Specifying Time Intervals Before or After an Event

[Lindsey.Wilcox]

You can use the start and end times of capsules to create new capsules with an arbitrary time before or after.  This is useful when the process expert knows that there is a time period of interest before or after a capsule start or end timestamp.  Refer to the example below.

Here we have a series for the Area A Compressor Power shown in blue.  We have created capsules shown in green for when the compressor is running in the high state, above 30kW.

In this example, we want to create a capsule series that starts when the compressor exits the high stage (goes below 30kW) and then ends at exactly 2 hours later (or any other arbitrary time specified by the user).  All we need to use is the following Seeq Formula:

This formula creates a new set of capsules that start at the end of the “Compressor Power > 30” capsules and end exactly 2 hours later.

The functions afterStart(), beforeStart() and beforeEnd() can be used similarly.  For example, to create a set of capsules that capture the two hours prior to our “compressor high” condition, we can simply modify the formula above by changing “afterEnd” to “beforeStart.”