The intention of this document is to highlight major changes in the VSS specification (syntax and/or signals). It shall include all changes that affect backward compatibility or may be important to know when upgrading from one version to another. It typically does not list all changes to signals. It includes changes that are included in released version, but also changes planned for upcoming releases.
This document only contains changes introduced in VSS 3.0 or later!
A new attribute instantiate has been added to the syntax to exclude a child-node from the instantiation of the direct parent node.
This attribute is by default true and is only relevant to use for signals
An example on how this signals shall be handled by tools:
Vehicle.X:
type: branch
instances: Test[1,2]
description: High-level vehicle data.
Vehicle.X.InstantiatedSignal:
type: attribute
description: "Instantiated Signal"
datatype: string
Vehicle.X.NotInstantiatedSignal:
type: attribute
description: "Not Instantiated Signal"
datatype: string
instantiate: FalseResults in the following dot-notated output:
Vehicle.X
Vehicle.X.NotInstantiatedSignal
Vehicle.X.Test1.NotInstantiatedSignal
Vehicle.X.Test2.NotInstantiatedSignal
The new attribute is not used for any signals in VSS 3.0. For more information see documentation.
The path Vehicle.Powertrain.Battery was renamed to Vehicle.Powertrain.TractionBattery.
The path name was changed to make it clear that the signals in the path concerns the traction battery (high voltage battery) used by electrical or hybrid vehicles,
and not the supply battery (low voltage battery, typically 12 or 24 Volts).
Before VSS 3.0 the attribute enum could be used to list allowed values for a VSS signals, like in the example below:
LowVoltageSystemState:
datatype: string
type: sensor
enum: [
"UNDEFINED", # State of low voltage system not known
"LOCK", # Low voltage system off, steering lock or equivalent engaged
"OFF", # Low voltage system off, steering lock or equivalent not engaged
"ACC", # Vehicle Accessories on/living
"ON", # Engine start enabled (e.g. ignition on, diesel pre-heating, electrical drive released)
"START" # Engine starter relay closed (not applicable for electrical vehicles)
]
description: State of the supply voltage of the control units (usually 12V).
From VSS 3.0 this attribute has been renamed to allowed. The background is that the old name was misleading,
as it does not correspond to enum definitions in many programming languages, but rather just is a limitation of what values
that are supported by the signal.
All signals in VSS previously using enumhas been updated to use allowed, like in the example below:
LowVoltageSystemState:
datatype: string
type: sensor
allowed: [
'UNDEFINED', # State of low voltage system not known
'LOCK', # Low voltage system off, steering lock or equivalent engaged
'OFF', # Low voltage system off, steering lock or equivalent not engaged
'ACC', # Vehicle Accessories on/living
'ON', # Engine start enabled (e.g. ignition on, diesel pre-heating, electrical drive released)
'START' # Engine starter relay closed (not applicable for electrical vehicles)
]
description: State of the supply voltage of the control units (usually 12V).
If the old keyword enum is used most tools will ignore it and give a warning.
Warning: Attribute(s) enum in element Position not a core or known extended attribute.
The signals in Vehicle.Cabin.Seat have been significantly refactored.
The background is that the old representation included limitations and ambiguities.
VSS has been extended with syntax to define structs, and to use them for signals. For VSS 3.1 support is only experimental and syntax may change.
Note: Only a subset of VSS-tools for VSS 3.1 supports structs!
VSS has two attributes sensor and actuator that gives the possibility to specify which system/entity that provides the value
or tries to actuate the value. A possible hypothetical example is shown below showing that it is TemperatureSensorUnderDriverSeat that
provides the values of Vehicle.Cabin.Temperature and it is HVACSystem that tries to assure that the specified temperature is achieved.
These two attributes have never been used by signals in the VSS repository and it has been decided that these attributes no longer shall
be part of the official VSS syntax. If needed, this type of information shall be provided by overlays.
Vehicle.Cabin.Temperature:
type: actuator
description: Temperature in cabin
datatype: float
unit: km/h
sensor: 'TemperatureSensorUnderDriverSeat'
actuator: 'HVACSystem'
For VSS 3.1 the two attributes will remain in the VSS Syntax, but are marked as deprecated. No change to tooling is implemented, as the vss-tools already today give a warning if the attributes are used:
Warning: Attribute(s) sensor in element Temperature not a core or known extended attribute.
Vehicle.TravelledDistancedeprecated from 3.1. New signalVehicle.TraveledDistanceadded. Background is to be aligned with VSS style guide using American English.Vehicle.Powertrain.FuelSystem.TimeSinceStartdeprecated from 3.1. New signalVehicle.StartTimeadded. Reason is thatTimeSinceStartis not powertrain-related and other signals related to current trip are located on top-level. After discussion it was agreed that it is better to have a signal for start time rather than duration.- Refactoring of signals in
Vehicle.Body.Lightsbranch performed, some signals have new names.
The VSS-syntax now supports structs. Note however that not all exporters in VSS-tools 4.0 support structs yet.
Previously many signals used position for instance, where position 1 meant the leftmost item.
This caused problems for some use-cases where it was more practical to reference to a door by its relative position,
like the "DriverSide" door, as you then can describe wanted behavior in the same way for both LHD and RHD vehicles.
By that reason instance handling has for some signal been changed to use ["DriverSide","Middle","PassengerSide"].
The attributes sensor and actuator, deprecated from VSS 3.1,
have been removed from the VSS syntax.
Vehicle.TravelledDistanceVehicle.Powertrain.FuelSystem.TimeSinceStart
Vehicle.Cabin.Seat.*.*.Heatingdeprecated from 4.1. New signalVehicle.Cabin.Seat.*.*.HeatingCoolingadded.