Loyd,
I don't believe you have to worry about 2 resets around 6:00 AM since M01
will not reset until midnight of the following day.
Ray
"Rick Rys" <[EMAIL PROTECTED]>@lists.TheCassandraProject.org> on
03/18/2001 10:10:09 AM
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Subject: RE: Accumulator Block
Loyd,
One item to be aware of is: TIM in the CALC block gets the time from the
CP
operating system (VRTX). As the CP (operating system) is a slave
timekeeper
that is updated about every 10 minutes it is possible to skip a particular
second if time is adjusted forward or if the time were set back, to pass
through the same "seconds from midnight" twice within a few seconds. This
would rarely happen as there are 600 seconds in 10 minutes and it would
depend on the CP clock drift relative to the Master timekeeper clock drift
and unknown details of how the time is actually updated. Some engineers
have had trouble with this i.e. when CALC blocks looked for a particular
"point" in time. It's not clear how much a CP clock can drift in 10
minutes, but unlike your PC motherboard the CP must keep time with the
relatively poor clock of the Intel CPU as it has no battery backed real
time
clock. Ray Chouinard gives a pretty good example CALC. If the clock
update
were a few seconds backwards it would appear possible to get 2 resets
within
a few seconds. Presumably this is tolerable.
Also upon a "power-off" CP reboot the CP time is unlikely to be correct
initially (I think it comes up Jan 1, 1986) until the master timekeeper
sets
the time - a few minutes later. CALC blocks using TIM will likely undergo
an abrupt change during this first time adjustment. This may present
problems if you have one master accum block reset function used for
multiple
CP's.
Rick Rys
R2Controls
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