SAR (Safe Acceleration Range)

SAR description for drive option Functional Safety 3.

Description

SAR, when active, monitors the acceleration and ensures that it stays in an acceleration window. The acceleration window is defined by two parameters: a_UL_SAR (acceleration upper limit) and a_LL_SAR (acceleration lower limit). If the acceleration leaves the acceleration window a configurable fault reaction will be activated.

Number of instances

Three instances per axis.

Function Input/Output variables

 

 

Inputs

• SAR Activate can be triggered by FSoE or safe digital inputs (must me mapped)
• Safe acceleration: acceleration signal from safe feedback

Outputs

• SAR Active: logical status of the SAR function
• Fault Activate: activate fault reaction

Activation

Activation by FSoE	For a drive profile overview, see FSoE (➜ # 1, FSoE). For setup and handling, see the AKD2G EtherCAT Manual.
Activation by safe digital inputs	To review the enclosure and wiring instructions, see Enclosure, wiring (➜ # 1, Enclosure, wiring). To see technical data for the safe inputs, see Technical Data (➜ # 1, Technical Data). For notes on activation by safe inputs, see Activation by Safety Digital Inputs (➜ # 1, Activation By Safe Digital Inputs).

Timing

Related Parameters

Safety parameters

Name	Variables	Default	Parameter
Function Activation	-	0 (Never active)	AXIS#.SAFEPARAM.SAR_#​.FUNCTIONACTIVATION
Safe Input	-	0 (Not used)	AXIS#.SAFEPARAM.SAR_#​.SAFEINPUT
FSoE	-	0 (Not used)	AXIS#.SAFEPARAM.SAR_#.FSOE
Acceleration Upper Limit	a_UL_SAR	1 (Acc user units)	AXIS#.SAFEPARAM.SAR_#​.ACCUPPERLIMIT
Acceleration Lower Limit	a_LL_SAR	1 (Acc user units)	AXIS#.SAFEPARAM.SAR_#​.ACCLOWERLIMIT
Fault Reaction	-	1 (STO)	AXIS#.SAFEPARAM.SAR_#​.FAULTREACTION

Diagnostic parameters

Name	Variables	Default	Parameter
Function Active Status	-	-	AXIS#.SAFE.SAR_#.ACTIVE
Function Internal Status	-	-	AXIS#.SAFE.SAR_#.INTERNALSTATE

 

State Diagram

SAR is active if internal state is "Monitoring (1)" or "Fault reaction (2)".

Setup in WorkBench

Select the drive and open the Safety Parameterization view (see "Parameters Editor").

Choose the axis (1), category (2), SAR function (3) and the instance number (4).

Fault Reaction / Failure Messages

SAR has a configurable fault reaction. STO is used by default but can be replaced by SS1 Instance 1 or SS2 Instance 1. When the fault reaction is activated, SAR remains active and the internal state (AXIS#.SAFE.SAR_#.INTERNALSTATE) is set to failed state (2).

Safety State / Status signals

The signal AXIS#.SAFE.SAR_#.ACTIVE can be monitored by safe digital outputs with OSSD pulses (see "OSSD"). The status signal must be mapped to the safe digital output. Two outputs can be combined to a dual channel output. For parameter description refer to Functional Safety Parameter Reference.

Safety Properties

Refer to (➜ # 1, Safety Properties Overview).