Two L61 controllers in single chasis

Dear All ,

I have currently at one site a 17 slot chassis , in whose left most chassis slot i have 1756-L61 and in the right most chassis slot i have another 1756-L61.. In between these two controllers there are certain I/O modules and communication modules...

I have been told that the L61 on the left most chassis slot controls one process through some I/O cards mounted besides it while the other L61 controls another process through remaining I/O cards.. Is it Possible ????

Now the customer wants to make the process controlled by left most L61 to be redundant (CPU redundancy only , no I/O redundancy). So we are planning to remove the left most CPU L61 and replace it with CNBR(take the data from the same old I/O cards) and let it be controlled through a another redundant system , while the right most CPU will continue to control its process as it was doing before ...

Now can anybody pls tell me whether the system described above is feasible and if it is then what precautions need to be taken ..

Yes, that is possible what has been described.

The first item to look into is if and how data is being shared between the two processors and/or the I/O. The processors can share data by producing/consuming tags between each other. They can also share I/O data by creating "listen only" connections to I/O modules that the other processor "owns".

If this data is being shared between the processors you need to spend quite a bit of time looking at the programs of both systems (this should be done, regardless) and how the process works. If you move that processor and it is sharing data, depending on required reaction times you could create an issue since the controlnet connection will be slower than the backplane.

Darren

First off, I'm not expert on CLX redundancy. But you can't have any I/O modules in the chassis with the processor except Ethernet and ControlNet. You'll need to flash the processor to a firmware that supports redundancy, and of course add the redundancy module. Download from the RA library the manual for redundancy. You must follow all the "rules" for it to work.