DCS systems

[Former Member]

Hi Experts

I have a requirement to fetch the data from different DCS systems, Do I need to Install UDS on each of the DCS or Is it possible to Install the UDS on xMII server?

Thanks in Advance

[Former Member]

Hi Prasanna,

Simple answer ...

No, you do not need a separate UDS installed for each DCS. You could have multiple UDSes running on one server.

The best solution would be to install the UDS close to the DCS-es in terms of network latency. xMII to UDS server communication is optimised. Make sure you use it.

If there is no difference in terms of network, between installing the UDS on the xMII server vs another server, you might be able to get away with installing the UDSes on the xMII server. This may put some strain on the server though.

If you have a server (any factory server) available, I would recommend that you install the UDSes on it.

Keep in mind that firewall may also need to be considered.

Hope this helps.

Cheers,

Jai.

[prasanna_vittal]

HI Jai, thanks for the quick responce,

I got most of the points that you have mentioned, I will follow the approach of installing the UDS on one common server and poll the different DCS's from there.

One Question though, what all points needs to be considered for Firewall, please put some more light on this issue.

Thanks in Advance

[Former Member]

Hi Prasanna,

xMII server communicates with the UDS via a proprietary protocol. UDS would communicate with the DCS via OPC protocol. If there is a firewall between xMII server and the DCS (good chance), you would need to ensure that communication using one of the protocols is allowed.

The reason I mention "one of the two protocols" is ...

Case one:

xMII Server - Firewall - UDS - DCS

> Firewall would need to allow the proprietary communication

Case two:

xMII Server - UDS - Firewall - DCS

> Firewall would need to allow the OPC communication

Hope this helps.

Cheers,

Jai.

[Former Member]

Just be REALLY REALLY careful with the pre-4.0 OPC UDS's (and use the proper configuration for a 4.0 UDS). Because of the way it puts tags "on scan" you can pretty easily overload the DCS, which would be a bad thing, of course.

[sufw]

To me, the easiest option here is to place the UDS behind the firewall. This is simply because xMII communicates with the UDS using TCP/IP, and each UDS instance listens on a single (configurable) TCP port which should be easier to configure in a firewall than the UDS <-> DCS/SCADA/OPC/etc comms...

Sascha

[Former Member]

I would never, ever put the UDS on the DCS system unless there were no other options. The DCS is intended to perform real-time process control, and anything that could negatively affect its performance should be avoided.

Make certain that you test your scenario before attaching to a live DCS so that you can gauge the impact on performance/safety first...

[Former Member]

Hi.

I have not tried to install UDS on the xMII server, I am sure, that the recomented is to install it on the datasource. I would always try and install UDS on the datasource.

But I would ALWAYS try to fetch data from a database, and make the DCS / MES store needed data into here. Much more reliable and safe.

BR.

Poul.