SCADA Questions? : LUSENET : -Players Only- : One Thread

Western Power supplies a large percentage of the state of Western Australia with electricity. Our power stations and power grid do not attach to or interface with any other company's power grid, ie we are a stand alone power utility. I have just been advised that some of our SCADA engineers believe our GE Harris M9400 real time SCADA system (running on an AIX operation system. With a Harris M9100 support SCADA system) can be switched to manual operation. Basically, the belief is wherever there is an automated system, there is also a manual override. Remember that this switching will take a finite amount of time using a finite number of staff members. Some others in our organisation dispute the manual operation idea.

The questions I put forward to this forum are:

1) Can the SCADA system be successfully switched into manual, albeit for a brief time? Hours, days, weeks???

2) The same SCADA system has a base/start date of 1973 and include events that utilise the day of the week. One contingency plan in the offing is to roll-back the SCADA system's date 28 years so that the leap year matches the days of the week. The problem I have is if we roll-back our SCADA system 28 years to 1972 will the SCADA accept a date one year before the base/start date? (This may not work with some old PC based systems either.)

-- Anonymous, April 14, 1998


Sorry to say that I can not help you, at all, with specific information on the SCADA system.

However, with respect to a date rollback strategy . . . .

First, remember that you would be planning to rollback *in 1999* (before "Midnight") thus 28 years makes it 1971 - not 1972.

Second, if you find that you cannot go back to 1971, consider two steps -- in 1999, rollback to 1982; later, you'll roll back to 1973, as follows:

*Real* System (thinks) 1999 1982 (you could even roll-back to 1981 right now) 2000 1983 2001 1984 (You can use the 1984 calendar 'till March 1, 2000; roll back to 1973 anytime on or before February 28) 2001 1973 (after February 29) 2002 1974 and so on 'till the system is remediated/replaced

Think this will work?



-- Anonymous, April 17, 1998

Ooops, that was supposed to be a table, like this:

*Real* System (thinks)

1999 1982 (you could even roll-back to 1981 right now)

2000 1983

2001 1984 (can use the '84 calendar until March 1, 2001 'cause there's no leapday in 2001)

2001 1973 (Hopefully, your "base/start" date is before March 1 1973)

2002 1974 and so on 'till the system is remediated/replaced

-- Anonymous, April 17, 1998

Thanks for your suggestions Stephen but with every date change we will have to readjust our database.

I have been told that even one date roll-back will cause no end of trouble with our event records (database) and trying to synchronise several date changes with be impossible.

Yes you are right a 28 year roll-back from 1999 will bring the date to 1971 not 1972, my mistake.

-- Anonymous, April 22, 1998

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