Ferdi Franceschini 2008-12-15 Raising and lowering of beamstops is implemented via the selbs  command. selbs raises the selected beamstop in a safe manner. It will leave the previously selected beamstop in place until the selected stop is fully raised and then lower the other beamstop. If you are changing the x z coordinates there is no safe sequence. You should set maximum attenuation or close the fast shutter before moving the beamstops. You can monitor the beamstop position via GumTree as it is being raised, and you can also see the state by reading angles. The odd and even numbered beamstops are on separate parallel axes which are horizontally offset by about 10cm. This means that beamstops must be raised to an angle which is a few degrees of vertical so that the odd and even beamstops will overlap, you will see that the odd numbered stops will be at roughly 93 degrees and the even numbered ones will be at 86 degrees to vertical when raised. selbs n x z Allowed n 1,2,3,4,5,6 where 1 = largest beamstop 6 = smallest beamstop x = beam x position in detector coordinates z = beam z position in detector coordinates The beam position (x,z) is optional This is a blocking command. You will not be able to run other commands in the session running selbs until it has finished. selbs 1 487.7 490 Select beamstop one and position it over the middle of the detector. selbs 2 Leave the beamstop carriage in place and select beamstop two. beamstop selbs also sets a variable called beamstop and saves it in the data file. Possible values for beamstop 0 selbs has never been run or the sics status.tcl file has been cleared -1 selbs failed while driving the beamstops n selbs completed driving successfully and has selected beamstop n The value of the "beamstop" variable persists between restarts of SICS. If someone drives the beamstops directly then the beamstop variable may be wrong Beamstop position can be checked visually (by eyes) from the vessel port with touch.  To do this,  you should drive the detector to position 9300mm, and view from the middle vessel port.