Guidelines - September 2023
Conventions for contextualization and mapping with Vista
Introduction
These guidelines provide a list of conventions for the generation of the LocalID with ISO19848 Annex C for data channel contextualization.
This document uses the term "channel" interchangeably to indicate: a physical sensor recording and sharing data (for example, a thermometer in the crew living room sending data via a wifi connection); a digital data channel transmitting data from an emitting unit to a receiving unit (i.e., a command from the control system to the rudder actuator via a cable); a manual logging of data in sheets, on paper-based or on digital transcripts (i.e., an operator logging readings and findings on notebooks, iPads and similar).
A channel tag is a non-standardized name given to the channel to characterize it uniquely and thus differentiate it from other channels.
Mapping is the process of assigning a channel tag to a LocalID, and a mapping is an instance of such an assignment. A labeler is an individual performing the mapping.
References
These guidelines are based on the following references:
ISO 19848 Annex C 2021
VIS 3-7a: Gmod, Locations, Quantities, Contents, Calculations, States, Commands, Positions, Signal types
Verbal forms
Verbal forms employed in this document:
Shall: Verbal form used to indicate requirements strictly to be followed to conform to this document.
Should: Verbal form used to indicate that among several possibilities, one is recommended as particularly suitable, without mentioning or excluding others.
May: Verbal form used to indicate a course of action permissible within the limits of the document.
Main conventions
Identify the category of the channel
Generally, channels available on a ship can be classified into the following four categories:
Channels transmitting a reading: these are channels that would report the value of a quantity read from a sensor (i.e., 0.54 bar)
Channels monitoring a state: these are channels that would report the state applicable to a component (i.e., "open", "closed")
Channels transmitting a command: these are channels primarily used by on-board control and safety systems sending commands to receiving units such as actuators (i.e., set starboard angle of the rudder)
Channels transmitting an alarm: these are channels which are reserved to warn when an alarm is triggered
Channels transmitting a set value: these are channels which transmit setpoints, threshold values, references, typically from control systems and similar systems
When mapping, the labeler shall determine which of these five categories the channel to be mapped belongs to. If uncertain, the labeler should consult with the tag(s) provider or, alternatively, with system experts.
Use all information available about the channel
Mapping shall reflect all pertinent information about the channel available to the labeler at the time of mapping. Available information shall at least contain the location and properties of the channel. Information about channel properties shall include at least the category of channel and the channel scope, i.e., quantity monitored, item commanded, type of alarm and so on.
Normally, a list of proprietary channel tags will not be sufficient to perform a satisfactory mapping. Access to additional information about the vessel and the channel setup (meta data) usually improves the quality of the mapping. Mapping shall thus reflect all information available, including elements possibly not captured in the channel tags.
Avoid speculation
All information available about a channel shall be used, and only that. Speculation and guesswork to supplement missing information shall be avoided. Whenever possible, additional information should be obtained by the provider of the channel tags.
Avoid duplication
In case of duplicated channel tags, duplicates shall be removed and only one instance per unique tag shall be mapped, unless additional information is available to differentiate duplicate tags. Whenever possible, duplicates shall be clarified with the provider of the channel tags.
Use of PrimaryItem
The PrimaryItem is mandatory and shall be set as the monitored item, i.e., the item on board the vessel:
The measurement is performed upon or the state is applicable for, or
The command is applicable for, or
The alarm is applicable for, or
The set value is applicable for
The monitored item is normally not the controlling / monitoring item.
EXAMPLES
| Channel tag | CARGO TK LEVEL | Description |
|---|---|---|
| Monitored item | 1021.1i/H121 | Cargo tank |
| Monitoring item | 1028.1/I101 | Cargo tanks level monitoring system |
| - Primary item | 1021.1i/H121 | Cargo tank |
Explanation: this sensor monitoring the cargo level in the tank is mapped to the monitored item, i.e., the tank, and not the monitoring item.
| Channel tag | DRAUGHT | Description |
|---|---|---|
| Monitored item | 111 | Ship hull structure |
| Monitoring item | 107.3/I101 | Draught and inclination indicating system |
| - PrimaryItem | 111 | Ship hull structure |
Explanation: the draught and inclination indicating system is the monitoring item, while the ship's hull is the item being monitored for its draught. Therefore, the PrimaryItem is set on the ship's hull.
