Static VI with Visa serial functions is very slow to display front panel

Question

THere is a delay time of about 10-20 seconds to "display" the first VI's front panel that has Visa serial functions in the source code.
All works fine after the first load but the initial delay of the front panel load makes it look like the PC could hang during this time. AFter this other VI's load immediately with no delay. I am concerned because I do not want to have to load a VI manually every time I start the APP which is the only workaround I can do at this time.
Im wondering if anyone else has seen this kind of behaviour.
I do not remember this happening until I upgraded my APP to LV7.
DEll optiplex GX260 with 500MB RAM, Win2k and using N.I PCI-232-16 card w/ LV7 now.
Attachments:
RECV_LOOP.vi ‏55 KB

Answer 1

I would like to resurrect this thread, as I am having the same problem. The problem stems from the VISA resource control on my front panel, because I have many COM ports registered on my system. The last suggestion from Scott B. was to "post the resulting .SPY file and I'll take a look at it". So, here is my .SPY file, and as you can see, it takes far too long. As many of these COM ports were registerd from USB converters, most of them are not actually present at this time on the system. However, even the ports that ARE present take a long time to register (i.e. COM1 is present and shows 3 seconds to register). These COM ports shown in my VISA resource do not correspond to those shown in my Device Manager, nor do they correspond to those shown in MAX under Devices and Interfaces.
I am using LV 7.0 on WinXP SP2, with VISA version 3.2.
OK, I just discovered something that mostly cured the delay. When I was getting the VISA version number just now, from MAX in the Software>NI-VISA item, there is a tab "VISA Options", and another tree structure in the middle pane. Selecting "General Settings>Aliases", there was a list of the old COM ports, so I cleared this list and then re-started MAX, checked again, and now only the COM ports shown in "Devices and Interfaces" matched this list (which still doesn't match my Device Manager, but no matter). When I re-opened the LabVIEW FP, it opened quickly, and the ports listed in the VISA resource matched those I saw in MAX.
At any rate, although I just cured the symptom, the original problem of old aliases in VISA causing unacceptable delay should be fixed by NI.
David Moerman
TruView Technology Integration Ltd.
P.S. the message poster didn't allow my to post a *.spy extension, so here is the *.zip of it.
Attachments:
Capture.zip ‏2 KB