TR-Electronic IH 8 Series, User Manual

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General information
 TR-Electronic GmbH 2016, All Rights Reserved Printed in the Federal Republic of Germany
Page 8 of 40 TR - ECE - BA - GB - 0120 - 13 10/23/2019
1.2 Abbreviations and terms used
I_58 Incremental encoder, all designs
DC
avg
D
iagnostic
C
overage
Average diagnostic coverage
ESD E lectro S tatic D ischarge
EU E uropean U nion
EMC E lectro M agnetic C ompatibility
Functional
safety
(FS)
Part of the overall system safety, which depends on the correct functioning of safety-
related systems for risk reduction. Functional safety is ensured when each safety
function is executed as specified.
Fault
exclusion
Compromise between the technical safety requirements and the theoretical possibility
of an error occurring
HTL H igh- T hreshold- L ogic
IEC International Electrotechnical Commission
IEEE I nstitute of E lectrical and E lectronics E ngineers
ISO I nternational S tandard O rganization
MTTF
d
M ean T ime T o F ailure (dangerous)
Mean time until dangerous failure
PFD
av
Av erage P robability of F ailure on D emand
Average probability of failure of a safety function with low demand
PFH
P robability of F ailure per H our
Operating mode with high requirement rate or continuous demand. Probability of
dangerous failure per hour.
PFH
D
P robability of a d angerous F ailure per H our
Average probability of a dangerous failure per hour according to ISO 13849-1.
PL
P erformance L evel, according to ISO 13849-1: Discrete level, which specifies the
capability of safety-related parts of a control to execute a safety function under
foreseeable conditions.
SIL
S
afety
I
ntegrity
L
evel, according to IEC 62061: Four discrete levels (SIL1 to SIL4). The
higher the SIL of a safety-related system, the lower the probability that the system
cannot execute the required safety functions.
SIS
S afety I nstrumented S ystem: is used to protect a dangerous process and reduce the
risk of an accident. Process instruments are a constituent of a Safety Instrumented
System. This comprises the essential components of a complete safety-relevant
process unit:
Sensor, fail-safe processing unit (control) and actuator
SCS S afety C omputer S ystem with control function
STP S hielded T wisted P air
TTL T ransistor- T ransistor- L ogic (RS422)
VDE
V erband d er E lektrotechnik, Elektronik und Informationstechnik (Association for
Electrical, Electronic and Information Technologies)
Repeat test
(proof test) Repetitive test to detect hidden dangerous failures in a safety-related system.