Read Visa

[hakan_s]

Hallo, i have a question,i am trying to read data with VISA

but i want to read aproximatly 8million Data. It takes 4 minutes to read.

I use a for loop.

i discussed with Experten, they said that i must write a treiber. Is it possible to write this with Labview CVI? I'ven't yet wrote any programm with CVI.

Can somebody help me, or send me an example...?

Thanks

[Dennis_Knutson]

I don't know what a 'trieber' is but if you want to read a lot of data with VISA, you should be using the VISA Peek instead of the VISA In. The VISA In does a Map Address and Unmap with each call so it's a lot faster to do each just once like in the attachment.

p.s. There is no such thing as LabVIEW CVI. There is LabVIEW like the example you posted and there is LabWindows/CVI which is ANSI C program development.

Message Edited by Dennis Knutson on 09-26-2006 09:09 AM

[hakan_s]

Hallo Dennis, Thank you very much for your reply... It takes 10 sec. Better than 4 min.:))

but i reasd that, Visa Move In 32 can read in 1 sec. 12 MB Data... and it takes 10 sec.

I want to read 8MB. that means it should be faster than 1 sec.

is it a mistake from Visa or my PC or ....??

i use VIsa 3.4.1....

Thanks...

[shoneill]

Dennis,

A "treiber" is a "driver", just in german....

As to the rate of transfer, I think this is also dependent on other variables....

You seem to be scanning linearly over a memory range (in 4-byte intervals).

Why don't you simply scan through it and generate one array, with each array element representing an increase in offset of 4.

You can then decimate the array afterwards to get the seperate channel information.  It is also perhaps better to use a shift register with the incrementing memory offset to avoid doing an unneccessary multiplication in each loop.....

Start at your base address, and then simply add 4 each time and save the new value for the next iteration in the shift register.....

Just my 2c

Shane.

Message Edited by shoneill on 09-27-2006 10:42 AM