Profinet - Page 1
Forum section: electronics / general

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 17, 2021, 06:15:34 pm
content: Hello, friends.It is supposed to add the Profinet protocol to the controller. I know about the site of this protocol, I know about the CHIP for this protocol, but there is a huge amount of information there, now there is no possibility to study in detail, I only need to estimate the costs. Maybe someone was developing MPU firmware with support for the Profinet protocol. Please tell me a few basic questions, help me save time, if it is not difficult for you.1. At what level is Profinet transmitted: MAC, UDP, PCP/IP?2. What is the idea of transferring data and binding PLC variables (Simatic S7-1500) to the TIA Portal?3. Is it generally a difficult protocol to implement? I've heard of a datagram system somewhat similar to modbus.

author: dany-boy
author_rank: Contributor
timestamp: January 18, 2021, 04:36:39 pm
content: Hi!When I was a student I took a course in industrial networking and extensively learned about S7 1200 and S7 1500. The name of the course is a bit misleading since we didn't actually learn about the low level details of the communication protocols. However for the final project we used a Raspberry Pi to pull data out of several 1500 PLC's through profinet. If I remember correctly for monitoring purposes pseudo-real time profinet works on top of TPC/IP. The estimated latency we got was in the order of a couple of ms as far as I remember. I recommend you take a look at this:https://github.com/devkid/profinetpython library as a starting point. If your application requires actual real time I think profinet defines another implementation at the MAC level, but I have no experience at that level.Cheers!

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 05:50:20 pm
content: Quote from: dany-boy on January 18, 2021, 04:36:39 pmThank you for your advice!Maybe you noticed during TCP/IP operation whether the socket is always kept open or whether the socket is opened at each request?How did you get the data - using ready-made libraries?

author: NWerner
author_rank: Contributor
timestamp: January 18, 2021, 06:53:13 pm
content: > 3. Is it generally a difficult protocol to implement? I've heard of a datagram system somewhat similar to modbus.It is a VERY complex protocoll. Another point to consider: you will have to implement a rather large protocol goodenough to pass certification - as certification is obligatory. From my point of view it is next to impossible for a single personto implement a profinet solution from scratch before getting fired.There are several options (modules, stacks, asics) when implementing profinet.Each and every having certain implications regarding development time and BOM cost.You will certainly need some decent SW support. check this before comitting to an option.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 08:22:28 pm
content: Quote from: NWerner on January 18, 2021, 06:53:13 pmNot sure exactly, but I need modules or asics... In general, I need to give only a few variables to the PLC. Do you think it will be difficult?

author: JOEBOBSICLE
author_rank: Regular Contributor
timestamp: January 18, 2021, 08:31:06 pm
content: I'd go with EtherCAT.You'd need someone who knows what they're doing plus an EE or two.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 08:57:23 pm
content: Quote from: JOEBOBSICLE on January 18, 2021, 08:31:06 pmI'm afraid TIA Portal won't understand EtherCAT...

author: dany-boy
author_rank: Contributor
timestamp: January 19, 2021, 04:15:57 pm
content: Quote from: S. Petrukhin on January 18, 2021, 05:50:20 pmUsed libraries to read or write bytes and ints from the plc directly. We did 2 reads/writes per second, so low throuput. The library that I linked keeps the socket open all the time.Cheers!

author: nctnico
author_rank: Super Contributor
timestamp: January 19, 2021, 04:41:37 pm
content: Quote from: S. Petrukhin on January 18, 2021, 08:22:28 pmUse a module. I have good experience with modules from this company:https://www.anybus.comfor a product which runs in several major car factories.

author: Yansi
author_rank: Super Contributor
timestamp: January 19, 2021, 05:02:35 pm
content: Why don't you do your homework first?There is a lot af answers to your question already everywhere. For example here:https://profinetuniversity.com/category/profinet-basics/Real time stuff goes with custom ETH frames, non-realtime stuff uses UDP/TCP.Profinet is an open standard, you can buy the necessary specifications from I thinkwww.profibus.com.Even though I haven't looked into profinet in that much low-level detail yet, but I wouldn't say it is in any way impossible to make a custom software stack for it in a single person*. But it will be completely different beast, if you need to get it certified!So it depends on what you want to do with it.//EDIT: *To a conformance class A, from B up it will start to be very much increasingly difficult//