Re: [time-nuts] GPIB on HP5382B counter
I'm out of practice with C, but shouldn't viScanf(vi, %t, buf); be viScanf(vi, %t, buf); [I'm not a language wizard.] It looks OK to me. Arrays are passed by pointer. buf is the same as buf[0] The compiler should complain if it is wrong. A quick google found examples without the . For production code I'd want to tell viScanf the max length. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPIB on HP5382B counter
Hal Murray wrote: I'm out of practice with C, but shouldn't viScanf(vi, %t, buf); be viScanf(vi, %t, buf); [I'm not a language wizard.] It looks OK to me. Arrays are passed by pointer. buf is the same as buf[0] The compiler should complain if it is wrong. A quick google found examples without the . Indeed: http://zone.ni.com/devzone/cda/tut/p/id/4727 Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPIB on HP5382B counter
If buf is defined as an array (eg. char buf[100];) its name is a constant that points to the start of the array. You can write it either as buf, or buf. -Chuck Harris Brent Gordon wrote: I'm out of practice with C, but shouldn't viScanf(vi, %t, buf); be viScanf(vi, %t, buf); Brent ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPIB on HP5382B counter
If buf is defined as an array (eg. char buf[100];) its name is a constant that points to the start of the array. You can write it either as buf, or buf. Not quite. You need buf[0] buf is a pointer to the array. (first element) buf is a pointer to that pointer. buf[0] is a pointer to the first element of the array. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPIB on HP5382B counter
Not quite. You need buf[0]
buf is a pointer to the array. (first element)
buf is a pointer to that pointer.
buf[0] is a pointer to the first element of the array.
Hal, try the following with your C compiler...
#include stdio.h
void main ()
{
char buf[100] = { 3,1,4,1,5 };
printf(0x%.8lX\n, buf);
printf(0x%.8lX\n, buf);
printf(0x%.8lX\n, buf[0]);
printf(0x%.8lX\n, buf[0]);
}
And see if your results and intuition agree.
0x0012FF1C
0x0012FF1C
0x0003
0x0012FF1C
/tvb
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Re: [time-nuts] GPIB on HP5382B counter
Hal Murray wrote:
If buf is defined as an array (eg. char buf[100];) its name is a
constant that points to the start of the array. You can write it
either as buf, or buf.
Not quite. You need buf[0]
buf is a pointer to the array. (first element)
buf is a pointer to that pointer.
buf[0] is a pointer to the first element of the array.
Not quite.
Piece of example code:
#include stdio.h
int main()
{
int buf[100];
printf(%p %p %p\n, buf, buf, buf[0]);
return 0;
}
Prints
0xbf933224 0xbf933224 0xbf933224
So they are the same in this context. That's how it works. I could
detail it in booring details if needed.
Cheers,
Magnus
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Re: [time-nuts] GPIB on HP5382B counter
At 04:46 PM 10/24/2009, Tom Van Baak wrote... Not quite. You need buf[0] buf is a pointer to the array. (first element) buf is a pointer to that pointer. buf[0] is a pointer to the first element of the array. Hal, try the following with your C compiler... BASIC is _so_ much easier. :-) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPIB on HP5382B counter
t...@leapsecond.com said: Hal, try the following with your C compiler... ... mag...@rubidium.dyndns.org said: Not quite. ... Argh/blush. Sigh. Thanks for the correction, and apologies for cluttering up the list with bogus info. I fished out my old copy of Andrew Koenig's C Traps and Pitfalls. Chapter 2 starts with Pointers and Arrays. It's Copyrighted 1989. Does anybody know of a other books that cover similar material? It's a very good book and I like the style. I'm just looking for additional info, a second opinion/viewpoint. Sometimes saying the same thing in a different way will click. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] GPIB on HP5382B counter
I'm still trying to get the HP5328B counter to work with GPIB. I don't have
any problems talking, however I can't receive data.
I think the basic (HP/Agilent) hardware/software are ok, with a similar type
of program I am able to send/receive to a 34401 Digital Multimeter.
It seems like it should be pretty straight forward to implement but I can't
figure out where I'm going wrong. There is a test oscillator driving the
counter at ~5MHz, The Oscillator drifts a bit, so I can see every time it
captures a new measurement. The counter is not in talk only mode
#include visa.h
#include stdio.h
#include windows.h
#include string.h
void main () {
ViSession defaultRM, vi;
char buf[25] = {0};
char buf1[25] = {Press Return to exit};
/* Open session to GPIB device */
viOpenDefaultRM (defaultRM);
viOpen (defaultRM, GPIB0::3::INSTR, VI_NULL,VI_NULL, vi); //This is
for USB to GPIB adapter
viPrintf(vi, PF4G6S024R, \n); // Frequencey
measurement, CH#A, 1Hz res, single measurement,
// Wait to output; Service request at end of meas. Output at end of Measure.
Sleep(2000);
viPrintf(vi, T, \n); // Trigger
Sleep(2000);
viScanf(vi, %t, buf); // read results
printf(DATA string 1: %s\n, buf); // Print results
viClose (vi); // Close session
viClose (defaultRM);
printf(buf1);
gets(buf1);// Program exit after RETURN
}
Thanks to all those who responded last week.
Best regards,
Jerome KC6ENE
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Re: [time-nuts] GPIB on HP5382B counter
I'm out of practice with C, but shouldn't viScanf(vi, %t, buf); be viScanf(vi, %t, buf); Brent Jerome Peters wrote: I'm still trying to get the HP5328B counter to work with GPIB. I don't have any problems talking, however I can't receive data. I think the basic (HP/Agilent) hardware/software are ok, with a similar type of program I am able to send/receive to a 34401 Digital Multimeter. It seems like it should be pretty straight forward to implement but I can't fi gure out where I'm going wrong. There is a test oscillator driving the counter at ~5MHz, The Oscillator drifts a bit, so I can see every time it captures a ne w measurement. The counter is not in talk only mode ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
