Question to set PAR

Technical Support and Questions

Hi, is there a way to set a question where the user can type in a PAR value to use?

  • created

    Aug 2016

  • last reply

    Sep 2016

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    9

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Greg Austic

Aug 2016

mmmm.... good question. I'll break it down, because there are several possible options here:

  • Can I set the PAR value at the time of measurement, through a user question?

ANSWER: No, not at this point... that would require fairly significant changes to the software. If there's many people who need this we could investigate.

  • Can I create a protocol with a different, fixed PAR value (just like the normal protocol, but the ambient PAR inside the chamber is a constant value like 300 uE or something)

ANSWER: Yes, this is definitely possible. Let's say we wanted to take the "Leaf Photosynthesis" protocol and just make the ambient PAR = 300uE.

If you open the protocol in the PhotosynQ Desktop App, you can change the "nonpulsed_lights_brightness" parameter from ambient light setting to a fixed amount... so it goes from this -->

"nonpulsed_lights_brightness": [["light_intensity"],["light_intensity"], ... ]...

to this -->

"nonpulsed_lights_brightness": [[300],[300], ... ]...

Once complete, then save your modified protocol as a new version (maybe call it "Leaf Photosynthesis 300uE ambient" or something) and use it in your project.

If you want to learn more about how to create or modify a protocol, please read the Device API here https://github.com/Photosynq/PhotosynQ-Firmware/wiki . It is the be-all-end-all for creating a new, or modifying an existing, protocols.

Good question!

Greg

Hi Greg,

Thank you. However, we are using the beta machine/LeafPhotosynthesis beta code. So I can't quite figure out how to translate this fix to the beta machine/code. Any hints?

Best Nate

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Greg Austic

Aug 2016

Shoot sorry about that, I didn't realize. On the beta machine, the key for actinic (constant) lights is "aintensities". So in the chrome app, open the protocol Leaf Photosynthesis MultispeQ BETA (or whatever it's called), find the "aintensities" key, and you'll see an array of numbers. There will be some -1 numbers, which on the beta indicates that for that pulse set, the values should be set equal to ambient par. Change those -1 values to something else and you're good.

I see you've already been working on it. I posted my comment on your protocol page -->

https://photosynq.org/protocols/leaf-photosynthesis-multispeq-beta-only-par300ue-nate?filter=protocols&q=leaf+photosynthesis+MultispeQ+BETA

"measlights" is it ekvivalent "pulsedlights" in V1.0? Which kind of pulsed wavelength is 14, 15, 12, 20 in meas_lights in beta?

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Greg Austic

Aug 2016

Correct. I tried to change the names so that things were clearer and more consistent across the platform as a whole (measurement wasn't clear, pulsed seems a lot more explanatory). We still have a way to go, but it's getting better. If you haven't seen it, there's a new protocol creation tool as well in the chrome app, and the newest version (to be released soon) as the wiki pages directly linked, so (hopefully!) it's easier to create and adjust protocols.

Hi. I study and want to understand how working, for example, of protocol "Chlorophyll content (SPAD) III". What kind of wavelengths for lights have of 14, 15 LED (meas_light) in MultyspeQ Beta and that sensitivity range of 34 and 35 detectors.

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Greg Austic

Sep 2016

Light 14 is 940nm, light 15 is 605nm. The sensitivity range of detectors 34 (main) and 35 (clamp) is kind of hard to define in a meaningful way because it depends on so many factors. You can effectively increase the range by: increasing pulse distance (fewer pulses), decreasing pulse size (shorter pulses), and decreasing measuring light intensity. But in reality it also depends on the sample - absorbance on a thick sample requires an increased range, while a thin sample requires a decreased range.

The detectors (photodiodes) have a pretty limited range for any given setting, so you have to play with those settings in real time to make it work from a broad array of samples (that's what we do on the chlorophyll content (SPAD) III measurement).

Hope that helps -

Thanks! meanslighs 20 - 650nm meanslight 12 - 420nm or not.

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Greg Austic

Sep 2016

Yep - light 20 is 650nm and light 12 is 940nm -

Remember, this is for the Beta MultispeQ only - the new one is way simplified, has lights 1 - 10 and hopefully is much easier to follow :)

Greg