Use of SecondaryItem
The SecondaryItem shall be used when the PrimaryItem is not sufficient to contextualise the channel. Generally, the SecondaryItem should be used for the item / system on board which is served by the PrimaryItem. The SecondaryItem should only be detailed to the level that is sufficient for creating a unique LocalID, whereas information covered by the PrimaryItem should not be repeated. The SecondaryItem may in some special situations be used for the controlling / monitoring item.
EXAMPLES
| Channel tag | EMERGENCY GENERATOR FUEL OIL PUMP FAILURE | Description |
|---|---|---|
| Monitored item | 621.22i/S110 | Fuel oil pumping unit |
| Served item | 521.1/C101 | Emergency generator engine |
| - Primary item | 621.22i/S110 | Fuel oil pumping unit |
| - Secondary item | 521.1/C101 | Emergency generator engine |
Explanation: the vessel has several fuel oil pumping units and the SecondaryItem is necessary to define which pumping unit of the many available on board is being monitored. This specific example assumes the pump is not integrated in the engine -- hence the present assignment. For cases where the pumping unit is integrated directly on the engine see the section "Use of engine mounted systems"
| Channel tag | PROPULSION ENGINE CYLINDER 7 CYLINDER COVER COOLING WATER OUTLET TEMPERATURE | Description |
|---|---|---|
| Monitored item | 411.1/C101.63/S206 | Propulsion engine > Cooling system |
| Served item | 411.1/C101.311i-7/C467 | Propulsion engine > Cylinder head 7 |
| - Primary item | 411.1/C101.63/S206 | Propulsion engine > Cooling system |
| - Secondary item | 411.1/C101.311i-7/C467 | Propulsion engine > Cylinder head 7 |
Explanation: one part of the engine (the cooling system) is serving another part of the engine (cylinder head 7).
Use the Gmod to its full depth
When mapping, the Gmod shall be used to its full depth, to the extent allowed by the information available.
EXAMPLE
| Channel tag | PROPULSION ENGINE CYLINDER 7 CYLINDER COVER COOLING WATER OUTLET TEMPERATURE | Description |
|---|---|---|
| Monitored item | 411.1/C101.63/S206 | Propulsion engine > Cooling system |
| Served item | 411.1/C101.311i-7/C467 | Propulsion engine > Cylinder head 7 |
| - Primary item | 411.1/C101.63/S206 | Propulsion engine > Cooling system |
| - Secondary item | 411.1/C101.311i-7/C467 | Propulsion engine > Cylinder head 7 |
Explanation: the SecondaryItem utilizes the entire path down to the cylinder head (i.e., node C101.311) instead of ending on a node higher up in the Gmod hierarchy.
Conventions on TagElements
Channels measuring quantities or reporting states
Most channels would typically transmit readings or states from sensors placed on components with the purpose of monitoring.
Mapping of channels measuring quantities:
shall use at least one of the following TagElements: Quantity, Content, Calculation, Position
shall avoid the following TagElements: State, Command, Type
Mapping of channels reporting states:
shall use the following TagElement: State
may use the following TagElements: Quantity, Content, Calculation, Position
shall avoid the following TagElements: Command, Type
EXAMPLES
| Channel tag | MAIN GENERATOR ENGINE 4 CYLINDER 3 LINER TEMPERATURE | Description |
|---|---|---|
| Monitored item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Primary item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Tag element | qty:temperature | quantity temperature |
Explanation: a sensor reading temperature is mapped with a single TagElement pointing to the quantity read by the sensor.
| Channel tag | MAIN GENERATOR ENGINE 4 CYLINDER 3 LINER TEMPERATURE RISING | Description |
|---|---|---|
| Monitored item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Primary item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Tag element | state:raising | state raising |
| - Tag element | qty:temperature | quantity temperature |
Explanation: a sensor reporting temperature state raising is mapped with the mandatory TagElement state, set to raising and the additional optional TagElement quantity set to temperature.
