My IO Device shall pass through IRT but shall not be an IRT device. How can i achieve this?

Q

A

This is not possible. PROFINET does not define a "pass through" IRT device.

When using PROFINET IRT all cyclic frames are planned offline in Engineering System regarding their

point in time of receiption
point in time of transmission

Putting an IO Device into an IRT line when the IO Device was not taken in account in Engineering will break IRT because the preplanned timings are no longer matching the real timing behaviour.

The only way to be able to use an IO Device in an IRT environment is that the IO Device itself is IRT capable according to its GSDML file.
This does not require the IO Device to implement a synchronous application. Only the communication part needs to be synchronized.

However the IO Device needs to state its IRT capabilities in the GSDML file and thus it needs to be certified for Conformance Class C.

See also...