18. GDA Demo¶
18.1. Basic commands¶
To get help:
help
scannable = software abstraction of angles, slits, energy, temperature probe, detector…
pos – show current positions of all scannables
e.g. pos x, pos y, pos z
shows extended syntax – no brackets
Move: pos x 10
ls – look at objects of certain types
e.g. ls Motor
Easy to write dummy scannables, e.g. x/y/z, for testing
18.2. Other scannables¶
t
shows time since initialisation
dt
shows time since last data point captured
w
waits for specified time. e.g. to wait 2 seconds:
>>> pos w 2
all single-value position so far
multi-input – can move to multi-value position – e.g. pos mi [2, 3]
multi-extra – read-only output values – e.g. pos me
can combine – mie – one input, two (read-only) outputs – pos mie 4
18.4. Beam focusing¶
fwhm = full width half maximum
minimise fwhmarea = area of spot on detector in pixels
Scan to show the images being plotted:
>>> scan f 430 600 20 pil 20
To display the images: images plotted on “Data Vector” panel
to focus on region of interest:
peak2d.setRoi(50, 50, 150, 150)
18.4.1. wide scan¶
>>> scan f 430 600 20 pil 20 peak2d
(finds 490 as the minimum)
data plotted as it’s collected
18.4.3. get feature details¶
>>> minval