S7 400 CP 443 Redundancy

[teh]

Folks,

I have a S7400 PLC with a CP 443 and link with a HMI software.

Is that possible that if i added another CP 443 as redundant

to HMI communication?

Regards

 

[gregoryg]

Yes, it is possible to communicate with S7 PLC via several links at the same time even from one HMI.
But if you have one PLC and only one HMI station, you are not on the right way...

 

[teh]

The existing CP443(ethernet) have connected to HMI, we just suggest
add another cp443 ( ethenet) as standby comm. What we want is, once

the existing CP 443 was down , the HMI will automatically poll the

data from second cp443.

Mr Geogoyg, what do you mean by not the right way...

Best Regards

 

[PeterW]

Why do you need redundancy between the HMI and the PLC?

The redundancy you are specifying only covers the CP card itself (which should be very resiliant) and the ethernet cable, so I would presume you would run the two cables a totally different route, as cable redundancy is installed to protect against damage to cable, which is normally caused by something cutting through it, so running them together would be self defeating.

But why make such redundancy? Redundancy is normally to protect the process, nice to have redundancy to the HMI but in most cases the HMI can be overidden by the tech's to get things moving. Its more common to have redundancy for the PLC and the process I/O.

Perhaps that is what gregoryg was referring to?

 

[gregoryg]

Yes Peter it is what i tried to say.
But if redundancy in HMI is needed than the best solution is to use two HMI's. They should be connected through independent links to the PLC and (of course i they are capable to) each one of them can use another HMI as backup path for connection to PLC (something similar to data gateway).