Sto Functional Safety Specification; Sto System Requirements - Servotronix CDHD2S User Manual

Troubleshooting
CDHD2S 2A
CDHD2S 2B

9.3 STO Functional Safety Specification

Note: At present, the STO function of all CDHD2S models are waiting for certification.
Features
Performance level
Safety integrity level
Reliability data

9.4 STO system requirements

STO power supply
To avoid excessive voltage levels at the STO input, safety-related parts must use low voltage.
AC 120/240V
AC 120/240V
Table 9-2
Meeting 4PLe category (ISO13849-1)
Meeting SIL3 (IEC61508/IEC62061/61800-5-2)
SFF MTTFd
98.9% 66757.5
**On-demand failure probability, calculated based on annual demand.
Figure 9-1 STO circuit wiring
1.5A, 3A
4.5A, 6A
Specification
PFH* PFDAVG**
1.71E-9 1.5E-4
*Failure probability per hour
STO_A3 Yes*
STO_A3 Yes*
PL Cat.
e
—
4
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