How to enumerate a list of valid topics for publish()

[orgua]

Coming from the UI it seems possible to:

• disable the voltage measurement
• change the sample frequency
• set a specific range

Looking through the example-repo I found a solution for the last task:

js.publish("s/i/range/mode", "manual")
js.publish("s/i/range/select", range_value)

Looking through the users-guide.pdf I found valid ranges:

ranges = ["180 mA", "18 mA", "1.8 mA", "180 µA", "18 µA"]

Funny enough, that I can't just copy values from the table on page 14/49 when it comes to micro-ampere, but also the micro-symbol from my keyboard got rejected with:

RuntimeError: jsdrv_publish failed 5 PARAMETER_INVALID | The parameter value is invalid | u/js220/002649/s/i/range/select

After some discouragement the third version of the micro-symbol worked though.

Beside that minor hurdle my main questions are:

• are these settings (disabling Voltage and changing sample rate) possible? the user guide generalizes 2 MSPS, so I have hope.
• is there a documented list of topics or is it possible to generate one? Keithley SMUs spill out the whole settings-tree on request. With the joulescope I have trouble finding the topic names at all.

[mliberty1]

We have two different API levels. For the joulescope package that I think you are using, you can find the parameters here: https://github.com/jetperch/pyjoulescope/blob/main/joulescope/parameters_v1.py

Starting with the JS220, we implemented a LOT more on the instrument, and the instrument is responsible for the available parameters. The joulescope package wraps the device topics. You can list the device topics using the pyjoulescope_driver entry point, like this:

python -m pyjoulescope_driver info -v "*"

[mliberty1]

Yes, the "micro" symbol is slightly cursed in Unicode. I keep this text file handy:

µ = \u00B5 micro sign (not μ = \u03BC greek small letter mu)
Δ = \u0394 greek capital letter delta
Ω = \u03A9 greek capital letter omega
± = \u00b1 plus-minus sign
τ

→ ↔ ←
⭐
π∫σωτ°√
✓✔❌
©®™
⚠
①②③④⑤⑥⑦⑧⑨⑩

https://unicodearrows.com/all-arrows

[orgua]

Okay - so it is possible on driver-level. That helps a lot - Thanks again!

[orgua]

Sorry for opening that up again, but I am not able to implement the desired functionality.

Reducing Sample Frequency

with joulescope.scan_require_one(config='auto') as js:
   js.publish("/h/fs", "1 kHz")
   print(js.output_sampling_frequency)
   print(js.sampling_frequency)
   data = js.read(contiguous_duration=duration)

both prints() still report 1000000 and read() never exits after changing frequency.

Allow 2 MSPS Current Measurement

The user guide implies 2 MSPS and I'd like to switch off voltage-measurements and only measure current with full rate. Even though that's above the lowpass cutoff it would be nice to only get the requested data. While /s/i/range/mode & /s/i/range/select has an off-option, the /s/v/range has not. Setting '/s/v/ctrl'=0 still produces that measurement stream.

There is now way, right?

[mliberty1]

So, if you are using the joulescope package, it's better to use the joulescope parameters as defined here: https://github.com/jetperch/pyjoulescope/blob/main/joulescope/parameters_v1.py

So, you would just js.parameter_set('sampling_frequency', 1000)

We have lots of examples.

Now, the joulescope v1 backend uses pyjoulescope_driver, and it does implement the publish method. However, I think the problem is the leading '/'. You just need js.publish("h/fs", "1 kHz").

It sounds like you are trying to accomplish some task or measurement. What is the actual objective? There is a good chance we have an example or even a command-line tool that will make this much faster.