Salvatore,
In the SPC Algorithm definition you had referred, we could see the following sentence just below the CPK definition where it explains about one -sided tolerance.
"A process is capble only when the Cpk value is 1.33 or greater. For a one-sided tolerance, the Cpk is equivalent to either Cpu or Cpl depending on which tolerance limit is specified.".
Here the Specification limit is ignored indirectly by choosing either CPU or CPL depending of the side.
In this case, if i have only USL spec. limit no LSL, then i will choose CPU instead of CPK .
But for Alarms i could not see such option , the action block considers the missing spec as 0 and gives false list of violations.
This is were we need help.
-Karthik