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Fixed timestep source and measure

Posted: March 15th, 2021, 9:58 am
by ashfly
Hello

I have an application where I am looking to vary the current across a device and measure the change in voltage at a small fixed time step. I am using a 2461 SMU which I am controlling through MATLAB using SCPI commands.

I am currently sourcing a voltage and varying the current limit using a configuration list and storing the results in a buffer. This works reasonably well but the time step is not consistent and can oscillate between different values. I would also like to increase the sample rate, it can currently change the current limit and measure the response at around 1 kHz, but I would like to increase this to 10 kHz if possible.

How do I run a configuration list with fixed source and measurement time steps without adding significant delays into the system, also can I increase the rate at which I change the current limit and perform measurements?

Thanks

Ash

Re: Fixed timestep source and measure

Posted: June 10th, 2021, 7:37 am
by Andrea C
What is the motivation for a different current limit with each config list entry? Just protective of the device or are you using the limit to control how much current, e.g. you are deliberately in compliance and not really a v-source.
Changes to the ranges or other aspects of the the setup can often be costly for throughput.

In the general case, better timing determinism from the trigger blocks is achieved by using Notify to start a timer and Waits for the timer events. The timer can issue events at better controlled time intervals vs. delay blocks.