Profinet

[S. Petrukhin]

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.

[dany-boy]

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/profinet python 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!

[S. Petrukhin]

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/profinet python 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!

Thank 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?

[NWerner]

> 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 good
enough to pass certification - as certification is obligatory.  From my point of view it is next to impossible for a single person
to 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.

[S. Petrukhin]

> 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 good
enough to pass certification - as certification is obligatory.  From my point of view it is next to impossible for a single person
to 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.

Not 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?

[JOEBOBSICLE]

I'd go with EtherCAT.

You'd need someone who knows what they're doing plus an EE or two.

[S. Petrukhin]

I'd go with EtherCAT.

You'd need someone who knows what they're doing plus an EE or two.

I'm afraid TIA Portal won't understand EtherCAT...

[dany-boy]

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?

Used 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!

[nctnico]

> 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 good
enough to pass certification - as certification is obligatory.  From my point of view it is next to impossible for a single person
to 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.

Not 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?

Use a module. I have good experience with modules from this company: https://www.anybus.com for a product which runs in several major car factories.

[Yansi]

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 think www.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//