording Interval specified, but records are purged from the history log based on their age. Newest records are kept at the Recording Interval, then as they age, the interval increases.
Seconds: records kept a one second intervals for maximum of 600 seconds.
Minutes: records kept at one minute intervals for maximum of 720 minutes.
Hours: records kept at one hour intervals for maximum of 768 hours.
Days: records kept at one day intervals for maximum of 744 days.
Months: records kept at one month intervals for maximum of 1200 months.
Recording Interval
Specify the time in seconds between entries in the history records.
Maximum Entries
Specify the maximum number of entries to be stored. When the maximum number of entries has been reached, the oldest records will be deleted as new records are added.
View History
Opens an additional web page that allows review and export of the historic values for this Point object.
