Application Of The Sto Function And Safety Parameters - Eaton Rapid Link 5 Manual

2 Engineering
2.8 Safe Torque Off (STO)

2.8.11 Application of the STO function and safety parameters

EN ISO 13849-1 PL e
IEC61508 SIL 3
IEC62061 SIL CL 3
IEC61800-5-2 SIL 3
Cat. = Category
DC = Average Diagnostic Coverage
avg
MTTF = Mean time to dangerous failure
d
PFH = Probability of dangerous failure per hour
d
PFD = Average probability of dangerous failure on demand
avg
PL = Performance level
SIL = Safety Integrity Level
SIL CL = Safety integrity level claim limit
60
DANGER

In certain applications, additional measuring and monitoring
equipment may be needed in order to meet the requirements of
the system's safety function.
The STO function does not include a motor brake and the
RASP5 braking function cannot be considered a fail-safe method
by itself.
If a motor braking function is required, an appropriate safety
relay and/or a mechanical braking system or a similar method
must be used.
The STO function is approved for use as a fail-safe method even in cases in
which the STO signal is not present and a single fault has occurred in the
drive.
The drive was accordingly tested in accordance with the following safety
standards:
Cat. 3
-10
PFH : 1.5 x 10
d
(1.5 % of SIL 3)
(High demand or continuous
mode)
The values specified here can only be adhered to if the STO function is
requested at least once every three months and if the RASP5 speed control-
ler is installed in an environment whose values meet the permissible limits:
• Ambient temperature range: -10 to +50 °C, taking into account any limits
that depend on frame size and degree of protection.
• Maximum installation height for rated operation: 1000 m above mean
sea level
with a power reduction of 1 % per 100 m above 1000 m (up to max.
4000 m IEC/max. 2000 m UL).
• Relative humidity: < 95 % (non-condensing).
The RASP5 speed controller must always be free of frost and moisture.
Rapid Link 5 · RAMO5 · RASP5 05/20 MN034004EN www.eaton.com
MTTF : 10000 years (High)
d
1/h PFD (T1 = 20 years): 1.6 x 10
avg
(0.2 % of SIL 3)
(Low demand mode)
DC : 91 %
avg
(Medium)
-5