Added in version 1.78

CreateEffectClipped works identical to CreateEffect, with an added Duration parameter.

Duration is the maximum number of frames to play the effect before ending it. Specifically useful for effects 12, 15 and 16, which will loop endlessly for the specified duration. All other effects can be cut short, but will not loop past their normal end.

For a list of effects, see CreateEffect.

# Play the Terp beam tip effect for 2 seconds.
CreateEffectClipped(15 CellToPixel(CurrentCoords) -1 1.5 1.5 0.05 60)

Look here for effect previews.