This is the instrument performance plot for the GIRAFFE fibre system. 
There are five different fibre systems: Medusa1/2, IFU1/2, and Argus.
For each of them, we display the QC1 parameter num_fib
(PRO.SLIT.NFIBRES), in order to monitor the number of
available fibres. A sudden deviation from the nominal behaviour might indicate
issues with broken fibres or  fibre
illumination problems. A certain minor deviation from a previous number might
also be due to a slightly moving spectral format. The pipeline extracts only
fibre signals not truncated by the CCD edge. </font><p><font size="2">

The plots are arranged per fibre system. They are fed from the regular 
Health Check
calibrations, taken as L543.1 setting every 3rd day in the Medusa slits,
and once a week in the IFU and Argus slits.</font><p><font size="2">

The reference values indicated here are the maximum values observed in the
history of the instrument.