invalid input parameter when file is being closed

[Daron]

Hi Veterans and no Newbies like me!!  😉

I am doing a program which will permit me to get back the resistance and the voltage given by a thin ceramic film. I have a keithley K-705 scanner which permits to 2diffenrents channels to be opened and closed allowing a HP34401A multimeter ( when channel is closed) to make the resistance and voltage measurements.

First of all i got a simply program to begin (cause it is too tricky for me :p) 

This one open a path file where the measurements will be recorded, take measurement of voltage, and do an average i want to be recorded and the time of acquisition in the meantime too.

But i got two problems :

---->  first, when i want to stop my acquisition, when labview program close the file, it gives me an known error some guys know in this forum cause i've seen it many times :

Error occured at close file :"----.vi"\

LabVIEW: An input parameter is invalid.
---
NI-488: Command requires GPIB controller to be in charge.

I have already tried to save it and change VI's and save again, it does nothing,  i have read here it was possible to changethe string command of misc icon  and write it to rsc 1, but as i don't know how it really works, i have spent 3hours on it, i haven't been able top manage it alone.

Does anyone have any clue to help me about that?

---->And then i have seen that the excel file i have created was empty 😐  (size : 0 bytes)

 Actually, when i control the running program, i see that nothing goes in my loop....

If anybody can help a great noob but who wanna improve his skills in Labview (just 2weeks on it and about 1week on this forum to learn faster :p) thanks in advance...

I give you my little program, hoping this helps

Daron 

[Daron]

Hiho!!

I was just wondering if this problem of closing file came from the fact my excel file is empty. That would imply the file to be closed has "invalid parameter"?

Anyone can make it clear for me plz???

[nyc_(is_out_of_here)]

How I would isolate this problem is that you should take your VI and strip out almost everything except for some code to write just one value to your Excel file and see what is causing your problem.

Message Edited by nyc on 05-25-2006 03:33 PM

[Daron]

Hi Nyc

Thanks for having answered me! 🙂

I have tried to let just the most important wiring in my program, but it hasn't worked.

Actually i've resolved my problem (i think) cause i had used a "for loop" (if you have seen my program) and i changed it into a "while loop". Finaly i works (dunno why, but after trying everything i rested that lol...) Actually, i got some data in my excel file and the error message linked to the input parameter problem doesn't appear anymore. So it seems to be good. I had checked up the wiring of my close data file item, but everything were OK, then i have thought about my loop. I hope this will help some noobs like me...

Nevertheless i thank you very much for your help, i think i'm not finish yet with my program, it is just the beginning, so be aware of my next message 😉

Daron

[f.grasdepot@laposte.net]

Hi,

when I hear about Excel files created from GPIB , I suggest to use
LabTab (www.LabTab.com) since it is quite straightforward for this ...
that is here in VBA:

output k705, channel_1_open_command ' manual is required for the close
command
output HP34401A, "MEAS?"
wait 0.5
enter HP34401A, a
output k705, channel_1_close_command
output k705, channel_2_open_command
output HP34401A, "MEAS?"
wait 0.5
enter HP34401A, a
output k705, channel_2_close_command

and you have the value in "a" as a string to put in Excel by:

ActiveSheet.cells(1,1)=a

you can then make your LabVIEW program by copying the command strings,
from something that works which is less painful...

Regards,

FG

[Daron]

Hi FG!

Thanks dude, i'll use it if i get more problems with my program. For the moment it works, but i 'm not finished yet, and i might have already used very complicated ways to do my program. Yours must be easier to manage. I didn't know it existed... :d

Brice

[Daron]

Hi !!

I now have to use your kind of program, but i don't really know how it works...

Actually i have already made two differents program with LabVIEW 8.0 which run. One about voltage measurement and another one about resistance measurement. For both i get the measurement by HP34401 Multimeter and i show the resuslts on screeen and in the same time i save the datas in an excel file.

But i can't run the both programs. I have got a  Keithley K-705 scanner that i must use for that but i don't really know how it works and how to switch channels... I  use the GPIB port.

So how is it possible to get both informations by Keithley scanner in switching channels in order to permit HP multimter to give me both Voltage and Resistance measurments?

I have already hear about NI-DAQmX what is that??? is it easier to use it?

I don't know how VBA works neither Labtab, however it could probably be a solution for me...

Best regards

Daron (really noob )

[Dennis_Knutson]

There is a LabVIEW driver for the switch at http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E94E3659CE034080020E74861 . If you don't have the programming manual for it, you should check with Keithley. Even with a driver, this is something you should have on hand.

DAQmx is a driver that is used for programming NI data acquisition boards. It's not relevant to any discussion of GPIB controlled instruments.

[Daron]

Hey Dennis!

Thanks for your help oh great Dennis!!!

Actually im gonna use this driver for opening and closing the channels of my Keithley scanner if i'm right... I'll just have to configure the wires my my multimeters through Labview and include this "sub- VI" in my VI program, won't I?

I have tried to understand how it works, for the moment i'm a little bit lost with, thus i'll try to use it in an easier program.

Thanks again buddy, i might need your help soon...

Regards,

Daron

[Dennis_Knutson]

I haven't looked at the driver, but yes, it's usually just a matter of calling the functions as subVIs. Look in the driver for a VI with "Getting Started" in the name. If it exists, it's a high level example of how to call some of the more common functions. A lot of the "Getting Started" examples are not really designed to be used as a subVI itself and often nothing is wired to the connector pane. It's usually more efficient to call the individual functions.

The reason that I suggested you have the manual on hand is that understanding the driver's functions is easier if you can compare them to the descriptions of the instrument's commands and functions in the manual.