The purpose of this paper is to summarize the test and certification policies used during a TUV certification of a safety component/subsystem. These components/subsystems are typically electrical/electronic/ programmable electronic systems.
What does the end user get with the certification?
The end user can be assured, the certified component/subsystem (e.g. PLC, sensor, actuator) was assessed by an independent approval agency against the requirements of the applied standards. The most used standards are:
DIN V 19250/05.94
Fundamental safety aspects to be considered for measurement and control equipment
DIN V VDE 0801/01.90
with amendment A1: 1994-10
Principles for computers in safety-related systems
IEC 61508, Part 1 - 7:
Functional safety of E/E/PES safety-related system
The set of used standards is always stated on the certificate.
The certification shows, that a component/subsystem can be used in a specific application according to a requirement class (RC) or a integrity level (SIL).
The system integrator and end user must always be aware of how to use certified components/subsystems in safety-related function, respectively a safety instrumented system. Because of the many different possibilities, how to configure a safety system, the end user must get the related information from the manufacturer of the certified component/subsystem.
Safety Guidelines/TUV Guidelines
The safety guidelines are part of the assessment process. Because these guidelines are often established during the TUV assessment, they are sometimes called "TUV Guidelines". Formerly they were called TUV restrictions and were published in the TUV test report. Nowadays we strongly recommend to publish this information as part of the user documentation. Typically this part of the user documentation is called "safety handbook/safety manual".
On every TUV certification there is a reference, where the safety guidelines for the use of the component/subsystem are documented. The typical paragraph on a certificate is:
"Besondere Bedingungen/Specific Requirements:
The TUV Guidance is contained in the user manuals XXXX and YYYY and must be considered for safety relevant applications"
Responsibility
The manufacturers, system integrators and end users are responsible for publication and information on how to apply the safety guidelines. This can not be the responsibility of the certification agencies.
All needed information is published on the certification.