Operating Instructions

Safe Torque Off Function

Failure Rate of the Drive Safety Function

380 | 443

Fig. 129: Figure 17-3

*1 is factory jumper wire shorting +24V-S1-S2. To use the Safety function, remove

this jumper wire. To disable the Safety function, short-circuit +24V-S1-S2 with a

jumper wire.

Failure Rate of the Drive Safety Function

See the table below for the relevant safe loop parameters.

Item

Definition

Standard

Performance

SFF

Safe failure fraction

IEC61508

S1–DCM = 88.35%

S2–DCM = 88.2%

HFT

(Type A subsystem)

Hardware fault tolerance

IEC61508

SIL

Safety integrity level

IEC61508

SIL 2

IEC62061

SILCL 2

PFH

Average frequency of dangerous failure [h-1]

IEC61508

1.36 × 10

-9