Management Summary - turck IM1-12-R Handbuch

Sicherheitshandbuch – Trennschaltverstärker

Management summary

This report summarizes the results of the hardware assessment carried out on the Isolating
Switching Amplifiers IM1-**(Ex)-* and MK13-R-Ex0.
Table 1 gives an overview of the different versions that belong to the considered devices.
The hardware assessment consists of a Failure Modes, Effects and Diagnostics Analysis
(FMEDA). A FMEDA is one of the steps taken to achieve functional safety assessment of a
device per IEC 61508. From the FMEDA, failure rates are determined and consequently the
Safe Failure Fraction (SFF) is calculated for the device. For full assessment purposes all
requirements of IEC 61508 must be considered.
Table 1: Version overview
Type
IM1-12Ex-R
IM1-12-R
IM1-12Ex-T
IM1-12-T
IM1-22Ex-R
IM1-22-R
IM1-22Ex-T
IM1-22-T
IM1-121Ex-R
IM1-121Ex-T
MK13-R-Ex0
The failure rates used in this analysis are the basic failure rates from the Siemens standard
SN 29500.
According to table 2 of IEC 61508-1 the average PFD for systems operating in low demand
mode has to be ≥10
consideration are only one part of an entire safety function they should not claim more than
10% of this range, i.e. they should be better than or equal to 1,00E-03.
The Isolating Switching Amplifiers IM1-**(Ex)-* and MK13-R-Ex0 are considered to be Type A
components with a hardware fault tolerance of 0.
For Type A components the SFF has to be 60% to < 90% according to table 2 of IEC 61508-2
for SIL 2 (sub-) systems with a hardware fault tolerance of 0.
The following failure rates are valid for operating stress conditions typical of an industrial field
environment similar to IEC 60654-1 class C (sheltered location) with an average temperature
over a long period of time of 40ºC. For a higher average temperature of 60°C, the failure rates
should be multiplied with an experience based factor of 2,5. A similar multiplier should be used
if frequent temperature fluctuation must be assumed.
The two channels on a redundant board shall not be used to increase the hardware fault tolerance
1
needed for a higher SIL as they contain common components.
2 Type A component:
© exida.com GmbH
Stephan Aschenbrenner
20
Description 1
1 input / 2 relay outputs
1 input / 2 transistor outputs
2 inputs / 2 relay outputs
2 inputs / 2 transistor outputs
1 input / 2 relay outputs (one used as error
message output)
1 input / 2 transistor outputs (one used as
error message output)
1 input / 1 relay output
-3 to < 10 -2 for SIL 2 safety functions. However, as the modules under
"Non-complex" component (all failure modes are well defined); for details see
7.4.3.1.2 of IEC 61508-2.
Parts List / Circuit Diagram
12296307 of 07.10.04 /
12296307 of 28.09.04
12296309 of 07.10.04 /
12296309 of 28.09.04
12296301 of 07.10.04 /
12296301 of 28.09.04
12296303 of 13.08.04 /
12296303 of 28.09.04
12296310 of 07.10.04 /
12296310 of 28.09.04
12296312 of 25.01.05 /
12296312 of 28.09.04
12296101 of 18.10.04 /
12296100 of 07.10.04
TURCK 04-07-14 R002 V3R0.doc; February 21, 2014
Hans Turck GmbH & Co. KG • Tel. +49 208/4952-0 • Fax +49 208/4952-264
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