PsiTSLen is a property supported by the time series functions enforcing the length of the process result; length must be an integer greater than 0.  Note:  This property only applies to the Analytic Solver Cloud App and is not supported in the Analytic Solver COM addin. 


PsiAR1(1,1,0,1,PsiTSTransform(2,2), PsiTSLen(10)) applies type = square and shift = 2 to each item in the series.  The series is of length 10 cells.