Tradiitonal DCS or WindowsNT based DCS?


Thread Starter

Junaid Ahmad

We are using TDC3000 DCS on our Ammonia Plant. The current software release of this system is non-windows based. The vendor (honeywell) has brought out new releases (Windows NT) and PC based operator stations. But the cost of hardware and software migration is very high.

I need to know what are the advantages of upgrading our system to WindowsNT, when our current configuration has not given us any problems? Can someone guide me about this.
Since I am not familiar with the Honeywell Software I will stick to the other issue, your existing hardware platform.

If you don't have plenty of spares sitting around waiting to take over when the main machine dies, now is a good time to put together a game plan on how to recover the system if it crashes.

One of the problems with legacy systems is fixing them after they break. Let's say your are running just fine on an old 386 with 340Meg hard drive and some graphics card. If one of the pieces takes a dive you may have a panic finding replacement parts that work.

If the main motherboard dies and you upgrade to some new fangled 500 MHZ something you may have interesting hardware problems. The old interface cards may not work any longer. You will need at least DOS 6.22 to work with the PCI bus (you will probably need to find a someone who has it sitting their MSDN CD Library). The software may not be able to deal with the high speed processor and do wierd things.

More likely the hard disk will croak, which will mean figuring out how to get a >1024 cylinder hard drive to coexist with your motherboard.

One of the companies I work for is currently dealing with older Real-Time UNIX based PCs that really need to be replaced but there isn't a direct replacement available. Everytime one of them dies it cost a lot of money to bring it back to life, often costing a plane ticket in addition to the hours fiddling with it.
Your main advantage of upgrading to a GUS (Honeywell's NT based OS)is the ability to share plant information with an existing LAN (LCN coming into your GUS and TCP/IP going out). Honeywell will sell you an APP node to do this but you can just as easily make use of Windows standard DDE calls to extract the data you're looking for. This portion of the software comes bundled with any GUS based system. Another advantage of a GUS (which I personally make extensive use of) is thier 'File Transfer' utility. This feature allows you to upload and download .CL files, .EB files etc. between the NET> on the LCN and your local harddrive, this makes project work a pleasure as the text editor within the TDC3000 system seriously sucks! the whole process is seemless to the user and it also supports normal drag & drop functionality.

At the end of the day, it looks like Honeywell are creating an open systems look and feel to thier very robust (but closed) DCS. If you don't need the functions mentioned above, it's a very expensive way of buying a new operator station!
Besides, I'm quite certain that the existing K4LCN boards will be around for a long time to come, so spares for your existing system should still be available.

What does your local Honeywell agent have to say?

Simon Lax
Senior Projects Engineer
BeST SA (Pty) Ltd

P.O. Box 1869
Pinetown, 3610
South Africa

Tel +27(31)702-8361
I agree with Simon Lax on the advantages of the GUS's and file transfer and would like to point out that within Honeywell, there is a group called EverGreen which design direct replacement parts for old hardware. Such as upgrade card files to replace old Hiway equipment to HPM I/O.

So concerns on not getting replacement parts is not a worry with Honeywell DCS Equipment.

If you need a new Window NT PC based interface you could look at using Plantscape.

End of the day it would depend on the actual hardware that is on site and cost.