Pilz Intern PMC SR6 Manual page 47

Glossary
Probability of a dangerous failure per hour
(PFH )
D
In accordance with DIN EN 61508/DIN EN 62061:
Average probability of a dangerous device failure
per hour. Together with PFH, one of the most impor-
tant bases for calculating the safety function reliabil-
ity of devices, the SIL.
Probability of a failure per hour (PFH)
In accordance with DIN EN 61508/DIN EN 62061:
Average probability of a device failure per hour. To-
gether with PFH , PFH is one of the most important
D
bases for calculating the reliability of the safety func-
tion of devices, the SIL.
Safe Stop 1 (SS1)
In accordance with DIN EN 61800-5-2: Procedure
for stopping a PDS(SR). With the SS1 safety func-
tion, the PDS(SR) performs one of the following
functions: a) Triggering and controlling the motor de-
lay variable within defined limits and triggering the
STO function if the motor speed falls below a speci-
fied limit value (SS1-d), or b) triggering and monitor-
ing the motor delay variable within defined limits and
triggering the STO function if the motor speed falls
below a specified limit value (SS1-r), or c) triggering
the motor delay and triggering the STO function af-
ter an application-specific delay (SS1-t). In this case,
SS1(-t) corresponds to the time-controlled stop in
accordance with IEC 60204-1, stop category 1(-t).
Safe Torque Off (STO)
In accordance with DIN EN 61800-5-2: Procedure
for stopping a PDS(SR). The STO safety function
prevents the motor from being supplied with any en-
ergy that could cause rotation (or motion in a linear
motor). The PDS(SR) does not supply the motor
with any energy that could generate torque (or force
in a linear motor). STO is the most fundamental
drive-integrated safety function. It corresponds to an
uncontrolled stop in accordance with DIN EN
60204-1, stop category 0.
Safety Integrity Level (SIL)
In accordance with DIN EN 61800-5-2: Probability of
a safety function failure. SIL is divided into levels 1 –
4 (lowest – highest level). SIL precisely assesses
systems or subsystems based on the reliability of
their safety functions. The higher the SIL, the safer
and more reliable the function in question is.
Safety Integrity Level Claim Limit (SIL CL)
Maximum SIL that can be claimed, based on the
structural limitations and systematized safety in-
tegrity of a SRECS subsystem. A SIL CL is deter-
mined by the hardware fault tolerance (HFT) and the
safe failure fraction (SFF) of the subsystems.
Manual PMC SR6 safety module
1005344-en-US-01
Intern
Safety Related Part of a Control System (SRP/
CS)
In accordance with DIN EN ISO 13849-1: Safety-re-
lated part of a controller that reacts to safety-related
input signals and generates safety-related output
signals.
STO reaction time
Time between activation of the STO safety function
(edge from 1 to 0) and disabling of the pulse pattern
on the power unit.
STO response time
Time between activation or deactivation of the STO
safety function and feedback in the STO status sig-
nals.
STO switch-off time
Time span starting from the activation of the safety
function until the power unit of the drive controller is
safely switched off.
Switching frequency (n
In accordance with DIN EN 13849-1: Average num-
ber of annual actuations.
Test pulse
In accordance with the German Electrical and Elec-
tronic Manufacturers' Association: Temporary
change of a signal voltage level for checking
whether the output or device functions properly or
for checking the transmission path.
Test pulse assessment (TA)
In accordance with the German Electrical and Elec-
tronic Manufacturers' Association: Part of the circuit
that assesses the test pulse needed for diagnostic
testing.
Test pulse generation (TE)
In accordance with the German Electrical and Elec-
tronic Manufacturers' Association: Part of the circuit
that generates the test pulse needed for diagnostic
testing.
)
op
Pilz | 47