Channels transmitting commands to actuators or other receiving units
Some channels may indicate the issuance of commands to items placed on board. This could be the case of a control system sending a command to an actuator or similar units. In these cases, the PrimaryItem shall be placed on the item being actuated / receiving unit.
Mapping of channels transmitting commands:
shall use the following TagElement: Command
may use the following TagElements: Quantity, Content, Calculation, Position, State
shall avoid the following TagElement: Type
EXAMPLE
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP 2 STOP | Description |
|---|---|---|
| Monitored item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| - Secondary item | 511.11-1/C101 | Main generator engine 1 |
| - Tag element | cmd:stop | stop command |
Explanation: the use of the TagElement command stop specifies that this channel represents a command sent from a system to the pump and avoids alternative interpretations, such as for instance the channel being an indication of the state of the fuel oil pump.
Channels signalling the triggering of alarms
Some channels may signal if certain alarms have been triggered. The PrimaryItem for these channels shall be placed on the item the alarm pertains to.
Mapping of channels transmitting alarms:
shall use the following TagElement: State (set to "alarm", "alarm.high", "alarm.low.low", etc)
may use the following TagElements: Quantity, Content, Calculation, Position
shall avoid the following TagElements: Type
EXAMPLE
| Channel tag | MAIN GENERATOR ENGINE 4 CYLINDER 3 LINER TEMPERATURE HIGH | Description |
|---|---|---|
| Monitored item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Primary item | 511.11-4/C101.313-3/C469 | Main generator engine 4 > Cylinder liner 3 |
| - Tag element | state:alarm.high | state alarm high |
| - Tag element | qty:temperature | quantity temperature |
Explanation: a channel indicating a high temperature alarm is mapped with the mandatory TagElement state, set to alarm.high and the additional optional TagElement quantity pointing to the quantity the state applies to.
Channels containing references and setpoints
Some channels report configuration details of various systems, such as reference values or setpoints for alarms in control systems. The PrimaryItem for these channels shall be placed on the item the reference relates to.
Mapping of channels containing references and setpoints:
shall use the following TagElement: Type
may use the following TagElements: Quantity, Content, Calculation, Position, State
The above applies also to channels relating to manually inserted data.
EXAMPLE
| Channel tag | MAIN ENGINE INTERNAL LOAD REFERENCE | Description |
|---|---|---|
| Monitored item | 411.11/C101 | Main propulsion engine |
| - Primary item | 411.11/C101 | Main propulsion engine |
| - Tag element | type:reference | type reference |
| - Tag element | quantity:load | quantity load |
Explanation: the use of type TagElement as reference indicates that this is a channel containing a configuration reference value, while the additional optional quantity TagElement quantity set to load specifies the quantity the reference applies to.
Use of detail
ISO19848 warns against excessive use of the TagElement detail. This document reiterates the warning: the TagElement detail is a "wildcard" which, while being useful in certain situations, shall be avoided as much as possible.
There are, however, situations where the use of detail cannot be avoided. Generally, detail should be used following these two principles:
convey information which is deemed essential for the correct characterization of the channel and which would otherwise be lost without its inclusion in detail
avoid duplication
Use detail for components not represented in Gmod
Detail should be used to characterize components which are not modelled in the Gmod, and which are considered important to characterize the channel properly. It is remarked that this convention is valid on the condition that the labeler has a proper understanding of the element to be included in detail and, more precisely, that: 1) the element relates to a component and; 2) the component is not available in the Gmod.
