Forums
Bruker Media
Community Media
Bruker AFM Probes
SPM Digest
Application Notes
NanoTheater
Website
中文
Brochures & Datasheets
Publications
Probes Catalog
Events
Manuals & Documentation
Presentations
Guide to AFM Modes
News
Journal Club
Webinars & Video
Nanovations
Other
hello,
I have a question related to the Nanoscope V controller that comes with the Multimode 8 AFM. Is possible to implement using the Nanoscope a custom controller other than the proportional integral one already provided? For instance if I wish to try an H infinity controller or something else can I do that?
Umar Khan.
Sorry Umar, we don’t provide access to the DSP or FPGA on our systems. If you think I could help on a specific application you are trying to accomplish, let me know.
Steve
I am working on applying an adaptive control method to the AFM. Ideally I would like to control the piezo input and read the PSD output in matlab, but if thats not possible I can modify the PI gains of the existing controller in Nanoscope. Is there a way I can change the PI gains from Matlab using for instance Nanoscript. Some one mentioned on the forum the vairables TMFbIgain and TMFbPgain which represent the gains. Can I set these from Matlab ?
Thanks,
Umar.
Hi Umar,
The only way I see it going to work, and maybe I am wrong, is that you take the deflection signal out of the system via the signal access module, multiply that signal with a factor derived by your custom algorythm, and feed the now modified deflection signal back into the NSV.
Stefan
Umar,
For what you describe I think Stefan’s recommendation is very good. You can interrupt the loop using the breakout box and inject your custom signals.
You can also control the PI gains via NanoScript or COM through Matlab, Labview, or other (and even read the PSD signal), however, this communication may be too slow for what you are trying to accomplish (~100ms).
Thanks for the information. Since I do not have a signal access module, I think modifying the PI gains through COM is the best option for me. Can you please suggest me a link or some other source where I can read about accesing the PI gains through COM.
To do this, you need to have the COM interface SW key. Contact me offline with your system information at steve.minne (at) bruker-nano.com.
Dear Stephen,
I have a question related to this.
I am also using a custom designed controller for the controlling the cantilever deflection, which is programmed on a separate FPGA. I make use of the In0-output of the SAM to read out the cantilever deflection signal and send it to the FPGA.
At the moment I managed to send the filtered signal from FPGA back to the NS5-controller via the In0-input of the SAM, and drive the Z with this signal by just setting the P-gain of the NS-5 controller to 1. However, I noticed that although the controller in NS is only set to the P-action there is also quite some low-pass filtering action going on before driving the Z. This low-pass filter is hampering the things we want to do.
My question therefore is: Is it possible to drive the Z-drive directly from an external signal, without this low-pass filtering? Either, by modifying the low-pass filter within the feedback controller of the NS5 system, or by routing an external signal directly to the Z-drive?
Thanks in advance!
Stefan,
The best way to drive Z would be to drive the Z Piezo directly. This would, of course, require High Voltage (+/- 220V). This method would give you ultimate Z-feedback control. You could accomplish this by piping the "In-0" Deflection signal to your FPGA Control system, then do your compensation (PID, Hinf, H2, etc) and output the control signal to a High Voltage Amplifier that meets your bandwidth requirements, then pipe the signal into the SAM's Z Input BNC (You'll need to toggle the switch to EXT -> MIC setting).
Hope this helps,
Fritz
Dear Fritz,
Thanks a lot for your reply! We will use an external piezodriver for our experiments as you suggested.