Multiple OPC Servers to SCADA

Hello,

We have 5 plants connected with either fibre or 150Mbps ptp ethernet radios. Each plant is running either RSView32 or Factorytalk.

We are in the middle of setting up a SCADA system at one of the plants and would like to bring all of the plant PLCs(CLXs, SLCs, Micros) into SCADA. We are currently talking to 2 remote station CompactLogix PLCs using RSLinx OPC residing on our SCADA servers.

What would be the best way to bring our plant PLCs into SCADA? Should we install RSLinx Gateway on each of the RSView and Factorytalk machines at the plants, and then access data from them into SCADA? Some people are leaning towards setting up the SCADA servers as RSLinx OPC servers to talk directly to the plant PLCs. But then we would have 2 OPC servers talking to each PLC and that could cause grief, but if not it would be a lot easier.

Any questions please ask. I look forward to your responses! Our SCADA host/OPC client is Telvent.

Thanks!

I'm a big fan of using Kepware (www.kepware.com). As long as the controls are reachable from the scada machine, just do it all in one spot. Sounds like you'd only need the AB Suite of drivers to get that job done.

Hey, thanks for the reply.

We are not going to get rid of the Factorytalk and RSView computers so either they or the SCADA servers will have to be clients. It would be a lot easier and I think safer to keep the RSView and Factorytalk computers the servers.

Anyone??

This is a trickier question than you might think, and I had read your post several times to figure out what your system is like.

I think the principal confusion is what software system you're calling "SCADA"; is this a system from Telvent, or is it a larger RSView32 or FactoryTalk View system ?

I think you should weigh these factors:

Remote OPC versus local OPC.

If your systemwide network is well managed enough and you or your staff have enough automation and IT experience to run Remote OPC, I think that installing an RSLinx Gateway license at each of the local HMI systems is the right way to go. But Remote OPC can be very tricky to configure and maintain, especially if each of these plants has separately managed Windows domains.

Automation network bandwidth.

This ties in to the Remote OPC issue a little bit: if two supervisory systems are requesting the same PLC data separately, that doubles the load on the PLC communications processor and on the PLC network. If all your controllers are connected right to Ethernet, this is seldom a problem. If you have a bunch of DH+ or DH485 networks, it might be.

PLC online monitoring/editing.

If you have a lot of local ControlNet or DH+ or DH485 networks and want to perform online editing or monitoring using tools like RSLogix (rather than your SCADA system) from a central location, then RSLinx Gateway is ideal because it lets you use those network interfaces across an Ethernet network as though they were local. This eliminates the need to have RSLogix licenses on the remote machines (or a network server for them) or to use bandwidth-intensive remote desktop protocols.

I tend to come down on the side of installing RSLinx Gateway licenses (or even FactoryTalk Gateway, for access to the FTView internal databases) on the various HMI computers around your system. It will cost more up front, and possibly be more difficult to implement at first, but I've seen enough badly-clogged automation networks to want to avoid doubling the visualization traffic to the PLCs.

RA and Westburne have some very good technical folks if you want to discuss this with somebody local in Vancouver.

Hi Ken,

Thank you for the excellent response. Our SCADA system is Telvent's Oasys DNA.

Almost all of our PLCs are ethernet..every one but 2, and we were just talking about upgrading the controllers to ethernet.

Currently our local HMIs are not on the SCADA domain, but they can be.

Six in one hand, half a dozen in the other.

This is my conclusion: To be safe in the end, RSView Gateway and Factorytalk Gateway at each of the HMI computers is the way to go.

Does RSLinx OPC store data when it polls a PLC? What is happening when an OPC client requests data? It is really hard to find documentation on how the OPC client retrieves data from the PLC.

Thanks again.

Just to give an update: We are going to discuss this further with a Westburne employee and RA architect.

Our FT servers are redundant and we need to know how to implement FT Gateway properly to retain the redundancy.

I will provide yous with an update.

To utilize the need for multiple facilities, you will likely need to go with OPC-UA.

Unified Architechure provides the ability to connect multiple locations. More information can be found through the following link:

http://www.eternity-sales.com/kepware/opc_ua.htm

We are a Kepware distributor.

If you would like to discuss your requirements further, feel free to email us through the link found in our signature.