EXAMPLE
| Channel tag | MAIN PROPULSION ENGINE TIMING RACK POSITION | Description |
|---|---|---|
| Monitored item | 411.11/C101 | Main propulsion engine |
| - Primary item | 411.11/C101 | Main propulsion engine |
| - Tag element | qty:position | quantity position |
| - Tag element | detail:timing.rack | detail timing rack |
Explanation: timing rack of the engine is not modelled in the Gmod, hence its inclusion in the TagElement detail.
Use detail to provide additional contextual information
Detail should be used to provide relevant contextual information, where the inclusion of said information in any other TagElement would be misrepresentative or misleading. It is remarked that this convention is valid on the condition that the labeler has a proper understanding of the contextual information which is being added.
EXAMPLE
| Channel tag | AZIMUTH THRUSTER GEARS - VISCOSITY 40°C BEFORE LO COOLER | Description |
|---|---|---|
| Monitored item | 433.1/C322.91/S205.3/C621 | Propulsion thruster, azimuth > Lubricating system > Coolers |
| - Primary item | 433.1/C322.91/S205.3/C621 | Propulsion thruster, azimuth > Lubricating system > Coolers |
| - Secondary item | 623.4/M211.12 | Lubricating oil data > properties > physical properties |
| - Tag element | cnt:lube.oil | content lube oil |
| - Tag element | qty:kinematic.viscosity | quantity kinematic viscosity |
| - Tag element | pos:before | position before |
| - Tag element | detail:40c | detail 40 degrees celsius |
Explanation: this channel reflects a test lab where the quantity being tested, lube oil viscosity, is customarily tested at different normative lube oil temperature levels -- in this case 40 degrees. Albeit this value is representative of a state the lube oil is at when the test is taken, the inclusion of this value in the State TagElement would characterize this channel as a state monitoring channel, which is incorrect. Hence the use of detail. Assignment of the SecondaryItem is performed in compliance with guideline for mapping of laboratory tests, see also the corresponding section "Results from laboratory tests".
Use detail to avoid mapping duplicates
Detail should be used to avoid duplication, for example in cases where the channel tags contain differentiating elements.
EXAMPLE
| Channel tags | DIESEL GENERATOR ENGINE PHASE, [PRIMARY/SECONDARY] | Description |
|---|---|---|
| Monitored item | 511.11/C101 | Main generator engine |
| - Primary item | 511.11/C101 | Main generator engine |
| - Tag element | qty:phase | quantity phase |
| - Tag element | detail:[primary/secondary] | either primary or secondary in detail |
Explanation: the use of detail here prevents mapping duplication between tag DIESEL GENERATOR ENGINE PHASE, PRIMARY and tag DIESEL GENERATOR ENGINE PHASE, SECONDARY.
Use detail to represent cross-assignment between components
In special cases there could be channels associated with two or more components, e.g., fuel consumption of main generators 1 and 2, or some flow measurement between two separate tanks. The following example is for an alarm signal triggered by abnormal condition in either of two pumps, thermal oil pump 1 or 2.
EXAMPLE
| Channel tag | CARGO HEATING (THERMAL OIL) PUMPS 1-2 ABNORMAL | Description |
|---|---|---|
| - Primary item | 613.33i-1/S110 | Thermal oil pumping unit |
| - Secondary item | 1032 | Cargo heating system |
| - Tag element | state:abnormal | state abnormal |
| - Tag element | detail:pumps.1.2 | detail pumps 1-2 |
Explanation: in such cases the primary item should be set to one of the items (here 613.33i-1/S110) and then a reference should be made to the other items in the detail meta tag (here pumps.1.2).
Use of specialized TagElement is preferred to use of detail
Detail shall be avoided for elements of the channel which knowingly pertain available TagElements. These elements shall be included in the pertaining TagElements -- as standard or as custom values, as needed.
