Tektronix Technical Forums are maintained by community involvement. Feel free to post questions or respond to questions by other members. Should you require a time-sensitive answer, please contact your local Tektronix support center here.

Inconsistent parameter delivery in fwd-ivsweep

Post Reply
nbenker
Posts: 4
Joined: July 23rd, 2018, 12:16 pm
Country: United States

Inconsistent parameter delivery in fwd-ivsweep

Post by nbenker » July 23rd, 2018, 3:11 pm

Hello,

I am running the fwd-ivsweep test on the 4200A-SCS. Right now I have the minimum and maximum voltage set to -5V and 5V. However, the actual sweep range is different each time: sometimes it goes from -4V to 2V, sometimes as narrow as -1.5V to 1.5V. Does anybody know what could cause this? I am not changing settings between test runs, and since I have a CV test set up afterwards, I am running the CVIV configure action each time I run this test. Also, whenever it delivers the correct range, it takes quite a long time to complete the sweep (as I would expect with a .5 second delay) but when it gives inconsistent ranges, it does not seem to observe that delay and completes the run very quickly, resulting in hysteresis.

Image

Image

Andrea C
Keithley Applications
Keithley Applications
Posts: 1244
Joined: October 15th, 2010, 10:35 am
Country: United States
Contact:

Re: Inconsistent parameter delivery in fwd-ivsweep

Post by Andrea C » July 23rd, 2018, 3:56 pm

The SMU1 current compliance is set for 0.001 Amp.
You are encountering the 1mA limit.
When SMU1 is in compliance limiting, it cannot also successfully source the requested voltage.
Try setting the current limit higher.

nbenker
Posts: 4
Joined: July 23rd, 2018, 12:16 pm
Country: United States

Re: Inconsistent parameter delivery in fwd-ivsweep

Post by nbenker » July 23rd, 2018, 4:41 pm

Thanks so much Andrea! Still not sure why sometimes it takes 45 minutes and sometimes it takes 10 but this is a big help!

Andrea C
Keithley Applications
Keithley Applications
Posts: 1244
Joined: October 15th, 2010, 10:35 am
Country: United States
Contact:

Re: Inconsistent parameter delivery in fwd-ivsweep

Post by Andrea C » July 24th, 2018, 9:22 am

Even for the 2002 points in your sweep, 45 minutes seems quite long.

In the data you posted, you are using full auto range. The low current ranges will impose more settling time. You might consider using limited auto and set a higher minimum measure range to use. Permit the most sensitive ranges only if you need the added accuracy and resolution.

Also, check the speed settings.
The Speed, Sweep Delay and the (one time) Hold Time will also affect the time required to run the 2002 point sweep.
4200A_Sweep_Timing.PNG
4200A_Sweep_Timing.PNG (23.29 KiB) Viewed 3227 times

nbenker
Posts: 4
Joined: July 23rd, 2018, 12:16 pm
Country: United States

Re: Inconsistent parameter delivery in fwd-ivsweep

Post by nbenker » July 24th, 2018, 11:14 am

That explains why the fastest runs seem to be the ones that cut off the edges--because they're higher current, hitting the compliance and a lower settling time. Thanks so much for answering my questions!

Post Reply

Return to “Solar Cell Measurements”

Who is online

Users browsing this forum: No registered users and 1 guest