keithley 6221 & 2182A sweep in terms of voltage

[island]

I am trying to use the "differential conductance mode" in software "KI6220.vi" to measure the conductance. In my case, I need to plot a 3-D graph which has source-drain voltage (X), gate voltage (Y) and conductance (Z). So I need to take a sweep in terms of VOLTAGE for source-drain bias. Then the program began to do "auto-test sequence running" but ended with a table saying it could not do it (please see my attached pics). This voltage sweep function works fine over a resistor, but not over a transistor. Appreciates for any advices. 

[EEsRULEtheWORLD]

Hi, island.

The Keithley 6221 driver is not a supported National Instruments driver, but I'll try to help you the best I can.

I downloaded the Keithley driver from Keithley's website and was able to access the KE662x VIs in LabVIEW, but I am unable to locate the KI6220.vi.  Is this a VI that you had created?  Please attach this VI to the reply of this post or point me in the direction to where you had found it.

For some reason, I was unable to open the data sheets and manuals on Keithley's website.  Can you tell me exactly what is "auto-test sequence running?"

Also, I would contact Keithley concerning the functionality of the 6221 and 2182A.  It is possible that there is some setting that needs to be made on these particular devices to voltage sweep a resistor versus a transistor.

[nitad54448]

Hi

I think that the 6221 plus 2182 with the conductance measurement software from Keithley are designed for resistor-like device : de "delta" like current pulses are followed by the nanovoltmeter measurement. I don't know if you can setup such a "transistor"measurement!?

rgds

[island]

Hi Sara,

Thanks for your reply. This "KI6220.vi" was downloaded from the website below. It is an example software written by the Keithley.

http://www.keithley.com/base_download?dassetid=16067

There is no manual of KI6220.vi on Keithley's website, some explanations are found in the software's help document, they do not explain what this "auto-test sequence running" is trying to do. But it seems trying to locate a resistance value for the device under test, that is unable to accomplished on a transistor. This is what I am thinking so far. But I could not figure out how to set it right.

Thanks and Regards

Nan

[EEsRULEtheWORLD]

Hi, Nan.

Since this is an executable and I am unable to view the Block Diagram, I cannot troubleshoot the code.  I tried running the program in "Demo mode" with your same settings, and the run was successful, without throwing a warning.  At this point, you may want to contact Keithley.  Nitad5448's comment concerning the 6221/2182's ability to set up a transistor measurement may need to be looked into.  As it says in the warning message, you may also want to check the connections of your transistor and verify that it is enough signal to be measured.  I noticed you selected 0 A for both the current start and stop values.  This may be the source of the warning; the sweep is starting and stopping at 0 A.

You can contact an engineer at Keithley here.  They will be better able to answer any questions regarding signal connections with the 6221 and 2182.

[island]

Hi Sara,

The problem happened when I chose the sweep in terms of voltage rather than current. Are you able to take a voltage sweep on a transistor? Thanks.

Nan

[JÞB]

As a side note:

This exe from Keithley is complied in LabVIEW 7.0 and runs on the 7.0RTE.  Be careful! You will need a NI-VISA version that supports LVTRE7.0!  And, of course, VISA wasn't really 'stable' (for lack of a better term) til LabVIEW 7.1.

Kiethley should really invest in updating its drivers and examples.  Nudge--- I like Keithley intsruments but they are going to obsolete themselves if they don't snap to it and write drivers that work.  

[nitad54448]

i agree with you jeff; i had to write a lot of routines for a 6221....

rgds

n

[venkky]

Does anyone has the block diagram for KI622x.vi .  I want to edit the program and make it convenient to me, as I suppose with my limited labview knowledge it will take more time if I strat from scratch. I feel people have written some program like KI622x.vi and I will be very thankful if they can share it here. Unfortunaltely keithley engineers are strongly committed not to provide the block diagram. 

[EEsRULEtheWORLD]

Hi venkky,

Island posted the link as:

http://www.keithley.com/base_download?dassetid=16067

Since this is an executable that has been created by Keithley, there is no way that anyone other than Keithley can provide access to the code.  Good luck in your applications!