Avoid detail for unnecessary information
Detail shall be avoided for elements of the channel which can be accessed in other standard data defined in ISO 19848, which do not assist in avoiding duplication, or generally whose capturing does not provide essential information for the correct representation of the channel.
EXAMPLE
| Channel tag | DIESEL GENERATOR KW REFERENCE | Description |
|---|---|---|
| Monitored item | 511.11/C101 | Main generator engine |
| - Primary item | 511.11/C101 | Main generator engine |
| - Tag element | qty:power | quantity power |
| - Tag element | type:reference | type reference |
Explanation: while the unit of measure kw in the channel tag is helpful in characterizing this channel as related to the engine power, its inclusion in detail is omitted as it does add anything to the correct characterization of said channel. Furthermore, the specification of the unit of measure is standardized as Data Channel Property in the main part of ISO19848.
Additional conventions and special cases
Inclusion of control, alarm or similar systems in the mapping
Sensors will usually be a part of a control, alarm or similar systems. These systems will normally receive data from the sensors installed on the items that are being monitored. For these cases -- as already described -- the PrimaryItem suffices and is assigned to the monitored item, whilst a reference to the control, alarm or similar systems shall be omitted from the mapping. Reference to the control, alarm or similar systems as a SecondaryItem shall however be included if necessary to make the mapping unambiguous -- i.e., avoid duplication of generated mappings. This may be the case of two sensors placed on the same item and each sending its readings to a separate system.
There could also be cases in which a channel is referenced multiple times to the same spatial location onboard the vessel, the only difference being an identifier in the channel tag. This could be the case of sensors placed in "cabin 01", "cabin 02", "cabin 03" and so on. In these cases, the "monitoring item" may be assigned to the SecondaryItem, even when such assignment is not justified by reasons of uniqueness. A similar approach may be opted for other control, monitoring, safety, alarm, or detection systems whose channels are tagged to many repetitive locations on board the vessel, e.g., watertight doors.
EXAMPLES
| Channel tag | CARGO HOLD NO.3 FIRE ALARM | Description |
|---|---|---|
| Monitored item | 1021.1i-3/H101 | Cargo hold 3 |
| Monitoring item | 831.1/G240 | Fire detection and alarm system |
| - Primary item | 1021.1i-3/H101 | Cargo hold 3 |
| - Tag element | state: alarm.fire | state fire alarm |
Explanation: this channel reports triggering of an alarm in the cargo hold. The Fire detection and alarm system is omitted in the mapping and only the item the alarm applies to, i.e., the cargo tank, is included as the PrimaryItem.
| Channel tag | CABIN 432 FIRE ALARM | Description |
|---|---|---|
| Monitored item | 972.1-432/H233 | Cabins |
| Monitoring item | 831.1/G240 | Fire detection and alarm system |
| - Primary item | 972.1-432/H233 | Cabins |
| - Secondary item | 831.1/G240 | Fire detection and alarm system |
| - Tag element | state: alarm.fire | state fire alarm |
Explanation: the SecondaryItem is used in addition to the PrimaryItem as there are multiple instances of this assignment across cabins.
Finally, there are cases where the control, monitoring, safety, alarm or detection system itself is the system that is being monitored, e.g., with a failure indication. In such cases the system shall be set as PrimaryItem while no SecondaryItem is necessary.
EXAMPLE
| Channel tag | FIRE DETECTION AND ALARM SYSTEM POWER FAILURE | Description |
|---|---|---|
| Monitored item | 831.1/G240 | Fire detection and alarm system |
| - Primary item | 831.1/G240 | Fire detection and alarm system |
Explanation: the fire detection and alarm system is the item being monitored, hence the use of only the PrimaryItem pointing to said system.
Avoid the inclusion of incomprehensible elements of the channel tag in the mapping
Channel tags may contain codes which are not immediately comprehensible unless additional information is collected. An explanation of these codes should always be sought with the objective to clarify the channels and improve the basis for mapping. If additional information is obtained explaining these codes, this additional information shall be used to improve the mapping, while the codes themselves shall not be included in any of the fields of the LocalID. There is an exception to this convention, namely if the codes are helpful in differentiating data channels which, should the codes be neglected, would result in duplicates. In these cases, the inclusion of said codes in the TagElement detail is permitted.
