Usually the easiest way for simple cases is to first create the graph with JMP's interactive tools:
![jthi_0-1648731395500.png jthi_0-1648731395500.png](https://community.jmp.com/t5/image/serverpage/image-id/41349i666A807C8371C236/image-size/medium?v=v2&px=400)
See if you can find the setting and make modifications and get the script from red triangle menu:
Control Chart Builder(
K Sigma(2.5),
Variables(Subgroup(:Sample), Y(:Weight)),
Chart(Position(1), Limits(Show Lower Limit(0))),
Chart(Position(2), Limits(Show Lower Limit(0)))
)
and see if the option appears in the script provided by JMP.
-Jarmo