UNE-EN IEC 60987:2021

I&C systems important to safety may be implemented using conventional hardwired

equipment, programmable digital equipment or by using a combination of both types of

equipment.

This document provides requirements and recommendations for the hardware aspects of I&C

systems whatever the technology and applies for all safety classes in a graded manner (as

defined by IEC 61513).

The requirements defined within this document guide, in particular, the selection of preexisting components, hardware aspects of system detailed design and implementation and

equipment manufacturing.

This document does not explicitly address how to protect systems against those threats

arising from malicious attacks, i.e. cybersecurity, for programmable digital item. IEC 62645

provides requirements for security programmes for programmable digital item for all their

development phases and on-site operation.

Pre-existing items may include microcontrollers or HPDs and, where firmware or programming

files are deeply-embedded, be effectively "transparent" to the user. In such cases, this

document can be used to guide the assessment process for such components. An example of

where this approach is considered appropriate is in the assessment of modern processors

which contain a microcode. Such code is generally an integral part of the "hardware", and it is

therefore appropriate for the processor (including the microcode) to be assessed as an

integrated hardware component using this document.

Software which is not deeply-embedded, as described above, is developed or assessed

according to the requirements of the relevant software standard (for example, IEC 60880 for

class 1 systems and IEC 62138 for class 2 and 3 systems).

In the same manner, HPDs which are not deeply-embedded, as described above, are

developed or assessed according to the requirements of the relevant HPD standard (for

example, IEC 62566 for class 1 systems and IEC 62566-2 for class 2 and 3 systems).