martinea@ireq.hydro.qc.ca (Alain Martineau) (01/28/91)
Hello,
I work for a large power utility and I am part of a group trying to
write the specifications for a new national control center. The old one
is obsolete, cannot be expanded and the computer models have been abandoned
by Control Data, which is on the verge of bankruptcy. So we try to incorporate
in our specs, as many standards as possible, we really need an OPEN system,
we don't want to repeat this 70 million dollars purchase every ten years.
I read in 'Communications Week' that there is the equivalent of GOSIP
for the utilities industry. Nobody I know ever heard of that. Does anybody
know anything about it ?
We try to get hold of the standards but there
seems to be many organisations with competing standards, IEEE, X/Open, COS,
ANSI, CCITT, OSF. It is confusing. I would need the addresses of those
organisms to get those standards, I have to read them if I want to specify
them, don't I ?
We have about 200 RTUS ( remote terminal units, data acquisition
equipement in the field ) each of them communicating over a dedicated
line at 1200 bps at the present time. The telecommunications department
of our company is setting up a X.25 private network and pressures us into
putting our data acquisition on it. We need the age of the data to not
exceed 1 second for digital and 5 seconds for the analog. We don't know of
anybody having done that, no manufacturer has done it and they are skeptical.
Does anybody know about a similar experience somewhere ?
Alain Martineau Hydro-Quebec
514-289-4484 Complexe Desjardins
514-289-3114 11e etage tour de l'est
martineau@atft.hydro.qc.ca P.O. Box 10000
Montreal, Canada, H5B 1B7shuford@cs.utk.edu (Richard Shuford) (02/03/91)
martinea@ireq.hydro.qc.ca (Alain Martineau of Hydro Quebec, Centre de Conduite du Reseau) writes: > ...trying to write the specifications for a new national control center. > ...So we try to incorporate in our specs as many standards as possible, > we really need an OPEN system; > we don't want to repeat this 70 million dollars purchase every ten years. Historically, the ISO committees have been more concerned to create standards with maximum generality than to design implementations that perform at high speed or withstand real-world stresses. Since you seem to have significant real-time performance concerns, the lengthy negotiation phase that most OSI protocols go through to establish a connection are a bottleneck that could become a pain in the neck. If you were to use your own physical media, your choice of protocols could reflect more closely the requirements of the problem than if you have to use whatever is available on somebody else's network. Therefore, instead of using X.25 links or any other shared-resource network, have you thought about getting your transmission people to install fiber-optic ground wire (FOGW) along your high-voltage transmission corridors? This puts the circuits right where you need data, and you can install fiber-optic transmitters and receivers (and other active hardware) of your own choosing. The bandwidth is typically limited by the electronics, not by the fiber, so future upgrades in capacity would not require stringing new cables. Such a design would give you complete control over the physical media for your data collection, giving a margin of confidence that you cannot have when your time-critical data are sharing a wire with somebody else's traffic. Of course, if you absolutely must have constant data flowing at a constant rate, you would be well advised to arrange for back-up circuits, which could be dial-up links on the switched network. Or perhaps you have non-co-routed redundant paths in your power- distribution network so that the FOGW links could also be routed for failsafe operation. -- ....Richard S. Shuford | These opinions here are held neither by the ....shuford@cs.utk.edu | University of Tennessee nor by the National ....BIX: richard | Football League.