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The accumulation interval function creates cumulative series for several intervals. For the first output timeStep time step in each interval the output value equals the input value for that timeSteptime step. For the other timeSteps time steps for a given timeStep time step the output value is equal to the sum of the input value for that timeStep time step and the previous output value. The intervals are defined by the selected time span or time step. If a time span is selected, then the function uses the time span as the size for the intervals and the first interval starts at the start of the period that is visible in the time series display. If a time step is selected, then the function uses the time step to create intervals and each period between two consecutive time steps is an interval.
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