I/O forcing from two stations for common processor

This is the same same qustion I have asked in previous thread.But I didn't get complete clarification.

The Main querry is possibility to made engineering functions from two locations such as I/O forcing,program changings etc ., with out disturbing other plants operation/program.

We are envisaging a common processing station for two different plants. However, work stations, engineering stations and I/O modules(Remote I/O) will be separately located for both plants.

1st plant:

Power plant comprising 1500 I/Os,1 engineering station ,2 operator stations.

2nd plant ;

steel plant comprising 1000 I/Os ,1 engineering station( To be decided),1 or 2 operator stations( depends upon engineering station finalisation)

I want to know the possibilities to "maintain two engineering stations for a single processor and each engineering station should not disturb other plants programme".


I want to clear one thing. Earlier I worked in a power plant (ABB- freelance 2000).It's having One engineering station comprising total plant, One operating station comprising graphics to opearate turbine only and another operating station for boiler.

In this case the two plants are at two locations at a distance of 1km.So there is possibility to design different graphics to operate respective plants.

The main thing is possibility to keep two engineering stations for doing engineering functions,such as i/o forcing ,programme changings etc.,

I am cleared about saving is low.Just I want know to technical possibilities.

Earlier I worked on Modicon(Quantum) PLCs(Programming software Concept v2.2) .The system having 1 engineering station and one opearting station.I loaded the software in to operating station also and loaded the programme to PLC.I succeeded to access the PLC programme monitoring ,I/O forcing etc.,But at the same time while accessing from engineering station ,there is showing version error.So again I loaded the programme in to PLC from Engineering station.Then it is O.K.But the pobem is shifted to Operating station .Again here it is showing version error.That means we can acess the PLC from one station only.But Iam not an expert in PLCs.So, may be I made some mistakes while doing the above.Please give your suggestions /comments for the above.

What brand and model of PLC? What network? What SCADA (I presume there is a SCADA)?

BobB said:

What brand and model of PLC? What network? What SCADA (I presume there is a SCADA)?

Click to expand...

Not at decided.It is a proposal for an upcoming project.

Unable to answer as you have no specifics.

As you are putting everything into the one and same PLC, then yes of course you can do everything like programming, forcing etc.
For the PLC it looks like one process.

Some PLCs can have multiple main processes. However I dont think it will mean much of a difference.

The problem is not that you can work on one process without disturbing the other.
The problem is that you cannot shutdown one process without disturbing the other.

And, if there are problems with the PLC, then the consequences are doubbly severe.

I cant see any advantages with putting all the eggs in the same basket.

edit:
I like to add that to make changes to the hardware configuration often require that the PLC is stopped.
And as your projects are relatively large then it is quite likely that hardware changes will be required.
It is thus much smarter to make a fine-grained solution in stead of a monolitic solution. Thereby only the small part of the proces that needs to be changed has to be stopped.
The trend as I see it is that CPUs and IO gets more and more distributed. The powerful networking that is available today then binds all the distributed CPUs, IO and HMIs together.

I agree, with a system this large, I would install at least 2 processors, perhaps more depending on the details. These processors could then be networked together or stand alone, each with it's on engineering station. You don't want to shut down the power station because of a problem in the steel mill, or vice versa.

THe processor we are planning is redundant.

I still think it is a bad plan. What will you do when you have to preform some function that requires taking the processor off line? Shut down both plants?

Why are you going down this path? Do you already have one plant running and plan to expand the system for two plants?

We designed earlier as seperate processors.But the main problem is some of our higher official has given this suggestion.I have to defend my proposal.
Both are new plants.