Reliability Data
Safety Function Standard Reference
The SIL* Stop function has priority over a stop triggered for operational reasons (EN ISO 13849-1, 5.2.1).
The performance level depends on the wiring category*, the MTTFd, and the DCavg.
The following diagram shows the positioning of TeSys™ island according to the category requirement.
TeSys island Positioning by Category Requirement
Simplified Procedure for Evaluating PL Achieved by Safety-Related Parts of Control Systems (SRP/CS)
|
Category |
B |
1 |
2 |
2 |
3 |
3 |
4 |
|---|---|---|---|---|---|---|---|
|
DCavg |
none |
none |
low |
medium |
low |
medium |
high |
|
MTTFd of each channel |
|||||||
|
Low |
a |
Not covered |
a |
b |
b |
c |
Not covered |
|
Medium |
b |
Not covered |
b |
c |
c |
d |
Not covered |
|
High |
Not covered |
c |
v |
d |
d |
d |
e |
According to TeSys island architecture and wiring category, the key indicators (DCavg, MTTFd, PL) for TeSys island comply with the values shown in the table below.
Values of Key Indicators for Single and Dual Channel Architectures
|
TeSys island system architecture |
Category |
Single fault tolerance* |
DCavg |
MTTFd of each channel |
Targeted PL |
|---|---|---|---|---|---|
|
Single channel |
1 |
No |
None |
High (≥ 30 years) |
c |
|
2 |
No |
Low (≥ 60%) to medium (≥ 90%) |
Low (≥ 3 years) to high (≥ 30 years) |
c, d |
|
|
Dual channel |
3 |
Yes |
c, d, e |
||
|
4 |
Yes |
High (≥ 99%) |
High (≥ 30 years) |
e |