■ Drive/inverter module STO function and an FSO module
The table below lists the safety data for the Safe disconnection function, including the safety
data of the FSO module, the FSE-31 module (optional) and the safety data of worst case
ACS880 Safe torque off (STO). See section One-channel or two-channel connection to an
FSO module (page 20).
Note:
• The PFD values of the drive STO and the FSO and FSE-31 modules are based on T1
(proof test interval) of 2 or 5 years. The safety data and SIL capability are valid only
when proof testing is done with an interval of maximum 2 or 5 years.
• The safety data in the table is valid only when parameter settings for the FSO digital
inputs are done according to section FSO module (page 27) in chapter Parameter
settings.
• The FSE-31 module is included in the calculations only if a safety encoder is used in
the application, the FSO-21 module is configured to activate the SS1 function (stop
category 1) in overtemperature situations and the ramp monitoring method is used in
the SS1 function.
• The safety integrity of the protection function must be verified as required in EN 50495.
The SIL capability of the drive/inverter module internal STO and the FSO and FSE-31
modules is up to SIL3 when parameter settings for the FSO digital inputs are done
according to section FSO module (page 27) in chapter Parameter settings.
• The PFD value defines the safety integrity for a low-demand application (demand rate
< 1/year) in respect to random failure rate.
• The safety data below contains the failure rates (PFD) of the FSO and FSE-31 modules
and the drive internal STO.
Two-channel pulsed digital inputOne-channel pulsed digital input
33SIL capability
1.05E-081.10E-08PFH (1/h, T
1
= 20 a)
8.57E-059.05E-05PFD
avg
(T
1
= 2 a)
2.06E-042.17E-04PFD
avg
(T
1
= 5 a)
> 99> 99SFF (%)
10HFT
2020T
M
(a)
3AXD10000113948 F
Safety block diagrams
The safety block diagrams show the components that are included in the safety data
calculations. The temperature sensor(s) and protection relay(s) are not included in the
calculations.
36 Technical data