Differential Conductance Measurement using Keithley 6221 & Agilent 34401

[Pimi810]

Hi.

I have a microelectrode pattern which is used for characterizing high resistance material. I want to do differential conductance measurement. There is a Keithley 6221 connected to my pc but the problem is that I don't have keithly 2687 nanovoltmeter to follow the standard routines provided by Keithley. Instead, I have to use Agilent 34401A for reading voltage.

Dose anyone know how to do it?

[nitad54448]

Hi

I think you can do it (i made it with Keithley 6221 and a Keithley 2001) but don't expect much precision nor the speed of a nanovoltmeter. If I remember correctly the 34401 is a relatively slow 6.5 digits DMM. Anyway, in the built-in differential measurement of 6221 there is a RS232 communication between the current source and the nanovoltmeter. The current source will apply a current, then trigger the voltmeter and then read it's buffer and so on. You need to built this in Labview :

1.  connect the 6221 through the gpib (or ethernet) cable

2. connect the 34401 with a gpib cable

3. start applying currents with the 6221, read the voltage with the 34401, make the calculations...

4. change the value of current, go back to 3 and so on

you need to read the 6221 manual and you will see what current to apply

you will not be able to make differential pulse measurements though

ask more if you need help

N

[Pimi810]

Tnx nitad. I succeeded. I'm so busy now but I'll  disclose the entire solution here graphically.