3.1.2 Additional terms and definitions
3.1.2.1 fail-safe
ability of a system that, by adequate technical or organizational measures, prevents from hazards either deterministically or by reducing the risk to a tolerable measure
3.1.2.2 fail-safe substitute values
values which are issued or delivered instead of process values when the safety function is set to a fail-safe state
3.1.2.3 flag
one-bit value used to indicate a certain status or control information
3.1.2.4 Globally Unique Identifier
128-bit number used to identify information in computer systems
3.1.2.5 MonitoringNumber
means used to ensure the correct order among transmitted safety PDUs and to monitor the communication delay
3.1.2.6 Non-safety-
predicate meaning that the respective object is a “standard” object and has not been designed and implemented to fulfil any requirements with respect to functional safety
3.1.2.7 OPC UA Mapper
non-safety-related part of the implementation of this document which maps the SPDU to the actual OPC UA services
3.1.2.8 process values
input and output data (in a safety PDU) that are required to control an automated process
3.1.2.9 qualifier
attribute (bit or Boolean), indicating whether the corresponding value is valid or not (e.g. being a fail-safe substitute value)
3.1.2.10 SafetyAutomationComponent
communication partner in a unidirectional safety link
3.1.2.11 SafetyConsumer
entity (usually software) that implements the data sink of a unidirectional safety link
3.1.2.12 SafetyData
application data transmitted across a safety network using a safety protocol
3.1.2.13 SafetyProvider
entity (usually software) that implements the data source of a unidirectional safety link
3.1.2.14 SafetyBaseID
randomly generated authenticity ID which is used to safely authenticate SafetyProviders having the same SafetyProviderID
3.1.2.15 SafetyProviderID
user-assigned, locally unique identifier which is used to safely authenticate SafetyProviders within a certain area
3.1.2.16 standard transmission system
part of the transmission system (implemented in hardware and software) that is not implemented according to any safety standards