EXAMPLES
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP UNIT 2 STOP XC | Description |
|---|---|---|
| Monitored item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| - Secondary item | 511.11-1/C101 | Main generator engine 1 |
| - Tag element | state:stopped | stopped state |
Explanation: a definition of the code XC is not available. The channel is thus interpreted by the labeler as a channel signaling if the pump has come to a stop, hence the assignment shown. The code itself is not included in the mapping.
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP UNIT 2 STOP XC | Description |
|---|---|---|
| Monitored item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| - Secondary item | 511.11-1/C101 | Main generator engine 1 |
| - Tag element | cmd:stop | stop command |
Explanation: a definition of the code XC is available, and it indicates that the channel transmits a command from the control system. The TagElement command is thus used in the mapping of the channel. The code itself is not included in the mapping.
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP UNIT 2 STOP [XC1/XC2] | Description |
|---|---|---|
| Monitored item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 621.22i-2/S110 | Fuel oil pumping unit 2 |
| - Secondary item | 511.11-1/C101 | Main generator engine 1 |
| - Tag element | cmd:stop | stop command |
| - Tag element | detail:[XC1/XC2] | either XC1 or XC2 in the detail field |
Explanation: a definition of the code XC is available, and it indicates that the channel transmits a command from the control system. The TagElement command is thus used in the mapping of the channel. The codes (one for each channel) are included as Detail in the mapping, as they are needed to differentiate between the two channels.
Use of engine mounted systems
The Gmod contains instances of a "engine mounted systems" section. As the name indicates, this section characterizes systems which are directly installed on (integrated in) the engine. This section should be used to disambiguate components which can also be found installed on systems of the vessel other than the engine.
EXAMPLES
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP 2 STOP | Description |
|---|---|---|
| Monitored item | 621.22i-2/S110.1/S101 | Fuel oil pump 2 |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 621.22i-2/S110.1/S101 | Fuel oil pump 2 |
| - Secondary item | 511.11-1/C101 | Main generator engine 1 |
| - Tag element | cmd:stop | command stop |
| - Tag element | cnt:fuel.oil | content fuel oil |
Explanation: this mapping identifies this channel as applying to a pump installed on a vessel-mounted system (i.e., not integrated in the engine directly): the PrimaryItem points to the fuel oil pump and the SecondaryItem points to the system served, i.e., the main generator.
| Channel tag | MAIN GENERATOR ENGINE 1 FUEL OIL PUMP 2 STOP | Description |
|---|---|---|
| Monitored item | 511.11-1/C101.62/S205.2-2/S110.1/S101 | Main generator engine 1 > Engine mounted systems > Lubricating oil system > Pumping unit 2 > Pump |
| Served item | 511.11-1/C101 | Main generator engine 1 |
| - Primary item | 511.11-1/C101.62/S205.2-2/S110.1/S101 | Main generator engine 1 > Engine mounted systems > Lubricating oil system > Pumping unit 2 > Pump |
| - Tag element | cmd:stop | command stop |
| - Tag element | cnt:fuel.oil | content fuel oil |
Explanation: this mapping makes use of the pump units available under the engine mounted systems of the main generator engine. This implies that the pump is an integrated element of the engine: the PrimaryItem points to the fuel oil pump of the main generator engine. The SecondaryItem is omitted here, since it would simply replicate information available in the PrimaryItem (i.e., the system served is the engine itself).
Drive compositions
Drive compositions are devices consisting of:
The driven item, e.g., pump, compressor, generator, fan
The driving item, e.g., engine, motor, turbine
Connecting and auxiliary devices, e.g., shaft, foundation
Common driving compositions in the Gmod are:
511.1i Main generator set
521i Emergency electric power generation arrangement
S110 Pumping unit
C662 Compressor unit
S130 Fan unit
Channels that apply to a composition shall be assigned to the level of that composition, whereas channels applicable to a single component shall be assigned at the level of the single component.
