A Data Source typically represents a physical data interface onboard a vessel. Each data source contains sensors that provides data. The connection between the data sources and the edge computer is managed by Connectors provided by either Kongsberg Digital or 3. parties.
A simplified topology of the communication is shown in diagram below. In real-world installations, the intercommunication between data sources and the edge computer is involving multiple layers of security barriers, imposed by different cybersecurity solutions and other network communication barriers.
Sensors
Each of the sensors can represent some physical property onboard, such as sensor measurements, machinery settings or parameters. The instrumentation setup varies between vessels, so there are multiple possible configurations of sensors to represent a system or process onboard. A typical scenario is propulsion systems and fuel supply, where the location of sensors, return flows, power outtake/intake and piping may vary. Information such as the system topology, where the sensors are located, what it measures and related sensors is typically described in either IO lists and dashboard mimics delivered together with the automation system. The naming of sensors between ships varies, due to different system vendors, deliveries and yards.
In Vessel Insight, these sensors are contextualized as described in the asset model section.
Connectors
The connectors are interfacing to sources using communication protocols suited to the vessel’s infrastructure. Each protocol and source can influence the behavior of the data, which may include:
- Regular or Irregular Intervals: Data points may be captured at consistent or varying time intervals.
- Value Changes or Fixed Frequency: Data points can be recorded when there is a change in value from the source or at a set frequency.
Examples of such interfaces include:
- Modbus Interface: Used with machinery equipment.
- NMEA Interface: Used with navigational equipment.
- MQTT Interface: Used with historians and third-party gateways.
- OPC UA Interface: Used with third-party data gateways.
Data Collection
Any data captured from the source system is treated as an update and is sent to the cloud, regardless of whether the value has changed or not. The value is sent as-is and no averaging or other decimation is performed. In some situations, the connector software might adjust the output based on offset corrections or minor arithmetic operations.
Details on time management
Vessel Insight expects all timestamps collected from source systems to be in UTC and is storing all timestamps in UTC. If timestamps are out of sync from a source system, please see this guide.
Timestamps
Timestamps from data sources are applied in a few different ways depending on protocol and configurations:
Data Source | Timestamp Source |
|---|
MQTT/OPC | Controlled by source, part of the payload. |
NMEA 0183/450 | Either uses timestamp column from telegram (configurable per sensor), otherwise timestamp will be applied at received time on the edge computer (UTC). |
Modbus TCP | Timestamp will be applied at received time on the edge computer (UTC). |
Metadata
Source systems can provide lists of available sensors they offer data for, and this list can include specific metadata like units. These specified metadata fields are added to timeseries storage when sensors are replicated.
