h(t) Channels:

The online h(t) reconstruction produces frames which contains at least the following channels:

• V1:h_20000Hz This is a FrProcData channel which contains the h(t) values sampled at 20000Hz and stored as a 4 bytes floating point.
  
• V1:h_16384Hz This is a FrProcData channel which contains the h(t) values sampled at 16384Hz and stored as a 4 bytes floating point.
• V1:h_4096Hz This is a FrProcData channel which contains the h(t) values sampled at 4096Hz and stored as a 4 bytes floating point.
• V1:Hrec_Veto_dataQuality. This is an FrAdcData channel which contains basic data quality  information sampled at 1 Hz and stored as a 4 bytes floating point. The meaning of this quality flag is:
• 0: ITF not locked or bad data.
• 4: ITF locked but h(t) reconstruction bad
  
• 8: ITF locked and h(t) reconstruction OK.
• 12: ITF locked, h(t) reconstruction OK, science mode OK and a few CAT2 veto OK like no saturation of the main channels (Pr_B1_ACq, Coil saturation and SSFS) + ITF locked since 300seconds and ITF locked for the next 10 seconds.
  

h(t) Frames and files

The h(t) information is put in the raw data frames (/virgoData/ffl/raw.ffl) and in a special stream named : /virgoData/ffl/HrecOnline.ffl.

• 4000 seconds long files. These are the reference files for the data transfer for the computing centers.
• 16 seconds long files stored in /data/procdata/bufferv11/HrecOnlineShortFiles/. They are keept only for 4 hours and are not archived to the computing center.