spec

Software for Diffraction

3.9.2. - Motor Scans



ascan motor start finish  intervals time
a2scan m1 s1 f1  m2 s2 f2  intervals time
a3scan m1 s1 f1  m2 s2 f2  m3 s3 f3  intervals time
mesh m1 s1 f1  intervals1  m2 s2 f2  intervals2 time

lup motor start finish intervals time
dscan motor start finish intervals time
d2scan m1 s1 f1  m2 s2 f2  intervals time
d3scan m1 s1 f1  m2 s2 f2  m3 s3 f3  intervals time
th2th tth_start_rel tth_finish_rel intervals time


The argument motor (and m1, m2 and m3) is a motor number or mnemonic, such as th, tth, chi, or phi. ascan, a2scan and a3scan are single-, two- and three-motor absolute-position scans. mesh is a nested two-motor scan, where the first motor scans through its range at each point of the second motor's scan. lup (or equivalently dscan), d2scan and d3scan are single- and two- and three-motor relative position scans. The starting and finishing positions are given relative to the current position, and the motors are returned to their starting position at the end of the scan. These relative position scans are defined in terms of the absolute-position scans.

The th2th macro is a special case of the d2scan that will scan the tth and th motors, with th moving half the range of tth. Its definition is,
def th2th '
      if ($# != 4) {
          print "Usage:  th2th tth_start_rel tth_finish_rel intervals time"
          exit
      } 
      d2scan tth $1 $2 th ($1)/2 ($2)/2 $3 $4
'