Alexandre Penaud

Hello Bradley,

Thanks to your help, my process with the SMU works properly, ramp speeds is now constant and repeatable.

Thanks again for your support!

Hello,

Many thanks for your comments and your support!
I will test it next week and give you the feedback.

Regarding your notes:
- For the smu.source.autodelay: this is an error from me for sure. 
- "Twice at each scan point with smu.measure.read()": I do this to differentiate between the actual voltage level and the previous sample. When the difference between these 2 samples exceeds a threshold, this indicates that our product under test has been triggered. 

Best regards,

Hello,

I join the code. Thanks for your support!

Hello and thank you for your feedback!

I measure the ramp speed with an oscilloscope and a current probe (I join an example) on the different ramp.
Then I put sliders to calculate di/dt directly on the scope.

In our method, we adapt the Istart signal based on the previous result to reduce the test duration. The same function is called with the same parameters (only start current value is adapted).

However, a few days ago, I did some tests to try to understand why the ramp might change between the 1st ramp and the other: 

To do that, I had no change the function's parameters (start and end current, ramp speed...). What I do is:
- Disconnect / Reconnect SMU: first ramp lower than the others
- Start a function (one pulse) then the ramp function: same, first ramp lower than the other
- I also did some tests in my code like removing the current readback: same behavior.

Thanks!

Alex

Hello,

I have a question concerning the sampling time of SMU 2460:

In my application I generate a DC current ramp and measure the voltage and current readback. I have some functions to handle it with a for loop and some conditions. The stopping of the ramp depends on the voltage variation between 2 samples and gives the current value.

However, with the same code and the same parameters I have 2 different behaviors concerning the generation of the DC current ramp:
- 1st time I call the function: the slope is around 160mA/sec
- When I call the same function with the same parameters the other times the slope becomes around 230mA/sec

My question is why the sample time might differ when the same function is called with the same parameters?
Is there a document to detail how to calculate or estimate sampling time depending on code, NPLC... or to master this sampling time?

Thanks for your answer,

Best regards,
Alex