Keithley 617 interfacing using Labview and GPIB

[mpshridhar]

Sir,

After a long gap, i m writing to you, coz i tried alll the ways to solve my problem,but all ways not at all working, so now i nee dyour help. U just simplify my vi which i sent before, Only problem is i m not at all getting readings between -1 to 1v. for this we have connected 1Kilo ohm resistor,We need to measure current across the resistor,

i hopr for the best sir, I struggled lot, I tried it for 2 months, its too costly for me, but what to to do, not at all getting results. I need to work on this,

Thanking You

Shridhar

[Dennis_Knutson]

The sweep operation is a simple mathematics operation and you can also look to see if you have the Ramp Pattern function on the Signal Generation Palette. Shown below is just a couple of ways to do it in LabVIEW with a for loop or while loop. This code will generate the correct values that you would input to the instrument. If you don't get the correct values out, then you may be programming the instrument incorrectly. You should post the code you aer using now.

[mpshridhar]

Sir,

Your mentioned vi is for only increment it seems, But I need within the voltage range -1v to 1v we need to measure current across the 1 kiloohm resistor, which we have connected as in Keithley Manual. So its becoming very tough for me to check where the error is occuring,when i run the program it will show 'derr'means d error near to triggering.but in my triggering all commands are good only.If uknow then solve it and send it to me Sir, I cant wait more for this.In this we are getting dynamic graph which must be linear.graph is current v/s voltage. I m going to attach my new vi. go through it.

[Dennis_Knutson]

What do you think the start and stop controls are for? They are not decorations.

[Dennis_Knutson]

And about all I can tell is that your sweep function is sort of working (it does not start at the initial voltage and does not stop at the final voltage). I do not have the instrument and you did not post a critical subVI. You can set breakpoints and single step through the code to see what the instrument is actually being programmed for and whether it is triggering or not. Unless someone who has the actual instrument sees this post and offers help, you will have to dig through the instrument manual.

p.s. What's the point of the measurement in the first frame? Why would you see if the function selected is greater than 4.1. What are you actually measuring in the first frame and how is it different in the third frame?

[mpshridhar]

Sorry Sir,

I m using GPIB card in my interfacing PC. So in my vi we have to use GPIB read, write and format&append. In your vi i m not seeing those, and one thing sir, i m using labview 5.1 version. sorry sit if i tried to write ising my 5,1 version. how shall i insert that 'set instrument' which is there in ur vi, if possible explain me, how to create set instrument.

Thanking You,

Shridhar

[mpshridhar]

Sir,

Here with missing subvi,as u told its nit at all starting with initial voltage and ending at final voltage, but i m getting reading for -1 v and 1v using my labview program. same as manually taken readings, instrument cant read the readings between -1v and 1v. dont know why. Here i m having instrument but not able to solve the problem.difficult sir,,

Thank u..

[Dennis_Knutson]

You don't get it. You posted the same VI without the subVI. A subVI IS A SEPARATE FILE! Posting a top level VI does not mean that you attach all of the subVIs.

And as I said, I don't have the instrument to do any debug. You can use the basic debug options in LabVIEW. Set a breakpoint at a function where you have a voltage set and you are reading a current. This will pause the program. You can then manually operate the instrument and try to take a measurement. Determine what needs to be done to the instrument in order to take the measurement. It may be something as simple as changing a range. Once you determine how the instrument needs to be changed, you will have to determine how to set it up programatically.

[mpshridhar]

Sorry sir, it was by  mistake, in my laptop its opening, try for this.

[mpshridhar]

Sorry sir, this is only subvi,