RookieWithRobots

So instead of using one "big" cpu/plc in system. Im thinking to another solution and maybe divide system control in few smaller cpus. What you think about this idea? How example safety communication from cpu to another works and how easy it is to transfer data between cpus?

That can work. It just depends on how the system is constructed and what update speeds you looking at.

The biggest challenge is the safety aspect which depends heavily on the construction. This could be cells or modules or control zones. You may elect to have a central safety controller or each controller handles its own cell.

We have a x2 S7-1200 controlled machine which interlinks with Ethernet/TCP. Interlinking speed is not an issue so we do not have to master/slave concepts. Each controller handles a zone witch which its multiple own single axis motion control. The safety aspect is not handled by the S7-1200 processors or any Siemens device.

Hello,

if you use TIA and the CPU's are in the same project, it is easy to communicate from one to another. To check communication you could a bit toggeling between "0" and "1" and check this bit in the other CPU.
I would only see an advantage using several CPU's when you are a machine builder and have modular systems which you combine according to customer needs. 

I don't see cost saving and when you are connected to the PLC's you also need to be aware to which you are connected. Also Speed is not realy improving.

Regards

Scott

Hello,

it works. I realize this in different projects also with safety-communication.

The communication between the CPU's can you realize in different ways

• with S7-communication via PUT/GET
  How do you configure and program an S7 connection and the “PUT” and “GET” instructions for data transfer between two S7 CPUs?
  
  
• define one CPU as "Master" and the other as I-Device
  this communication you can use also for a safety communication
  Configuration and Application of the PROFINET I-Device Function
  
  

regards
CaOd