What does it actually mean for a process to be "in control"?

Being in control is not the same as being good. A process can be entirely in control and still fail to meet what the customer asked for; the reverse also happens. They are two separate questions: control is consistency against the process’s OWN history, while capability is sufficiency against the tolerance. Teams that conflate them look at a control chart and say "no problem", when the chart only says "today is no different from yesterday". SenSight QMS builds these charts from the inspection measurements you already record, not from a separate data entry — so nothing is typed twice.