Sto Technical Data - Danfoss VLT Midi Drive FC 280 Operating Manual

Safe Torque Off (STO)
4. Remove the 24 V supply for terminal 38 and
verify that the LCP shows alarm 188, STO Function
Fault if the LCP is mounted. If the LCP is not
mounted, verify that alarm 188, STO Function Fault

6.5 STO Technical Data

The Failure Modes, Effects, and Diagnostic Analysis (FMEDA) is performed based on the following assumptions:
•
®
VLT Midi Drive FC 280 takes 10% of the total failure budget for an SIL2 safety loop.
•
Failure rates are based on the Siemens SN29500 database.
•
Failure rates are constant; wear-out mechanisms are not included.
•
For each channel, the safety-related components are considered to be of type A with a hardware fault tolerance
of 0.
•
The stress levels are average for an industrial environment and the working temperature of components is up
to 85 °C (185 °F).
•
A safe error (for example output in safe state) is repaired within 8 hours.
•
No torque output is the safe state.
Safety standards
Safety function
Safety performance
1)
Reaction time
Table 6.3 Technical Data for STO
1) Reaction time is the amount of time from an input signal condition triggers the STO until the torque is off on the motor.
2) For proof test procedure, refer to chapter 6.4 Maintenance and Service for STO.
MG07A402
Operating Guide
Safety of Machinery
Functional Safety
Safe Torque Off
ISO 13849-1
Category
Diagnostic coverage (DC)
Mean time to dangerous failure
(MTTFd)
Performance level
IEC 61508/IEC 61800-5-2/IEC 62061
Safety Integrity Level
Probability of dangerous failure per
hour (PFH) (high demand mode)
Probability of dangerous failure on
demand (PFD for PTI = 20 years)
avg
(low demand mode)
Safe failure fraction (SFF)
Hardware fault tolerance (HFT)
2)
Proof test interval
Common cause failure (CCF)
Diagnostic test interval (DTI)
Systematic capability
Input to output response time
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is logged in parameter 15-30 Alarm Log: Error
Code.
5. Reapply 24 V supply to terminal 38 and verify
that resetting the alarm is successful.
ISO 13849-1, IEC 62061
IEC 61508
IEC 61800-5-2
Cat. 3
60% (Low)
2400 years (High)
PL d
SIL2
7.54E-9 (1/h)
6.05E-4
For dual-channel parts: >84%
For single-channel parts: >99%
For dual-channel parts: HFT = 1
For single-channel parts: HFT = 0
20 years
β = 5%; β = 5%
D
160 ms
SC 2
Enclosure sizes K1–K3: Maximum 50 ms
Enclosure sizes K4 and K5: Maximum 30 ms
6 6
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