Keithey 2410 - How To Read Out All Filtering Measurements?

[a4gb0s23]

Hi,

I'm using a Keithley 2410 (controlled via python) to source a list of voltages and measure the current at each voltage. The Keithley's "repeating filter" is enabled so that the current reading at each voltage is actually an average of 10 measurements. In the end I get a list of voltages and the corresponding (averaged) current at each voltage -  but I want also want to know the details of the 10 individual measurements that were taken at each voltage. Does anyone know how I can read out this information?

Any suggestions would be much appreciated!

Thanks

[Henrik_Volkers]

RTFM?

SCNR

[Minions]

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@a4gb0s23 wrote:

Hi,

I'm using a Keithley 2410 (controlled via python) to source a list of voltages and measure the current at each voltage. The Keithley's "repeating filter" is enabled so that the current reading at each voltage is actually an average of 10 measurements. In the end I get a list of voltages and the corresponding (averaged) current at each voltage -  but I want also want to know the details of the 10 individual measurements that were taken at each voltage. Does anyone know how I can read out this information?

Any suggestions would be much appreciated!

Thanks

---

From the Keithley 2400 Series SourceMeter User's Manual:

There are two averaging filter types to choose from: repeating and moving (Figure

7-1). For the repeating filter (which is the power-on default), the stack (filter count)

is filled, and the conversions are averaged to yield a reading. The stack is then

cleared, and the process starts over.

The only way to get individualized values is to turn off the filtering and produce an average on your own.

[a4gb0s23]

Thanks for the comments. I had already read the manual but it didn't really answer the question. I certainly didn't see anything to suggested that it was impossible. The values of the individual measurements must be stored in a buffer and so I would expect that they can be read out. I'd be very surprised if this isn't the case. I guess I was looking for feedback from an expert - someone who can tell me whether or not this is possible.

Thanks

[a4gb0s23]

Sorry... I didn't see the reply from "Minions" until after my last post. Thanks.

But is it not possible to read out the buffer before it is cleared? Or copy the buffer to a separate one that can be read out? etc. etc. I'd expect that there must be a way to do it somehow?

[Henrik_Volkers]

This mode is created to ease the reading of a mean value. As stated above, you can always read as many values individually as you want and do all kind of analyses .. mean , standard deviation.. different kind of variances ... 

I'm quite shure that there is a LabVIEW driver for your Keithley and fetching and storing 10 to some thousands of measurements  isn't a problem...

[a4gb0s23]

Thanks a lot for the suggestion but I'm using Python at the moment and I think I'd prefer to stick with Python rather than LabVIEW. There is also a bigger issue here and that is I also want to include a time delay between setting the source and taking the measurements. So for instance I'm currently performing an IV sweep which is doing something like:

source 10 volts, wait 10 seconds and then take 100 measurements and get the average

source 20 volts, wait 10 seconds and then take 100 measurements and get the average

source 30 volts, wait 10 seconds and then take 100 measurements and get the average

etc, etc.

As far as I can tell, if I were to just take 100 independent measurements at each voltage and calculate the average myself, the time delay would apply to each of the individual measurement and the process would take far too long. So I'm not sure if taking individual measurements is really the answer.

Thanks

[Minions]

Last time I checked, Python was able to do nested loops.

Vset=0

Vinc=10

Loop 5

  Vset += Vinc

  Set voltage to Vset

  wait 10s

  Iavg = 0

  loop 100

    Iread = Measured current

    Iavg += Iread

    wait 0

  Iavg = Iavg/100

Set Voltage back to 0