GuardLogix Safety Data
The following examples show probability of a dangerous failure on demand (PFD) and average frequency of a dangerous failure per hour (PFH) values for
GuardLogix®
1oo1 SIL 2 system or 1oo2 SIL 3 system:- 1oo1 is a single-channel system.
- 1oo2 is a dual-channel system.
Useful Life
The useful life of GuardLogix controllers is 20 years.
Safety Data
For safety I/O devices safety data, including PFD and PFH values, see the manuals for those products, as listed in the Additional Resources.
The library file is available for download at https://www.rockwellautomation.com/en-us/ capabilities/industrial-safety-solutions/safety-system-development-tools.html.
Product Failure Rates
The data in the following tables applies to mission times up to and including 20 years. Mission time (MT) is the length of time over which the device maintains the stated PFD, PFH, and λ ratings before replacement is required.
A detected failure is a failure that is identified by diagnostic tests, proof tests, operator intervention, or normal operation.
Attribute | GuardLogix 5580 Controllers and Safety Partner | GuardLogix 5580 Controller | Compact GuardLogix 5380 SIL 2 Controller | Compact GuardLogix 5380 SIL 3 Controller |
|---|---|---|---|---|
Hardware Fault Tolerance (HFT) The hardware fault tolerance equals n , where n +1 faults could cause the loss of the safety function. An HFT of 1 means that 2 faults are required before safety is lost. | 1 | 0 | 0 | 1 |
No Part/ No Effect Detected Failure Rate (λ NPED ) [hr] | 2.80E-06 | 2.58E-06 | 4.04E-06 | 3.17E-06 |
Safe Failure Rate (λ) [failures/hr] | 7.24E-07 | 6.61E-07 | 7.33E-07 | 6.26E-07 |
Dangerous Failure Rate (λ D ) [failures/hr] | 7.10E-07 | 6.61E-07 | 7.33E-07 | 6.13E-07 |
Dangerous Detected Failure Rate (λ DD ) [failures/hr] | 7.10E-07 | 6.54E-07 | 7.26E-07 | 6.13E-07 |
Dangerous Undetected Failure Rate (λ DU ) [failures/hr] | 7.38E-11 | 6.40E-09 | 7.23E-09 | 6.45E-11 |
Automatic Diagnostic Test Interval (λ D ) [hr] | — | <SRT | <SRT | — |
Useful Life [yr] | 20 | 20 | 20 | 20 |
Systematic Capability (SC) Systematic capability is defined in IEC 61508-4 as the confidence that the systematic safety integrity meets the requirements of the specified SIL rating. | 3 | 3 | 3 | 3 |
NOTE:
- GuardLogix 5580 controller values are product failure rates to be used when the product is represented as a block in a reliability block diagram (RBD).
- GuardLogix 5580 controller failure rates are valid for ambient temperatures up to 70 °C (158 °F) and altitudes of up to 2000 m (6561.7 ft). See publications 1756-TD001 and 1756-IN048.
- The HFT value in the preceding table is the product internal HFT.
Attribute | GuardLogix® 5580 Controllers and Safety Partner | GuardLogix® 5580 Controller | Compact GuardLogix® 5380 SIL 2 Controller | Compact GuardLogix® 5380 SIL 3 Controller |
|---|---|---|---|---|
PFD ave | 6.46E-06 | 5.61E-04 | 6.33E-04 | 6.26E-06 |
PFH | 7.38E-11 | 6.40E-09 | 7.23E-09 | 6.45E-11 |
STR | 4.23E-06 | 3.90E-06 | 5.50E-06 | 4.41E-06 |
MTTF d [yr] | 160.82 | 172.74 | 155.66 | 186.08 |
Assumptions for safety calculations:
- Component failure rates are constant over the life of the product.
- All detected failures (safe and dangerous) result in the safe state (MRT=0).
- Within the specified useful life (20 years), no proof test is needed.
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