Hi All,

I need to configure a redundant system, and the customer requires 2 Modbus Server ports and 2 Modbus Client ports. Could you please confirm whether this configuration can be achieved directly with a redundant CPU, or if additional hardware will be required?

Could you please advise if this setup is possible?

Looking forward to your positive response

Regards,

Yogendra

For this type of situation where you are working directly with your customer to solve a problem with a redundant system, to get the _best_ answer(s), I suggest contacting Siemens Support using the link above these online forums (Support Request).

https://support.industry.siemens.com/cs/my/src

They may have a link to an example application - you did search for a sample application already, correct?... and may offer the requirements for this type of comms request.

I take it they want the S7-1500 redundant system to be both a MB client and a MB server?  Usually people want one or the other, but generally not both.

They want the IP / MB/TCP default port for both S7-1500 CPU network ports you intend to use for MB/TCP (is it a comm co-processor [CP/CM] or the main PLC's PN ports?).  You can give it to them now.

It may be simpler / cheaper / faster to purchase a MB/TCP <--> Profinet Gateway device to handle the MB/TCP traffic.  Not saying it will be, but it _could_ provide more flexibility in the right environment and project requirements, possibly offering a better long-term experience.

Me, I like coding in the PLC, but I am horrible at error-handling all the possible edge-cases.  A MB/TCP-PN gateway handles all that for you in a predictable way which is why I mention it.  After all, you said it's for a redundant S7-1500 system where the customer is expecting redundant MB/TCP comms - always online, always responsive, even when unexpected edge cases _do_ appear.

YogendraK

Hi All,

I need to configure a redundant system, and the customer requires 2 Modbus Server ports and 2 Modbus Client ports. Could you please confirm whether this configuration can be achieved directly with a redundant CPU, or if additional hardware will be required?

Could you please advise if this setup is possible?

Looking forward to your positive response

Regards,

Yogendra

Thanks for your reply.

Hi,

Better go for,2 IP redundant mod bus gateway from siemens itself instead of using direct plc IP's. This will clear most of the issues. configure it well.