How to set the sweep voltage speed (V/s) when sweeping voltage using keithley 2400

[serge_leaf]

Dear all,

I want to measure the current and source a dynamic voltage. For example, source a voltage with speed 5V/s and sweep from -5V to 5V while measure the current. There is no function like this in Keithley 2400.

Therefore, I found in manual that the time between each step consist of measure delay and measure time(defined by NPLC). Then I set NPLC=0.06 and measure delay=1ms, which means that the time between each step is 0.06*(1/60)+0.001=0.002s. When test, I find that it took about 3.75s to sweep 500 points.

Is there any other factor impacting the time between each step?

Or do you have a better idea to set the sweep voltage speed using keithley 2400?

I am a new hand to use Labview and Keithley 2400, thanks so much if you could help me.

[scmave]

Hey Serge,

Where did you get the information on how to calculate the time for each step? I'm not sure how relevant this page is to your tool, but it looks like Keithley instruments allow for an NPLC to be set only from 0.1 to 10. I'm not really familiar with NPLC and don't know how it comes into play when calculating step time, so if you can share that resource it'd be helpful.

Also, how are you communicating with this device? Are you using basic VISA calls or is there an driver for this device on IDNet?

http://www.tek.com/sites/tek.com/files/media/media/resources/NPLC.html

[serge_leaf]

In the information you provide," it read Typically, the NPLC can be set for values between 0.01 and 10." Then the power line is 60Hz, thus measuring time is 1ms.

Meanwhile , I set measure delay 1ms.

In the keithley 2400 user's manual, I found following in 6-10;

The attachment is my program.

I just want to source a sweep voltage with precise speed and measure voltage and current 

simultaneously. To test the property of memristors.

[scmave]

I'm sorry, but I still don't understand how you use NPLC to calculate step time. Can you please point me to a resource you used to figure out that equation of NPLC*f+measure delay?

I also can't see what's going on in your code because "Keithley 2400 Sweep.vi" was not included.

[serge_leaf]

In the pic I post. Fig 6-1

[scmave]

I'm sorry, Serge, but I really don't see where the equation can be derived from that figure. Can you please send me resources so I can understand how this property actually works and where you got that equation from? I see that it is Delay+Measure, but how do you figure Delay is NPLC*Frequency? If I can read through this resource I can try and figure out what might be the issue here.

[Perseus]

http://research.physics.illinois.edu/bezryadin/labprotocol/Keithley2400Manual.pdf

NPLC properties are described on page 194 (section 7-7) under the heading "Speed."

Additionally, trigger delay should also affect the time between each step.

[Perseus]

Therefore, the formula for voltage speed should be as follows:

[Perseus]

It should be 1/f rather than f*