SLP (Safely Limited Position)

SLP description for drive option Functional Safety 3.

Description

When active, SLP monitors the position and ensures that it stays in a position window. The upper limit of the position window is defined by the parameter s_UL_SLP and the lower limit is defined by the parameter s_LL_SLP. If the position leaves this position window while the function is active, a configurable fault reaction will be activated.

If necessary, the start of monitoring can be delayed by using the configurable parameter t_D_SLP.

Number of instances

Three instances per axis.

Function Input / Output Variables

 

 

Inputs

  • SLP Activate can be triggered by FSoE or safe digital inputs (must be mapped)
  • Safe Position: position signal from safe feedback

Outputs

  • SLP Active: logical status of the SLP 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

Timing

Related Parameters

Safety parameters

Name

Variables

Default

Parameter

Function Activation

-

0 (Never active)

AXIS#.SAFEPARAM.SLP_#​.FUNCTIONACTIVATION

Safe Input

-

0 (Not used)

AXIS#.SAFEPARAM.SLP_#​.SAFEINPUT

FSoE

-

0 (Not used)

AXIS#.SAFEPARAM.SLP_#​.FSOE

Position Upper Limit

s_UL_SLP

1 (Pos user units)

AXIS#.SAFEPARAM.SLP_#​.POSUPPERLIMIT

Position Lower Limit

s_LL_SLP

1 (Pos user units)

AXIS#.SAFEPARAM.SLP_#​.POSLOWERLIMIT

Time Delay Monitoring

t_D_SLP

0 ms

AXIS#.SAFEPARAM.SLP_#​.TIMEDELAYMONITORING

Fault Reaction

-

1 (STO)

AXIS#.SAFEPARAM.SLP_#​.FAULTREACTION

Diagnostic parameters

Name

Variables

Default

Parameter

Function Active Status

-

-

AXIS#.SAFE.SLP_#.ACTIVE

Function Internal Status

-

-

AXIS#.SAFE.SLP_#​.INTERNALSTATE

 

State Diagram

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

 

Setup in WorkBench

Select the drive and open the Safety Parameterization view Parameters Editor.

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

Fault Reaction / Failure Messages

SLP 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, SLP remains active and the internal state
(AXIS#.SAFE.SLP_#​.INTERNALSTATE) is set to failed state (2).

Safety State / Status Signals

The signal AXIS#.SAFE.SLP_#.ACTIVE can be monitored by safe digital outputs with OSSD pulses. 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 Safety Properties Overview.