The variables ~usl~, ~lsl~, ~usl2~ and ~lsl2~ will return the spec limit value which is in the database or which has been calculated. Limits are absolute or relative. Spec limits are absolute limits. Tolerances are considered a relative limit.
There is only an upper spec limit. There is no lower spec limit. Unilateral tolerances do not allow conflicts. You can not have both a unilateral hi and a unilateral lo. If both exist, only the value for the unilateral hi will be used. If you want to change from tol to spec limits, you would create a new process baseline.
Spec Limits are inputs based on the design specifications.
Design: 20.30 + 0.15
Upper Spec = 20.45
Lower Spec = none
There is only a lower spec limit. There is no upper spec limit. Unilateral tolerances do not allow conflicts. You can not have both a unilateral hi and a unilateral lo. If both exist, only the value for the unilateral hi will be used. If you want to change from tol to spec limits, you would create a new process baseline.
Spec Limits are inputs based on the design specifications
Design: 20.30 - 0.15
Upper Spec = none
Lower Spec = 20.15
For backward compatibility, Implied Unilateral Spec Limits can be used.