Real time Sercos with Industrial PLC

[Sid]

I am working of my university project in which I have to create a simulator that can connect with industrial PLC with sercos network and read and write data as real time communication.
I am looking for device to program in order to perform tasks. Revo Pi supports Sercos but I am not sure with Revo Pi can communicate in real time with PLC on sercos network. Can anyone explain to me if it is possible or what are possibilities?

[dirk]

Hi Sid, ok I see you are evaluaing an application in the area of Sercos III Real Time Communication.
So this involves time critical processing.

You can do the hardware configuration via

• Sercos III Gateway Module
• plus either RevPi Core or RevPi Connect

The Real Time requirement must be clarified.
The group runtime for data transmission is approx. 2* (fieldbus runtime+ PiBridge cycle time + code processing)
The PiBridge cycle time is in the variable RevPiIOCycle see documentation here:
https://revolutionpi.com/pictory-neues- ... -2-jessie/
Code processing is then the target application e.g. script accessing process image or Codesys Control, etc.

Here is a tutorial about measurement of analogue values which can help you understanding the cycle time a bit better:
https://kunbus-gmbh.atlassian.net/servi ... 1340120307

You just have to register with your E-Mail address to access it.
The registration page is currently in German language only so here is a short animation how it works:

[dirk]

Good news - you can do Sercos with Codesys, have a look here:
https://www.codesys.com/products/codesy ... ercos.html
So just use this hardware configuration:
https://revolutionpi.de/shop/en/revpi-c ... s-16gb-186

[Sid]

Hello dirk,
Thanks for your response. I have to yet look into link provided by you.

But for the Sercos III Gateway Module, there is limit for Supported Size of the Process Data. In the manual it states that
"The gateway component for SERCOS supports process data up to a length of 250 bytes per direction. Of these 250 bytes, 4 bytes of control data (for Connection Control and I/O-Control/status) are reserved."

But I have to integrate it with PLC system which sends data upto 1360 bytes in one packet. I am not sure, If this data limit for Sercos III Gateway Module will slow down the communication or what affects will it have. Can you please clarify it to me if possible?

[dirk]

Hi Sid, thank you for your message and I can understand your concerns mathematically 1360 is a lot bigger than 250 bytes, that's clear ...
Maybe you can solve your application completely in software via Codesys. I hope you can fulfil your project successfully.