I'm going to a site to look into issues with some spurious alarms due to faulty plant signals.  I've received a photo of the PLC setup that appears to show two S7-300 processors next to each other in the first two slots of a rack.  Can't find any info about this setup.

What am I likely to find is going on with these CPUs when I get there?

James

do you have the project for the setu?

i think from project this are 2 s7-300 station in one project or 2 projects with 1 S7-300 station each.

you can mount a lot of S7-300 PLC on one rail but use different projects /projected station, this should be no problem

 Hello,

Freemaster

I'm going to a site to look into issues with some spurious alarms due to faulty plant signals.  I've received a photo of the PLC setup that appears to show two S7-300 processors next to each other in the first two slots of a rack.  Can't find any info about this setup.

What am I likely to find is going on with these CPUs when I get there?

James

 

 one logical tip, if you can do that unplug any of that CPU from rack and check if are connected together with black bus back side connector. This is what is important to know to my opinion because it is strange from your screenshot. Next important, is not clear to read both CPUs MLFB and other text so hard to think about next things here (different types of CPU, idea to have both next to each other). If there is black back side bus connector then is strange this and you can simply connect to CPUs and upload what is insde to your PC/PG, then you can investigate further. Look at first CPU, there isn't any connection cable to this CPU, no connection to next CPU, only power supply wires looks like. From my point of view and quick looking, it is strange cfg here from your screenshot. 

Hello Ayman,

this is ok  I wanted to put user to some effort to do research of actual situation more preciselly. Simply he then see after disassembly what is matter there  I was in hope that he will return here and tell us what he discovered  Simply in this case I'll offer to users some tip to not ask but do some own steps that logically shows reason of actual situation, HW cfg  No problem, he have now also some info what he can expect, also after my tip how it can be configured at actual situation.

Hello those of you that posted.  I didn't get any notifications so I'm afraid I've only just come back to this!

My guess, though I'm still not sure, is that the left hand CPU is simply a spare to be swapped if the other fails.  There's no I/O in the system that isn't connected to the other CPU.  I didn't have a project available so had to upload from what I could find on the PROFINET which was just the one CPU.

That LH CPU only has power connected, no PROFIBUS nor PROFINET.  I couldn't dismantle the rack to check for a backplane connector, but if there was would that CPU be able to make use of the comms via the other CPU ?

Thanks for getting involved.

James

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 Hello,

James at Freemaster

Hello those of you that posted.  I didn't get any notifications so I'm afraid I've only just come back to this!

My guess, though I'm still not sure, is that the left hand CPU is simply a spare to be swapped if the other fails.  There's no I/O in the system that isn't connected to the other CPU.  I didn't have a project available so had to upload from what I could find on the PROFINET which was just the one CPU.

That LH CPU only has power connected, no PROFIBUS nor PROFINET.  I couldn't dismantle the rack to check for a backplane connector, but if there was would that CPU be able to make use of the comms via the other CPU ?

Thanks for getting involved.

James

 

let me say my opinion, simply same as I said already before. Your actual situation is not required because left side CPU (lets say for replace in case) is not required there under power, it eats power now without any benefit. You can easy have this on safe storage for future use. To your last question, this CPU can't have connection to next CPU and also to first functional module on rack, only now working CPU is connected to first module via back bus connector. Again, therefore I've recommended to put that left CPU out of rack and check any possible connection at back side, you don't need do any full rack manipulation as you afraid. Simply this situation is same as I've expected. Really I don't know who at your side did this cfg as is actually and what benefit was expected, to me no any benefit.