CT

Consecutive Time Field (timestamp in a safety-related frame)

EMU

Execution Monitoring Unit

HWT

Hardware Test

LSB

Least Significant Byte

MALLOC

Memory Allocation Mechanism

MMU

Memory Management Unit

MSB

Most Significant Byte

RxSPDO

openSAFETY Receive Process data Object

SADR

openSAFETY Address. According to the openSAFETY specifications, this is the address of an safety-related node (SN) within an safety-related domain (SD).

Safe State

According to IEC 61508-4, the safe state is “the state of the equipment under control when safety is achieved.” The safe state of a machine or process is a state defined by the user, machine builder and/or system integrator on the basis of, for example, a risk assessment as per ISO 12100-1.

Safety-Related Function

Safety-related functions are intended to maintain the user-defined safe condition of the installation or prevent hazardous conditions arising at the installation. IEC 61800-5-2 specifies a number of such functions such as STO, SS1, SS2, among others.

Safety-Related Module

A safety-related module is a piece of safety-related equipment that can, for example, provide additional safety-related functions for a drive or a logic controller.

SCM

Safety Configuration Manager. According to the openSAFETY specifications, this is a service which is responsible for managing safety-related services such as configuration, parameterization, and others. Each network with safety-related features requires at least one SCM.

SCMAR

Safety-Related Configuration Manager in Automation Runtime. An automation runtime system can be, for example, an SLC.

SD

openSAFETY definition: Safety Domain. According to the openSAFETY specifications, a safety-related domain (SD) is an address space for up to 1023 openSAFETY safety-related nodes (SN).

SDG

openSAFETY definition: Domain Gateway. According to the openSAFETY specifications, this is a gateway to share data between different openSAFETY safety-related domains (SD).

SDN

openSAFETY definition: Domain Number. According to the openSAFETY specifications, this is the identification of an openSAFETY safety-related domain (SD).

SHNF

Safety-Related Hardware Near Function

SLC

Safety-Related Logic Controller

SN

openSAFETY definition: Safety-related Node. According to the openSAFETY specifications, this is a node with a safety-related function.

SN_FAIL

openSAFETY object that implements an error group and an error code to allow an openSAFETY node (SN) to respond to specific detected errors.

SNMT

openSAFETY Network Management. According to the openSAFETY specifications, this comprises the services for openSAFETY layer management.

SOD

openSAFETY Object Dictionary. According to the openSAFETY specifications, this is the repository of all data objects accessible via openSAFETY communication.

SPDO

openSAFETY Process Data Object. According to the openSAFETY specifications, this is an object for process data exchange between openSAFETY safety-related nodes (SN).

SRT

Safety-Related Reaction. This is the defined response of the safety-related system to given events.

SSADR

Safety-Related Station Address

SSDO

openSAFETY Service Data Object

TADR

Additional SADR for timing information

TxSPDO

openSAFETY Transmit Process data Object

UDID

openSAFETY definition: Unique Device Identification. According to the openSAFETY specifications, this is the global, unique identification of a device.