OPC Relative Time is used to represent date and time in an easy to read format that allows users to navigate or select a period of time without explicitly specifying a date. An example use is NOW-5M which simply translates to the current time minus 5 minutes. All times are relative to the user profile timezone.
OPC Relative Time syntax:
<basetime> [ ( + ¦ - ) <interval> ]
Base Time: | A time that is relative to ‘now’, the present time. You can enter a base time in either short or long format. |
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Interval: | An optional further offset that you can either add or subtract from the base time. You specify this offset in the OPC Time Format. |
Example usage:
H (start of the current hour)
D+9H (9am current day)
NOW-7D+6H (6 days and 18hours ago)
Keyword Long (short) | Base Time | Interval |
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NOW | The current time | N/A |
FIRST | Earliest data value time | N/A |
LAST | Most recent data value time | N/A |
SECOND (S) | The start of the current second | Offset from time in seconds |
MINUTE (M) | The start of the current minute | Offset from time in minutes |
HOUR (H) | The start of the current hour | Offset from time in hours |
DAY (D) | The start of the current day | Offset from time in days |
WEEK (W) | The start of the current week | Offset from time in weeks |
MONTH (MO) | The start of the current month | Offset from time in months |
YEAR (Y) | The start of the current year | Offset from time in years |
Note
You can specify both the <basetime> and <interval> in either short or long format.