System Bogging Down

  • Thread starter Thread starter TerryW
  • Start date Start date
T

TerryW

We have successfully built our xpe box and are very happy with it. We
do wonder though why we experience some latency. We use dlportio to
check the state of a hardware address (say &h379) and we check the
state to see how many changes per second occur there we usually test @
50 hz. We notice that when we minimize and maximize forms it takes
longer to get the pulses( it seems to miss them). Is there something
that we can use to sure up these events (real Time Extensions?)

TIA

Terry H.
 
Terry,

I'm not sure that I even understand what you are asking, but...

You can buy some real time extensions from www.vci.com

You can write drivers or you can set high time critical priority for your
process and thread.

Regards,
Slobodan

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Thanks for the reply,

Sorry that I haven't been more clear. What I am trying to Do is
setup a call back timer that alerts me every 10 ms to check a dio
point (&H379) parallel port input. I have a square wave generator
that produces 25 pulses per second. I seem to miss some pulses when
we are moving forms around. I know xpe isn't hardReadTime but this
doesn't seem to be asking too much. Am I missing something


TIA
Terry
 
Yes you have been very clear and I gave you the answers you were and were
not seeking.

For increased performance accuracy you should use Win32 API functions:
SetThreadPriority, SetPriorityClass

Recently someone was seriously (or not) asking if XPe can do real-time 500
ms. (Without missing any signal).
There is no answer with 100% accuracy.

I mean if you will make head chopper device that if misses one pulse will
chop someone's head off then I would say no it is not possible. (You never
know what can go wrong disk access or some other thing).
But for most well tuned applications (99.9999%) this can be done even for
counting up to 50Hz pulses without driver support.

But if this is really important to you why don't you make simple driver that
is interrupt driven in that case there is no chance on earth that you will
miss any of signals at ultra slow speeds like 1000+ Hz or much much higher
speeds.

Or even you can use some cheap 2$< microcontrollers chips from Atmel or
Microchip to do all real time handling.

Regards,
Slobodan

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