I am wondering if there is a check list on how do we choose a PC model to run a Scada software, for example, Wonderware Intouch.

PC suppliers (e.g. Dell) have various models of PCs, for example, "home PC", "Small Office PC", "Large Office PC", "WorkStation PC", "Servers PC", etc.... And the price range is very big. Are there any risk in using the "cheapest" "Home PC" model to run a Scada software for Operations in a "Critical Process"?

That is to say, are they any difference in the reliability of a "home PC" and a "Workstation PC".

Thank you.

 

I'm running about 25 home PCs and 15 industrial PCs at work. For me, home PCs are the same in reliability with one exception:
Because the technology changes so quickly, you cannot trust that you can buy the same hardware in even two months again. And sometimes cheap PCs contain components which are not fully compatible or not supported by the BIOS.
But this may happen with the workstation type as well. And it may be hard claim that a PC is not fit for your purpose, unless the dealer explicitly stated it.
Therefore I should allways prefer to buy from a local dealer where I can say "let me try another box" if I get into trouble.
The major source of failures are harddisks, both on home, office or industrial PCs when they run 7x24.
On our machinery, we run continous production processes. Once set up, the machine and it's PLC continue to run. If the SCADA fail's you cannot watch and change anything and no data is recorded, but we can change a PC without disturbing production.
HTH

 

Forget about home vs. workstation pc's. What you need if your application is truely critical is an industrial pc. There are definite advantages in reliability, etc. There are many manufacturers, Advantech, SquareD, Phoenix Contact just to name a few.

 

The key question to ask is "What happens WHEN the PC fails?" If the answer is "We can't let it fail" then you have to figure out some sort of redundant system. If failure of the PC is no problem, then you might look at an inexpensive "home" PC and plan on having a fully-configured spare on hand.

The second question is "What environment will the PC operate in?" Industrial PCs are really tough, but very expensive. If the PC is located in an office, why pay for NEMA enclosures? If the PC is on the shop floor, then maybe a high-quality emclosure (ICE Station or similar) will let you use an inexpensive computer.

Every application is different, just remember ALL computers fail eventually.

 

Trying not to be too glib, but you get what you pay for.

Talking to the SCADA OEM about recommended platforms is always a good idea.

RA

 

We use Wonderware for our Oil&Gas operations and it's a critical app. We needed a cheap but reliable solution and we selected Dell's Poweredge
servers with RAID arrays and redundant fan. Their servers are great and the price tag is lower than HP(compaq). Also their support is very effective.
It all depends on how critical is your app, how dynamic is your field operations, and finally what's your clients expectations (downtime zero,
99.99,etc). You could go with a desktop, but e prepared for the unexpected..

william carrillo
scada engineer
Petroleos de Venezuela S.A. (PDVSA)
Maracaibo,venezuela

 

The one problem I have had with industrial PCs over the years is poor quality. We have tried lots of vendors and had too much infant mortality on the early part of the bath tub reliability curve. Not to say that we just did not try the right vendor though.

As far as superior reliability, we have had problems with both industrial and office-grade PCs. I have never seen a definitive study without bias showing which is better. I do not consider my own experiences statistically useful. I am sure many users will have office-grade stuff that they have sitting out on the shop floor covered in muck that run day after day.

Someone needs to prove that they are worth the extra money, anecdotes (including my own) are not enough.

One aside is that we had a customer with a ruggedised box that is so ugly no one would ever steal it (however, when he got the box the first thing he said was "industrial my a*s" nothing the lack of seals on closures, open vents et cetera). Office-grade boxes and laptops have a habit of disappearing if you are not careful.

RA

 

Here is a typical reason to only buy name-brand PCs. One of my colleagues was trying to find out why his mother-in-law's PC was overheating. The heat sink was firmly attached to the CPU, he managed to rip it off (breaking the CPU in two) and found out that her 300+ MHz AMD K6 system was relying on an over-clocked 200 MHz component.

Also, look on the web at feedback regarding your local PC vendor. I read lots of interesting stuff when I looked into one we had been dealing with for many years.

As far as when you get to Dell or HP and buy a home of office PC, I do not see much in it. As pointed out by others, what you buy on Friday is not the same as Monday for either type of platform. I know that Dell do not even stock their own components, when your order comes in it is prepared in three days via just in time and suppliers having the stock.

We bought some customer-specified thin clients from a less-than-brand-name vendor and on one unit the CPU had a bent pin and on another unit the CPU was loose in the CPU box.

I have never been entirely happy with any brand of PC. Too much commoditisation and too little muscle from automation customers.

RA

 

If you are using Windows the hardware reliability issue should be statistically insignificant except that the MTTR is longer. In other words, the hardware is the least of your concerns.

Regards

cww