here 'Sammel' refers to the fact that this indicator is illuminated if any fault condition is present; there are probably other indicators for specific faults. It's thus a sort of 'master' fault indicator or overall go/no-go indicator.

examples:
ref 1: the temperature of the regeneration air. In addition, all alarm functions are shown
on a potential-free collective fault indicator.
ref 2: Output demand, system operation, collective fault
indicator, output to peripheral humidifier Steam output On/off or modulating ...

also for 'master fault' (but note that 'master fault' is apparently also used in several other senses and contexts):
A master fault indicator also lights to
alert the user to the problem. (www.apogee-sound.com/products/amplifiers/MA_Series/)

the top right of the screen reading "Master Fault". Which analyser has the active
fault is ... ON (www.aeat.co.uk/netcen/airqual/reports/lsoman/ambign1.html)