Jeff,
John's point of having to reset the PC time-of-day is right on. A PC is
driven by an interrupt system and the I/O ports where sensors are connected
and the internal time-of-day clock are the lowest priorities due to the
slow data rates (compared to what is going on inside the PC at 200Mhz +)
and this lower priority causes the time-of-day clock (and the .001 second
requirement) to vary slightly.
All of the software timing solutions are cost effective (if you don't count
the cost of the PC) and offer the driver registration and scoring, some
offer the timing also. Software timing will vary slightly from one PC to
another based on what's in the PC, so comparing results from one region to
another would not be accurate to .001 seconds. Comparing results from one
event to another would require using the same PC hardware for both events,
but even then, that would not guarantee .001 second accuracy for both
events.
Hardware timers have accuracy far beyond the .001 seconds. Comparing
timing results from one event to another or one region to another would be
completely accurate irregardless of which hardware timer was used (okay
there are some really old timers that would be excluded).
--- I meant 'timers that are old' and not 'old-timers', okay ---
Most hardware timers and most software packages interface to large displays
to display race results. The only difference here is what information can
be displayed, that varies with the display as well as the hardware/software
used to score.
Cost is always a factor in timing equipment. Redundancy should be
considered just as important, after all, when the automated timing goes
away ... it's back to stopwatches.
I would be glad to provide additional detailed background on hardware and
software timing features and advantages. If you are interested, give me a
call at (408) 988-6188 or reply back with a phone number and I will give
you a call.
Dennis Laczny
RACEAMERICA Timing Systems
http://www.raceamerica.com
>Mark,
>
>I am definitely not an electrical engineer but I have heard from more than
>one expert that Computers are not accurate enough to keep time down to .001
>second. I notice that my system clock needs to be corrected quite often. If
>accuracy is not a concern the stand alone system would be the way to go. Also
>remember that the switches are not created equal in the accuracy department.
>If I purchased a software for Timing/Scoring I would get software that could
>be used with or without a timer. Redundancy is nice to have!
>
>John Taylor
>assistant timer @Gulfcoast Autocrossers Ltd.
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