# White Beam Attenuator Object¶

The WhiteBeamAttenuator class handles the ESRF White Beam Attenuator. The ESRF White Beam Attenuators are Icepap driven coper poles with sevaral holes/filters. Each attenuator pole has positive/negative limit switch and a home switch active for each filter. The configuration procedure tries to find the home switchwes and set the position of each filetr at the middle of the home switch position.

The configuration is defined in .yml file, but can also be changed/removed interactively. All the changes are saved in the corresponding .yml file.

A hook to the Frontend object is optional: if given no movement of the attenuator will be possible when the frontend (a TangoShutter) is not on a state considered safe.

## YAML configuration example¶

class:
plugin: bliss
name: wba
attenuators:
- attenuator: $wba_Al - attenuator:$wba_Mo
- attenuator: $wba_Cu frontend:$frontend


attenuator

Each attenuator is confugured as MultiplePosition object.