SSR (Safe Speed Range)

SSR description for drive option Functional Safety 3.

Description

SSR, when activated, monitors the velocity and ensures that it stays in a configured velocity window. The parameter n_UL_SSR defines the upper limit and the parameter n_LL_SSR defines the lower limit of this window. If the velocity leaves the velocity window a configurable fault reaction will be activated.

Once the activation request is received, SSR will become active depending on what occurs first:

• The time to velocity monitoring is elapsed (t_SSR)
• The current velocity stays in the configured velocity window for a given amount of time (t_L_SSR)

Optionally, the deceleration ramp can be monitored after some delay (t_D_SSR) to check whether the current velocity is below the computed velocity ramp (a_SSR). If the velocity is above the computed velocity ramp, the fault reaction will be activated.

Number of Instances

Three instances per axis.

Function Input / Output Variables

 

 

Inputs

• SSR Active can be triggered by FSoE or safe digital inputs (must be mapped)
• Safe velocity: velocity signal from safe feedback

Outputs

• SSR Active: logical status of the SSR 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.SSR_#​.FUNCTIONACTIVATION
Safe Input	-	0 (Not used)	AXIS#.SAFEPARAM.SSR_#​.SAFEINPUT
FSoE	-	0 (Not used)	AXIS#.SAFEPARAM.SSR_#.FSOE
Time To Velocity Monitoring	t_SSR	2 ms	AXIS#.SAFEPARAM.SSR_#​.TIMETOVELMONITORING
Velocity Upper Limit	n_UL_SSR	0 (Vel user units)	AXIS#.SAFEPARAM.SSR_#​.VELUPPERLIMIT
Velocity Lower Limit	n_LL_SSR	0 (Vel user units)	AXIS#.SAFEPARAM.SSR_#​.VELLOWERLIMIT
Time For Velocity in Limits	t_L_SSR	1 ms	AXIS#.SAFEPARAM.SSR_#​.TIMEFORVELINLIMITS
Deceleration Monitoring	-	0 (Disabled)	AXIS#.SAFEPARAM.SSR_#​.DECMONITOREN
Deceleration Limit	a_SSR	0 (Dec user units)	AXIS#.SAFEPARAM.SSR_#​.DECLIMIT
Time Delay Deceleration Monitoring	t_D_SSR	1 ms	AXIS#.SAFEPARAM.SSR_#​.TIMEDELAYDECMONITORING
Fault Reaction	-	1 (STO)	AXIS#.SAFEPARAM.SSR_#​.FAULTREACTION

Diagnostic parameters

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

SSR is active if internal state is "Monitoring (4)" or "Fault reaction (5)".

Setup in WorkBench

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

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

Fault Reaction / Failure Messages

SSR 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, SSR remains active and the internal state
(AXIS#.SAFE.SSR_#.INTERNALSTATE) is set to failed state (5).

Safety State / Status Signals

The signal AXIS#.SAFE.SSR_#.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).