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VRf-Serial_Problems

Question asked by VRFuser on Apr 9, 1997
> I'm porting a large program written originally in VEE 3.12 to VEE 4.0 =
> under Win NT. I'm experiencing a difference in operation with the =
> "EXECUTE RESET" command in a direct IO to an RS-232 port. It seems that =
> in 3.12 the execute reset waited several seconds before allowing =
> execution to proceed. In 4.0 the execute reset continues immediately and =
> subsequent RS-232 communication is corrupted or times out.=20
>
> A delay statement after the execute reset seems to solve the problem, =
> but with a large program finding and changing all the occurrences will =
> be time consuming. I'm also concerned about intermittent behavior if =
> other communication over the rs-232 is similarly affected.
>
> Also this behavior is different depending on if the functions are =
> executed stand-alone or imported into a main program???
>
> Does anyone know what is going on here??

Sir:

I tried to do a simple experiment to duplicate your problem:  Running VEE 4.0
(released bits) with SICL F.01.01 on WinNT 4.0 ... I set up a 34401 DMM to
operate over RS-232, then used a Direct I/O object to execute the following
commands:

    EXECUTE RESET
    WRITE TEXT "*IDN?" EOL
    READ TEXT x STRING

I banged this a dozen times and saw no problems.  Do you have any details on
how our configurations differ or how we might be better able to duplicate the
problem?

[Steven Morisse] 
I'm using SICL rev D.02.00 and using the RS-232 to control my UUT. No handshaking is utilized. The EXECUTE RESET is intended to clear the RS-232 buffer at times when the UUT might have outputted corrupt data (such as on power-up) or to ensure communication is in sync..

If possible you could just EXECUTE RESET to an unused COM port under VEE 3.12 and under 4.0, and the difference in execution time is obvious......ah! Maybe I've just answered my own question. It could be that my UUT required the delay??

What exactly does EXECUTE RESET do for a serial port? And why does it seem to be so much faster under VEE 4.0?

Thanks for any comments.






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