If a slit is read with the keyword all, ONLINE returns a string which contains cx, cy, dx, dy.
The limits of the slit jaws may also be read, e.g. the call
* = slit( Name, cx_uli)
return the unit-limit-min of the position of the center.
If slit_name is s1, ONLINE expects these symbols pointing to motors: s1_top, s1_bottom, s1_right, s1_left. And be sure to have slit_names defined, e.g.: slit_names = (s1).
e.g.:
* = slit(s1, cx)
slit(s1, cx) = 5
The coordinate system: z points in the direction of the photons, y points upwards, x completes the right-handed coordinate system. 'right' points in the x-direction, like in school.
Note that slit parameters can also be scanned: scan/slit
(section 8.1.9).