### Control Limits

Machine Dependent Control Limits

Control limits are now machine dependent. In the legacy version of DataPage this wasn't the case, and you could only have one set of control limits for a variable. For example, Feat0.X would have looked like this:

LCL: -0.004
UCL: +0.004

Suppose now, however, that you have the latest version Datapage+ and 10 CNC machines involved in your manufacturing. Since the control limits are now machine dependent, with a set of control limits per machine, your control limits might look something like this:

SET0 for CNC0: -0.0035, 0.0004
SET1 for CNC1: -0.0035, 0.0004
SET2 for CNC2: -0.0038, 0.0041
...
SET9 for CNC9: -0.004, 0.0039

For compatibility with legacy DataPage and early versions of Datapage+, a final set is defined for those cases where control limits are not assigned to a machine (CNC=null).

SET10 for CNC=null: -0.004, 0.0004

Priority of Macine Dependent and Non-Machine Dependent Control Limits

While a null value CNC control limit set is still valid, it does have a lower priority than other machine-specific sets. Datapage+ will always attempt to first use any machine-specific control limits.

For example, if you had CNC6 and you wanted to find the control limits for Feat0.X, it would first search for a set of control limits associated with that machine (SET6). But if it couldn't find an associated set of control limits, it would look a set of control limits associated with a null value CNC and use those instead (SET10). If it still couldn't find any control limits, Datapage+ would then calculate the control limits values on its own.

Control Limit Calculations

For an explanation of control limit calculations for the following charts, see the topics below:

- Control Limit Calculations for Run Charts

- Control Limits for Individual Charts

- Control Limits for XBAR & R Chart

- Control Limits for XBAR & S Charts

- Control Limits for X Tilde & R Charts