The Safe torque off function 363
Abbreviations
Declaration of conformity
See Electrical planning instructions for ACS880 multidrive cabinets and modules
(3AUA0000102324 [English]).
TÜV certificate
The TÜV certificate is available on the Internet. Refer to Document library on the Internet
on the inside of the back cover.
Abbr. Reference Description
Cat. EN ISO 13849-1 Classification of the safety-related parts of a control system in respect
of their resistance to faults and their subsequent behavior in the fault
condition, and which is achieved by the structural arrangement of the
parts, fault detection and/or by their reliability. The categories are: B, 1,
2, 3 and 4.
CCF EN ISO 13849-1 Common cause failure (%)
DC EN ISO 13849-1 Diagnostic coverage
HFT IEC 61508 Hardware fault tolerance
MTTF
D
EN ISO 13849-1 Mean time to dangerous failure: (Total number of life units) / (Number of
dangerous, undetected failures) during a particular measurement
interval under stated conditions
PFD
avg
IEC 61508 Average probability of dangerous failure on demand, that is, mean
unavailability of a safety-related system to perform the specified safety
function when a demand occurs
PFH IEC 61508 Average frequency of dangerous failures per hour, that is, average
frequency of a dangerous failure of a safety related system to perform
the specified safety function over a given period of time
PL EN ISO 13849-1 Performance level. Levels a…e correspond to SIL
SC IEC 61508 Systematic capability
SFF IEC 61508 Safe failure fraction (%)
SIL IEC 61508 Safety integrity level (1…3)
SILCL IEC/EN 62061 Maximum SIL (level 1…3) that can be claimed for a safety function or
subsystem
STO IEC/EN 61800-5-2 Safe torque off
T
1
IEC 61508-6 Proof test interval. T
1
is a parameter used to define the probabilistic
failure rate (PFH or PFD) for the safety function or subsystem.
Performing a proof test at a maximum interval of T
1
is required to keep
the SIL capability valid. The same interval must be followed to keep the
PL capability (EN ISO 13849) valid.
See also section Maintenance (page 361).
T
M
EN ISO 13849-1 Mission time: the period of time covering the intended use of the safety
function/device. After the mission time elapses, the safety device must
be replaced. Note that any T
M
values given cannot be regarded as a
guarantee or warranty.
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