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2S Drive Systems / 0185-1174_E_1V1_SM_C1251-2S / NTI AG
3 Standards and Regulations
3.1 Aims
Manufacturers and operating companies of equipment, machines, and products are responsible for ensuring the
required level of safety. This means that plants, machines, and other equipment must be designed to be as safe as
possible in accordance with the current state of the art. For this purpose, companies describe in the various standards
the current state of the art covering all aspects relevant to safety. If it can be justifiably assumed that all of the relevant
standards are complied with, this ensures that state-of-the-art technology has been utilized and, in turn, a plant builder
or a manufacturer of a machine or a piece of equipment has fulfilled his appropriate responsibility.
Safety systems are designed to minimize potential hazards for both people and the environment by means of suitable
technical equipment, without restricting industrial production and the use of machines more than is necessary. The
protection of man and environment must be assigned equal importance in all countries based on internationally
harmonized rules and regulations. This is also intended to avoid competitive advantages or disadvantages due to
different safety requirements in different countries.
There are different concepts and requirements in the various regions and countries of the world when it comes to
ensuring the appropriate degree of safety. The legislation and the requirements of how and when proof is to be given
and whether there is an adequate level of safety are just as different as the assignment of responsibilities.
The most important thing for manufacturers of machines and companies that set up plants and systems is that the
legislation and regulations in the country where the machine or plant is being operated apply. For example, the control
system for a machine that is to be used in the US must fulfill local US requirements even if the machine manufacturer
(OEM) is based in the European Economic Area (EEA).
3.2 Functional Safety
Safety, from the perspective of the object to be protected, cannot be split-up. The causes of hazards and, in turn, the
technical measures to avoid them can vary significantly. Therefore, a differentiation is made between different types of
safety (e.g. by specifying the cause of possible hazards). "Functional safety" is involved if safety depends on the correct
function.
To ensure the functional safety of a machine or plant, the safety-related parts of the protection and control devices must
function correctly. In addition, the systems must behave in such a way that either the plant remains in a safe state or it is
brought into a safe state if a fault occurs. In this case, it is necessary to use specially qualified technology that fulfills the
requirements described in the associated standards. The requirements to implement functional safety are based on the
following basic goals:
Avoiding systematic faults
Controlling random faults or failures
Benchmarks for establishing whether a sufficient level of functional safety has been achieved include the probability of
hazardous failures, the fault tolerance, and the quality that is to be ensured by avoiding systematic faults. This is
expressed in the standards using specific classification. In IEC/EN 61508, IEC/EN 62061 "Safety Integrity Level" (SIL)
and /ISO13849-1/ "Category" and "Performance Level" (PL).
0185-1174_E_1V1_SM_C1251-2S / 2021-11-26 16:43 (Rev. 12500)
Page 17 of 150
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