BECKHOFF EL6900-FB - Manual (Page 58)

Function blocks
56 Function blocks for TwinSAFE logic terminals
Via the ‘MutingActive’ button a signal can be linked that can be used for a muting lamp, for example.
The ‘MapState’ and ‘MapDiag’ checkboxes are used to specify which FB diagnostic functions are mapped
to the cyclic process image.