Tags, use case 1: detectors

Consider an experiment where Tango is used only to control a Pilatus or a Mythen detector. Both of the detectors are not mounted all the time. In this case online.xml looks like this:

<?xml version="1.0"?>
<hw>
  <device>
    <name>pilatus</name> 
    <tags>pilatus</tags> 
    <type>DETECTOR</type> 
    <module>PILATUS100K</module>
    <device>h1/pilatus/300k</device> 
    <control>tango</control> 
    <hostname>hash1:10000</hostname>
  </device>

  <device>
    <name>mythenII</name>
    <tags>mythenII</tags> 
    <type>type_tango</type>
    <module>module_tango</module>
    <device>h1/exp/mythenii</device>
    <control>tango</control>
    <hostname>hash1:10000</hostname>
  </device>
</hw>

Depending on the available hardware Online will be started by one of the commands:

online -tki -tags pilatus
online -tki -tags mythenII
online -tki -tags None
online -tki

If '-tags None' is supplied, none of the detectors will be defined for the Online session because there is no matching <tags> field.

If the '-tags' parameter is omitted, both detectors are defined.