dchartier

Hello Kashir;

You have a S7-200 PLC with a EM 277 Profibus slave module. And you would like to connect it to a redundant Profibus-DP master, namely a S7-400 H system.

Siemens recommends a Y-Link as a solution in such a situation, where a redundant master system needs to connect to one or more single-port, non-refundant slave(s). It connects each Profibus master in the redundant H-system with the connected slave and maintains the master-slave link in case of switch-over of the S7-400H CPUs.

Here is an article that describes the function and configuration if a Y-Link with a S7-200 slave:

https://support.industry.siemens.com/cs/us/en/view/9952749

You will find details for the elements needed to build a Y-Link in the following document:

https://support.industry.siemens.com/cs/us/en/view/6847578

Hope this helps,

Daniel Chartier 

 hello  s7 200 cpu 224xp  EM 277   can be  master?

------------------------------------------------------------------------------------------
Split from S7-400H communication with EM 277 PROFIBUS DP slave.

Hello y2941;

An EM277 can only  act as a slave on a Profibus-DP nerwork. See the product description below.

Could you describe your project, we could offer some suggestions.

Hope this helps, 

Daniel Chartier