EXAMPLES
| Channel tag | LUBRICATING OIL TRANSFER PUMP 2 RUNNING | Description |
|---|---|---|
| - Primary item | 623.22i-2/S110 | Lubricating oil pumping unit 2 |
Explanation: although the data channel name indicates the pump, it the whole pumping unit which is running, hence the assignment pointing to the pumping unit composition.
| Channel tag | LUBRICATING OIL TRANSFER PUMP 2 OUTLET PRESSURE | Description |
|---|---|---|
| - Primary item | 623.22i-2/S110.1/S101 | Lubricating oil pumping unit 2 > Pump |
Explanation: the pressure measurement is carried out at the pump component of the pumping unit, hence the assignment pointing to that specific component and not the entire composition.
| Channel tag | MAIN GENERATOR ENGINE 3 SPEED | Description |
|---|---|---|
| - Primary item | 511.11-3/C101 | Main generator engine 3 |
Explanation: the speed of the engine is not necessarily the same as the speed of the generator, as there may be a gear in between.
Groups vs individuals
Some data channels monitor or serve an individual item, while others monitor or serve a group of items. In many cases, the group and individual items are modelled in the Gmod as a parent/child pair:
621.22 Fuel oil pumping units
621.22i/S110 Fuel oil pumping unit
Primary and secondary items shall be assigned to the group or to the individual depending on what the channels serve.
In other cases, the individualizing function is also a composition. In the example below, individualization is performed at 511.1i, which is a composition consisting of 511.11 through 511.17.
511.1 Main electric power generator arrangements
511.1i Main generator set
511.11/C101 Main generator engine
511.12/CS16 Main generator coupling
511.13/C291 Main generator gear
511.14/C221 Main generator driver to generator shaft
511.15/E32 Main generator
511.16/CS19 Main generator driver foundation
511.17/H601 Main generator set supporting structures
EXAMPLES
| Channel tag | MAIN GENERATOR ENGINES FUEL OIL TEMPERATURE | Description |
|---|---|---|
| - Primary item | 511.1 | Main electric power generator arrangements |
Explanation: a channel monitoring the fuel consumption for all main generator engines is mapped as 511.1 as it is the only parent available for all main generator engines. To note, however, that with this assignment the information that it is the engines that consume the fuel is lost.
| Channel tag | MAIN GENERATOR ENGINES FUEL OIL TEMPERATURE | Description |
|---|---|---|
| - Primary item | 511.11/C101 | Main generator engine |
Explanation: to reintroduce the notion that it the engines which consume fuel oil -- see previous example -- it is acceptable to set 511.11/C101 as PrimaryItem, with no individualization, making it a valid assignment for all main generator engines.
| Channel tag | MAIN GENERATOR ENGINE 3 FUEL OIL TEMPERATURE | Description |
|---|---|---|
| - Primary item | 511.11-3/C101 | Main generator engine 3 |
Explanation: for a channel monitoring the fuel temperature for a specific main generator engine the usual assignment is carried out.
Results from laboratory tests
Although ISO 19848 and DNV's naming standard is mainly used for measurements from installed sensors and data transmission onboard a ship, asynchronous, off-vessel, events can also be supported. The analysis of a sample taken from the fuel oil or lubricating oil on a ship, may been seen as event data. Such samples are taken to detect different contamination in the oil, to reveal quality problems or unexpected wear, tear or damages. The different results (data points) in a lab analysis report may be regarded as channels in their own rights, that may be given names (LocalIds) according to DNV's VIS naming rule. In mapping said samples, the PrimaryItem shall be used to represent where the sample is taken, whereas the SecondaryItem shall be assigned to a specifically modelled section in the Gmod (623.4/M211.1; lubricating oil data, properties), see following examples.
