Question on redundant machines

G

Thread Starter

Ganesh Ranganathan

Hello

My project involves connecting a server computer to the hardware and having a redundant machine in case the server computer fails. I have to do 10 such configurations. I know and have used Wonderware. I am looking for a cheaper alternative.

Are there any software in the market where I don't
have to pay extra for the redundant computer.

I would appreciate any replies.

Thanks
Ganesh
 
L
Hello Ganesh. I'm not sure if I understood your posting however you might
want to take a look at an HMI package called Citect. With Citect, a
standard feature of the software is automatic fail over to a redundant I/O
server if the main server fails. You set up both servers with the standard
server set up wizard provided by Citect. You still have to but a redundant
server of course however, you don't need and additional software. Also your
main and redundant servers can be the hardware of your choice, industrial
grade or standard desk top. You can find the Citect web site at the address
below.

http://www.citect.com

I have seen at least one other software product that gives you redundancy
and they claim to also provide protection from Operating System crashes.
>From what I recall, they go into Windows NT and strip out, modify, or
enhance the OS to do what they want, and it's suppose to give you some
additional protection from an OS crash. I don't know much about their
product but if you would like more information e-mail or call me, and I will
try to find out the name of the company for you. With their solution, you
would of course have to buy additional software and at the time I saw the
product is was kind of high priced. It may have come down in price since I
saw it last.

Cheers

Larry Kiel
Kennedy Space Center Fl
407-867-1415
 
M
The only way that I know that you could do this is with a freeware (non-commercial) package, or one that you wrote yourself. You may be able to
get special dispensation from the manufacturer (Wonderware in the case of Intouch) but that is unlikely. Generally, when using COTS packages (such as Intouch, MS-SQL Server, RSView etc) you need a license for EVERY machine that the software is installed on.

Some houses allow you to have a two installs as a courtesy, under special circumstances, e.g. Lotus used to allow you to install a copy of SmartSuite
at home provided that you were using an enterprise version at work.

I don't know of any one in our field that would offer you a similar deal on SCADA (generally I would suspect that they make a fair amount of money out of redundant systems).

I don't know of any freeware MMI/SCADA packages either.

A good, fast, freeware RDBMS is MySQL. It is only free under certain circumstances though. Details are on its web site. http://www.tcx.se/.
 
B
You have to pay for the redundant computer. You cannot avoid that. It is the actual hardware that you must buy. Wonderware doesn't charge extra for the redundancy. You buy the package and configure the way you want it. Redundant or Non-Redundant system they don't care, it is all up to your system requirements.

As far as the cost of the software goes you may be able to find a cheaper package. However, remember that for a complex system as yours the initial cost of buying the software should not be a deciding factor.
 
R

Robert Nickel

As for free HMI/MMI, I don't know of one either, but for free SQL servers, there are several. MYSQL is one. Another is Sybase's Adaptive Server Enterprise. It's free on Linux and it is quick. Just for general information, Micro$oft SQL has a Sybase code base.

--Robert
 
J

Jack Gallagher

Larry Wrote:

>>I have seen at least one other software product that gives you redundancy and they claim to also provide protection from Operating System crashes.
From what I recall, they go into Windows NT and strip out, modify, or enhance the OS to do what they want, and it's suppose to give you some
additional protection from an OS crash. I don't know much about their product but if you would like more information e-mail or call me, and I will try to find out the name of the company for you. ...<<

I think the product you are thinking of is the Marathon Technologies
solution.

^^^^^^^^^^^^^^^^^^^^^^^^
Jack Gallagher
SES CO Inc.
3 Vision Drive
Natick, MA 01760
Phone: (508) 650-9147
Fax: (508) 650-9310
^^^^^^^^^^^^^^^^^^^^^^^^
 
The piece most people overlook when building a redundant system is that the network rather than the computers are more likely to fail. When building a redundant system, network cabling redundancy between all components that are
important (PLCs, viewers, servers) is critical, after all the purpose of redundancy is to avoid a single point of failure. Your network is way more
likely to fail (by the cleaning lady unplugging the hub for instance), than the computers.

The main cost of a redundant system is not the software, but rather the engineering time that goes into designing the application to work
redundantly. Look for a package that provides redundancy within the product rather than relying on you to write scripts to synchronize point and alarm data and manage cable failures.

_________________________________
Pete Sage
CIMPLICITY Development Engineer
GE Fanuc Automation, NA
[email protected]
www.cimplicity.com
 
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