[time-nuts] Prologix GPIB-USB vs. GPIB-LAN vs. NI was: AW: Prologix GPIB-USB vs. GPIB-LAN

Ulrich Bangert df6jb at ulrich-bangert.de
Mon Jul 6 04:00:11 UTC 2009


Gents,

as you know I have tried in my utility EZGPIB to supply the user with high
level functions for data communications which keep him away from the low
level tasks of direct communication with the interface. Since EZGPIB not
only supports the Prologix products (USB & LAN) but also GPIB32.DLL based
products (i.e. the complete line of NI GPIB interfaces) a script written in
EZGPIB is independent from a certain manufacturer to a high degree. 

That is the point that I wanted to add to the current discussion.

Please allow me to note that this independence has its limits that I just
happened to come across. I had tried to run a script for my SR620 counter
which was set to a gate time of 100 s. The script was a quick and dirty one
and set the timeout for GPIB communications to 120 s so that there was
enough time for the counter to answer, even if the data was read immediatly
after tze start of a new measurement. This script would not run ok on my
Prologix GPIB-ETHERNET interface although I was sure that is was ok when I
wrote it. 

It took me some time to realize that I was fooling myself: I had written the
script with my NI interface which's DLL allows for some decades of magnitude
of timeouts while the Prologix provide a maximum timeout of 4000 ms. That
means: Some things cannot translated 1:1 between different manufactures. I
changed the script so that the conunter's status byte was read once a second
and the "data valid bit" is detected in the status byte. Then the counter's
result is read. This of course run ok (also on NI hardware). I will include
a warning in the manual of EZGPIB.

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Chad Simpson
> Gesendet: Montag, 6. Juli 2009 04:41
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Prologix GPIB-USB vs. GPIB-LAN
> 
> 
> Good points...  and pretty much in line with my thinking.  
> Based on the comments here, I'm strongly leaning toward the 
> LAN version now.  I'll definitely have a closer look at the 
> KE5FX toolkit, there are some very interesting applications there.
> 
> Thanks everyone for your input.  Looks like I have a bit more 
> homework to do on the software end of things, but this has 
> been very informative.
> 
> - Chad.
> 
> 
> On Sun, Jul 5, 2009 at 7:50 AM, Esa Heikkinen 
> <scifiscifi at sci.fi> wrote:
> 
> > If it's about "Ethernet vs. USB" queston I would always suggest 
> > Ethernet. - With any kind of equipment in question!
> >
> > Ethernet is simpy much better: you don't need device 
> drivers, it works 
> > with longer cables (over 10 times longer than USB), it's 
> routable, you 
> > can use it remotely (VPN), you can turn it wireless (WLAN) 
> and because 
> > there are no need for drivers it's much more platform / OS 
> independent 
> > than USB.
> >
> > USB is good for devices which can draw their power from USB 
> port, like 
> > mices or keyboards. But it has many drawbacks: some USB 
> devices won't 
> > work with Windows Vista. Some USB devices has stupid drivers which 
> > need to be installed for each USB port in the computer. I'm talking 
> > about the issue when you install a driver and later plug it into 
> > different USB port the system will ask you to isntall the driver 
> > again. Also, many USB devices based on some kind of USB-Serial chip 
> > (like FTDI) may have different COM-addresses for different 
> USB ports 
> > and this leads to same kind of issue: it works only with 
> one USB port 
> > witout changing some settings. In the worst case you must 
> remember the 
> > corrent USB port for each device.
> >
> > With Ethernet it's not essential which port (or to which 
> switch) you 
> > plug in your device, as long the switch you are using is a part of 
> > your local network (or there is VPN remote connection to your 
> > network).
> >
> > But... of course this in only my opinion. :-)
> >
> > I have used the Prologix (LAN version) with KE5FX GPIB toolkit. You 
> > can use it for capturing plots from oscilloscopes, spectrum 
> analyzers 
> > etc. and write some kind of command scripts for the 
> instruments. Maybe 
> > it's not best possible software for Prologix but it it's free.
> >
> > --
> > 73s!
> > Esa
> > OH4KJU
> >
> >
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