EXAMPLES
| Channel tag | Luboil sample from Stern Tube -- Water contents (%) | Description |
|---|---|---|
| - Primary item | 412.726/S205 | Propeller shaft lubricating system |
| - Secondary item | 623.4/M211.14 | Lubricating oil data > properties > contamination |
| - Tag element | qty:percentage | content percentage |
| - Tag element | cnt:water | content water |
Explanation: water in lube oil is regarded as contamination, hence the assignment of the SecondaryItem to contamination under 623.4/M211.14.
| Channel tag | Luboil sample from Stern Tube -- Nickel Content (Ni) (ppm) | Description |
|---|---|---|
| - Primary item | 412.726/S205 | Propeller shaft lubricating system |
| - Secondary item | 623.4/M211.14 | Lubricating oil data > properties > contamination |
| - Tag element | qty:particle.concentration | quantity particle concentration |
| - Tag element | detail:nickel | detail nickel (*) |
Explanation: nickel is a contaminating substance, hence the assignment of the SecondaryItem to contamination under 623.4/M211.14 and the use of a custom content TagElement. Nickel and other contaminating substances may be included in the contents codebook in a future version of VIS.
| Channel tag | Luboil sample from Stern Tube -- Viscosity \@40c | Description |
|---|---|---|
| - Primary item | 412.726/S205 | Propeller shaft lubricating system |
| - Secondary item | 623.4/M211.12 | Lubricating oil data > properties > physical properties |
| - Tag element | qty:kinematic.viscosity | quantity kinematic viscosity |
| - Tag element | detail:40c | detail 40 degrees celsius |
Explanation: viscosity is a physical property of the oil, hence the assignment to physical properties (623.4/M211.12). Detail is used to provide additional context related to the test.
Operational data
Some channels provide data related to the operation of the vessel that can be shared, for instance, to other offboard systems. Such data is additional to the description of the vessel as such, and some additional functions have been defined to provide a context for such channels:
081.1/F201 Voyage data
081.2/F411 Loading data
620.1/M201 Fuel data
623.4/M211 Lubricating oil data
710.1/F211 Navigation data
940.1/F221 Environmental data
1000.1/F401 Cargo data
EXAMPLES
| Channel tag | LONGITUDE | Description |
|---|---|---|
| Monitored item | 710.1/F211.1 | Navigation data > Position |
| Monitoring item | 711/NS3d | Position fixing system |
| - Primary item | 710.1/F211.1 | Navigation data > Position |
| - Tag element | qty:longitude | quantity longitude |
Explanation: the channel reports the vessel longitude; the PrimaryItem is assigned to the position of the vessel and not to the position system.
| Channel tag | WIND SPEED VS VESSEL | |
|---|---|---|
| Monitored item | 940.1/F221.1 | Environmental data > Wind |
| Monitoring item | 941/I101 | Environmental monitoring system |
| - Primary item | 940.1/F221.1 | Environmental data > Wind |
| - Tag element | qty:wind.speed.vs.vessel | quantity wind speed versus vessel |
Explanation: the channel reports wind speed relative to the vessel speed; the PrimaryItem is assigned to the environmental data and not to the environmental monitoring system.
| Channel tag | MAIN ENGINE FUEL CONSUMPTION | Description |
|---|---|---|
| Monitored item | 411.1-1/C101 | Propulsion engine 1 |
| Consumer | 620.1/M201.32 | Fuel data > Amount consumed |
| - Primary item | 411.1-1/C101 | Propulsion engine 1 |
| - Secondary item | 620.1/M201.32 | Fuel data > Amount consumed |
Explanation: the channel reports the fuel consumption of the main engine; the use of both PrimaryItem and SecondaryItem is needed here to fully characterize the channel. The PrimaryItem is assigned to the monitored item, i.e., main propulsion engine, whereas the secondary item is assigned to fuel data.