Can the humidity setpoint be adjusted?

The setpoint is adjustable within the range of the grade you ordered. The grade defines the window the cabinet is built and calibrated for — a grade C cabinet is specified to hold 1–10% RH, so it will not hold 30% RH as a matter of course. If your process needs different windows at different times, tell us before ordering: in several cases a single grade covers the requirement once we understand the full cycle.