The following requirements apply for the development of the OPC UA Safety technology:

1. Safety communication suitable for Safety Integrity Level up to SIL4 (see IEC 61508) and PL e (see ISO 138491).
2. Combination of SIL 1 – 4 OPC UA Safety devices as well as non-safety devices on one communication network.
3. Implementation of the safety transmission protocol is restricted to the safety layer.
4. The safety-relevant time-out monitoring is implemented in the safety layer.
5. Safety communication meet the requirements of IEC 617843.

f)[RQ4.1] The OPC UA Safety stack is intended for implementation in safety devices exclusively. Exceptions (e.g. for debugging, simulation, testing, and commissioning) shall be discussed with a notified body.