Missing

Standards

MISSING STANDARDS

Within the SLAM-DAST project, an analysis of
current standard and related specifications has been carried out, in order to
provide a comprehensive review as well as to identify the most important
technical features lacking in current standardization documents. While existing
and upcoming standards cover the performance of the equipment, general
nomenclature and some details on the survival of sensing cables in harsh
environment, on the other side the interoperability between equipment from
different vendors is neglected. Also, it is necessary to standardize file formats,
control protocol and hardware. Moreover, standards focusing on sensing cables
are required as it is critical for design of strain sensing & sounds
applications. SLaM-DAST combines Brillouin analysis
and phase-Sensitive reflectometry
to create a “sensor” made of light pulses that travels along a fibre and reads
it individually at any point. Tables 3 and 4 (below) gives a short overview of
the aspects and parameters which can conveniently be included in the upcoming
standards for Brillouin distributed sensing and phase-sensitive reflectometry.

Table 3 and 4. identified Key parameters of Brillouin and phase-sensitive
reflectometry distributed sensing equipment and measurements that are not
covered by existing standards or standards in development

Table 3 – BRILLOUIN

Topic	Key parameter	Note
File format for Brillouin RAW DATA	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time – Data format header explaining how the data table is organized and what data units are used – *Data table* containing the raw acquired data (intensity vs. frequency shift and time)	File header should contain all information influencing the absolute value of the data listed: – info influencing numerical values – Pump wavelength (see text) Pump and probe power and linewidth Type of peak detection algorithm used and its parameters – info identifying the equipment – Equipment maker and serial no. Hardware and software revisions – info identifying the acquisition – Time/date of acq. Start and end Mux channel (if mux present) Measured fiber attenuation (if avail.) – info on the data format and units – Intensity scale (log/linear) Intensity units (arbitrary/dBm/…) Sampling interval Frequency interval Start/stop frequency File compression should be taken into account only when the file exceeds 1MB size and a freeware tool for embedding file decompression should be provided.
File format for Brillouin PEAK FREQUENCY META-DATA	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time – Data format header explaining how the data table is organized and what data units are used – *Data table* containing columns for distance,, peak 1 peak frequency, (peak 1 FWHM), (peak 1 symmetry), (peak 2 peak frequency), (peak 2 FWHM), (peak 2 symmetry)…
File format for strain/ temperature processed data	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time, Brillouin temperature and strain coefficients, reference baseline file – Data format header explaining how the data table is organized and what data units are used – *Data table* containing columns for distance, strain/temperature
File formats for equipment measurement configuration	Xml file containing all the information for configuring the equipment	Pump pulse width (real for time domain analysers or equivalent for frequency-domain ones) Frequency-shift range and step Receiver filter bandwidth Sampling rate Receiver gain Pump and probe power Mux channel Averaging Type of algorithm for peak detect Connectivity configuration (DHCP, IP, ports, etc.)
File format for script	File containing a sequence of commands to be executed
Remote control protocol for interrogator equipment	Standard commands for: – upload/download equipment config. – start acquisition – schedule acquisition – setup equipment clock – equipment self-diagnostics – download raw data – download meta-data – download strain/temperature data – hardware reset – cancel ongoing operation – standby/resume – shutdown – download calibration data – download/upload/execute script – read file from internal equipment disk – list file from internal equipment disk – delete file from internal equipment disk – transfer file from/to internal equipment disk
Data sheets for sensing cables:
Strain cable	Shear lag for steel, concrete, plywood
Strain cable Temperature cable	-Max elongation (@ 3db optical attenuation) -Typical failure elongation -Max/typ. Creep @ 1000 and 3000ustrain and 0, 25, 50°C -Strain coefficient(s) and validity interval(s) -Temperature coefficient(s) and validity interval(s) -Bare fiber temperature coefficient (thermo-optical coefficient) -Brillouin shift @25°C and no applied strain -Max and typ. Dispersion of Brillouin shift @25°c and no applied strain -Suggested glue -Stripping procedure incl. Suggested stripping length and force -Temperature lag
Temperature cable	Stripping procedure including suggested stripping length and force

Table 4 – PHASE-SENSITIVE REFLECTOMETRY (PSR)

Topic	Key parameter	Note
File format for PSR RAW DATA	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time – Data format header explaining how the data table is organized and what data units are used – *Data table* containing the raw acquired data (intensity vs. frequency shift and time)	File header should contain all information influencing the absolute value of the data listed: – info influencing numerical values – Pump wavelength (see text) Pump and probe power and linewidth Type of peak detection algorithm used and its parameters – info identifying the equipment – Equipment maker and serial no. Hardware and software revisions – info identifying the acquisition – Time/date of acq. Start and end Mux channel (if mux present) Measured fiber attenuation (if avail.) – info on the data format and units – Intensity scale (log/linear) Intensity units (arbitrary/dBm/…) Sampling interval Frequency interval Start/stop frequency File compression should be taken into account only when the file exceeds 1MB size and a freeware tool for embedding file decompression should be provided.
File format for PSR PEAK FREQUENCY META-DATA	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time – Data format header explaining how the data table is organized and what data units are used – *Data table* containing columns for distance,, peak 1 peak frequency, (peak 1 FWHM), (peak 1 symmetry), (peak 2 peak frequency), (peak 2 FWHM), (peak 2 symmetry)…
File format for strain/ temperature/sounds processed data	File structure: – *File header* listing the data acquisition parameters, equipment identification and acquisition time, Brillouin temperature and strain coefficients, reference baseline file – Data format header explaining how the data table is organized and what data units are used – *Data table* containing columns for distance, strain/temperature
File formats for equipment measurement configuration	Xml file containing all the information for configuring the equipment	Pump pulse width (real for time domain analysers or equivalent for frequency-domain ones) Frequency-shift range and step Receiver filter bandwidth Sampling rate Receiver gain Pump and probe power Mux channel Averaging Type of algorithm for peak detect Connectivity configuration (DHCP, IP, ports, etc.)
File format for script	File containing a sequence of commands to be executed
Remote control protocol for interrogator equipment	Standard commands for: – upload/download equipment config. – start acquisition – schedule acquisition – setup equipment clock – equipment self-diagnostics – download raw data – download meta-data – download strain/temperature data – hardware reset – cancel ongoing operation – standby/resume – shutdown – download calibration data – download/upload/execute script – read file from internal equipment disk – list file from internal equipment disk – delete file from internal equipment disk – transfer file from/to internal equipment disk
Data sheets for sensing cables:
Strain cable	Shear lag for steel, concrete, plywood
· Strain cable · Temperature cable · Sound cable	-Max elongation (@ 3db optical attenuation) -Typical failure elongation -Max/typ. Creep @ 1000 and 3000ustrain and 0, 25, 50°C -Strain coefficient(s) and validity interval(s) -Temperature coefficient(s) and validity interval(s) -Bare fiber temperature coefficient (thermo-optical coefficient) -Brillouin shift @25°C and no applied strain -Max and typ. Dispersion of Brillouin shift @25°c and no applied strain -Suggested glue -Stripping procedure incl. Suggested stripping length and force -Temperature lag
· Temperature cable	Stripping procedure including suggested stripping length and force

The project leading to this application has received funding from the European Union’s Horizon 2020 EIC-FTI 2018-2020 programme under SLAM-DAST grant agreement No 971149.

National Research Council, Territorial Research Area of Bologna – Via Piero Gobetti, 101, 40129 Bologna BO, Italy