An oft-heard question: “Why does a PROFINET device need an IP address? PROFINET uses names.” You may have heard the misinformation that PROFINET does not use TCP/IP. The correct information is that PROFINET does use TCP/IP and devices do have IP addresses!
So, the short answer to that oft-heard question: PROFINET uses TCP/IP and therefore needs an IP address.
The long answer is pretty simple: PROFINET uses TCP/IP where it makes sense (that is, where the data is not time critical). For example:
- Configuration
- Parametrization
- Diagnostics
Therefore, an IP address is needed for these functions. There are also other benefits. Many devices have embedded web servers. This allows you to type in their IP address into a web 
browser and access them like a webpage. One of the biggest reasons people are moving to PROFINET is DATA ACCESS. By using IP addresses, it helps integrate device-level information vertically into higher level MES systems.
Now PROFINET does not use the IP address for real-time data; it just uses the physical address, the MAC address. This means it can skip TCP/IP for faster, more deterministic performance.
To dig deeper, read our white paper “PROFINET for network geeks (and those who want to be).”
Want to learn more about device naming? A past Tech Tip came from Hunter Harrington, PROFINET Consulting Engineer, at the PROFI Interface Center. He answers the question: “What’s in a (PROFINET device) name?” Give it a read.