SLI (Safely Limited Increment)

SLI description for drive option Functional Safety 3.

Description

SLI, when active, monitors the incremental position and ensures that it stays in a position window. This position window is defined as follows:

The position is taken at the time where the function gets activated. For the upper limit the parameter s_UL_SLI is added. For the lower limit the parameter s_LL_SLI is substracted. If the position leaves the position window a configurable fault reaction will be activated.

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

Number of Instances

Three instances per axis.

Function Input / Output Variables

 

 

Inputs

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

Outputs

  • SLI Active: logical status of the SLI 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

s_cp defines the safe position which is taken while the function gets activated. It is used to compute the range of allowed position values that the axis can take while the position monitoring is activated. The range is computed by adding or subtracting s_UL_SLI/s_LL_SLI to/from the parameter s_cp.

Related Parameters

Safety parameters

Name

Variables

Default

Parameter

Function Activation

-

0 (Never active)

AXIS#.SAFEPARAM.SLI_#​.FUNCTIONACTIVATION

Safe Input

-

0 (Not used)

AXIS#.SAFEPARAM.SLI_#​.SAFEINPUT

FSoE

-

0 (Not used)

AXIS#.SAFEPARAM.SLI_#.FSOE

Position Relative Upper Limit

s_UL_SLI

1 (Pos user units)

AXIS#.SAFEPARAM.SLI_#​.POSRELUPPERLIMIT; usable value range depends on used encoder type, see (➜ # 1, Limitations for SMM R_02-07-000)

Position Relative Lower Limit

s_LL_SLI

1 (Pos user units)

AXIS#.SAFEPARAM.SLI_#​.POSRELLOWERLIMIT; usable value range depends on used encoder type, see (➜ # 1, Limitations for SMM R_02-07-000)

Time Delay Monitoring

t_D_SLI

0 ms

AXIS#.SAFEPARAM.SLI_#​.TIMEDELAYMONITORING

Fault Reaction

-

1 (STO)

AXIS#.SAFEPARAM.SLI_#​.FAULTREACTION

Diagnostic parameters

Name

Variables

Default

Parameter

Function Active Status

-

-

(see "AXIS#.SAFE.SLI_#.ACTIVE")

Function Internal Status

-

-

(see "AXIS#.SAFE.SLI_#.INTERNALSTATE")

State Diagram

SLI is active if internal state is "Monitoring (2)" or "Fault reaction (3)".

Setup in WorkBench

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

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

Fault Reaction / Failure Messages

SLI 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, SLI remains active and the internal state
(AXIS#.SAFE.SLI_#.INTERNALSTATE) is set to failed state (3).

Safety State / Status Signals

The signal AXIS#.SAFE.SLI_#.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).