Rockwell Process Logix Comments


Thread Starter

J Evans

Had a demonstration of Process Logix (Rockwells DCS system) today by Rockwell Automation and I was very impressed. I Would appreciate any comments on this system by users, ie. Is it as simple as it looks, what are the downsides to this product (are there any ?)


Colin T. Marsh

I understand that A-B DH+ module for a Process Logix system has a limited implementation of PLC-5 Typed R/W messages (ASCII but not Binary). This can surprise the unwary.

Michel A. Levesque, ing.

Concerning the ProcessLogix (or PLX) system from Rockwell, we have done successful
implementations so here are the major points:

1. The PLX system from Rockwell is almost identical to the Honeywell Plantscape.
Honeywell and Rockwell did a technology sharing agreement back in 1996.
Honeywell supplied the client, server and controller.
Rockwell supplied racks, I/O's and networking (ControlNet).
Honeywell and Rockwell are competitors with the basically the same system now.

2. The PLX can integrate with the ControlLogix (CLX). However Plantscape cannot.
The I/O's, racks and networking components are shared between CLX and PLX.
You can put both CLX and PLX controllers in same chassis. PLX would handle time-based processing and the CLX would handle scan-based processing.

3. The PLX server can talk to just about anything out there. The PLX controllers can talk to the 1756 I/O's or to the CLX (depending on versions of the PLX system).
Talking to other AB PLC's can be done thru ControlNet, DH+, etc. but some conversations
can be limited. But then, which DCS can talk to PLCs without limitations?

4. As is the case with most DCS systems, the PLX has a single global database with built-in point displays, group displays and system displays. You can get down to a 5 msec loop time (this is right up there with PLC speeds). You can even do firmware upgrades of the controllers on the fly (try that on any system).

5. You can use VBA for scripting and you can put ActiveX documents, videos and a "SafeBrowser" for intra/extra/internet browsing.

So far this system works well with no major bugs. We have yet to implement a hot-backup so that feature isan unknown right now (for us anyway). The only big problem we have found is that Rockwell is basically unknown in the DCS market. They have some major catching up to do in terms of DCS vendor credibility. If they were as well known in the DCS market as they are in the PLC market, you would be hearing a lot more about the PLX.

I believe that the PLX/CLX hybrid system is probably one of the best automation solutions
available. Only time and marketing will tell.

Michel A. Levesque eng., mcp
Directeur Bureau Montreal
AIA Inc.
[email protected]