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marceluda / rp_lock-in_pid

Lock-in and PID application for RedPitaya enviroment
https://marceluda.github.io/rp_lock-in_pid/
GNU General Public License v3.0
41 stars 22 forks source link

Some small questions and suggestions #6

Open nicksauerwein opened 3 years ago

nicksauerwein commented 3 years ago

Dear Marcelo,

I am a Ph.D. student in a cold atom lab (LQG) at EPFL, Switzerland. We are currently setting up a new experiment. We would like to use your software in order to lock our lasers and stabilize their power. We ran into several problems when trying our your code:

  1. Output of square modulation: We were wondering about where the square modulations are output. In the paper, you mention that it is some fast DO, but which one is it?

  2. Slow harmonic lock-in: Is there a version where one has the fast square locking on the digital output pin and the slow harmonic modulation added to an fast analog output?

  3. PID as input of other PID: Is there an option to add the second PID at the output of the first PID?

I would find it super nice if we could have some short discussion about these topics via zoom or something. Would you be available?

Thanks in advance!

marceluda commented 3 years ago

El vie., 13 nov. 2020 a las 8:43, nicksauerwein (notifications@github.com) escribió:

Dear Marcelo,

I am a Ph.D. student in a cold atom lab (LQG) at EPFL, Switzerland. We are currently setting up a new experiment. We would like to use your software in order to lock our lasers and stabilize their power. We ran into several problems when trying our your code:

Hello nicksauerwein.

First of all ... which version of the Lock-in+PID are you using?

1.

Output of square modulation: We were wondering about where the square modulations are output. In the paper, you mention that it is some fast DO, but which one is it?

Yes... I have to put this in the documentation. It should be the DIO7_N Pin ( https://redpitaya.readthedocs.io/en/latest/developerGuide/125-14/extent.html )

The signal tied to the square modulation is the wire digital_modulation in the code: https://github.com/marceluda/rp_lock-in_pid/blob/master/lock_in%2Bpid/fpga/rtl/red_pitaya_top.v

1. 2.

Slow harmonic lock-in: Is there a version where one has the fast square locking on the digital output pin and the slow harmonic modulation added to an fast analog output?

No ... I don't have that feature in any version. I couldn't make it work because the actual implementation it's at its limit on physical resources. When I try to ADD features to Lock-in+PID ... each added feature breaks another one. That's why I've made the lock-in+PID-harmonis version, with only one oscillator.

What do you need on your specific application? Please, write me at marceluda@gmail.com with some details of what you need and what you don't need ... I may be able to provide some specific solution...

1. 2.

PID as input of other PID: Is there an option to add the second PID at the output of the first PID?

No... That option was not implemented.

1.

I would find it super nice if we could have some short discussion about these topics via zoom or something. Would you be available?

Right now I'm a bit short of time, and I've a lot of virtual meetings. But let's try some e-mail exchange ... and then I can tell you if I can help or not in what you need.

Thanks in advance!

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stephtr commented 3 years ago

Is there an option to add the second PID at the output of the first PID?

Since we had the same need, we forked the project and added this feature. However, we did so back in July and didn't yet merge the changes being done by marceluda since then.

marceluda commented 3 years ago

To be honest, I can't handle merge and parallel versions very well, yet. I haven't had time to learn how to maintain the project with the collaborations that arise. But I'm glad to hear that, through the fork, the new posts are still available.

Sorry for not doing the merge. I've put a link to this fork in the main App project rp_lock-in_pid, so more people can find it.

stephtr commented 3 years ago

You don't have to be sorry about that! Maintaining different versions and combining different features from different locations can be indeed tricky by the way the original base project was structured. Independently, thank you for the effort you put into this project so far! If at some point you are interested in (and have time for) merging some features, I'm happy to help.

While looking over the changes made since summer, I already happily noticed the link 😉 Currently I'm in the process of porting some of the changes (PID chaining & customizable integrator reset values, such that one can use the full PID/scan range) to your _h project.