source problem at mV and mA

[CETIN]

Hi everyone,

I m a Keithley 2612 user and I can give as current or voltage when Volts or Amps.(for example 1 V, -1 V , 1 A) but when I want to source 200 mV or 20 microamper device does not work. I think I have a range problem but I cannot solve it. If you had similiar problem, please share your experience.

Thank you.

[njacacia]

First, you need to make certain the instrument is capable of this.

Second, you need to verify how to do it from the Keithley's front panel.

Third, then you program using LabVIEW.

[Taylorh140]

I couldn't get your VI to download, but i did look at the specs for the device and it has better resolution the 1V or 1A:

Models 2611 and 2612 source-measure capabilities:

Measure ±DC current => 1pA to 1.531A

Measure ±DC voltage => 1μV to 204V

It looks like the command to read current is: print(smua.measure.i())

I would probe the string value returned from this measurement.

If i were trouble shooting this first thing i would check is that the value is not coerced into a singed integer somewhere along the acquisition process. Make sure you are using the fract/Exp string to number and not the decimal string to number. That would be my initial guess.

[cstorey]

Couldn't download your vi.  Are you trying to do this with the Keithley 2600 LabVIEW driver?  It's available here.. https://www.tek.com/source-measure-units/2635-software/keithley-series-2600-2600a-2600b-native-labvi...

If you're using that make sure you wire the channel and source type.  See below..

You can just send TSP commands directly to the instrument using VISA or GPIB, then the string looks something like..

"smua.source.levelv = 0.001000" for 1mV on Channel A

or

"smub.source.leveli = 1.000000E-6" for 1uA on Channel B

Hope that helps.

[CETIN]

Thank you for your answers. I tried fract/Exp string to number but it does not work. I again send  my VI. 

[CETIN]

  cstorey 

MEMBER

‎10-23-2017 12:22 PM - edited ‎10-23-2017 12:23 PM

Couldn't download your vi.  Are you trying to do this with the Keithley 2600 LabVIEW driver?  It's available here.. https://www.tek.com/source-measure-units/2635-software/keithley-series-2600-2600a-2600b-native-labvi...

Yes I use keithley 2600 labview driver.

[CETIN]

Couldn't download your vi.  Are you trying to do this with the Keithley 2600 LabVIEW driver?  It's available here.. https://www.tek.com/source-measure-units/2635-software/keithley-series-2600-2600a-2600b-native-labvi...

Yes I use keithley 2600 labview driver.

[cstorey]

Have you used debugging to look at the string that is being sent to the instrument?  Maybe do a reset before you try..perhaps your instrument is set to a source range where the resolution on the display just isn't showing what you want.  I would try to source then measure what you source.  (Source 10mV across a resistor and then measure I and V and see if V is in fact 10mV).

Your filename has a comma "," in it and I think that's a problem since I can't download that version either.  Please remove or replace the comma with a "_" and try again.

Cheers.

Craig

[CETIN]

I can change range of the SMU (mV appear on screen of the device) but before and after making "channel on" both number doesnt appear on the screen and I cannot detect any voltage of the device output (I use other volt/amp meter to measure output of device) I again download my VI. 

[CETIN · Accepted solution]

Thanks for all.

The problem is solved with your valuable contrubutions. Keithley cannot read decimal point of the computer. to solve problem, you can either remove check tick at labview> tool>options>use localized decimal point or changing "." instead of "," decimal point of computer at windows > destop settings.

[cstorey]

Glad to hear it!  Good luck with the measurements.