Playback

This component reads the contents of log file(s) and publishes it on DDS. The log file(s) must have the same structure as that created by RatatoskLogger. A typical use case for this component is to provide realistic DDS signals as a mock-up of a real vessel, for the purpose of development and testing. This can be valuable when developing software for interfacing ship systems or as a prerequisite for a virtual testbed for such software.

• Options:
  • Speed: The ratio between playback speed and the original recording speed of the log file.
• LogSpecification:
  • Dir: The directory where the log files are found.
  • LogPrefix: The prefix of the log file names, assuming the name to be <prefix><timestamp>.nc
• PlaybackSignals: A yaml list of output signals and how they are created from the log file data. Each element are of the following format:
  • Topic: The topic to output on.
  • Type: The DDS type to output.
  • Mapping: Where the data is found in the log file. This can be of two different formats:
    1. The name of the variable.
    2. A yaml list with the following structure, mapping the fields of the output type to the variables in the log file:
       • Field: The topic field name.
       • Var: The variable name in the log file

An example input file is shown below, as well as here.

Options:
  Speed: 2.49
 
LogSpecification:
  Dir: logs
  LogPrefix: Logs_
 
 
PlaybackSignals:
  - Topic: In1
    Type: DoubleVal
    Mapping: Nav_Depth.depthBelowTransducer
  - Topic: In2
    Type: Float3
    Mapping:
      - {Field: x, Var: Hull_Euler_rad.x}
      - {Field: y, Var: Hull_Euler_rad.y}
      - {Field: z, Var: Hull_Euler_rad.z}
  - Topic: In3
    Type: DoubleVal
    Mapping: Hull_Euler_rad.y