Single S7 315 CPU with Redundant IO

Hello Everyone,

I am working on a enquiry for a project where the client is asking for a Siemens S7 300 based system with Redundant IO. The CPU required is S7 315-2PN/DP which is of single quantity.

The problem is that the customer has specified that the redundancy required should only be at the IO level only and not at the CPU level.

Kindly help me with the possible solution and architecture for this type of job and how will a single controller manage IO redundancy. Any system architectures will be highly appreciated. 

Your valuable feedback awaited eagerly.

Steve 

Hello Std21,

If I understand your question correctly, what you can try is select a Hardware configration for the system with 2 SM modules instead of 1: e.g. if you have 16 basic digital inputs, then select two 16DI cards for them. One card for the basic inputs and the other for redundant inputs.

Inside the program you will have to "OR" the basic and redundant inputs. e.g. if I0.0 and I4.0 are the same input signals, then you should OR them and then use in the program, so that if one input is not working then the other should give the input.

Hope this helps,

Regards.

i think yes it is possible in s7 400h...

https://support.industry.siemens.com/cs/ww/en/view/1186523

in the above link page 121,possible redudant io configurations are given...pls go through it,

if possible in h system the same should be possible in software redudancy in s7300 also...

Thanks for the reply.......I know its possible with S7 400H CPU but in my case the customer is asking the system with S7 300 single CPU and redundant IOs.......Siemens is also not officially confirming on this......

Can anybody confirm if it is possible or not and also if this can be achieved with logic development in software.

Regards,

Steve