Tango: Alternative online.xml

The file /online_dir/online.xml contains the Tango devices that are used by an online session. It is possible to use an alternative version of the file, e.g.:

online -tki -c online_galil.xml

Depending on the selections which are made by the alternative .xml file, it may be necessary to do some changes to /online_dir/exp_ini.exp and to /online_dir/TkIrc.pl. The following lines could be part of exp_ini.exp. They modify its behaviour depending on which .xml file is loaded:

beamline = haspp23
!
! (1)
!
if compare( "online_galil.xml", trnlnm( online_xml))
  beamline = dummy_line
endif

!
! (2)
!
if compare( "online.xml", trnlnm( online_xml))
  def vm1
  def vm2
  def vm3
endif

Here are the explanations:

 (1) If the symbol beamline is set to dummy_line, online does not try to identify the monochromator device.

 (2) In this example the virtual motors are defined for the 'normal' session only. Most likely because the virtual motors use real motors that are not listed in online_galil.xml.

Here is the begin of a TkIrc.pl file which is modified to take alternative .xml files into account:

if( $ENV{'ONLINE_XML'} eq "online.xml")
{
    $Spc::res_h{ blsc} = "usr, lom500, pilatus, microscope, abs, det, bst, slit, pumpGL";
}

In short: beamline-specific code is enabled only, if online.xml was loaded. The reason is that the BLSC widgets may depend on devices which are not contained in the aternative .xml file.