Fields for which you are required to specify a time period have an adjacent browse button. You can use the browse button to display an Interval Window that you can use to specify the required time period.
To manually enter a time period in the OPC Time Format, you enter the time value as a numeral, followed by the time unit as either a single letter (short format) or as a word or partial word (long format).
So, to enter a time period that represents ten minutes, you specify either 10M (short OPC Time Format) or 10 Minutes (long OPC Time Format). You can also enter a combination of units to represent a time—for example, 2H 30M (short OPC Time Format) or 2 hours 30 minutes (long OPC Time Format). The format is case insensitive and spaces are optional.
On configuration Forms, the format in which a time period is displayed depends on whether the field is a string or numeric field. With numeric fields, ClearSCADA displays time periods in short OPC Time Format, regardless of whether the entry was specified using short or long OPC Time Format. With string fields, ClearSCADA displays time periods exactly as they are specified, including any character spaces.
The time units that ClearSCADA supports are:
| Unit | Example (short format followed by long format) |
|
|---|---|---|
| Short Format | Long Format | |
|
S |
Seconds |
5S 5 Seconds To enter a time in milliseconds, use a fraction, for example: 1.500S 1.500 Seconds |
|
M |
Minutes |
10M 10 Minutes |
|
H |
Hours |
1H 1 Hour |
|
D |
Days |
2D 2 Days |
|
W |
Weeks |
3W 3 Weeks |
|
MO |
Month |
2MO 2 Months |
|
Y |
Year |
3Y 3 Years |
Example:
An engineer wants the x-axis of a digital point’s Trend to display time over a 30-minute interval. The engineer enters 30M in the Interval field, within the Trend section of the Digital Point Form. 30M is the short OPC Time Format for a 30-minute interval.
You can prefix a time value with + or -. Where a prefix is omitted, this equates to +.
You can specify an individual time value or combine several values to produce the time period that you require.
Example:
2H+30M is the same as 2H 30M.
2H-30M is equivalent to 1H 30M.
In some instances, there is a limit to the minimum time that you can enter. For example, whole minutes rather than seconds. You will be prompted if you try to enter an unacceptable time for a particular item.
Be aware that Years and Months are only supported in a few select places, each of which are not fixed periods—for example a Trend’s x-axis interval. Where Years and Months are used, they are combined with an Offset. For instance, with an Offset of ‘Y’ (the beginning of this year), you can specify an Interval of ‘1Y’ (to give ‘this year’).