Appendix E-Sto Function; Description Of Safety Function; Figure 53. Functional Block Diagram; Figure 54. Reliability Block Diagram - Eaton PowerXL DG1 Installation Manual

Appendix E—STO function

Description of safety function

Safety function and safe state
The STO (Safe Torque Off) function of PowerXL Series AC
drive is implemented only by hardware and no software is
involved to perform the STO function.
The STO function is available for operator to turn off the
motor torque. It is intended to be used in the safety related
applications up to SIL 1 / SIL CL 1 acc. to IEC 61800-5-2, IEC
61508 and IEC 62061, and up to Cat. 1 / PL c acc. to ISO
13849-1
Safety function
The power that can cause rotation (or motion in the case
of a linear motor) shall be switch off from the motor
when demand.
Safe state
The safe state is the power supply of motor is switch off.
System response time
The time from the operator press emergency stop button to
the motor power supply switch off is ≤ 1ms.
Safety related parameters
Operation mode FR0
Operation mode High demand
Safety integrity level SIL 1 / SIL CL 1
Systematic capability SC 1
Safety architecture 1oo1
Category 1
Performance level c
HFT 0
SFF of each element > 78%
PFD 5.07E-03 (at PTI =
AVG
20 years, 5.07% of SIL1)
PFH 5.79E-08 (0.58% of SIL1) 9.82E-08 (1% of SIL1)
MTTFd 1.00E+ 5 years (high)
Proof Test Interval (PTI) 20 years
MRT 0 hour
MTTR 0 hour
(total failures) —
(safe failures) —
S
(dangerous —
DD
detected failures)
(dangerous —
DU
undetected failures)
N ote: 1 FIT = 10 -9 /h
All the above mentioned safety related parameters are
calculated based on the assumptions:
•
•
•
•
The above mentioned parameters are calculated without
considering failure rates of external devices e.g. buttons,
power supply, etc.
Safety architecture and reliability block diagram

Figure 53. Functional block diagram

FR1–FR6
High demand
SIL 1 / SIL CL 1
SC 1
1oo1
1
c
0
> 60%
8.60E-03 (at PTI =

Figure 54. Reliability block diagram

20 years, 8.6% of SIL1)
1162 years (high)
20 years
0 hour
0 hour
944.04 FIT
845.25 FIT
0.00 FIT
98.21 FIT
POWERXL SERIES VFD MN040002EN—February 2018 www.eaton.com
Failure rate of each component is based on the Siemens
SN29500 data base.
Component failure rates are constant over the life of
the device.
Operating at a maximum ambient temperature of 60ºc.
The equal distribution is used for the failure modes ratio of
each component.
INFORMATION
STO Functional Block of Subsystem 3
+24V
VCC
Power supply Input circuit
Appendix E—STO function
~
IGBT Power Section
Gate
Driver
Enable
(+5V)
Output circuit
M
101