I/O mismatch configuration with Profibus and Profinet IRT modules

We are right now in the validation phase of our firmware; a task performed by another team. They have noticed a strange behaviour when testing Profibus and Profinet IRT acessories. For both networks, no matter the size of exchanged I/O data set in the controller/PLC, the module always go online. For instance, if I set 2 words for input and 2 words for output (1 word = 1 ADI) and set a different size in the PLC, our device goes online. This doesn’t happen for CIP-based protocols. For EtherNet/IP the settings of these words must match exactly, otherwise it does not go to online state. The same should happen for Profibus and Profinet.

Have checked the code and the generated GSDML file, did not find anything unusual. Have read both specific manuals as well with no luck.

We also checked old products in our portfolio based on NP30 and NP40 with old library (in compatibility mode) and we don’t see this behaviour. Hence, only conclusion is that I am missing something in this code.

Appreciate any information to fix this issue.

Best Regards,

Hi Lucian,

Our embedded team will have to take a look at this, so can you please create a case at https://support.hms-networks.com and include the article or serial number of the device or devices you are working with?

Thank you,


Hello Lucian,

To post here for the public in case anyone else runs into the issue. This issue is from a combination of Strict IO matching for Ethernet/IP. Along with how Profibus and Profinet support IO remapping. Ethernet/IP uses multiple assemblies for different IO configurations.