Redundant ethernet on single PLC-300

[jeilers]

I have been trying to find out if there are any redundant ethernet possibilities with a single PLC and 2 ethernet connections. The idea is that the 2 connections share the same IP/network. Currently i only know of 1 solution which is using a PLC-400 with CP-443 and use a media converter on the AUI port.

I am wondering if there are any other solutions for the PLC-300, PLC-400 series. Just adding a CP to the rack is not enough, because as i understand it this will require a new unique IP address...

Thanks for your help

Jos

 

[Amr Hassan]

i am not sure about this solution , but i am thinking with a loud voice . May be some one can add something to make it is feasible


the ethernet cp needs a 24 volts power supply .Can u make this power supply through a relay contact so u have the power on only one module ? the realy is switched according the diag of the cp


Note : Siemens uses a similar idea when connecting an op to an H system

 

[gregoryg]

Amr Hassan.
If you remove supply from ethernet CP in S7-300, PLC will go to STOP mode. Siemens recomends supplying CPU and CP's from the same line (through one fuse/contactor).

 

[jeilers]

Actually physically connecting the 2nd CP card into the rack is not a problem at all, what i want is a software redundant solution, if the first card fails, the second one will take over on the same tcp/ip network with the same ip address (as you would have when using the cp443 with aui extension)....

 

[dchartier]

Hello jeilers;

I do not know if this product will cover yopur needs, but Siemens offers a software package for "fault-tolerant connections" called S7-Redconnect. I seem to remember it was used for fault-tolerant PLCs (S7-400-H); possibly iot can be extended to S7-300 CPUs.
Here is a link to technical data on the software:
http://support.automation.siemens.com/WW/skm/pdfviewer.asp?HitsPerSite=50&ehbid=html_76%2Fehb%2F13650980%2Ehtm&query=fault%2Dtolerant+ethernet+connections&lang=en&nodeid=13650209&page=38&view=new
Hope this helps,
Daniel Chartier

 

[Amr Hassan]

Daniel


as far as i know u need to use the s7-redconnect when u want to connect a pc to a redundant system (h system) . In H system u have identical addresses on both CPU

 

[jeilers]

thanks for the replies, so as far as i understand it i will have to use the H-system if i want to be able to do network-redundancy. ;-)

 

[JesperMP]

Hello jeilers.

You didnt state what is in the other end of the ethernet connection.
A HMI ? If so which type ?
Another PLC ?
Or something else ?

Depending on what you connect to, and what your requirements are, there may still be some possibilities with a 'regular' S7-300.

 

[Money4Nothing]

Are you looking for media redundancy to protect against a cable being broken? Or are you looking for connection redundancy to protect against a connection failure? Or device redundancy to protect against a device failure?

Connection redundancy is best implemented by protocol, rather than hardware. The best one that I know of is Spanning Tree Protocol. However, I don't think the PLC industry has begun to implement this anywhere. At least I haven't heard of anything.

Anyway, you can read a bit here: http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/sw_ntman/cwsimain/cwsi2/cwsiug2/vlan2/stpapp.htm

Good luck,

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