19.3 Defining the DAS Instrument Box

The DAS Instrument Box object is shown in Figure 19.3-1 . This represents the hardware equipment located at the site that is responsible for generating DAS measurements. The DAS instrument box is usually located next to the facility element for which DAS surveys are taken (a well or a pipeline, for example). It consists of, among other devices:

• An optoelectronic instrument to which the optical fiber is attached. This instrument contains:

• a controllable light source
• optical switches

• photonic detection devices

• In some cases, a computer or server is connected to the instrument that is responsible for capturing the measurements and initiating the data transmission.

Hardware setup can vary widely from one deployment to the next and also depends on the vendor and the make/model of the hardware used. The data schema was created to capture the relevant parameters of the installation without worrying about how the hardware is physically laid out. Attributes available for the instrumentation cover areas such as:

• Make/model of the instrument
• Number of channels
• Software version
• Factory calibration information

• Calibration parameters

Figure 19.3-1 DAS Instrument Box model. Note that the Instrument element contains further generic details about the hardware.